Systems and methods for power engine air path recirculation management

Abstract

Procedure that includes the following: Arranging an inlet valve (152) coupled to a cylinder (30) of an internal four-stroke internal combustion engine (10) in an open position during a section of an inlet stroke up to a section of a compression stroke of a piston (36) moving back and forth in the cylinder (30); Supplying air to the inlet valve (152) from a first source, wherein the supply of air to the inlet valve (152) from a first source comprises supplying air from an air compressor (162) arranged in an inlet channel (42) and directing the air via said inlet channel (42) into an inlet port (202) to the inlet valve (152) and being driven by one of the following: a turbine (164) coupled to an outlet of the engine; or a crankshaft (40) of the engine (10); or an electric motor; and Blowing air to the inlet valve (152) from a second source while the inlet valve (152) is open during the compression stroke, wherein blowing air to the inlet valve (152) from a second source includes blowing air from a reservoir via an air injector (190) connected to the inlet port, which accumulates air from one or more of the following: a portion of the air from the first source; or an electric air pump.

Description

Technical field

[0001] The present description concerns general methods and systems for a power engine with a Miller cycle. Background / Brief description

[0002] Conventional combustion cycles of four-stroke engines, also known as Otto cycle engines, comprise four distinct strokes: the intake, compression, power, and exhaust strokes. During all four strokes, a piston moves within a cylinder of the four-stroke engine between top dead center (TDC) and bottom dead center (BDC). As the piston moves toward BDC, the volume formed between the piston crown and the combustion chamber increases, and vice versa as the piston moves toward TDC. During the intake and power strokes, the piston moves from TDC to BDC, whereas during the compression and exhaust strokes, the piston moves from BDC to TDC. However, during the intake stroke, one intake valve is open and one exhaust valve is closed.During both the compression stroke and the power stroke, the intake and exhaust valves are typically kept closed. During the exhaust stroke, the intake valve closes and the exhaust valve opens.

[0003] Document US 2012 / 0279218A1 describes a method for operating a four-stroke internal combustion engine with a Miller cycle, in which an intake valve closes late after the start of the compression stroke for one engine cylinder. Disadvantages of the Miller cycle, such as power loss due to reduced cylinder filling caused by backflow into the intake manifold, are compensated for by additional supercharging of the intake air, possibly using a second source of supercharging.

[0004] In the publication DE 10 2012 221 403 A1, a method is described for increasing the boost pressure of a four-stroke internal combustion engine by injecting compressed air from a pressure tank using an air injection valve, in addition to air charging via an exhaust gas turbocharger.

[0005] Therefore, in conventional four-stroke engines, the intake valve opens during the intake stroke, and gases enter the combustion chamber due to the vacuum created as the piston moves towards bottom dead center (BDC). Additionally, fuel can be injected directly into the combustion chamber via a fuel injector during the intake stroke. Once the piston reaches BDC and begins its return to top dead center (TDC) at the start of the compression stroke, the intake valve closes. A spark plug ignites the air-fuel mixture in the combustion chamber before the piston reaches TDC. As a result of this ignition, the air-fuel mixture expands when the piston reaches TDC and begins its return to BDC. Therefore, during the subsequent power stroke, the ignited air-fuel mixture exerts a force on the piston, driving it back to BDC.Therefore, power is generated by the engine during the power stroke. Finally, during the exhaust stroke, the exhaust valve opens, allowing the air-fuel mixture to leave the combustion chamber.

[0006] In an effort to increase the thermodynamic efficiency of the engine, many internal combustion engines employ a combustion cycle known as the "Miller cycle." Unlike the conventional four-stroke combustion cycle described above, in an engine with a Miller cycle, the intake valve is held in an open position during the first part of the compression stroke. As the piston initially moves toward top dead center (TDC) during the compression stroke, some of the air-fuel mixture, and under certain conditions, such as operation under high engine load, recirculated exhaust gases, can be forced back through the still-open intake valve into an intake port toward the engine's intake manifold.This movement of a portion of the air-fuel mixture and exhaust gases back through the combustion chamber towards the intake manifold can be described as a recirculation event. The efficiency of a Miller-cycle engine is increased by using a boost system, either a supercharger or a turbocharger. Furthermore, such engine systems may include an intercooler to cool the intake air.

[0007] Since the air-fuel mixture can only be compressed after the intake valve closes, it can only be compressed during the last approximately 25% of the compression stroke. In conventional Otto-cycle engines, the compression ratio is limited due to auto-ignition (e.g., detonation) of the compressed, and therefore hot, air-fuel mixture. However, because of the lower compression of the air-fuel mixture during the compression stroke in a Miller-cycle engine, the compression ratio can be higher compared to Otto-cycle engines. Therefore, the efficiency of a Miller-cycle engine can be higher compared to Otto-cycle engines.

[0008] However, the inventors have recognized potential problems with such Miller-cycle engine systems. For example, due to residual heat from previous combustion cycles, the air-fuel mixture in the combustion chamber may be at a higher temperature than the gases in the intake port and manifold. Specifically, the heat generated during each combustion cycle may not be completely dissipated at the end of the cycle, resulting in the combustion chamber being at a higher temperature than the intake port and manifold. If the air-

[0009] When the fuel-air mixture and recirculated exhaust gases are routed back towards the intake manifold through the open intake valve during the first part of the compression stroke, the hotter air-fuel mixture can reduce the effectiveness of an intercooler in cooling the incoming air charge, and the recirculated exhaust gases can leave particles in the intercooler. Furthermore, continued contact with the hot air-fuel mixture and recirculated exhaust gases can lead to deterioration of the intercooler. In both cases, the cooling efficiency of the incoming air charge entering the combustion chamber during the intake stroke can be reduced. The reduced cooling efficiency of the intercooler can lead to increased intake air temperatures, which can cause unintended detonation, also known as engine knock.Furthermore, crankcase oil can accumulate in the charge air cooler substrate, which can dilute the air-fuel mixture and thereby reduce the fuel's octane rating. A reduction in fuel octane rating can also contribute to unintended detonation events.

[0010] Furthermore, the portion of the air-fuel mixture that flows out of the combustion chamber during the recirculation event flows against the direction of the gases in the intake port during the intake stroke. Therefore, it can take some time for the flow direction in the intake port to reverse before the next intake stroke. Consequently, there can be a delay in the flow of gases into the combustion chamber, and therefore in the torque delivered by the engine, when an intake stroke is initiated.

[0011] In one example, the problems described above can be addressed by a method that involves positioning an intake valve coupled to a cylinder of an internal four-stroke combustion engine in an open position during a portion of the intake stroke up to a portion of the compression stroke of a piston moving back and forth in the cylinder, supplying air to the intake valve from a first source, and blowing air against the intake valve from a second source, with the intake valve remaining open during the compression stroke. In this way, the amount of air-fuel mixture flowing out of the combustion chamber through the intake valve during a portion of the intake stroke can be reduced.

[0012] In another representation, the problems described above can be addressed by a procedure that includes: opening an intake valve coupled to a cylinder of an internal four-stroke combustion engine during a Intake stroke of a piston arranged in the cylinder, wherein the engine comprises an intake manifold coupled to the intake valve by an intake port, supplying air from the intake manifold through the intake port into the intake valve, recirculating a portion of the exhaust gases from the engine into the intake valve, closing the intake valve during a compression stroke of the piston, recirculating a portion of the air and the recirculated exhaust gases from the cylinder through the intake valve and the intake port during the compression stroke while the intake valve is open, and injecting air from an air reservoir into the intake port towards the intake valve against the recirculated air and exhaust gases, wherein the intake valve is open during the compression stroke.

[0013] As an example, the process can additionally or alternatively include providing compressed air through a heat exchanger to cool the compressed air and directing the cooled compressed air into the inlet manifold.

[0014] In another example, the method may additionally or alternatively include controlling the timing and duration of air injection into the inlet channel to reduce the recirculation of air and exhaust gases or essentially prevent them from entering the heat exchanger.

[0015] In another representation, a power engine system may comprise: an air injector located in an intake port upstream of a power engine cylinder and downstream of a compressor and charge air cooler; an air reservoir flow-coupled with the air injector to provide compressed air to it; and a control system with computer-readable instructions. The computer-readable instructions may include instructions to inject a desired quantity of compressed air from the air reservoir into the intake port via the air injector when the power engine cylinder is in the first part of a compression stroke, wherein the first part of the compression stroke is a part of the compression stroke in which an intake valve of the power engine cylinder is in an open position, allowing gases to flow between the cylinder and the intake port, and wherein otherwise no air is injected from the air reservoir into the intake port.

[0016] In this way, the amount of air-fuel mixture recirculated through an open intake valve to an intake port during a portion of a compression stroke can be reduced. By decreasing the amount of air-fuel mixture recirculated through the intake valve, the deterioration of the charge air cooler can be reduced. Furthermore, a degree of mixing and atomization of the air-fuel mixture can be achieved by injecting compressed air into the intake port. In particular, the air injected into the intake port can be directed opposite to the flow direction of the air-fuel mixture entering the intake port from the combustion chamber. As a result, the mixing and atomization of the air-fuel mixture can be increased. Additionally, injecting the air can reverse the direction of flow of the recirculated air-fuel mixture and therefore reduce its momentum.In this way, the engine's responsiveness can be improved. By reducing the momentum of the air-fuel mixture to the intake port during the compression stroke, gases can flow more quickly into the combustion chamber during a subsequent intake stroke.

[0017] It is understood that the above summary is provided to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to reveal any key or essential features of the claimed subject matter of the invention, the scope of which is defined solely by the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that overcome the disadvantages mentioned above or in any other part of this disclosure. Brief description of the drawings Fig. Figure 1 shows a schematic representation of an exemplary power machine system. Fig. Figure 2 shows a schematic representation of an exemplary cylinder of a power machine system. Fig. Figure 3 shows a flowchart of a process for blowing air into an inlet channel of a power engine system. Fig. Figure 4 shows a flow diagram of a process for regulating the flow of compressed air into an air reservoir. Fig. Figure 5 is a diagram that represents the changes in a quantity of air that is blown into an inlet duct of a power engine system under varying engine operating conditions. Detailed description

[0018] The following description refers to systems and methods for blowing air from a compressed air source into an inlet port of a Miller-cycle power engine. A power engine system, such as the one described in Fig. The engine system shown in Figure 1 can comprise one or more engine cylinders. Each engine cylinder can complete one four-stroke engine cycle, with each stroke in the cycle defined by the direction of piston movement in the respective cylinder and the position of the intake and exhaust valves of each cylinder. During an intake stroke of the four-stroke engine cycle, an intake valve of one of the engine cylinders is held in an open position. Intake air enters a combustion chamber of the cylinder as the piston moves from top dead center (TDC) to bottom dead center (BDC), expanding the volume created between the piston crown and the combustion chamber. In the Miller-cycle engine, the intake valve is held in the open position after the piston reaches BDC and begins the compression stroke.When the piston initially moves towards top dead center (TDC) during the compression stroke, a portion of the air-fuel mixture and any recirculated exhaust gases can be forced back into an intake port towards the engine's intake manifold through a still-open intake valve. This movement of a portion of the air-fuel mixture and the recirculated or remaining exhaust gases in the combustion chamber back towards the intake manifold can be referred to as a recirculation event.

[0019] However, the recirculation event can reduce the cooling efficiency of an intercooler, and it can decrease the engine's response to increases in desired engine torque levels. To reduce the amount of gases moving from the combustion chamber toward the intake manifold during a recirculation event, an air injector can be positioned in the intake port, as shown in Fig. 2 shown. The air injector can be designed to inject air into the intake port during a recirculation event, provided certain engine operating conditions are met, as shown in Fig. 3 and Fig. 5 described. Furthermore, the air injector can receive compressed air from a secondary source other than the inlet manifold. In particular, the air injector can receive compressed air from an air reservoir. Compressed air can be supplied to the air reservoir from downstream of a compressor under certain engine operating conditions, as described in Fig. The 4 exemplary procedures shown are described.

[0020] Therefore, the amount of gases flowing from the combustion chamber to the intake port during a recirculation event can be reduced by injecting air into an intake port via an air injector positioned in the intake port.

[0021] Fig. Figure 1 shows a power machine system 100 for a vehicle. The vehicle can be a road vehicle with drive wheels in contact with a road surface. Power machine system 100 comprises a power machine 10, which includes several cylinders. Fig. Figure 1 describes such a cylinder or combustion chamber in detail. The various components of the power engine 10 can be controlled by an electronic power engine control unit 12.

[0022] The engine 10 comprises a combustion chamber 30 (also referred to as cylinder 30) and cylinder walls 32 with a piston 36 located therein and connected to a crankshaft 40. The combustion chamber 30 is shown connected to an intake manifold 144 and an exhaust manifold 148 via an intake valve 152 and an exhaust valve 154, respectively. Each intake and exhaust valve can be actuated by an intake cam 51 and an exhaust cam 53. Alternatively, one or more of the intake and exhaust valves can be actuated by an electromechanically controlled valve coil and armature assembly. The position of the intake cam 51 can be determined by the intake cam sensor 55. The position of the exhaust cam 53 can be determined by the exhaust cam sensor 57.

[0023] In the illustration, a fuel injector 66 is positioned to inject fuel directly into cylinder 30, a process known to those skilled in the art as direct injection. Alternatively, fuel can be injected into an intake port, a process known to those skilled in the art as port injection. The fuel injector 66 supplies liquid fuel proportional to the pulse width of the FPW signal from the controller 12. Fuel is supplied to the fuel injector 66 by a fuel system (not shown) comprising a fuel tank, a fuel pump, and a fuel distributor. The fuel injector 66 is supplied with operating current by a driver 68 that responds to the controller 12. Furthermore, in the illustration, the intake manifold 144 is connected to an optional electronic throttle valve 62, which adjusts the position of a throttle plate 64 to control airflow to engine cylinder 30.This can include controlling an airflow of charged air from an inlet charging chamber 146. In some embodiments, throttle valve 62 can be omitted, and airflow to the engine can be controlled via a single air intake system throttle valve (AIS throttle valve, AIS - Air Intake System) 82, which is coupled to an air intake duct 42 and positioned upstream of the inlet charging chamber 146.

[0024] In some embodiments, the engine 10 is designed to provide exhaust gas recirculation (EGR). In the case of EGR, it is fed to the engine air intake system via an EGR channel 135 and an EGR valve 138 at a position downstream of the air intake system throttle valve (AIS throttle valve) 82 from a point in the exhaust system downstream of the turbine 164. EGR can be drawn from the exhaust system to the intake air system if a pressure differential is present to drive the flow. A pressure differential can be generated by partially closing the AIS throttle valve 82. The throttle plate 84 controls the pressure at the inlet to the compressor 162. The AIS throttle valve can be electrically controlled, and its position can be adjusted based on an optional position sensor 88.

[0025] Ambient air is drawn into a combustion chamber 36 via an inlet duct 42, which includes an air filter 156. Therefore, air first enters the inlet duct 42 through the air filter 156. A compressor 162 then draws air from the air inlet duct 42 to charge the combustion chamber 146 via a compressor outlet pipe (in Fig. (1 not shown) to supply compressed air. In some examples, the air inlet duct 42 may include an airbox (not shown) with a filter. In one example, the compressor of the 162 may be a turbocharger, with the power to the compressor 162 being drawn from the exhaust gas flow through the turbine 164. Specifically, exhaust gases rotate the turbine 164, which is coupled to the compressor 162 via a shaft 161. A vacuum-operated wastegate actuator 72 allows exhaust gases to bypass the turbine 164, so that boost pressure can be controlled under different operating conditions. In alternative embodiments, the wastegate actuator may be pressure- or electrically operated. The wastegate 72 may be closed (or the wastegate opening may be reduced) in response to an increased boost demand, such as when a pedal is actuated by an operator.Closing wastegate 72 increases the exhaust pressures upstream of turbine 164, thereby increasing the turbine speed and peak power output. This allows for an increase in boost pressure. Furthermore, wastegate 72 can be moved to the closed position to maintain the desired boost pressure when the compressor recirculation valve is partially open. In another example, wastegate 72 can be opened (or the wastegate opening can be enlarged) in response to a reduced boost demand, such as when an operator releases a pedal. Opening the wastegate reduces exhaust pressures, thereby decreasing the turbine speed and power output. This allows for a decrease in boost pressure.

[0026] However, in alternative embodiments, the compressor 162 can be a compressor, with the power to the compressor 162 being drawn from the crankshaft 40. Therefore, the compressor 162 can be coupled to the crankshaft 40 via a mechanical linkage 166, which can be any suitable linkage for mechanically coupling the crankshaft 40 to the compressor 162, such as a belt. Thus, a portion of the rotational energy output by the crankshaft 40 can be transmitted to the compressor 162 via the mechanical linkage 166 to drive it.

[0027] A compressor recirculation valve 158 (CRV) can be provided in a compressor recirculation path 159 around the compressor 162, allowing air to move from the compressor outlet to the compressor inlet to reduce any pressure that may build up around the compressor 162. A charge air cooler 157 can be positioned in a charging chamber 146 downstream of the compressor 162 to cool the charged air charge being supplied to the engine inlet. However, in other examples, such as in Fig. As shown in Figure 1, the charge air cooler 157 is positioned downstream of the electronic throttle valve 62 in an intake manifold 144. In some examples, the charge air cooler 157 may be an air-to-air charge air cooler. However, in other examples, the charge air cooler 157 may be a liquid-to-air charge air cooler.

[0028] In the illustrated example, the compressor return path 159 is designed to return cooled compressed air from downstream of the charge air cooler 157 to the compressor inlet. In alternative examples, the compressor return path 159 can be designed to return compressed air from both downstream of the compressor and upstream of the charge air cooler 157 to the compressor inlet. The CRV 158 can be opened and closed by an electrical signal from the controller 12. The CRV 158 can be designed as a three-position valve with a standard half-open position, from which it can be moved to a fully open or fully closed position.

[0029] A distributorless ignition system 90, in response to the control unit 12, delivers an ignition spark to the combustion chamber 30 via the spark plug 92. The ignition system 90 can be an induction coil ignition system, in which an ignition transformer is connected to each spark plug of the engine. A universal exhaust gas oxygen sensor 126 (UEGO sensor, UEGO - Universal Exhaust Gas Oxygen) is shown coupled upstream of the catalyst 70 to the exhaust manifold 148. Alternatively, the UEGO sensor 126 can be replaced by a bistable exhaust gas oxygen sensor. The catalyst 70 can, in one example, comprise several catalyst bricks. In another example, several exhaust aftertreatment systems, each with several bricks, can be used. The catalyst 70 can, in one example, be a three-way catalyst.Although the UEGO probe 126 is shown upstream of the turbine 164 in the illustrated example, it is understood that in alternative embodiments the UEGO probe may be positioned in the outlet manifold downstream of the turbine 164 and upstream of the compressor 70.

[0030] Control unit 12 is located in Fig. Figure 1 shows a microcomputer comprising: a microprocessor unit 102, input / output ports (I / O) 104, a read-only memory (ROM) 106, a random access memory (RAM) 108, a cache memory (KAM) 110, and a conventional data bus. In the illustration, the controller 12 receives, in addition to the signals discussed previously, various signals from sensors coupled to the engine 10, including: the engine coolant temperature (ECT) from a temperature sensor 112 coupled to the cooling sleeve 114; a position sensor 134 coupled to an input device 130 for detecting the pedal position (PP) of the input device set by a vehicle operator 132; and a knock sensor for determining the ignition of exhaust gases (not shown). a measurement of an engine intake manifold pressure (MAP) from a pressure sensor 121 coupled to the intake manifold 144;a measurement of boost pressure from the pressure sensor 122 coupled to the charging chamber 146; a power engine position sensor from a Hall effect sensor 118, which detects the position of the crankshaft 40; a measurement of air mass entering the power engine from sensor 120 (for example, a hot-wire air flow meter);and a measurement of the throttle position from a sensor 58. The barometric pressure can also be acquired for processing by the controller 12 (sensor not shown). In a preferred aspect of the present description, an engine position sensor 118 generates a predetermined number of uniformly spaced pulses at each revolution of the crankshaft, from which the engine speed (rpm) can be determined. The input device 130 can include an accelerator pedal and / or a brake pedal. Therefore, the output of position sensor 134 can be used to determine the position of the accelerator pedal and / or brake pedal of the input device 130 and thus determine a desired engine torque. In this way, a desired engine torque, as requested by the vehicle operator 132, can be estimated based on the pedal position of the input device 130.

[0031] In some embodiments, the power unit can be coupled with an electric motor / battery system in a hybrid vehicle. The hybrid vehicle can incorporate a parallel configuration, a series configuration, or a variation or combination thereof.

[0032] During operation, each cylinder within engine 10 typically completes a four-stroke cycle: the cycle comprises the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 154 generally closes, and the intake valve 152 opens. Both the exhaust valve 154 and the intake valve 152 can be adjusted between closed first positions and open second positions. Furthermore, the position of valves 154 and 152 can be adjusted to any position between their respective first and second positions. In the closed first position of the intake valve 152, no air and / or air-fuel mixture flows between the intake manifold 144 and the combustion chamber 30. In the open second position of the intake valve 152, air and / or an air-fuel mixture flows between the intake manifold 144 and the combustion chamber 30.In the closed second position of the exhaust valve 154, no air and / or air-fuel mixture flows between the combustion chamber 30 and the exhaust manifold 148. However, when the exhaust valve 154 is in the open second position, air and / or an air-fuel mixture can flow between the combustion chamber 30 and the exhaust manifold 148.

[0033] Therefore, during the intake stroke, the exhaust valve 154 is in the closed first position, so no air and / or air-fuel mixture can flow between the combustion chamber 30 and the exhaust manifold 148. However, the intake valve 152 can be in the open second position during the intake stroke, allowing air and / or an air-fuel mixture to flow from the intake manifold 144 to the combustion chamber 30. It is important to note that when the intake valve 152 is not in the closed first position, the direction of airflow between the intake manifold 144 and the combustion chamber 30 depends on the position of the throttle disk 84 and the throttle disk 64, as well as on the pressure differential between the inside and outside of the combustion chamber 30.Therefore, under engine operating conditions where the combustion chamber 30 has a higher pressure than the intake manifold 144 and the intake valve 152 is not in the closed first position, gases can flow out of the combustion chamber 30 and towards the intake manifold 144. Conversely, if the combustion chamber 30 has a lower pressure than the intake manifold 144 when the intake valve 152 is not in the closed first position, such as during the intake stroke, gases can flow from the intake manifold 144 into the combustion chamber 30.

[0034] Therefore, during the intake stroke, air is introduced into the combustion chamber 30 via the intake manifold 144, and the piston 36 moves towards the bottom of the cylinder to increase the volume in the combustion chamber 30. The position in which the piston 36 is near the bottom of the cylinder and at the end of its stroke (for example, when the combustion chamber 30 has reached its maximum volume) is generally referred to by those skilled in the art as bottom dead center (BDC). During the compression stroke, the exhaust valve 154 is closed for the entire duration of the compression stroke, whereas the intake valve 152 is closed only for a portion of the exhaust stroke. In particular, the intake valve 152 may remain in the open second position after the piston 36 reaches BDC and begins to move away from BDC at the beginning of the compression stroke.Therefore, the compression stroke includes a period in which the exhaust valve 154 remains in the closed position and the movement of the piston 36 from top dead center (TDC) near the top of the cylinder and at the end of the compression stroke (e.g., when the combustion chamber 30 has its smallest volume), which is typically referred to by those skilled in the art as top dead center (TDC). During an initial part of the compression stroke, the intake valve 152 may remain in an open position, allowing gases to flow between the combustion chamber 30 and the intake manifold 144. Furthermore, as described below with reference to... Fig. As described in more detail in 2-3, an air injector 190 in the engine system 100 is coupled downstream of the charge air cooler 157 and upstream of the combustion chamber 30 to inject air from an air reservoir 91 during the first part of the compression stroke when the inlet valve 152 is not in the closed first position.

[0035] The air reservoir 91 can be coupled to the power unit 10, and in particular to the inlet charging chamber 146, via a compressed air channel 171. Therefore, the compressed air channel 171 can be coupled at one end to the charging chamber 146 and at the other end to the air reservoir 91 to establish a flow connection between them. To control the airflow from the charging chamber 146 to the air reservoir 91, a reservoir valve 131 can be positioned in the air channel 171 between the charging chamber 146 and the air reservoir 91. The valve 131 can be an electronically controlled valve, such as an electronic throttle valve 62, and therefore the position of the valve 131 can be adjusted based on signals received from the controller 12. In particular, an electronic actuator comprising a coil and an armature can be electrically connected to the controller 12.Therefore, the electronic actuator of a valve 131 can adjust the position of the valve 131 between a closed first position, in which gases do not flow between charging chamber 146 and air reservoir 91, and an open second position, in which gases can flow between the charging chamber 146 and the air reservoir 91, based on signals received from the controller. In other embodiments, the valve 131 can be a passively controlled valve whose position can be adjusted based on the pressure differential across the valve.

[0036] The valve can be selectively and easily opened during power engine operating conditions to charge the reservoir 91 with compressed air from the inlet charging chamber 146, with the compressed air being supplied to the charging chamber 146 by the compressor 162 coupled to the power engine. Once the air reservoir reaches a threshold pressure, the valve can be closed to maintain the pressure in the reservoir 91. In some examples, the air reservoir 91 may include a pressure sensor 123 for sensing the pressure within the reservoir 91. Therefore, the controller can adjust the position of the valve 131 based on the outputs from the pressure sensor 123.In particular, when the controller determines, based on the outputs from pressure sensor 123, that the pressure in the air reservoir has reached the threshold (threshold is used synonymously with threshold value here and in the following), the controller can send a signal to valve 131 to set the position of valve 131 to the closed first position. Furthermore, as described below with reference to... Fig. As described in more detail in section 4, the position of the valve 131 is adjusted based on the desired engine torque, as estimated from an input by the vehicle operator 132 via the input device 130. Therefore, the valve 131 can only be opened if opening the valve 131 does not impede the provision of engine torque as requested by the vehicle operator 132.

[0037] In other embodiments, the air reservoir 91 may include its own secondary compressor 163 for supplying compressed air to the air reservoir 91. The compressor 163 may be an electric pump or another type of electrically driven compressor suitable for providing a compressed air source. If included, the secondary compressor 163 may be electrically connected to the controller 12. Therefore, the controller 12 may send signals to the secondary compressor 163 to adjust its operation. Furthermore, the operation of the compressor 163 may be adjusted based on the pressure in the air reservoir, which can be estimated based on the outputs from the pressure sensor 123, as described above.

[0038] Compressed air can be supplied to the air injector 190 from the air reservoir via a supply line 173. Therefore, the supply line 173 can be connected to the air reservoir 91 at one end and to the air injector 190 at the other end to establish a flow connection between them. As described below with reference to Fig. As described in more detail in section 2, the air injector 190 can be a valve (e.g., electronic valve 231, as in Fig. 2 shown) to control the quantity of compressed air that is blown into the engine system 100 downstream of the charge air cooler 157.

[0039] Therefore, during the first part of the compression stroke, when the inlet valve 152 is held in an open position, compressed air can be supplied from the air reservoir 91 via the air injector 190 downstream of the charge air cooler 157. As described below with reference to Fig. As described in more detail in section 3, the injection of air during the first part of the compression stroke can reduce the amount of gas that can flow from the combustion chamber 30 towards the inlet manifold 144.

[0040] The first part of the compression stroke can include the portion of the compression stroke where the piston 36 is located between the lower top dead center (UDC) and a second position, with the second position being between UDC and top dead center (TDC). In some examples, the second position may be closer to UDC than TDC. However, in other examples, the second position may be closer to TDC than to UDC. In still other examples, the second position may be equidistant from UDC and TDC. Therefore, the inlet valve 152 can only be held in an open position during the compression stroke while the piston 36 moves from UDC to the second position. After the piston 36 reaches the second position, the position of the inlet valve 152 can then be adjusted to the closed first position.

[0041] After the intake valve 152 closes, piston 36 continues to move towards the cylinder head and to top dead center (TDC) to compress the air inside the combustion chamber 30. Before piston 36 reaches TDC, the injected fuel is ignited by a known ignition device, such as the spark plug 92, in a process referred to below as ignition, resulting in combustion. During the power stroke, the expanding gases push piston 36 back to bottom dead center (BDC). The crankshaft 40 converts the piston movement into torque of the crankshaft. Finally, during the exhaust stroke, the exhaust valve 154 opens to release the burnt air-fuel mixture to the exhaust manifold 148, and the piston returns to TDC. The exhaust gases can then flow from the exhaust manifold 148 through an exhaust pipe 180 to the turbine 164.It should be noted that the above is described only as an example and that the opening and / or closing times of the inlet and outlet valves may vary to provide positive or negative valve overlap, late closing of the inlet valve, or various other examples.

[0042] Now referring to Fig. Figure 2 shows a schematic representation of a combustion chamber coupled with inlet and outlet ports, with an air injector (as in Fig. 1) is contained in the inlet channel. In particular, it shows Fig. 2 a schematic representation of part of an exemplary engine cylinder of the in Fig. 1 shown power machine 10. Fig. Figure 2 shows an example of the relative sizes and positions of the components within the power machine 10. However, it is important to note that the relative sizes and positions of the components of power machine 10 may differ from those shown in Figure 2. Fig. 2 shown. Fig. 2 is therefore drawn approximately to scale. Furthermore, the components of the in Fig. The two power machines shown (10) have the same components as those in Fig. 1 will be shown. Therefore, the components of the power machine 10, which are referred to above, are shown. Fig. 1 is described, and may not be described in detail below. As in Fig. Figure 1 shows a cylinder of the power engine 10.

[0043] The engine 10 comprises the combustion chamber 30, the flow of gases into and out of the combustion chamber 30 being regulated by the positions of the inlet valve 152 and the exhaust valve 154. In particular, the position of the inlet valve 152 can be adjusted to regulate the flow of gases between the combustion chamber 30 and an inlet port 202, which is in flow communication with the inlet manifold 144. Thus, the inlet port 202 can serve as a conduit for transferring gases between the inlet manifold 144 and the combustion chamber 30. Therefore, the inlet port 202 can be located downstream of the inlet manifold 144 and upstream of the combustion chamber 30, between the inlet manifold 144 and the combustion chamber 30. Similarly, the exhaust valve 154 can be adjusted to regulate the flow of gases between the combustion chamber 30 and an exhaust port 204, which is in flow communication with the exhaust manifold 148.The exhaust port 204 can thus be a conduit for transferring gases from the combustion chamber 30 to the exhaust manifold 148. Therefore, the exhaust port 204 can be located upstream of the exhaust manifold 148, between the combustion chamber 30 and the exhaust manifold 148.

[0044] The positions of inlet valve 152 and exhaust valve 154 can each be adjusted by the corresponding inlet cam 51 and exhaust cam 53. However, in other embodiments, as described above with reference to Fig. As described in Figure 1, the positions of the inlet valve 152 and the exhaust valve 154 are set by electromechanically controlled valve coil and armature assemblies. Furthermore, the inlet valve 152 and the exhaust valve 154 can be set between closed first positions 210 and 214, respectively, and open second positions 212 and 216, respectively. In the closed first position 210, the inlet valve 152 can fluidically seal the combustion chamber 30 against the inlet port 202, preventing gases from flowing between them. In particular, in the closed first position 210, the inlet valve 152 can come into physical contact with the inner walls 203 of the inlet port 202, preventing any gases from passing between them.

[0045] Air separates the outer surface of the inlet valve 152 from the inner walls 203. Therefore, when in the closed first position, the inlet valve 152 can directly form a seal between the interior of the combustion chamber 30 and the inlet port 202. outside the combustion chamber 30. However, if the inlet valve 152 is in the open second position 212 and / or any position between the closed first position 210 and the open second position 212, gases can flow between the combustion chamber 30 and the inlet port 202. For example, the gases flowing from combustion chamber 30 to inlet port 202 during a recirculation event can only be air. As described above, Here, "recirculation event" can be used to refer to engine operating conditions in which the intake valve is not in the closed first position 210 and a higher pressure exists in the combustion chamber 30 than in the intake manifold 144, causing gases to flow from the combustion chamber 30 towards the intake manifold 144. However, in other embodiments, the gases flowing out of the combustion chamber 30 during a recirculation event may be an air-fuel mixture containing fuel. Therefore, if the intake valve 152 is not in the closed first position 210, gases can flow between the intake manifold 144 and the combustion chamber 30, and the direction of gas flow depends on the pressure difference between them.

[0046] In the closed first position 214, the exhaust valve 154 can fluidly seal the combustion chamber 30 against the exhaust port 204, preventing gases from flowing between them. However, if the exhaust valve 154 is in the open second position 216 and / or any position between the closed first position 214 and the open second position 216, gases can flow between the combustion chamber 30 and the exhaust port 204. Therefore, if the exhaust valve 154 is not in the closed first position 214, gases can flow from the combustion chamber 30 to the exhaust manifold 148.

[0047] As above with reference to Fig. As described in section 1, the outputs from the intake cam sensor 55 and exhaust cam sensor 57 can be used to determine the position of the intake cam 51 and the exhaust cam 53, respectively. Since the position of the intake cam 51 is adjusted to set the position of the intake valve 152, and the position of the exhaust cam 53 is adjusted to set the position of the exhaust valve 154, the positions of the intake cam 51 and the exhaust cam 53 are directly related to the positions of the intake valve 152 and the exhaust valve 154, respectively. Therefore, the positions of the intake valve 152 and the exhaust valve 154 can be estimated based on the outputs from the intake cam sensor 55 and the exhaust cam sensor 57, respectively.

[0048] The air injector 190 can be coupled to the inlet port 202, as shown in Fig. 2 shown. As above with reference to Fig. As described in Figure 1, the air injector 190 can receive compressed air via the supply line 173. The amount of compressed air injected into the inlet port 202 can be regulated by an injection valve 231 and an injection nozzle plate 233. The valve 231 can be an electronically controlled valve, such as one described in Figure 1. Fig. 1 shown electronic throttle valve 62, and therefore the position of the valve 231 can be determined based on the one shown in Fig. The injection valve 231 can be adjusted based on signals received from the controller 12 as shown in Figure 1. In particular, the injection valve 231 can include a coil and an armature and can be electrically connected to the controller 12. Therefore, the injection valve 231 can adjust the position of the injection nozzle plate 233 between a closed first position, in which gases do not flow between supply line 173 and inlet port 202, and an open second position, in which gases can flow between supply line 173 and inlet port 202, based on signals received from the controller. Furthermore, the position of the injection nozzle plate 233 can be adjusted to any position between the closed first position and the open second position to adjust the amount of compressed air flowing to the inlet port 202.In particular, the amount of compressed air flowing to the inlet port 202 can increase with increasing deflection of the injection nozzle plate 233 away from the closed first position towards the open second position. In other embodiments, the valve 231 can be a passively controlled valve whose position can be adjusted based on the pressure differential across the valve.

[0049] Furthermore, the air injector 190 in the inlet port 202 can be oriented such that when the valve opens (e.g., by adjusting the position of the injection nozzle plate 233 from the closed first position towards the open second position), compressed air can flow through the air injector 190 and into the inlet port 202, towards the combustion chamber 30 and away from the inlet manifold 144. Therefore, the direction of the compressed air flow into the inlet port 202 can be indicated by the flow arrow 241.

[0050] in Fig. 2 will be shown. As will be explained in more detail below with reference to Fig. As described in section 3, air can only be injected into the inlet port 202 under certain engine operating conditions during the compression stroke if the inlet valve 152 is not in the closed first position. During the compression stroke, when the inlet valve 152 is not in the closed first position, gases can flow from the combustion chamber 30 to the inlet port 202 in the direction of the inlet manifold 144. During the recirculation event, when gases from the combustion chamber 30 flow back into the inlet port 202, the injection valve 231 can adjust the position of the injection nozzle plate 233 towards the open second position and inject compressed air into the inlet port 202. Therefore, the air injected by the air injector 190 can flow in the opposite direction to the flow of gases in the inlet port 202 during the recirculation event. An exemplary method for controlling the quantity of air that is blown into the inlet port 202 via the air injector 190 is described below with reference to Fig. 3 described.

[0051] Now referring to Fig. Figure 3 shows an exemplary method 300 for blowing air into an inlet port of a power engine. In particular, air can be blown into the inlet port during a portion of the compression stroke, with an inlet valve held in an open position. As above with reference to Fig. As described in 1 & 2, the intake valve can be held in the open position, allowing an air-fuel mixture, and under certain operating conditions recirculated exhaust gases, to flow from a combustion chamber to the intake port during a portion of the compression stroke. However, since the temperature of the air-fuel mixture can be higher than that of an incoming air charge, the air-fuel mixture can heat the incoming air charge and / or reduce the efficiency of an intercooler in cooling the incoming air charge. A method such as the one described in Fig. 3 Exemplary methods shown 300 can be carried out to inject air into the intake channel during the recirculation event in order to reduce the amount of air-fuel mixture and recirculated exhaust gases that are forced back from the combustion chamber into the intake channel.

[0052] Instructions for executing procedure 300 can be issued by a controller (e.g., controller 12, as in Fig. 1 shown) based on instructions stored in a memory of the controller and in conjunction with various sensors of the power machine system, such as the ones mentioned above with reference to Fig. The control system can execute the signals received from the sensors described in section 1. The system can utilize the vehicle system's power actuators to adjust power operation according to the procedures described below.

[0053] Procedure 300 begins at 302, which involves estimating and / or measuring engine operating conditions. Engine operating conditions may include engine temperature, intake manifold vacuum, intake valve position, throttle valve position, etc.

[0054] After estimating and / or measuring engine operating conditions at 302, procedure 300 continues at 304, which includes determining whether a piston (e.g., piston 36, as in Fig. 1 shown) in a cylinder of a power engine (e.g., power engine 10, as in Fig. (shown in 1) is located in the first section of a compaction stroke. As above with reference to Fig. As explained in sections 1 & 2, the piston moves away from bottom dead center (BDC) towards top dead center (TDC) during the compression stroke. Therefore, the volume of a combustion chamber decreases (e.g., combustion chamber 36, as shown in [reference]). Fig. 1 shown) during the compression stroke. Additionally, and in contrast to the exhaust stroke, during which an exhaust valve (e.g., exhaust valve 154, as shown in ) opens Fig. (shown in 1 & 2) is in an open second position, which provides a flow connection between the combustion chamber and an exhaust manifold (e.g., exhaust manifold 148, as shown in Fig. 1) or an outlet channel (e.g. outlet channel 204, as shown in Fig. (2 shown) provides the necessary flow, allowing the gases in the combustion chamber to flow from the combustion chamber to an exhaust manifold. During the compression stroke, the exhaust valve is in a closed first position, which fluidically seals the combustion chamber against the exhaust manifold, preventing gases from flowing between the combustion chamber and the exhaust port. Therefore, the compression stroke necessarily involves the piston moving away from the lower top dead center (UBT) position towards the upper top dead center (OTC) position, and the exhaust valve being in the closed first position.

[0055] The first position of the compression stroke is a segment of the compression stroke where the piston is in a position between lower top dead center (uT) and a second position located between uT and upper top dead center (oT). Therefore, the first segment of the compression stroke can be a segment that begins at the start of the compression stroke, when the piston is at uT, and ends before the piston reaches oT. Thus, the first segment of the compression stroke is a segment of the compression stroke where the piston moves away from uT into the second position, which is located between uT and oT.

[0056] In some examples, the second position may be equidistant from both uT and oT. In other examples, the second position may be closer to uT than oT. In still other examples, the second position may be closer to oT than uT. In another example, the second position may be one where the distance between the piston and uT is approximately three times the distance between the piston and oT. In yet another example, the second position may be one where the distance between the piston and uT is approximately four times the distance between the piston and oT. In other words, in some examples, the second position may correspond to the last 20-30% of the compression stroke. In yet another example, the second position may be one where the distance between the piston and oT is approximately three times the distance between the piston and uT.In another example, the second position could be one where the distance between the piston and top dead center (TDC) is approximately four times the distance between the piston and bottom dead center (BDC). In other words, the second position could correspond to the last 20-30% of the compression stroke.

[0057] Therefore, the first part of the compression stroke covers a range of piston positions between bottom dead center (BDC) and the second position, while the exhaust valve is in the closed first position. Therefore, method 300 at 304 can include determining whether the exhaust valve is in the closed first position and whether the piston is between BDC and the second position, moving from BDC towards top dead center (TDC). The output from a crankshaft position sensor (e.g., a Hall sensor 118, as in Fig. (1 shown) can be used to determine the position and direction of movement (e.g., speed) of the piston. Therefore, based on the outputs from the crankshaft position sensor, it can be determined whether the piston is moving away from the lower top dead center (UBT) position towards the upper top dead center (OT) position. Furthermore, the position of an exhaust valve can be determined based on the output from an exhaust valve position sensor (e.g., exhaust cam sensor 57, as shown in Fig. (1 & 2 shown). Therefore, based on the outputs of the exhaust valve position sensor, it can be determined whether the exhaust valve is in the closed first position and whether exhaust gases are flowing from the combustion chamber into the exhaust port or exhaust manifold. Thus, both the position of the piston, as estimated based on the outputs from the crankshaft position sensor, and the position of the exhaust valve, as estimated based on the outputs from the exhaust valve position sensor, can be used to determine whether the piston is in the first part of the compression stroke.

[0058] If at 304 it is determined that the piston is between uT and the second position and is moving away from the uT position towards the oT position, and that the exhaust valve is in the closed first position, procedure 300 continues at 306, which holds an intake valve (e.g., intake valve 152, as in Fig. 1 & 2 shown) in an open second position (e.g., open second position 212, as in Fig. 2) includes. When the intake valve is in the open second position, an air-fuel mixture and recirculated exhaust gases can pass between the combustion chamber and an intake port (e.g., intake port 202, as shown in Fig. 2 shown) flow. As above with reference to Fig. As described in 1 & 2, the intake valve is held in the open second position during the intake stroke to allow air and / or fuel to enter from an intake manifold (e.g., intake manifold 144, as shown in Fig. (1 shown) or to enter the combustion chamber via the intake port as the combustion chamber volume expands as the piston moves away from top dead center (TDC) towards bottom dead center (BDC). Method 300, as shown in 306, involves holding the intake valve in the open second position during the first part of the compression stroke. The position of the intake valve can be set by an intake valve cam (e.g., intake cam 51, as shown in Fig. (1 & 2 shown). Therefore, the intake valve cam can hold the position of the intake valve in the open second position during the first part of the compression stroke.

[0059] In other embodiments, the inlet valve can be held in an open position, which includes any position between a closed first position (e.g., closed first position 210, as in Fig. 2) and the open second position, as long as the intake valve is not in the closed first position. In other words, the term "open position" can be used here to refer to any position of the intake valve that provides a flow connection between the intake port and the combustion chamber, allowing gases to flow between them. Therefore, Method 300 at 306 comprises holding the intake valve in the open second position, or any position between the closed first position and the open second position, that provides a flow connection between the combustion chamber and the intake port, allowing air and / or fuel to flow between the combustion chamber and the intake port during the first part of the compression stroke.

[0060] Therefore, the intake valve can be set by the intake valve cam to one or more positions where gases can flow between the combustion chamber and the intake port during the intake stroke, and remain in one or more positions when the piston reaches bottom dead center (BDC) and begins to move back towards top dead center (TDC) at the beginning of the compression stroke. The intake valve can remain open during the first part of the compression stroke until the piston reaches the second position between BDC and TDC. Therefore, the intake valve can remain open throughout the entire intake stroke and the first part of the compression stroke, allowing gases to flow between the combustion chamber and the intake port during both the intake stroke and the first part of the compression stroke.In other words, the procedure 300 at 306 involves holding the position of the intake valve in one or more positions so that during the first part of the compression stroke gases can flow between the combustion chamber and the intake port, with the exhaust valve in the closed first position and the piston moving away from uT towards oT until the piston reaches the second position.

[0061] Procedure 300 can then proceed to steps 306 through 308, which involves determining whether the desired engine torque is less than a threshold. In some examples, the threshold at step 308 can be stored in the controller's memory and may correspond to a specific engine torque level. The desired engine torque can be determined based on input from a vehicle operator (e.g., vehicle operator 132, as in Fig. 1 shown) via an input device (e.g. input device 130, as in Fig. (1 shown). Therefore, the desired machine torque can be based on the position of an accelerator pedal and / or brake pedal of the input device. The position of the accelerator pedal and / or brake pedal of the input device can be determined based on outputs from a position sensor (e.g., position sensor 134, as shown in Fig. 1), which is designed to monitor the position of the accelerator or brake pedal, can be estimated. The position of the accelerator and / or brake pedal can correspond to a desired engine torque, as described above with reference to Fig. 1 described. If the desired engine torque is less than the threshold at 308, procedure 300 can proceed to 310, which involves determining whether a charging level is less than a threshold.

[0062] The boost level can be a pressure of compressed air and / or fuel in the intake manifold. Therefore, the boost level can be determined based on the outputs of a pressure sensor positioned in the intake manifold (e.g., pressure sensor 121, as shown in...). Fig. (shown in Figure 1) can be estimated. In this way, the pressure in the intake manifold, and thus the boost level, can be estimated based on the outputs of the pressure sensor. If the pressure in the intake manifold, and therefore the boost level, is less than the threshold at 310, procedure 300 continues at 312, which involves estimating a desired amount of air to be injected into the intake port.

[0063] In particular, the method 300 at 312 includes estimating a quantity of air supplied by a compressed air source (e.g., air reservoir 91, as in Fig. 1 shown) via an air injector (e.g., air injector 190, as in Fig. (shown in 1 & 2) is to be blown into the intake port, based on various operating parameters, such as the intake port temperature, manifold pressure, air mass flow to the combustion chamber and desired Engine torque level. The temperature in the intake port can be determined based on outputs from a temperature sensor positioned in the intake port (e.g., temperature sensor 223, as shown in Fig. 2) can be estimated. In other examples, the temperature in the inlet channel can be estimated by a temperature sensor positioned elsewhere in the engine (e.g., temperature sensor 112, as shown in Fig. (shown in 1). The desired engine torque can be estimated in the manner described above for Block 308 of Procedure 300, and the manifold pressure can be estimated in the manner described above for Block 310 of Procedure 300.

[0064] As explained above for Block 306, the intake valve can remain open during the first part of the compression stroke. Because of the open intake valve, gases can flow between the intake port and the combustion chamber during this initial phase. Therefore, as the piston moves towards top dead center (TDC) during the compression stroke, an air-fuel mixture, along with any residual or recirculated exhaust gases in the combustion chamber, can be forced back into the intake port. In other words, as the combustion chamber is compressed as the piston moves towards TDC, some of the air-fuel mixture and any residual or recirculated exhaust gases can flow back into the intake port. In the description here, this backflow into the intake port during the first part of the compression stroke can be referred to as a recirculation event.Procedure 300 includes, at 312, determining a desired quantity of air to be blown into the inlet channel during the recirculation event.

[0065] Method 300 can therefore further include determining a desired quantity of compressed air to be injected into the intake manifold, based on engine operating parameters such as the intake manifold temperature, the desired engine torque, manifold pressure, and an estimated air mass flow rate from the intake manifold to the combustion chamber. The desired air injection quantity can be based on the amount of air flowing between the intake manifold and the combustion chamber during the recirculation event. In one example, the air mass flow rate in the intake manifold can be determined based on outputs from an air mass meter (e.g., air mass meter 120, as in Fig. (1 shown). A relationship between the estimated air mass flow in the intake manifold and the desired air injection quantity can be stored in the control unit's memory. In particular, the desired quantity of air to be injected into the intake port can increase as the estimated air mass flow decreases. Therefore, if the air mass flow into the intake manifold decreases, the quantity of gases flowing from the combustion chamber through the intake port towards the intake manifold can increase. Conversely, if the estimated air mass flow decreases, the desired quantity of air to be injected into the intake port can increase to reduce the quantity of gases flowing from the combustion chamber towards the intake manifold.

[0066] However, in another embodiment, the desired air injection quantity can be based on the intake port temperature, the desired engine torque, and the manifold pressure. In other words, the air mass flow rate can be estimated based on the intake port temperature, the desired engine torque, and the manifold pressure. A relationship between the intake port temperature, the desired engine torque, the manifold pressure, and the desired air injection quantity can therefore be stored in the control unit's memory. In particular, the desired quantity of air to be injected into the intake port can increase with higher estimated intake port temperatures, decreasing desired engine torque levels, and decreasing manifold pressure.Therefore, the procedure 300 at 312 can include estimating the inlet duct temperature, manifold pressure and desired engine torque level and then determining the desired amount of air to be injected into the inlet duct based on a known relationship between the inlet duct temperature, manifold pressure, desired engine torque level and desired air injection quantity, which may be stored in the control unit's memory.

[0067] After determining the desired air injection quantity at 312, procedure 300 can then proceed at 313, which involves injecting the desired quantity of air into the intake port by adjusting the position of an air injection valve for a certain duration. As above with reference to Fig. As explained in sections 1 & 2, the air injector can have a valve (e.g., valve 191, as shown in Fig. (2 shown) include, which can be actively controlled by the controller. In such examples, the position of the air injection valve can be adjusted by an electromagnetic actuator based on signals received from the controller. In other examples, the valve can be a passive valve whose position can be adjusted by changes in the pressure differential across the valve.

[0068] The valve position can be adjusted between a closed first position, where no air flows between the air reservoir and the intake port, and an open second position, where air flows between the air reservoir and the intake port. Additionally, the valve can be adjusted to any position between the closed first position and the open second position to regulate the amount of air flowing to the intake port. Therefore, the amount of air flowing from the air reservoir to the intake port increases as the valve is moved further away from the closed first position to the open second position. Air can flow from the air reservoir to the intake port as long as the valve is not in the closed first position.

[0069] The amount of air injected into the intake manifold via the air injector can also be controlled by the duration the air injection valve is held in an open position. Therefore, the valve can be adjusted back and forth between the closed first position and the open second position. In the description given here, a valve closing event can be used to refer to when the valve is set to the closed first position. Similarly, a valve opening event can be used to refer to when the valve is set to the open second position. Furthermore, the duration of a valve opening event can be used to refer to the period of time the valve is continuously held in an open position other than the closed first position.Therefore, the duration of a single valve opening event can be used to refer to the time between a valve opening event and a subsequent valve closing event. Thus, the total amount of air flowing from the air reservoir, through the air injector, to the intake port depends on both the position of the air injection valve and the duration of a valve opening event. The amount of air injected into the intake port can increase with increasing durations the valve is held in the open position. Put simply, the longer (e.g., a greater amount of time) the valve is held in an open position (adjusted away from the initial closed position), the greater the amount of air flowing into the intake port.The total amount of air flowing through the valve to the intake port can therefore depend on the pressure differential between the air reservoir and the intake port, the position of the air injector valve, and the duration the valve is held in a position other than the closed position. Thus, the air injection valve can be held open for longer periods, allowing more air to be injected into the intake port to increase intake port temperatures, reduce manifold pressures, and lower desired engine torque levels. Consequently, under engine operating conditions where the amount of gas flowing from the combustion chamber into the intake port increases, the amount of air injected into the intake port can also increase.Therefore, the amount of air blown into the intake manifold can increase to reduce the desired engine torque, which can lead to reductions in manifold pressure and thus to a greater amount of gas flowing from the intake manifold to the combustion chamber.

[0070] The position of the air injection valve can be adjusted by increasing its deflection towards the open second position away from the closed first position, thus increasing the desired air injection volume. Additionally or alternatively, the duration of the valve opening event can be increased with increasing desired air injection volume. Therefore, both the position of the air injection valve and the duration it is held in a position can be determined based on the desired air injection volume and a pressure differential between the air reservoir and the inlet duct. The pressure in the air reservoir can be determined based on the outputs of a pressure sensor positioned in the air reservoir (e.g., air reservoir pressure sensor 123, as shown in...). Fig. 1 shown) can be estimated.

[0071] Therefore, the procedure 300 at 313 can additionally include determining and estimating a quantity of air that would flow to the inlet duct, based on the pressure difference between the inlet duct and the compressed air in the air reservoir, the position of the air injection valve, and the duration that the air injection valve can be held in that position. The specific quantity of air flowing to the inlet duct can be determined based on a relationship stored in the controller's memory that relates the position of the air injection valve, the duration of the injection valve's opening event, and the pressure difference between the air reservoir and the inlet duct to a quantity of air flowing to the inlet duct.Therefore, the procedure 300 can include determining a desired quantity of air to be injected into the intake port at 312, and then determining the position and duration to which the air injector intake valve should be set to adjust the quantity of air injected into the intake port to the desired quantity. Thus, the desired quantity of air injected into the intake port at 313 can be achieved by determining how far and for how long the valve should be opened, based on a known relationship between the valve position, the pressure difference between the intake port and the air reservoir, and the duration of the valve opening event. In other words, to achieve the desired quantity of air injected at 312, the procedure 300 can include determining at 313 how far and for how long the valve should deviate from the closed initial position.

[0072] In some examples, the air injected into the intake port via the air injector may oppose the flow of gases in the intake port. As described above, during the first part of the compression stroke, when the intake valve is in an open position, some of the air-fuel mixture in the combustion chamber may flow from the combustion chamber to the intake port in the direction of the intake manifold. However, the air injector can be positioned in the intake port as described above. Fig. 2 described, such that the air injected into the intake port flows in the opposite direction to the flow of the air-fuel mixture from the combustion chamber to the intake port. Thus, in some examples, Method 300 at 313 may include the flow of compressed air from the air reservoir through the air injector into the intake port and towards the combustion chamber. Therefore, Method 300 at 313 may include injecting air into the intake port in a direction opposite to the flow of gases from the combustion chamber towards the intake manifold.

[0073] Thus, procedure 300 at 313 involves injecting air into the intake port during the first part of the compression stroke when the intake valve is in the open position, allowing gases to flow between the intake port and the combustion chamber. By injecting air into the intake port during the recirculation event, the amount of gas flowing from the combustion chamber into the intake port can be reduced. After the desired amount of air is injected at 313, procedure 300 returns.

[0074] However, if, upon returning to 304, it is determined that the piston is not in the first part of the compression stroke, procedure 300 continues at 314, which includes determining whether the piston is in the intake stroke. As above with reference to Fig. As explained in sections 1 & 2, during the intake stroke, the intake valve is held in the open second position, and the piston moves away from top dead center (TDC) towards bottom dead center (BDC). During the power stroke, the piston moves away from the TDC position towards the BDC position, but the intake valve is in a closed position, so gases do not flow between the intake port and the combustion chamber. Therefore, determining whether the piston is in the intake stroke necessarily involves determining whether the intake valve is in the closed first position, so that gases do not flow between the intake port and the combustion chamber. Therefore, procedure 300 at 314 involves determining the position and direction of movement of the piston and the position of the intake valve. The position of the intake valve can be estimated based on outputs from an intake cam sensor (e.g., intake cam sensor 55, as described in [reference]). Fig. (1 & 2 shown). Furthermore, the position and direction of movement (e.g., speed) of the piston can be estimated based on outputs from the crankshaft position sensor in the manner described above at Block 304 of Procedure 300. Thus, if the piston is moving away from the TDC position toward the UDC position and the intake valve is in the closed first position, it can be determined at 314 that the piston is in the intake stroke. If it is determined at 314 that the piston is in the intake stroke, Procedure 300 can proceed to 316, which involves holding the intake valve in the open second position and injecting fuel into the combustion chamber. The intake valve can be held in the open second position in the manner described above at Block 306 of Procedure 300. Fuel can be injected via a fuel injector (e.g., fuel injector 66, as shown in Fig. (shown in Figure 1) is injected into the combustion chamber. In some examples, the fuel injector may be positioned within the combustion chamber, as shown above with reference to Figure 1. Fig. Figure 1 shows the fuel injector. However, in other examples, the fuel injector may be positioned in the intake port and / or the intake manifold. The amount of fuel injected into the engine cylinder can be based on a desired air-fuel ratio, such as a stoichiometric air-fuel ratio, and a measurement of the mass of air supplied to the engine, derived from air mass sensor 120. Instead of measuring air, an estimate of the air supplied to the engine can be determined from the intake manifold pressure and the engine speed.

[0075] In further embodiments, the method 300 at 316 can additionally or alternatively involve directing a portion of the exhaust gases downstream of an exhaust gas turbine (e.g., turbine 164, as in Fig. 1 shown) to downstream of an air intake system throttle valve (e.g. AIS throttle valve 82, as shown in Fig. (1 shown). Therefore, the method 300 at 316 can include routing a portion of EGR gases from downstream of the exhaust manifold to upstream of an intake manifold via an EGR channel (e.g., EGR channel 135, as shown in Fig. 1) include. In particular, the routing of the EGR gases can include adjusting the position of an EGR valve (e.g., EGR valve 138, as shown in Fig. (1 shown) between a closed first position, in which EGR gases do not flow from downstream of the exhaust manifold to upstream of the intake manifold, and an open first position, in which EGR gases can flow from downstream of the exhaust manifold to upstream of the intake manifold. Therefore, the method 300 at 316 may include adjusting the position of the EGR valve towards a more open position, closer to the open second position, to allow an increase in the amount of EGR gases flowing upstream of the intake manifold.

[0076] Procedure 300 can then move from 316 back to 304 and determine whether the piston has reached the bottom dead center (BDC) position and is therefore in the first part of the compression stroke. Thus, procedure 300 can move from 304 to 314, to 316, and back to 304 as long as the piston is in the intake stroke. Therefore, the intake valve can be held in the open second position for the duration of the intake stroke. Once the piston has reached BDC and the intake stroke is complete, signaling the start of the compression stroke, procedure 300 can proceed to 306 and hold the intake valve in the open second position for the first part of the compression stroke, as described above.

[0077] However, if at 314 it is determined that the piston is not in the intake stroke, procedure 300 can proceed at 318, which involves setting the intake valve to the closed first position. As described above with reference to block 306 of procedure 300, the intake valve position can be set by the intake cam. If the intake valve is already in the closed first position at 318, procedure 300 at 318 can involve maintaining the intake valve position in the closed first position.

[0078] Method 300 can then proceed from 318 to 305, which involves not injecting air into the intake port. Therefore, method 300, at 305, can include setting the position of the air injection valve to the closed first position, where the intake port and the air reservoir are not fluidically connected, so air does not flow from the air reservoir into the intake port. Thus, when the piston is not in the intake stroke, the air injection valve is set to the closed first position, and air is not injected from the air reservoir into the intake port.

[0079] If, upon returning to 308, it is determined that the desired engine torque is not less than the threshold at 308, procedure 300 continues at 305, and the position of the air injection valve is set to the closed first position, so that no air is injected into the intake port. If, in addition, it is determined at 310 that the boost level 30 is not less than the threshold, procedure 300 proceeds from 310 to 305, and the position of the air injection valve is set to the closed first position. Procedure 300 then returns.

[0080] Therefore, the air injection valve can be set to the closed second position, preventing air from flowing from the air reservoir to the intake port when the piston is not in the first part of the compression stroke, the desired engine torque is greater than the threshold at 308, or the boost level is greater than the threshold at 310. Thus, air injection into the intake port can only be activated during engine operating conditions where the piston is in the first part of the compression stroke, the desired engine torque is less than a threshold, and the boost level (e.g., manifold pressure) is less than a threshold.Furthermore, if the engine operating conditions are such that air injection into the intake port is activated, and the air injection valve is set to a position other than the closed first position, the valve position, and thus the amount of air flowing into the intake port, can be controlled based on operating parameters such as manifold pressure, intake port temperature, and desired engine torque. Specifically, the valve position can be adjusted with increasing deflection towards an open second position, away from the closed first position, thereby increasing the amount of air flowing into the intake port, which in turn increases the intake port temperature, decreases the manifold pressure, or reduces the desired engine torque.

[0081] In this way, a method can involve injecting compressed air from a compressed air source into an intake port of an engine cylinder during a portion of a compression stroke. Specifically, the method can involve holding an intake valve in an open position for a period immediately after the end of an intake stroke, allowing gases to flow between the intake port and a combustion chamber of the engine cylinder immediately after the beginning of the compression stroke. Therefore, the intake valve is held in an open position during the intake stroke, allowing gases to flow from the intake port into the combustion chamber. Additionally, fuel can be injected into the combustion chamber during the intake stroke. Thus, an air-fuel mixture is introduced into the expanding combustion chamber as the piston moves from top dead center (TDC) to bottom dead center (BDC) during the intake stroke.If the piston reaches the uT position during the intake stroke and then begins to return to the oT position during the start of the compression stroke, the procedure may involve holding the intake valve in the open position.

[0082] Therefore, during a portion of the compression stroke where an exhaust valve is in a closed position, preventing gases from flowing from the combustion chamber to an exhaust port, and where the piston is moving away from lower top dead center (UDC) towards upper top dead center (ODC), the intake valve can remain in an open position. Furthermore, the intake valve can remain open during the compression stroke until the piston reaches a second position between UDC and ODC. Thus, the intake valve can remain open for a first portion of the compression stroke, where the first portion of the compression stroke coincides with the beginning of the compression stroke when the piston is at UDC and ends at a point in the compression stroke when the piston is at the second position.Therefore, the first part of the compression stroke can include a series of piston positions during the compression stroke between uT and the second position.

[0083] While the intake valve is in an open position during the initial portion of the compression stroke, some of the air-fuel mixture admitted to the combustion chamber during this stroke, and, depending on engine conditions, some exhaust gases, can flow back into the intake port as the combustion chamber volume decreases. To reduce the amount of air-fuel mixture and exhaust gases flowing back into the intake port, air from a compressed air source can be injected into the intake port via an air injector that includes an adjustable valve. Therefore, during a recirculation event, where the intake valve is held in an open position during a portion of the compression stroke, air is injected into the intake port to reduce the flow of gases from the intake port toward the intake manifold.In particular, compressed air from an air reservoir can be directed to the intake port during the first part of the compression stroke if the desired engine torque and manifold pressure are both below a certain threshold. Furthermore, the desired quantity of air to be injected into the intake port can be determined based on the manifold pressure, the desired engine torque, and the intake port temperature. The desired quantity of air can be injected into the intake port by adjusting the position of an air injector valve for a specific duration, where the duration is a quantity of time.

[0084] Now referring to Fig. Section 4 presents an exemplary method for regulating the airflow to an air reservoir (e.g., air reservoir 91, as in Fig. 1 shown) from downstream of a compressor (e.g. compressor 62, as in Fig. 1 shown). Furthermore, the compressed air stored in the air reservoir can be supplied via an air injector (e.g., air injector 190, as shown) under certain engine operating conditions. Fig. 1 & 2 shown) to an inlet channel (e.g. inlet port 202, as in Fig. 2) can be conducted. Therefore, a procedure such as the one shown in Fig. The methods shown in Figure 400 are used to control the pressure of compressed air supplied to the inlet port of a power machine (e.g., power machine 10, as in Figure 400). Fig. 1) is supplied via the air injector to regulate.

[0085] Instructions for executing procedure 400 can be issued by a controller (e.g., controller 12, as in Fig. 1 shown) based on instructions stored in a memory of the controller and in conjunction with various sensors of the power machine system, such as the ones mentioned above with reference to Fig. The control system can execute the signals received from the sensors described in section 1. The system can utilize the vehicle system's power actuators to adjust power operation according to the procedures described below.

[0086] Procedure 400 begins at 402, which involves estimating and / or measuring engine operating conditions. Engine operating conditions may include boost pressure level, engine temperature, intake manifold vacuum, intake valve position, throttle valve position, etc.

[0087] After estimating and / or measuring power machine operating conditions at 402, procedure 400 then proceeds at 404, which involves determining whether the pressure in the air reservoir is less than a threshold. The pressure in the air reservoir can be determined based on outputs from a pressure sensor (e.g., pressure sensor 123, as in Fig. (shown in Figure 1). The threshold can represent a threshold pressure below which more air may need to be supplied to the air reservoir. Furthermore, in some examples, the threshold can be stored in the memory of the controller. However, in other examples, the threshold can be estimated based on a pressure in an inlet manifold (e.g., Inlet Manifold 144) from outputs of a pressure sensor (e.g., Pressure Sensor 121) positioned in the inlet manifold. Therefore, the threshold can change depending on engine operating conditions and the pressure in the inlet manifold. The threshold can be a threshold pressure that is higher than the pressure in the inlet manifold. Therefore, if the pressure in the air reservoir is greater than the threshold, air can flow from the air reservoir to the inlet manifold, provided a flow path to it is provided. Method 400 includes, at 404, determining whether the air reservoir pressure is less than a threshold.In other words, procedure 400 at 404 can include determining whether the amount of air in the air reservoir is less than a threshold. Furthermore, procedure 400 at 404 can include determining whether air needs to be added to the air reservoir.

[0088] If, at 404, it is determined that the pressure in the air reservoir is not less than a threshold, procedure 400 can proceed to 406, which involves adjusting the position of an air reservoir valve (e.g., reservoir valve 131, as in Fig. (1 shown) to a closed first position and non-flow of compressed air to the air reservoir. As above with reference to Fig. As shown in Figure 1, the air storage valve can be arranged in a flow path between the air storage and a source of compressed air. In some examples, the source of compressed air can be from a duct (e.g., charging chamber 146, as shown in Figure 1). Fig. (1 shown) downstream of the compressor. If the air reservoir valve at 406 is already in the closed first position, procedure 400 at 406 may involve holding the valve in the closed first position. Therefore, the air reservoir in the closed first position can restrict the flow of air between the air reservoir and the compressed air source, so that no air flows between them. Procedure 400 then reverses.

[0089] However, if it is determined at 404 that the air reservoir pressure is less than the threshold at 404, procedure 400 continues at 408, which involves determining whether the desired engine torque is less than a threshold. In some examples, the threshold at 408 can be stored in the controller's memory and can correspond to a specific engine torque level.

[0090] The desired engine torque can be set based on input from a vehicle operator (e.g., vehicle operator 132, as in Fig. 1 shown) via an input device (e.g. input device 130, as in Fig. (1 shown). Therefore, the desired machine torque can be based on the position of an accelerator pedal and / or brake pedal of the input device. The position of the accelerator pedal and / or brake pedal of the input device can be determined based on outputs from a position sensor (e.g., position sensor 134, as shown in Fig. 1), which is designed to monitor the position of the accelerator or brake pedal, can be estimated. The position of the accelerator and / or brake pedal can correspond to a desired engine torque, as described above with reference to Fig. 1 described.

[0091] The threshold can represent a desired torque level above which a maximum amount of boost pressure is required to achieve the desired engine torque. Therefore, in some examples, if the desired torque requested by the vehicle operator exceeds the threshold, all or nearly all of the air compressed by the compressor may be required by the engine to deliver the amount of torque requested by the vehicle operator. In other words, the threshold at 408 can represent an engine torque level above which, if some of the compressed air is directed to the air reservoir, the engine's ability to produce the desired amount of torque would be reduced. If the desired torque is greater than the threshold at 408, procedure 400 at 406 can proceed to adjust the position of the air reservoir to the closed first position, as described above.Procedure 400 then returns.

[0092] However, if it is determined in 408 that the desired engine torque is less than a threshold, procedure 400 can proceed to 410, which involves setting the position of the air reservoir valve to an open second position and allowing compressed air to flow to the air reservoir. The open second position of the air reservoir valve can be a position of the valve in which gases can flow between the compressed air source and the air reservoir. However, in other examples, procedure 400 at 410 can additionally or alternatively involve setting the position of the air reservoir to any position between the closed first position and the open second position.Therefore, the amount of air directed to the air reservoir can be adjusted by adjusting the position of the valve, whereby the amount of air flowing to the air reservoir increases with increasing deflection of the valve away from the closed first position towards the open second position.

[0093] In this way, the procedure can include 400 rules governing airflow to the air reservoir based on the pressure in the air reservoir and the desired engine torque. Air can only be supplied to the air reservoir if the pressure in the air reservoir is less than a threshold and if the desired engine torque is less than a threshold. If directing some of the compressed air to the air reservoir would prevent the engine from producing the desired amount of torque, the air reservoir can be closed, and no air can flow to it. Therefore, air can only be supplied to the air reservoir if doing so does not reduce the engine's power output.

[0094] In this way, a method can include positioning an intake valve coupled to a cylinder of an internal four-stroke internal combustion engine in an open position during a portion of the intake stroke of a piston moving back and forth in the cylinder, supplying air to the intake valve from a first source, and blowing air against the intake valve from a second source, with the intake valve being open during the compression stroke. Supplying air to the intake valve from a first source includes supplying air from an air compressor driven by one of the following: a turbine coupled to an exhaust of the engine; or a crankshaft of the engine; or an electric motor. The method can additionally or alternatively include cooling the air supplied to the intake valve from the first air source by means of a heat exchanger.The method may additionally or alternatively include injecting fuel into the intake valve during the intake stroke. In some examples, the fuel may be injected directly into the cylinder. The power engine may be one of the following: a spark-ignition gasoline engine; or a diesel engine. Blowing air against the intake valve from a second source includes blowing air from a reservoir that accumulates air from one or more of the following: a portion of the air from the first source; or an electric air pump.

[0095] In another embodiment, a method may comprise: opening an intake valve coupled to a cylinder of an internal four-stroke internal combustion engine during an intake stroke of a piston positioned in the cylinder, the engine comprising an intake manifold coupled to the intake valve by an intake port, supplying air from the intake manifold through the intake port into the intake valve, recirculating a portion of the exhaust gases from the engine into the intake valve, closing the intake valve during a compression stroke of the piston, recirculating a portion of the air and the recirculated exhaust gases from the cylinder through the intake valve and the intake port during the compression stroke while the intake valve is open, and injecting air from an air reservoir into the intake port towards the intake valve against the recirculated air and exhaust gases, the intake valve being open during the compression stroke.In some examples, supplying air to the intake manifold may additionally include providing compressed air through a heat exchanger to cool the compressed air and directing the cooled compressed air into the intake manifold. Furthermore, the injected air from the reservoir may be controlled in terms of timing and duration to reduce or substantially stop the entry of recirculated air and exhaust gases into the heat exchanger. The control of the injected air may relate to one or more of the following: load on the engine, mass airflow supplied to the intake manifold, torque produced by the engine, pressure in the intake manifold, or temperature of the recirculated air. In some examples, the method may additionally include... Alternatively, the method may include shutting off the injected air when the pressure in the intake manifold reaches a predetermined level. Furthermore, the method may additionally or alternatively include adding fuel to the cylinder during a portion of the intake stroke, and the recirculation of some of the air and exhaust gases from the cylinder may include some of the added fuel.

[0096] Now referring to Fig. Figure 5 shows a graph 500, which displays settings for a quantity in an intake channel (e.g., intake port 202, as in Fig. 1 shown) one Power machine (e.g., power machine 10, as in Fig. 1) represents injected air based on engine operating conditions. In particular, Graph 500 shows changes in a desired torque at Plot 502, an intake manifold pressure at Plot 508, a piston position at 504, an intake valve position at 506, an intake temperature at Plot 510, and an air injection quantity at Plot 512.

[0097] As above with reference to Fig. As described in section 3, the amount of air blown into the intake port of the engine can be determined by the position of a piston (e.g., piston 36), the position of an intake valve (e.g., intake valve 152, as in Fig. (shown in Figures 1 & 2), the stroke of the engine, the intake manifold pressure, the temperature of gases in the intake port, and the desired engine torque. Therefore, Plot 512 shows changes in the amount of air injected into the intake port based on the engine operating conditions described in Plots 502-510. The amount of air injected can be adjusted by changing the position of a valve (e.g., injection valve 231, as shown in Figure 1). Fig. 2 shown) in an air injector (e.g., air injector 190 as in Fig. 1 & 2), which are positioned in the inlet channel and connected to a compressed air source (e.g., air reservoir 91, as shown in Fig. The air injection valve, coupled to the intake manifold (as shown in Figure 1), can be adjusted. Specifically, the position of the injection valve can be adjusted between a closed first position, where no air flows from the injection nozzle to the intake duct, and an open second position, where air can flow from the injection nozzle to the intake duct. The air injection quantity at the lower first level, A0, as shown in Plot 512, can be adjusted. The value will be approximately zero. Therefore, at A0, the injection valve can be in the closed first position, and air cannot flow from the air injector to the intake port.

[0098] The desired torque can be set by a vehicle operator (e.g., vehicle operator 132, as in Fig. (shown in 1) is the specified amount of engine torque. For example, the desired torque can be set by a vehicle control unit (e.g., control unit 12). Fig. 1) based on input from the vehicle operator via an input device (e.g. input device 130, as in Fig. 1), which may include a brake pedal or an accelerator pedal, can be estimated. Therefore, as explained in more detail below with reference to Fig. As explained in 1 & 2, the control system can determine a desired torque based on the position of the input device.

[0099] In response to changes in the desired torque, as requested by a vehicle driver, the amount of air flowing to the engine can be adjusted to match the driver's torque demand. To increase the amount of air flowing, a throttle valve (e.g., electronic throttle valve 62, as in Fig. (1 shown) can be adjusted to allow more air to flow to one or more engine cylinders of the engine. However, if the desired torque increases above a certain threshold, a compressor (e.g., compressor 62, as shown in Fig. (shown in 1) is designed to compress the intake air, increase its pressure, and therefore supply more air per unit volume to the engine. The threshold D1 shown in Plot 502 corresponds to a desired engine torque level above which the compressor can be engaged and the intake air compressed. Similarly, the upper first threshold P2 in Plot 508 represents the pressure in the intake manifold above which the compressor can be engaged. Therefore, the compressor can compress the intake air at intake manifold levels above the upper first threshold P2. As the desired torque increases, a pressure in an intake manifold (e.g., intake manifold 144, as shown in 1) can develop. Fig. (1 shown). Changes in the intake manifold pressure are shown in Plot 508. In particular, the intake manifold pressure can be increased by operation of the compressor and a throttle valve positioned downstream of the compressor (e.g., electronic throttle valve 62, as shown in Fig. (shown in Figure 1). Furthermore, pressure in the intake manifold can be controlled by the control system based on outputs from a pressure sensor coupled in the intake manifold (e.g., pressure sensor 121, as shown in Figure 1). Fig. 1 shown) can be estimated.

[0100] The piston's position is shown in plot 504. As above, with reference to Fig. As explained in 1-3, the piston can move back and forth between the uT and oT positions. The piston's position can be determined based on outputs from a crankshaft position sensor (e.g., Hall sensor 118, as shown in ). Fig. (shown in Figure 1) can be estimated. Therefore, outputs from the crankshaft position sensor can be used to determine the position and direction of movement (e.g., speed) of the piston. Thus, based on the outputs from the crankshaft position sensor, it can be determined whether the piston is moving away from the uT position towards the oT position or not, as detailed above with reference to Figure 1. Fig. 1-3 described. Furthermore, in Plot 504, the four engine strokes are labeled with corresponding numbers. Thus, the intake stroke is labeled 1, the compression stroke 2, the power stroke 3, and the exhaust stroke 4. As above with reference to Fig. As described in 1-3, the stroke of the power engine can be determined both by the direction of movement of the piston and based on the positions of the inlet valve and an exhaust valve (e.g., exhaust valve 154, as in Fig. 1 shown) can be determined. As above with reference to Fig. As explained in 2-3, the position of the intake valve and the exhaust valve can be determined based on outputs from an intake cam sensor (e.g., intake cam sensor 55, as in Fig. 1 & 2 shown) or an exhaust cam sensor (e.g. exhaust cam sensor 57, as shown in Fig. (shown in 1 & 2). As seen in Plot 504, the power machine strokes can become shorter in duration as the desired power machine torque increases. Therefore, in response to increases in the desired power machine torque, the speed of the power machine can increase.

[0101] Plot 506 shows changes in the intake valve position. The intake valve can be set between a closed first position, where gases do not flow between a combustion chamber (e.g., combustion chamber 30) and the intake port, and an open second position, where gases can flow in between. I1 represents the closed first position of the intake valve, and I2 represents the open second position of the intake valve. Therefore, gases can flow between the intake port and the combustion chamber as long as the intake valve is not in position I1. The intake valve position can be estimated in the manner described above in connection with the intake cam sensor. As above, with reference to Fig. As described in 1-3, the intake valve can be held in the open second position I2 throughout the entire intake stroke and during the first part of the compression stroke, where the first part of the compression stroke is defined as a section of the compression stroke that coincides with the beginning of the compression stroke when the piston is at bottom dead center (BDC) and ends at a point in the compression stroke when the piston is at the second position. The second position is a position of the piston between top dead center (TDC) and bottom dead center (BDC).

[0102] Plot 510 shows changes in the temperature of gases in the inlet channel. The temperature can be determined based on outputs from a temperature sensor located in the inlet channel (e.g., temperature sensor 223, as shown in...). Fig. 2) can be estimated. However, in other examples, the temperature sensor may be located elsewhere in the power machine, such as near a power machine cooling sleeve (e.g., temperature sensor 112, as shown in Fig. 1 shown).

[0103] As above with reference to Fig. As described in Figure 3, the amount of air injected into the intake port, as shown in Plot 412, can decrease the desired torque and therefore the manifold pressure with increasing intake port gas temperature. Furthermore, air can only be injected into the intake port if the manifold pressure is less than the upper first threshold P2 and the piston is in the first part of the compression stroke, with the intake valve in the open position I2. It is important to note that the Fig. The relative time intervals shown in Figure 5 are only examples. Therefore, other relative time intervals and combinations of engine operating conditions are possible. For example, the intake valve may be used for different compression stroke proportions than those shown in Figure 5. Fig. 5 shown, are held in the open second position I2.

[0104] Referring now to the plots shown in Graph 500, which begin before t0, the desired engine torque is below the threshold D1, as shown in Plot 502. In response to the desired engine torque being below D1, the compressor can remain off before t0, and the manifold pressure can remain below P2 and, in particular, can fluctuate around a lower second level P0. The intake port temperature can decrease from a mid-second level T1 to a lower first level T0. Furthermore, the piston can be in an exhaust and intake stroke before t0, and therefore the air injection can remain at the lower first level A0.

[0105] At t0, however, the desired engine torque can remain below D1, and the manifold pressure can remain below P2. Additionally, the piston can reach the uT position and begin the compression stroke. Therefore, at t0, the intake valve can be held in the open second position I2 for the first part of the compression stroke, which can span the time interval from t0 to t1. In response to the initiation of the compression stroke at t0, the desired engine torque being below D1, and the intake valve being in the open second position I2, the amount of air injected into the intake port can increase from the lower first level A0 to a second, intermediate level A2. Furthermore, the intake port temperature at t0 can be approximately at the lower first level T0.

[0106] Between t0 and t1, the intake valve can remain in the open second position I2. Therefore, the time interval between t0 and t1 can represent the first part of the compression stroke, which began at t0. Consequently, the piston can move from the lower second position (uT) towards the upper third position (oT) between t0 and t1. Furthermore, the manifold pressure can remain approximately at the lower second level P0, and the temperature can remain approximately at the lower first level T0. Therefore, the air injection quantity can remain at the middle second level A2.

[0107] At t1, the piston can reach its second position, and in response to the piston reaching its second position, the intake valve position can be adjusted from the open second position I2 to the closed first position I1. Therefore, at t1, the first part of the compression stroke, which began at t0, can be completed. As a result of the intake valve closing (e.g., being adjusted to the closed first position I1), the air injection quantity is reduced to the lower first quantity A0. Thus, air injection can be switched off at t1. Furthermore, at t1, the desired engine torque can remain below D1, and the manifold pressure can remain below P2. Additionally, the intake port temperature at t0 can be approximately at the lower first level T0.

[0108] Between t1 and t2, the desired torque can increase monotonically but remain below the threshold D1. In response to the increase in the desired engine torque, the intake airflow can be increased, thus raising the manifold pressure from the lower second level P0 to a middle third level P1. The middle third level P1 is lower than the upper first level P2. Therefore, the compressor can remain off between t1 and t2. Furthermore, the temperature can fluctuate around the lower first level T0. No compression strokes can occur between t1 and t2. Therefore, the air injection quantity can remain at the lower first level A0.

[0109] At t2, the desired engine torque can remain below D1, and the manifold pressure can remain below P2, at approximately the mid-third level P1. Additionally, the piston can reach the uT position and begin a compression stroke. Therefore, at t2, the intake valve can be held in the open second position I2 for the first part of the compression stroke, which may span the time interval from t2 to t3. In response to the initiation of the compression stroke at t2, the desired engine torque remaining below D1, and the intake valve being in the open second position I2, the amount of air forced into the intake port can increase from the lower first level A0 to a mid-third level A1. The third level A1 may be lower than A2.Therefore, since the manifold pressure at t2 is higher than it was at t0, the amount of air injected into the intake port at t2 may be smaller than at t0. Specifically, the amount of air flowing from the combustion chamber through the open intake valve into the intake port at t2 may be smaller than at t0, because the manifold pressure at t2 is higher than at t0. Since fewer gases flow from the combustion chamber into the intake port at t2 compared to t0, less air may need to be injected to counteract the flow of gases from the combustion chamber into the intake port. Furthermore, the intake port temperature at t0 may be approximately at the lower first level T0.

[0110] Between t2 and t3, the intake valve can remain in the open second position I2. Therefore, the time interval between t2 and t3 can represent the first part of the compression stroke, which began at t2. Consequently, the piston can move from the lower top dead center (uT) position towards the upper top dead center (oT) position between t2 and t3. Furthermore, the manifold pressure can remain approximately at the middle third level P1, and the temperature can remain approximately at the lower first level T0. Therefore, the air injection quantity can remain at the middle third level A1.

[0111] At t3, the piston can reach its second position, and in response to the piston reaching its second position, the intake valve position can be adjusted from the open second position I2 to the closed first position I1. Therefore, at t3, the first part of the compression stroke, which began at t2, can be completed. As a result of the intake valve closing (e.g., being adjusted to the closed first position I1), the air injection quantity is reduced to the lower first quantity A0. Thus, air injection can be switched off at t3. Furthermore, at t3, the desired engine torque can remain below D1, and the manifold pressure can remain below P2. Additionally, the intake port temperature at t3 can be approximately at the lower first level T0.

[0112] Between t3 and t4, the desired torque can increase monotonically but remain below the threshold D1. In response to the increase in the desired engine torque, the intake airflow can be increased, and thus the manifold pressure can rise from the middle third level P1 but remain below the upper first level P2. Therefore, the compressor can remain off between t3 and t4. Furthermore, the temperature can rise monotonically from the lower first level T0 to above the middle second level T1. No compression strokes can occur between t3 and t4. Therefore, the air injection quantity can remain at the lower first level A0.

[0113] At t4, the desired engine torque can reach threshold D1. In response to the desired engine torque reaching D1, the compressor can be engaged, and consequently, the manifold pressure can rise above P2 at t4. The intake port temperature can continue to rise at t4 in response to the increasing intake air pressure. The air injection quantity can remain at the lower first level A0 at t4 because the piston is in its intake stroke at t4. Furthermore, the intake valve can be in the open second position I2 at t4 because the piston is in its intake stroke.

[0114] Between t4 and t5, the desired torque can fluctuate around the threshold D1. Therefore, the manifold pressure can remain above the upper first threshold P2. Furthermore, the temperature can fluctuate around an upper third level T2, where T2 is higher than T1. However, in response to the desired torque being above D1 and the manifold pressure being above P2, the air injection quantity is maintained at A0 between t4 and t5. The air injection quantity remains at A0 even during the first part of any compression stroke between t4 and t5, because the manifold pressure is high enough to reduce the flow of gases from the combustion chamber to the intake port when the intake valve is in position I2 during the compression stroke.

[0115] At t5, the desired engine torque may begin to decrease monotonically. In response to the decrease in the desired engine torque at t5, the compressor may be switched off, and / or the power supplied to the compressor may be reduced, which may cause the manifold pressure at t5 to fall below P2. The inlet port temperature may fluctuate around T2. The air injection quantity may remain at the lower first level A0 at t5, as the piston is in its working stroke at t5. Furthermore, the inlet valve may be in the closed first position I1 at t5, as the piston is in its working stroke.

[0116] Between t5 and t6, the desired torque can drop to D1. The manifold pressure can remain approximately at P1. Furthermore, the temperature can fluctuate between T1 and T2. The air injection quantity remains at A0, as no compression strokes occur between t5 and t6.

[0117] At t6, the desired engine torque can fall below D1, and the manifold pressure can remain below P2, at approximately the middle third level P1. Additionally, the piston can reach the uT position and begin a compression stroke. Therefore, at t6, the intake valve can be held in the open second position I2 for the first part of the compression stroke, which may span the time interval from t6 to t7. Furthermore, the temperature in the intake port at t6 can be approximately T2. In response to the initiation of the compression stroke at t6, the desired engine torque falling below D1, and the intake valve being in the open second position I2, the amount of air forced into the intake port can increase from the lower first level A0 to an upper fourth level A3. The fourth level A3 can be greater than A2.However, in other examples, the fourth level A3 may be approximately the same as A2. Therefore, since the inlet duct temperature is higher at t6 than it was at t2, the amount of air blown into the inlet duct at t6 may be greater than at t2.

[0118] Between t6 and t7, the intake valve can remain in the open second position I2. Therefore, the time interval between t6 and t7 can represent the first part of the compression stroke, which began at t6. Consequently, the piston can move from the lower top dead center (UBT) position towards the upper top dead center (OTT) position between t6 and t7. Furthermore, the manifold pressure can remain approximately at the middle third level P1, and the temperature can remain approximately at T2. Therefore, the air injection quantity can remain at A3.

[0119] At t7, the piston can reach its second position, and in response to the piston reaching its second position, the intake valve position can be adjusted from the open second position I2 to the closed first position I1. Therefore, at t7, the first part of the compression stroke, which began at t6, can be completed. In response to the intake valve closing (e.g., being set to the closed first position I1), the air injection quantity is reduced to the lower first quantity A0. Thus, the air injection can be switched off at t7. Furthermore, at t7, the desired engine torque can continue to fall monotonically below D1, and the manifold pressure can remain below P2. Additionally, the intake port temperature at t7 can be approximately T2.

[0120] Between t7 and t8, the desired torque can fluctuate, but remain below the threshold D1. The manifold pressure can remain below the upper first level P2, approximately at the middle third level P1. Therefore, the compressor can remain switched off between t7 and t8. Furthermore, the temperature can decrease monotonically from T2 to below the middle second level T1. No compression strokes can occur between t7 and t8. Therefore, the air injection quantity can remain at the lower first level A0.

[0121] At t8, the desired engine torque may be below D1, and the manifold pressure may remain below P2, at approximately the middle third level P1. Additionally, the piston may reach the uT position and begin a compression stroke. Therefore, at t8, the intake valve may be held in the open second position I2 for the first part of the compression stroke, which may span the time interval from t8 to t9. Furthermore, the temperature in the intake port at t8 may be approximately T1. In response to the initiation of the compression stroke at t8, the desired engine torque falling below D1, and the intake valve being in the open second position I2, the amount of air injected into the intake port, starting from the lower first level A0, may increase.

[0122] Between t8 and t9, the intake valve can remain in the open second position I2. Therefore, the time interval between t8 and t9 can represent the first part of the compression stroke, which began at t8. Consequently, the piston can move from the lower top dead center (UBT) position towards the upper top dead center (OBT) position between t8 and t9. Furthermore, the manifold pressure can remain approximately at the middle third level P1. However, the temperature in the intake port can rise monotonically above T1 between t8 and t9. Therefore, the air injection quantity can increase from A0 to approximately A2 between t8 and t9. The extent of the increase in air injection quantity can be proportional to the temperature increase between t8 and t9. Therefore, the amount of air injection can increase with temperature increases between t8 and t9.

[0123] At t9, the piston can reach its second position, and in response to the piston reaching its second position, the intake valve position can be adjusted from the open second position I2 to the closed first position I1. Therefore, at t9, the first part of the compression stroke, which began at t8, can be completed. In response to the intake valve closing (e.g., being adjusted to the closed first position I1), the air injection quantity is reduced to the lower first quantity A0. Thus, air injection can be switched off at t9. Furthermore, at t8, the desired engine torque can continue to fall monotonically below D1, and the manifold pressure can remain below P2. Additionally, the intake port temperature at t9 can be above T1 but below T2.

[0124] Between t9 and t 10The desired torque can fluctuate, but can continue to fall monotonically below D1. The manifold pressure can remain below the upper first level P2 at approximately the middle third level P1. Therefore, the compressor can operate between t9 and t 10 remain switched off. Furthermore, the temperature can fluctuate between T1 and T3. Between t9 and t 10 No compression strokes can occur. Therefore, the air injection quantity can remain at the lower first level A0.

[0125] At t 10 The desired engine torque can be below D1, and the manifold pressure can begin to drop below P1. Additionally, the piston can reach the bottom dead center (BDC) position and begin a compression stroke. Therefore, the intake valve can close at t 10 for a first section of the compaction stroke, which covers the time interval of t 10 are 11can include, held in the open second position I2. Furthermore, the temperature in the inlet channel at t8 can be approximately T0. In response to the initiation of the compression stroke at t 10 and on the condition that the desired engine torque remains below D1, and on the condition that the inlet valve is in the open second position I2, the amount of air blown into the inlet channel can be increased from the lower first level A0.

[0126] Between t 10 and t 11 The inlet valve can remain in the open second position I2. Therefore, the time interval between t 10 and t 11 represent the first section of the compaction stroke, which occurs at t 10 has begun. Therefore, the piston can move between t 10 and t 11from the uT position towards the oT position. Furthermore, the temperature in the intake port can remain approximately at T0. However, the manifold pressure can drop monotonically from P1 to P0 between t8 and t9 due to the reduction in the desired engine torque. Therefore, the air injection quantity can change between t 10 and t 11 from A0 to approximately A2. The extent of the increase in the air injection quantity between t 10 and t 11 can be inversely proportional to the decrease in temperature between t 10 and t 11 be. Therefore, there can be a difference between t 10 and t 11 Increase the amount of air injection by reducing the size of the manifold.

[0127] At t 11The piston can reach the second position, and in response to the piston reaching the second position, the position of the intake valve can be adjusted from the open second position I2 to the closed first position I1. Therefore, at t 11 the first section of the compaction stroke, which occurs at t 10 Once started, the process is completed. In response to the inlet valve closing (e.g., set to the closed first position I1), the air injection quantity is reduced to the lower first quantity A0. Thus, the air injection can be stopped at t 11 be switched off. Furthermore, at t 11 The desired engine torque continues to fall monotonically below D1, and the manifold pressure can remain approximately at P0. Furthermore, the intake port temperature at t 11 approximately remain at T0.

[0128] Therefore, air can only be injected into the intake port during the first part of the compression stroke if the intake valve is in the open second position, the desired engine torque is below the threshold, and the manifold pressure is below the threshold. Furthermore, the amount of air injected into the intake port can depend on the manifold pressure and the intake port temperature. The amount of air to be injected into the intake port can increase with higher intake port temperatures, lower desired engine torque levels, and / or lower manifold pressures.

[0129] In this way, a power engine system can comprise: an air injector positioned in an intake port upstream of a power engine cylinder and downstream of a compressor and charge air cooler; an air reservoir fluidically coupled to the air injector to provide compressed air for it; and a control system with computer-readable instructions. The computer-readable instructions can include instructions to inject a desired quantity of compressed air from the air reservoir into the intake port via the air injector when the power engine cylinder is in the first part of a compression stroke, wherein the first part of the compression stroke can be a part of the compression stroke in which an intake valve of the power engine cylinder is in an open position so that gases flow between the cylinder and the intake port, and wherein otherwise no air is injected into the intake port from the air reservoir.In some examples, the air injector may further include an electronic valve that can be adjusted between a first position, in which compressed air does not flow from the air injector to the intake port, and a second position, in which compressed air flows from the air injector to the intake port. The injection of compressed air may also include the exclusive injection of compressed air into the intake port under engine operating conditions when a desired engine torque and an intake manifold pressure are below their respective thresholds.The desired amount of compressed air to be injected into the intake manifold can be estimated based on the temperature of gases in the intake manifold, the intake manifold pressure, the desired engine torque, or the airflow in the intake manifold. The intake manifold pressure can be estimated based on outputs from a pressure sensor located in the intake manifold of the engine system. The desired engine torque can be estimated based on inputs from a vehicle operator, and the airflow in the intake manifold can be based on an air mass meter located in the intake manifold. In some examples, the temperature of gases in the intake manifold can be estimated based on outputs from a temperature sensor located in the intake manifold.Furthermore, the air reservoir can be connected to a charging chamber of the engine system via a first valve positioned between the air reservoir and the charging chamber. This first valve is adjustable between a first position, in which gases do not flow between the air reservoir and the charging chamber, and a second position, in which gases flow between the air reservoir and the charging chamber. The charging chamber can be located downstream of the compressor and upstream of the charge air cooler and a throttle valve, the position of which can be adjusted to regulate the airflow to the cylinder. Additionally or alternatively, the first valve can be set to the second position only under engine operating conditions where the desired engine torque is less than a threshold.

[0130] In this way, a method can involve injecting compressed air from a compressed air source into an intake port of an engine cylinder during a portion of a compression stroke. In particular, the method can involve holding an intake valve in an open position for a duration immediately following the end of an intake stroke during the beginning of the compression stroke, the valve in the open position allowing gases to flow between the intake port and a combustion chamber of the engine cylinder. Thus, the method can involve holding the intake valve in the open position when the piston reaches the lower top dead center (UDC) position during the intake stroke and then begins to return to the upper top dead center (ODC) position during the start of the compression stroke. Furthermore, the intake valve can remain open during the compression stroke until the piston reaches a second position between UDC and ODC.Therefore, the inlet valve can remain open for a first section of the compression stroke, where the first section of the compression stroke is a section of the compression stroke that coincides with the beginning of the compression stroke when the piston is at uT, and ends at a point in the compression stroke when the piston is at the second position.

[0131] However, while the intake valve is in an open position during the initial part of the compression stroke, some of the air-fuel mixture admitted to the combustion chamber during the intake stroke can flow back into the intake port as the combustion chamber volume decreases. The air-fuel mixture in the combustion chamber can be at a higher temperature than the gases in the intake port and manifold due to various factors. For example, residual heat present in the combustion chamber from previous combustion cycles can cause the air-fuel mixture to be at a higher temperature than the gases in the intake port. In particular, the heat generated during each combustion cycle may not be completely dissipated at the end of the cycle, resulting in the combustion chamber being at a higher temperature than the intake port and manifold.Furthermore, exhaust gases that are recirculated to the engine intake manifold can also increase the temperature of the intake air, which can reduce the efficiency of the charge air cooler.

[0132] Due to the higher temperatures of the air-fuel mixture when it is recirculated to the intake manifold during the initial compression stroke, the effectiveness of the charge air cooler may be reduced. Furthermore, continued contact with the hot air-fuel mixture can lead to further deterioration of the charge air cooler. In both cases, the cooling efficiency of the incoming air charge entering the combustion chamber during the intake stroke may be diminished. Additionally, during the portion of the compression stroke when the intake valve is held open, the portion of the air-fuel mixture flowing out of the combustion chamber towards the intake port flows in the opposite direction to the flow of gases during the intake stroke. During the intake stroke, gases flow from the intake manifold and intake port to the combustion chamber.In other words, during the recirculation event, when the air-fuel mixture flows from the combustion chamber to the intake port, the flow direction of the air-fuel mixture is opposite to the flow of gases during the intake stroke.

[0133] Since gases in the intake port can flow in the opposite direction during the recirculation event, it can take time for the flow direction to reverse before the next intake stroke. Therefore, between two combustion cycles, particularly between the compression stroke of one cycle and the intake stroke of the following cycle, the direction of gas flow in the intake port may need to be reversed before gases can enter the combustion chamber. Consequently, there may be a delay in the flow of gases into the combustion chamber when an intake stroke is initiated. Furthermore, this delay can cause a delay in the torque delivered by the engine.

[0134] In this way, a technical effect of reducing deterioration at an intercooler is achieved by injecting compressed air into an intake port during a portion of the compression stroke, when the intake valve is in an open position, allowing gases to flow between the intake port and a combustion chamber of an engine cylinder. Thus, by injecting air into the intake port during the portion of the compression stroke when the intake valve is open, the amount of air-fuel mixture flowing from the combustion chamber to the intake port can be reduced. Reducing the amount of air-fuel mixture flowing from the combustion chamber to the intake port can increase the efficiency of the intercooler and therefore lower the temperature of the incoming air charge. Consequently, spontaneous combustion events and engine knock can be reduced.Another technical effect of increasing the mixing and atomization of an air-fuel mixture can be achieved by injecting compressed air into the intake port. Specifically, the air injected into the intake port can flow in the opposite direction to the air-fuel mixture entering the intake port from the combustion chamber. As a result, the mixing and atomization of the air-fuel mixture can be improved. Furthermore, injecting air into the intake port can reduce the momentum of the recirculated air-fuel mixture. This achieves a further technical effect of improving the engine's responsiveness by injecting air into the intake port during a portion of the compression stroke, when the intake valve is in an open position.By reducing the momentum of the air-fuel mixture to the intake port during the compression stroke, while the intake valve is held in an open position, gases can flow more quickly into the combustion chamber during a subsequent intake stroke. This results in a reduced response time to the available torque, allowing for a more immediate response to increases in engine torque.

[0135] It should be noted that the exemplary control and estimation routines contained herein are applicable to various power machine and / or vehicle system designs. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and can be executed by the control system, including the controller, along with the various sensors, actuators, and other power machine equipment. The specific routines described herein may incorporate one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Therefore, various actions, operations, and / or functions shown may be performed in the sequence presented, in parallel, or, in some cases, omitted.Accordingly, the processing sequence is not strictly necessary to achieve the features and advantages of the embodiments described here, but merely serves to facilitate presentation and description. One or more of the actions, processes, and / or functions shown can be performed repeatedly, depending on the strategy used. Furthermore, the described actions, processes, and / or functions can graphically represent code to be programmed into the non-volatile memory of the computer-readable storage medium in the power machine control system, wherein the described actions are carried out by executing the instructions in a system that comprises the various power machine hardware components in combination with the electronic control.

[0136] It is understood that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be interpreted in a limiting sense, as numerous variations are possible. The above technology is applicable, for example, to V6, I4, I6, V12, 4-cylinder boxer, and other types of power engines. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and designs, and other features, functions, and / or properties disclosed herein.

[0137] The following claims highlight certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims should be understood as encompassing one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether their scope of protection is broader, narrower, the same, or different with respect to the original claims, shall also be considered to be included in the subject matter of the present disclosure.

Claims

[1] Procedure comprising the following: Arranging an inlet valve (152) coupled to a cylinder (30) of an internal four-stroke internal combustion engine (10) in an open position during a section of an inlet stroke up to a section of a compression stroke of a piston (36) moving back and forth in the cylinder (30); Supplying air to the inlet valve (152) from a first source, wherein the supply of air to the inlet valve (152) from a first source comprises supplying air from an air compressor (162) arranged in an inlet channel (42) and directing the air via said inlet channel (42) into an inlet port (202) to the inlet valve (152) and being driven by one of the following: a turbine (164) coupled to an outlet of the engine; or a crankshaft (40) of the engine (10); or an electric motor; and Blowing air to the inlet valve (152) from a second source while the inlet valve (152) is open during the compression stroke, wherein blowing air to the inlet valve (152) from a second source includes blowing air from a reservoir via an air injector (190) connected to the inlet port, which accumulates air from one or more of the following: a portion of the air from the first source; or an electric air pump. [2] Method according to claim 1, further comprising cooling the air supplied to the inlet valve (152) from the first air source by means of a heat exchanger before the compressed air is directed via the inlet channel (42) into the inlet port (202) to the inlet valve (152). [3] Method according to one of the preceding claims, further comprising direct injection of fuel into the cylinder (30) through the inlet valve (152) by means of a fuel injector nozzle (66) during the inlet stroke section. [4] Method according to any of the preceding claims, wherein the engine (10) comprises one of the following: a spark-ignition gasoline engine; or a diesel engine. [5] Procedure comprising the following: Opening an inlet valve (152) coupled to a cylinder (30) of an internal four-stroke internal combustion engine (10) during an inlet stroke of a piston (36) in the cylinder, wherein the power unit (10) comprises an intake manifold (144) coupled to the intake valve (152) via an intake port (42); Supplying air from the intake manifold (144) through the intake port (42) to the intake valve (152); Returning a portion of the exhaust gases from the engine (10) to the inlet valve (152); Closing of the inlet valve (152) during a compression stroke of the piston (36); Recirculation of a portion of the air and the recirculated exhaust gases from the cylinder (30) through the inlet valve (152) and the inlet port (42) during the compression stroke, with the inlet valve (152) open; and Air is injected from an air reservoir (91) into the inlet port (202) in the direction of the inlet valve (152) against the recirculated air and the recirculated exhaust gases, with the inlet valve (152) being open during the compression stroke. [6] Method according to claim 5, wherein the supply of air to the inlet manifold (144) further comprises the supply of compressed air through a heat exchanger for cooling the compressed air and the directing of the cooled compressed air into the inlet manifold (144). [7] Method according to claim 6, wherein the air blown in from the air storage (91) is controlled with respect to time and duration in order to reduce or substantially stop the entry of the recirculated air and the recirculated exhaust gases into the heat exchanger. [8] Method according to claim 7, wherein the control of the injected air relates to one or more of the following: load on the engine (10), mass flow of air supplied to the inlet manifold (144), torque produced by the engine (10), pressure in the inlet manifold (144) or temperature of the recirculated air. [9] Method according to claim 5, further comprising switching off the injected air when the pressure in the inlet manifold (144) reaches a predetermined pressure. [10] Method according to claim 5, further comprising adding fuel to the cylinder (30) during a portion of the intake stroke, wherein the recirculation of a portion of air and exhaust gases from the cylinder (30) includes a portion of the added fuel. [11] Power machine system (100) comprising the following: one in an inlet channel (42) upstream of a power engine cylinder (30) and air injector (190) positioned downstream of a compressor (162) and charge air cooler (157); an air reservoir (91) fluidically coupled to the air injector (190) for providing compressed air for the same; and a controller (12) with computer-readable instructions for: Injecting a desired quantity of compressed air from the air reservoir (91) into the inlet channel (42) via the air injector (190) when the engine cylinder (30) is in a first section of a compression stroke, wherein the first section of the compression stroke is a section of the compression stroke in which an inlet valve (152) of the engine cylinder (30) is in an open position so that gases flow between the cylinder (30) and an inlet port (202); and otherwise not injecting air from the air reservoir (91) into the inlet channel (42). [12] Power machine system (100) according to claim 11, wherein the air injector (190) further comprises an electronic valve (231) which is adjustable between a first position in which compressed air does not flow from the air injector (190) to the inlet port (202) and a second position in which compressed air flows from the air injector (190) to the inlet port (202). [13] Power engine system (100) according to claim 11, wherein blowing in compressed air further comprises blowing exclusively compressed air into the inlet channel (42) under power engine operating conditions when a desired power engine torque and an inlet manifold pressure are less than their respective threshold values. [14] Power engine system (100) according to claim 11, wherein the desired quantity of compressed air to be injected into the inlet channel (42) is estimated based on a temperature of gases in the inlet channel (42), an inlet manifold pressure, a desired power engine torque, or an airflow in an inlet manifold (144), wherein the inlet manifold pressure is estimated based on outputs from a pressure sensor (121) positioned in the inlet manifold (144) of the power engine system (100), the desired power engine torque is estimated based on inputs from a vehicle operator, and the airflow in the inlet manifold (144) is based on an air mass meter (120) positioned in the inlet manifold (144). [15] Power machine system (100) according to claim 14, wherein the temperature of gases in the inlet channel (42) is estimated based on outputs from a temperature sensor (223) positioned in the inlet channel (42). [16] Power engine system (100) according to claim 11, wherein the air reservoir (91) is in targeted flow communication with a charging chamber (146) of the power engine system (100) via a first valve (131) positioned between the air reservoir (91) and the charging chamber (146), wherein the first valve (131) is adjustable between a first position in which gases do not flow between the air reservoir (91) and the charging chamber (146) and a second position in which gases flow between the air reservoir (91) and the charging chamber (146), wherein the charging chamber (146) is located downstream of the compressor (162) and upstream of the charge air cooler (157) and a throttle valve (62), and wherein the position of the throttle valve (62) is adjustable to control the airflow to the cylinder (30). [17] Power machine system (100) according to claim 16, wherein the first valve (131) is set to the second position only under power machine operating conditions where a desired power machine torque is less than a threshold.

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