Pressurized air intake system

Abstract

The present disclosure provides a "pressurized air intake system". Methods and systems for supercharging an engine system are provided. In one example, a system may include a pressurized air intake system having two paths, a first path for delivering ambient air to the engine and a second path for delivering pressurized air to the engine. The pressurized air intake system is also adapted to store the pressurized air so as to supply the boost pressure more quickly when more engine torque is required.

Description

Technical Field

[0001] The present description generally relates to methods and systems for controlling a vehicle engine to provide a charge of pressurized air.

[0002] Background technology / invention content

[0003] By incorporating a turbocharger, which includes a compressor driven by a turbine, into a vehicle's engine, the efficiency and power output of the engine can be increased. The forced introduction of additional air into the engine's combustion chamber in proportion causes the combustion of additional fuel, thereby generating more power than would be obtained from intake air at ambient pressure. The pressurized or boosted air is typically heated during the compression process because it could increase the risk of engine knock if burned directly. Therefore, the charge air is typically cooled by flowing it through a charge air cooler (CAC) before it enters the engine's intake manifold, a process that also increases air density and improves intake valve throttle response.

[0004] The air compression provided by the compressor of the turbocharger can be achieved by the rotation of the turbine. Typically, at least a portion of the exhaust gas is routed to the turbine, and the expansion of the exhaust gas causes the turbine to rotate. Since the turbine is mechanically coupled to the compressor, when the turbine speeds up, the compressor also speeds up. However, there may be a delay between the time when the torque increase is required and the time when the compressor provides the corresponding boost pressure. The delay, also known as turbo lag, is due to the inertia and friction of the turbine when operating at low engine loads, and corresponds to the duration required for the engine to produce enough exhaust gas (e.g., exhaust flow and temperature) to accelerate the turbine in order to drive the compressor. During this turbo lag, the performance of the supercharged engine may be degraded.

[0005] Various approaches have been developed to address the problem of turbo lag, including providing alternative paths for supplying air to the engine. An exemplary approach is shown in U.S. Patent 6,561,169 by Sealy et al. In the patent, a charge air management system is disclosed in which a first air duct supplies air at ambient pressure to the intake manifold, and a second air duct flows cooled charge air from downstream of a charge air cooler (CAC) to the intake manifold. Based on the engine speed and load, air flow through the first air duct or the second air duct is controlled via a valve. During low loads, air is delivered via the first duct. During higher loads, cooled dense air is delivered via the second duct and the CAC.

[0006] However, the inventors herein have recognized potential problems with such systems. There may be situations where the air provided via the second conduit does not improve boosted engine performance. In Sealy's approach, closing the valve during low-load conditions allows cooled and dense compressed air to remain in the second conduit and be released when the valve opens during subsequent high-load conditions. Since Sealy's charge air management system is adapted to less frequent demands on the turbocharger, the CAC is not operated during low-load conditions to improve fuel economy. Therefore, based on ambient conditions, and the duration that the compressed air is maintained in the second conduit without the CAC operating, the boost potential of the compressed air may be degraded. For example, during conditions of high ambient temperature or humidity, the density of the compressed air maintained in the second conduit may decrease, thereby reducing the throttling response of the engine when the compressed air is subsequently released. If the CAC is operated while the air is retained in the sealed second conduit, the fuel economy benefits of the boosted engine may be lost.

[0007] In one example, the above problem can be solved by a method for reducing turbo lag, the method comprising: at higher engine loads, drawing cooled compressed air into the engine via an intake passage, and at lower engine loads, drawing ambient air into the engine via a duct while retaining the cooled compressed air in the intake passage. Additionally, based on the heat transferred to the compressed air during the lower engine load, the compressed air is released from the intake passage. In this way, the boost pressure response time after a transient increase in torque demand can be improved.

[0008] As an example, a dual-path intake system may be applicable to an engine of a vehicle. The intake system may include a first air passage coupled to an intake manifold via a first throttle valve, the first air passage being configured to deliver fresh air at ambient pressure to engine cylinders at low engine speeds and loads. The intake system may also include a second air passage coupled to the intake manifold via a second throttle valve, the second passage including a turbocharger compressor and a CAC for delivering cooled compressed air to the engine cylinders during high engine speeds and loads. The first passage may be coupled to the second passage via a coupler such as a T-body. In addition, the flow to each passage may be controlled via a diverter valve (e.g., a proportional valve) or via respective first and second throttle valves. In response to an operator stepping on an accelerator pedal, the flow through the second passage may be increased while the flow through the first passage is reduced. In response to a subsequent operator releasing the accelerator pedal, CAC operation is disabled, the flow through the first passage may be increased, and the flow through the second passage may be closed so as to retain a certain amount of cooled compressed air in the second passage. The rate of temperature rise of the trapped air is estimated when the second passage is closed. For example, the heat transferred to the trapped air may be estimated based on ambient temperature, humidity, trapped air volume, boost level achieved before the second throttle valve is closed, etc. If the heat transferred exceeds a threshold, such as when the inferred temperature of the trapped air exceeds a threshold temperature, the engine controller may open the second throttle valve and release the trapped hot air, even if higher torque is not required. The first throttle valve may be closed accordingly and one or more engine operating parameters may be adjusted (e.g., spark timing may be retarded from MBT) to reduce torque transients.

[0009] In this way, by trapping cooled compressed air within the duct, the duct can be used as a boost pressure reservoir to quickly provide boost pressure to the engine cylinders during a tip-in. This therefore reduces turbo lag. The technical effect of discharging the trapped compressed air when torque demand is low in response to a rise in the inferred temperature of the trapped air is that the boost performance of the engine can be kept elevated. Specifically, only compressed air that is cooled and has a high density (and therefore is able to improve throttle response when discharged) is retained within the duct. By discharging hot and less dense trapped air during conditions of low boost demand, the adverse effects of hot air on throttle response are reduced. The duct can be replenished with fresh air that is quickly cooled during subsequent CAC operation. In this way, boosted engine performance is improved.

[0010] It should be understood that the above summary is provided to introduce a series of concepts in a simplified form, which are further described in the detailed description. This is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 An exemplary engine system for a single turbocharged hybrid vehicle is shown.

[0012] Figure 2 A schematic diagram showing an engine adapted for use with a pressurized air intake system.

[0013] Figure 3A A top view of a first embodiment of a pressurized air intake system is shown.

[0014] Figure 3B An isometric perspective view of a first embodiment of a pressurized air intake system is shown.

[0015] Figure 4A A top view of a second embodiment of a pressurized air intake system is shown.

[0016] Figure 4B A cross-sectional view of a second embodiment of a pressurized air intake system is shown.

[0017] Figure 5 A high level flow chart depicts an exemplary method for controlling operation of a pressurized air intake system.

[0018] Figure 6 to Figure 7 Exemplary operation of a pressurized intake air reservoir system according to the present disclosure is shown for improving boosted engine performance.

[0019] FIG. 3A to FIG. 4BAn exemplary configuration with relative positioning of various components is shown. In at least one example, if it is shown as directly contacting or directly connected to each other, then such elements can be referred to as directly contacting or directly connected respectively. Similarly, in at least one example, the elements shown as being adjacent or adjacent to each other can be adjacent or adjacent to each other respectively. As an example, the components that are coplanar in contact with each other can be referred to as coplanar in contact. As another example, in at least one example, the elements that are positioned separately from each other with only a spacing therebetween and no other components can be referred to as such. As another example, the elements shown as being above / below each other, on both sides opposite to each other, or on the left / right side of each other can be referred to as such relative to each other. In addition, as shown in the figure, in at least one example, the topmost element or the topmost point of the element can be referred to as the "top" of the component, and the bottommost element or the bottommost point of the element can be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, above / below can be relative to the vertical axis of the accompanying drawings, and are used to describe the positioning of the elements of the accompanying drawings relative to each other. Thus, in one example, the element shown as being above other elements is vertically positioned above other elements. As yet another example, shapes of elements depicted in the drawings may be referred to as having these shapes (e.g., such as, rounded, straight, planar, curved, rounded, chamfered, angled, etc.). Additionally, in at least one example, elements shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Still further, in one example, an element shown as being within another element or an element shown as being outside another element may be referred to as such. DETAILED DESCRIPTION

[0020] The following description relates to a method for transmitting air via a pressurized air intake system such as Figure 2 systems) to engine systems (such as Figure 1 The pressurized air intake system may include a first air path and a second air path for airflow, each path coupled to a fresh air duct at a first end and to an intake plenum located upstream of an engine cylinder at a second end. Figure 2 As shown, the first air path may flow fresh ambient air to the engine, while the second air path may flow air through the compressor and charge air cooler (CAC). Flow through the first and second paths may be controlled via respective throttle valves, such as FIG. 3A to FIG. 3B Alternatively, the relative flow between the passages can be controlled via a diverter valve, such as FIG. 4A to FIG. 4B The controller may be configured to execute a control program (such as Figure 5) to adjust the position of one or more valves based on engine speed-load conditions so that a certain amount of cooled compressed air can be stored in the second passage acting as a reservoir, which is released in response to an increase in torque demand to reduce turbo lag. The controller may also adjust one or more valves to exhaust any trapped air based on an inferred amount of heat transferred to the air. Figure 6 to Figure 7 An exemplary operation of a pressurized intake system is described. In this manner, supercharged engine performance is improved.

[0021] Figure 1 An example of a cylinder of internal combustion engine 10 of vehicle 5 is depicted. Engine 10 may be controlled at least partially by a control system including controller 12 and by input from a vehicle operator 130 via an input device 132. In this example, input device 132 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. Cylinder 14 of engine 10 (which may be referred to herein as a combustion chamber) may include combustion chamber walls 136 and a piston 138 positioned therein. Piston 138 may be coupled to a crankshaft 140 such that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 140 may be coupled to at least one drive wheel of a passenger vehicle via a transmission system. Further, a starter motor (not shown) may be coupled to crankshaft 140 via a flywheel to enable a starting operation of engine 10.

[0022] The engine 10 is a supercharged engine including a turbocharger 175 for providing a pressurized intake air charge. Although the engine 10 is shown as being coupled to one turbocharger, other embodiments of the engine 10 may include more than one turbocharger to provide boost. The turbocharger 175 is configured with a compressor 174 and an exhaust turbine 176. The compressor 174 is arranged in the intake passage 142, and the compressor 174 draws fresh ambient air into the engine 10. The compressor 174 is driven by the exhaust turbine 176. As the compression of the air heats the air charge, the pressurized air flows through a charge air cooler (CAC) 192, where it is cooled and then delivered to the engine cylinders. The CAC 192 may be a water-to-air or air-to-air based heat exchanger. The turbine 176 is positioned in the exhaust passage 148 downstream of the cylinder 14 and upstream of the emission control device 178. Turbine 176 is mechanically coupled to compressor 174 via shaft 180. Flow of hot expanding exhaust gas from cylinder 14 through exhaust passage 148 toward emission control device 178 drives rotation of turbine 176, the rotation of turbine 176 at least partially powering rotation of the compressor via shaft 180. Engine 10 also includes a pressurized air intake (PAI) system 199 configured to deliver air to cylinder 14. PAI system 199 includes a bypass conduit 194 coupled at a first end to intake passage 142 at a location upstream of compressor 174 and coupled at a second end to intake plenum 146. In this manner, bypass conduit 194 may constitute a first air path for PAI system 199, while intake passage 142 leading to intake passage 198 including compressor 174 and CAC 192 constitutes a second air path for PAI system 199. Configuration of PAI system 199 in Figure 2 An exemplary embodiment of the PAI system 199 is described in detail in FIG. 3A to FIG. 3B and FIG. 4A to FIG. 4B Described in detail in.

[0023] Cylinder 14 may receive intake air via intake passages 142, 198, 144 and bypass conduit 194 and intake boost chamber 146, which is generally represented as follows: Figure 1 Intake boost chamber 146 may be in communication with other cylinders of engine 10 in addition to cylinder 14 . Figure 1Engine 10 is shown configured with a turbocharger 175 including a compressor 174 disposed between intake passages 142 and 198 and a turbine 176 disposed along exhaust passage 148. Intake passage 142 and bypass duct 194 flow air at ambient conditions, while intake passages 198 and 144 contain air that is temporarily pressurized by compressor 174. CAC 192 may be disposed in intake passage 198 downstream of compressor 174 and upstream of first throttle 162, with pressure relief valve (PRV) 164 positioned between compressor 174 and CAC 192. First throttle 162 (also an air throttle) and second throttle 196 (also a boost throttle) may be disposed along bypass duct 194 and intake passage 144 of the engine, respectively, to vary the flow rate and / or pressure of intake air provided to the engine cylinders. For example, first throttle 162 may be positioned downstream of CAC 192, such as Figure 1 As shown, or alternatively may be disposed upstream of CAC 192 .

[0024] Exhaust passage 148 may receive exhaust gas from other cylinders of engine 10 in addition to cylinder 14. Exhaust gas sensor 128 is shown coupled to exhaust passage 148 upstream of emission control device 178. For example, sensor 128 may be selected from a variety of suitable sensors for providing an indication of exhaust air-fuel ratio, such as, for example, a linear oxygen sensor or UEGO (Universal or Wide-range Exhaust Gas Oxygen), a two-state oxygen sensor or EGO (as depicted), HEGO (Heated EGO), NOx, HC, or CO sensors. Emission control device 178 may be a three-way catalyst (TWC), a NOx trap, various other emission control devices, or combinations thereof.

[0025] Each cylinder of engine 10 may include one or more intake valves and one or more exhaust valves. For example, cylinder 14 is shown as including at least one intake poppet valve 150 and at least one exhaust poppet valve 156 located at an upper region of cylinder 14. In some examples, each cylinder of engine 10 (including cylinder 14) may include at least two intake poppet valves and at least two exhaust poppet valves located at an upper region of the cylinder.

[0026] Intake valve 150 may be controlled by controller 12 via actuator 152. Similarly, exhaust valve 156 may be controlled by controller 12 via actuator 154. In some cases, controller 12 may change the signals provided to actuators 152 and 154 to control the opening and closing of the corresponding intake valve and exhaust valve. The positions of intake valve 150 and exhaust valve 156 may be determined by corresponding valve position sensors (not shown). The valve actuator may be an electric valve actuation type or a cam actuation type, or a combination thereof. The intake valve timing and exhaust valve timing may be controlled simultaneously, or any possibility of variable intake cam timing, variable exhaust cam timing, dual independent variable cam timing, or fixed cam timing may be used. Each cam actuation system may include one or more cams, and may utilize one or more of a cam profile switching system (CPS), a variable cam timing (VCT), a variable valve timing (VVT), and / or a variable valve lift (VVL) system that may be operated by controller 12 to change valve operation. For example, cylinder 14 may alternatively include an intake valve controlled via electric valve actuation and an exhaust valve controlled via cam actuation including CPS and / or VCT. In other examples, the intake and exhaust valves may be controlled by a common valve actuator or actuation system or a variable valve timing actuator or actuation system.

[0027] Cylinder 14 may have a compression ratio, which is the ratio of volumes of piston 138 when located at bottom dead center to top dead center. In one example, the compression ratio is in the range of 9:1 to 10:1. However, in some examples using different fuels, the compression ratio may be increased. For example, this may occur when using a higher octane fuel or a fuel with a higher latent enthalpy of vaporization. If direct injection is used, the compression ratio may also be increased due to the effect of direct injection on engine knock.

[0028] In some examples, each cylinder of engine 10 may include a spark plug 193 for initiating combustion. Under select operating modes, ignition system 190 may provide an ignition spark to cylinder 14 via spark plug 193 in response to spark advance signal SA from controller 12. However, in some embodiments, spark plug 193 may be omitted, such as where engine 10 may initiate combustion by auto-ignition or by injection of fuel, as is the case with some diesel engines.

[0029] In some examples, each cylinder of engine 10 may be configured with one or more fuel injectors for providing fuel thereto. As a non-limiting example, cylinder 14 is shown as including two fuel injectors 166 and 170. Fuel injectors 166 and 170 may be configured to deliver fuel received from fuel system 8. Fuel system 8 may include one or more fuel tanks, fuel pumps, and fuel rails. Fuel injector 166 is shown as being directly coupled to cylinder 14 for injecting fuel directly into the cylinder in proportion to the width of a pulse signal FPW-1 received from controller 12 via electronic driver 168. In this manner, fuel injector 166 provides what is known as direct injection of fuel (hereinafter referred to as "DI") into combustion cylinder 14. Although Figure 1 Injector 166 is shown positioned to one side of cylinder 14, but injector 166 may alternatively be located at an overhead position of the piston, such as near the location of spark plug 193. Such a location may improve mixing and combustion when the engine is operated using alcohol-based fuels, as some alcohol-based fuels have lower volatility. Alternatively, the injector may be located at an overhead position and near the intake valve for improved mixing. Fuel may be delivered to fuel injector 166 from a fuel tank of fuel system 8 via a high pressure fuel pump and a fuel rail. In addition, the fuel tank may have a pressure sensor that provides a signal to controller 12.

[0030] In a configuration that provides so-called port fuel injection (hereinafter “PFI”) into the intake port upstream of cylinder 14, fuel injector 170 is shown arranged in intake boost chamber 146, rather than in cylinder 14. Fuel injector 170 may inject fuel received from fuel system 8 in proportion to the width of pulse signal FPW-2 received from controller 12 via electronic driver 171. It should be noted that a single driver 168 or 171 may be used for both fuel injection systems, or multiple drivers may be used, such as exemplary driver 168 for fuel injector 166 and driver 171 for fuel injector 170, as depicted.

[0031] In an alternate example, each of fuel injectors 166 and 170 may be configured as a direct fuel injector for injecting fuel directly into cylinder 14. In yet another example, each of fuel injectors 166 and 170 may be configured as a port fuel injector for injecting fuel upstream of intake valve 150. In still other examples, cylinder 14 may include only a single fuel injector configured to receive different fuels in different relative amounts from a fuel system as a fuel mixture and further configured to inject the fuel mixture directly into the cylinder as a direct fuel injector or to inject the fuel mixture upstream of the intake valve as a port fuel injector.

[0032] During a single cycle of the cylinder, fuel may be delivered to the cylinder by both injectors. For example, each injector may deliver a portion of the total fuel injection that is burned in cylinder 14. In addition, the distribution and / or relative amount of fuel delivered from each injector may vary with operating conditions, such as engine load, knock, and exhaust temperature, such as described below. Port-injected fuel may be delivered during an open intake valve event, a closed intake valve event (e.g., substantially before the intake stroke), and during open and closed intake valve operation. Similarly, for example, direct-injected fuel may be delivered during the intake stroke, and partially during the previous exhaust stroke, during the intake stroke, and partially during the compression stroke. In this way, even for a single combustion event, the injected fuel may be injected from the port injector and the direct injector at different timings. In addition, for a single combustion event, multiple injections of the delivered fuel may be performed per cycle. The multiple injections may be performed during the compression stroke, the intake stroke, or any suitable combination thereof.

[0033] Fuel injectors 166 and 170 may have different characteristics. These different characteristics include size differences, for example, one injector may have a larger spray hole than the other. Other differences include, but are not limited to, different spray angles, different operating temperatures, different aiming targets, different injection timings, different spray characteristics, different locations, etc. Moreover, depending on the distribution ratio of the injected fuel among injectors 170 and 166, different effects may be achieved.

[0034] The fuel tank in the fuel system 8 can accommodate fuels of different fuel types, such as fuels with different fuel qualities and different fuel compositions. The differences may include different alcohol contents, different water contents, different octane numbers, different heats of vaporization, different fuel blends and / or combinations thereof, etc. An example of a fuel with different heats of vaporization may include gasoline with a lower heat of vaporization as a first fuel type and ethanol with a larger heat of vaporization as a second fuel type. In another example, the engine may use gasoline as a first fuel type and an alcohol-containing fuel blend as a second fuel type, such as E85 (approximately 85% ethanol and 15% gasoline) or M85 (approximately 85% methanol and 15% gasoline). Other feasible materials include water, methanol, a mixture of alcohol and water, a mixture of water and methanol, a mixture of alcohol, etc.

[0035] The controller 12 Figure 110 is shown as a microcomputer, which includes: a microprocessor unit (CPU) 106, input / output ports (I / O) 108, an electronic storage medium for executable programs and calibration values ​​(in this particular example, shown as a non-transitory read-only memory (ROM) chip 110 for storing executable instructions), a random access memory (RAM) 112, a keep alive memory (KAM) 114, and a data bus. Controller 12 can receive various signals from sensors coupled to engine 10, in addition to those previously discussed, including a measurement of intake mass air flow (MAF) from a mass air flow sensor 122; an engine coolant temperature (ECT) from a temperature sensor 116 coupled to a cooling sleeve 118; a surface ignition sensing signal (PIP) from a Hall effect sensor 120 (or other type) coupled to a crankshaft 140; a throttle position (TP) from a throttle position sensor; and a manifold absolute pressure signal (MAP) from a sensor 124. An engine speed signal, RPM, can be generated by controller 12 from the signal PIP. Manifold pressure signal MAP from a manifold pressure sensor may be used to provide an indication of vacuum, or pressure, in the intake manifold.Controller 12 may infer engine temperature based on the engine coolant temperature.

[0036] As described above, Figure 1 Only one cylinder of a multi-cylinder engine is shown. As such, each cylinder may similarly include its own set of intake / exhaust valves, one or more fuel injectors, spark plugs, etc. It should be appreciated that engine 10 may include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders. In addition, each of these cylinders may include a control module connected to the control module via a control module. Figure 1 Some or all of the various components described and depicted with reference to cylinder 14 .

[0037] In some examples, the vehicle 5 may be a hybrid vehicle having multiple torque sources available for one or more wheels 55. In other examples, the vehicle 5 is a conventional vehicle having only an engine. In the example shown, the vehicle 5 includes an engine 10 and an electric motor (M / G) 52. The electric motor (M / G) 52 may be a motor or a motor / generator. When one or more clutches 56 are engaged, the crankshaft 140 of the engine 10 and the electric motor (M / G) 52 are connected to the wheels 55 via the transmission 54. In the depicted example, the first clutch 56 is disposed between the crankshaft 140 and the electric motor (M / G) 52, and the second clutch 56 is disposed between the electric motor (M / G) 52 and the transmission 54. The controller 12 may send a signal to the actuator of each clutch 56 to engage or disengage the clutch so as to connect or disconnect the crankshaft 140 with the electric motor (M / G) 52 and the components connected to the electric motor (M / G) 52, and / or to connect or disconnect the electric motor (M / G) 52 with the transmission 54 and the components connected to the transmission 54. The transmission 54 may be a gearbox, a planetary gear system, or another type of transmission.The powertrain may be configured in a variety of ways, including, for example, parallel, series, or series-parallel hybrid vehicles.

[0038] The electric machine (M / G) 52 receives power from the traction battery 58 to provide torque to the wheels 55. The electric machine (M / G) 52 may also operate as a generator to provide power to the charging battery 58, such as during braking operations.

[0039] As described above, a vehicle may be equipped with a pressurized air intake (PAI) system coupled to the engine for improved performance during operation requiring increased torque. Figure 2 2 shows a pressurized air intake (PAI) system 200 which may be coupled to an engine intake manifold 202. Figure 1 Elements common to the components of FIG. 1 are labeled with the same reference numerals. The engine intake manifold 202 can direct airflow to multiple cylinders (such as Figure 1 The PAI system includes a first path 204 for delivering ambient air and a second path 206 for delivering compressed cooling air to the intake manifold 202. The direction of airflow through both the first path 204 and the second path 206 of the PAI system is indicated by arrow 210. Air may be received in the PAI system 200 via an intake passage 142, which in one example may be Figure 1 The air may then flow into the first path 204 and / or continue to flow along the intake passage 142 into the second path 206 .

[0040] The first path 204 of the PAI system 200 is coupled to the intake passage 142 via a coupling (shown as a T-shaped body 212 in this example). However, other couplings may be used as well. The T-shaped body 212 has a first joint 214 from which a bypass conduit 216 of the first path 204 extends. In one example, the bypass conduit 216 may be Figure 1 Bypass duct 216 diverts air drawn from intake passage 142 to intake plenum 146 while bypassing the compressor. As a result of the bypass duct, first path 204 has a shorter length relative to second path 206, thereby enabling rapid delivery of air at ambient pressure to engine intake manifold 202 when needed by increasing the opening of first path 204. Thus, first path 204 acts as a shortcut for supplying ambient air to engine intake manifold 202 during low engine loads and speeds where little or no boost is needed (e.g., after a tip-out). By supplying ambient air to engine intake manifold 202 that has not been cooled prior to delivery, condensation within first path 204 may be avoided.

[0041] The first path 204 may also include a first throttle valve 162 positioned at a downstream end of the bypass conduit 216, the downstream end being located distally relative to the T-body 212 and proximal to the intake plenum 146 of the engine intake manifold 202. In one example, the first throttle valve 162 may control the flow through the first path 204 to the engine intake manifold 202 based on a signal received from the controller 12. The controller 12 may command an opening degree of the first throttle valve 162 based on an input indicative of a torque demand, such as based on an input from an accelerator pedal. Based on the opening degree of the first throttle valve 162, a certain amount of air flowing through the intake passage 142 may be drawn through the first junction 214 of the T-body into the bypass conduit 216 and then delivered to the engine intake manifold 202 when passing through the first throttle valve 162. In this way, the air diverted into the first path 204 bypasses the components included in the second path 206 that pressurize and cool the air contained therein.

[0042] The second path 206 is coupled to the intake passage 142 downstream of the T-body 212 via the second joint 220. The second joint 220 may be arranged perpendicular to the first joint 214. In one example, the coupling of the second path 206 to the first path 204 via the T-body may provide a Y-shaped structure for the PAI system. Specifically, by incorporating a T-body into the intake passage 142 so as to couple the bypass duct 216 to the intake passage, the PAI system 200 may have a Y-shaped shape in an area including the intake passage 142, the T-body 212, and the bypass duct 216.

[0043] Air flowing into the PAI system 200 may flow through the second junction 220 of the T-body 212 and then enter the second path 206. The second path 206 is a charge air path including the compressor 174 and the CAC 192. In one example, the compressor 174 is coupled in the turbocharger 175 and driven via the exhaust turbine 176.

[0044] The intake passage 142 extends into a second path 206 located downstream of the second junction 220 of the T-body 212 and is coupled to the intake boost chamber 146 located downstream of the compressor 174 and the CAC 192. The second path 206 also includes a second throttle valve 196 positioned at a downstream end of the second path 206, which is located proximal to the intake boost chamber 146. The second throttle valve 196 may be actuated in a manner similar to the first throttle valve 162 via a command from the controller 12 in response to an input device (such as an accelerator pedal). Air may be delivered from the second path 206 to the engine intake manifold 202 by actuating the second throttle valve 196 between fully open and fully closed positions (to any position therebetween). For example, when torque demand increases and the engine is operating in a mid-to-high speed load region, the compressor 174 may be operated and the second throttle valve 196 may be opened to deliver boost air.

[0045] The second path 206 includes a first branch 222 that defines an area of ​​the second path 206 from downstream of the junction 220 to the inlet of the CAC 192, and a second branch 224 that defines an area of ​​the second path 206 from the outlet of the CAC 192 to the location where the second path is coupled to the intake boost chamber 146. Air flows through the second path 206 in a downstream direction from the second junction 220 of the T-body 212 to the compressor 174, then passes through the PRV 164, and then flows into the CAC 192. Then, the air compressed by the compressor 174 is cooled while passing through the CAC 192. Then, the cooled compressed air flows from the CAC 192 into the intake boost chamber 146 via the second throttle valve 196.

[0046] Air flowing through the intake passage 142 may first be compressed by the compressor 174 (hereinafter referred to as boost air), and then pass through the PRV 164. The PRV 164 may be a one-way valve that ensures that boost pressure is contained on the downstream side of the PRV 164 so that a reverse flow of boost air through the second path 206 cannot occur. The PRV 164 is kept closed until a pressure threshold is exceeded. For example, the pressure threshold may be a non-zero preset value based on a safety level of pressure tolerance of the walls of the first branch 222 and the second branch 224 or accessories connecting the first branch 222 and the second branch 224 to the CAC 192. In one example, the pressure threshold may be 14 Psi. When the boost pressure downstream of the PRV 164 exceeds the threshold, the PRV 164 may open to release the pressure.

[0047] Continuing along the airflow path in the second path 206, the air may flow through the PRV 164 into the first branch 222 and then through the CAC 192. In one example, the CAC 192 may be coupled to an engine cooling circuit that enables heat transfer from air heated during compression through the surface of the CAC 192 to the coolant. The heat exchange that occurs at the CAC 192 both cools the air and increases the density of the air flowing through the CAC 192, which is ultimately delivered to the engine intake manifold 202, thereby improving the intake throttle response of the boosted engine. The flow of coolant through the CAC 192 may vary based on boosted engine operating conditions. For example, when the engine is operating under boost, such as when the compressor 174 is operating and the second throttle valve 196 is at least partially open, the coolant may be enabled to flow through the CAC 192. As another example, coolant flow through the CAC 192 is prohibited when the engine is operating without boost, such as when the compressor 174 is not operating and the second throttle valve 196 remains closed. By limiting the operation of the CAC 192 to conditions when the engine is operating with boost, engine fuel economy may be improved by minimizing wasteful operation of the CAC 192. Additionally, component life of the CAC 192 is increased.

[0048] After exiting the CAC 192, the cooled charge air enters the second branch 224 of the second path 206 and flows through the second throttle valve 196. The second throttle valve 196 controls the delivery of the cooled charge air from the second path 206 into the intake boost chamber 146. The intake boost chamber 146 then directs the cooled charge air to the engine intake manifold 202 and on to the engine cylinders.

[0049] In addition to providing a path for boost air when the second throttle valve is open, the second path 206 may also serve as a reservoir for boost air when the second throttle valve 196 is closed. For example, in response to a tip-out after boosted engine operation, the second throttle valve 196 may be closed to retain compressed air within the second path 206, such as within at least the second branch 224 of the second path 206. In this way, when the second throttle valve 196 is closed, the second path 206 may serve as an intake air reservoir. During low engine loads, when boost air is not needed, the first throttle valve 162 is opened and the second throttle valve 196 is closed, so that boost air can be stored within the PAI system 200. During a subsequent tip-in, the stored boost air may be quickly delivered to the intake boost chamber 146 via the opening of the second throttle valve 196, and then delivered to the engine intake manifold 202, while accelerating the compressor 174. In this way, releasing the stored air from the second path 206 reduces turbo lag.

[0050] In this way, the boost support potential of the stored charge air may be affected by its temperature. Specifically, as long as the compressed air is sufficiently cold, releasing the cooled compressed air stored in the second path 206 during the accelerator pedal release, and releasing the cooled compressed air from the second path 206 during the subsequent accelerator pedal release, can reduce turbo lag. However, when the second path 206 is in a passive state while maintaining the reservoir of charge air and disabling the cooling operation of the CAC 192, heat can be transferred to the stored air. The amount of heat transferred can be determined according to environmental conditions. For example, as the ambient temperature rises and / or the ambient humidity rises, the amount of heat transferred from the ambient air around the PAI system 200 to the cooled compressed air retained in the second path 206 can increase. The heating of the charge air can reduce the air density, thereby reducing the throttle response when the charge air is released, and thereby reducing the amount of boost it can provide. Therefore, the PAI system 200 can be adapted to discharge the stored charge air from the second path 206 when a temperature or time threshold is exceeded, independent of the torque demand.

[0051] For example, when the second throttle valve 196 is closed, the controller may estimate or infer the amount of heat transferred to the stored air. In one example, when the second throttle valve 196 is closed, the output of the intake humidity sensor 230 and the intake air temperature (IAT) sensor 232 arranged upstream of the T-body 212 along the intake passage 142 may be used to estimate the ambient humidity and ambient temperature, respectively. Based on the measured ambient conditions, the controller may calculate the amount of heat transferred to the stored charge air, the rate of temperature rise, and the inferred charge air temperature. The inferred charge air temperature may be determined additionally or alternatively based on the charge air temperature when the second throttle valve 196 is closed, and the duration elapsed since the second throttle valve 196 was closed. In one example, the controller may use a model or algorithm to infer the temperature of the charge air retained in the second path 206 in real time. If it is determined that the inferred temperature of the stored air exceeds a threshold before a subsequent accelerator pedal event, the controller may actuate the second throttle valve 196 to at least a partially open position to discharge the stored air to the engine while still at a low engine speed or load. In one example, the second throttle valve 196 may be momentarily switched to a fully open position to release the stored air and then returned to a closed position. The opening of the first throttle valve 162 may be adjusted based on the momentary opening of the second throttle valve 196, such as Figure 5 In addition, one or more engine operating parameters (such as spark timing) may be adjusted to reduce torque transients associated with releasing hot compressed air into the engine intake manifold 202.

[0052] In the depicted example, each of first throttle valve 162 and second throttle valve 196 may be equipped with an actuation mechanism that receives a separate signal from controller 12. This allows the two throttle valves to be operated independently. FIG. 3A to FIG. 3B , shows a detailed embodiment of a PAI system 200 with different throttle valves. Alternatively, a single actuation mechanism can control the opening and closing of both the first throttle valve 162 and the second throttle valve 196 in unison. In yet another embodiment, as shown in reference FIG. 4A to FIG. 4B As described in detail, the air flow from the first path 204 and the second path 206 to the engine can be controlled by a single diverter valve arranged in the intake plenum 146, in the merging area 226 of the bypass conduit 216 and the second branch 224 of the second path 206. In this arrangement, the air delivered via the first path and / or the second path is simultaneously controlled by a single valve having a size optimized for the geometry at the merging area 226 of the intake plenum 146. The use of a throttle valve ( FIG. 3A to FIG. 3B ) and diverter valves ( FIG. 4A to FIG. 4B ) an embodiment of directing airflow to an engine.

[0053] exist FIG. 3A to FIG. 3BPAI systems (such as Figure 2 A first embodiment 300 of the PAI system 200 of the present invention is shown. A set of reference axes 304 is provided for comparison between views, indicating that "z" is the lateral direction, "x" is the horizontal direction, and "y" is the vertical direction. Figure 3A A top view 350 of the first embodiment 300 of the PAI system 200 is depicted. The first path and the second path, reference Figure 2 The first path 204 and the second path 206 are cut off upstream of the first throttle valve 162 along the line AA' and upstream of the second throttle valve 196 along the line BB' to provide Figure 3A View shown. Reference Figure 2 , the first throttle valve 162 is coupled to the downstream end of the bypass conduit 216 of the first path 204, and the second throttle valve 196 is coupled to the downstream end of the second branch 224 of the second path 206. The bypass conduit 216 and the second branch 224 merge into the intake boost chamber 146 at the merging area 226. The intake boost chamber 146 is connected to a vehicle (such as Figure 1 The intake manifold 302 of the vehicle 5).

[0054] The bypass duct 216 and the second branch 224 merge so that the merging area 226 is Y-shaped. The air flowing into the intake manifold 302 from the first bypass duct 216 or the second branch 224, or both, is directed into the merging passage 303 (e.g., the stem of the Y) of the intake plenum 146 before entering the engine intake manifold 302. When ambient air enters the intake plenum 146 from the bypass duct 216 and the charge air enters via the second branch 224, the two types of air mix in the merging passage 303 of the intake plenum 146 and then flow to the engine intake manifold 302. In this way, the air entering the engine intake manifold 302 can have a temperature and pressure determined by the proportional mixing of the warmer ambient air and the cooler charge air.

[0055] from Figure 3BThe depicted view 360 of the first throttle 162 and the second throttle 196 taken in the direction of the second branch 224 of the second path 206 shows that the first throttle 162 and the second throttle 196 can block airflow by extending the first sealing wall 317 completely across the first opening 316 in the first throttle 162. Similarly, the flow through the second throttle 196 can be blocked by extending the second sealing wall 319 completely across the second opening 318. The first sealing wall 317 and the second sealing wall 319 can be adjustable so that the first opening 316 and the second opening 318, respectively, can be partially open. For example, the first sealing wall 317 can extend a portion across the first opening 316 in the first throttle 162, and similarly, the second sealing wall 319 can extend a portion across the second opening 318 of the second throttle 196, wherein the portion can include 1% to 99% of the area of ​​the first opening 316 and the second opening 318. In other words, the first opening 316 of the first throttle valve 162 and the second opening 318 of the second throttle valve 196 may be reduced from a fully open position such that the first sealing wall 317 does not extend completely across the first opening 316 and the second sealing wall 319 does not extend completely across the second opening 318 .

[0056] Based on engine speed and operation, a signal may be sent from the controller to each of the first throttle valve 162 and the second throttle valve 196 to adjust the first opening 316 and the second opening 318, respectively. During low engine speeds and operating loads, the first throttle valve 162 is actuated to an open (e.g., fully open) position, while the second throttle valve 196 is simultaneously actuated to a closed (e.g., fully closed) position, so that fresh air may be delivered via the first path 204. Conversely, during high engine speeds and heavy operating loads, the first throttle valve 162 may be fully closed, while the second throttle valve 196 is fully opened, so that cooled charge air may be delivered only via the second path 206. In addition, detection of a tip-out may result in a fully open or partially open position of the first throttle valve 162, while the second throttle valve is fully closed. After a tip-out and independent of torque demand, if a time or temperature threshold calculated for the stored charge air is exceeded, the charge air is discharged from the reservoir. Among them, when the second throttle valve 196 is simultaneously actuated to at least a partially open position, the first throttle valve 162 may receive a signal to fully close or reduce the first opening 316. Therefore, air from the first path 204 and the second path 206 are delivered to the merging passage 303 of the intake boost chamber 146 and mixed in the merging passage 303 before flowing to the engine intake manifold 302.

[0057] As discussed above, air flow in the PAI system may be controlled by a pair of throttle valves, one each disposed in each of the first path and the second path, or a diverter valve. FIG. 4A to FIG. 4B A second embodiment of a PAI system 400 is shown in FIG. Only the intake plenum 440 is depicted, which may be Figure 1 401 to the intake plenum 440. The intake plenum 440 has a first conduit 450 that can be coupled to a first path of the PAI system 400 that flows ambient air, and a second conduit 452 that can be coupled to a second path that delivers cooled charge air. Air can enter each of the first conduit 450 and the second conduit 452 in the direction indicated by arrows 410 and exit the intake plenum 440 through a single channel 403 into which the first conduit 450 and the second conduit 452 merge. The single channel 403 can direct the airflow into the engine intake manifold, such as Figure 2 The engine intake manifold 202 is provided.

[0058] exist Figure 4A Intake plenum chamber 440 is viewed from above, and Figure 4B A cross section of the inlet chamber 440 is shown in FIG. 4 along a plane formed by the "z" lateral direction and the "x" horizontal direction. FIG. 4A to FIG. 4B In the embodiment, a single diverter valve 401 is used instead FIG. 3A to FIG. 3B The first throttle valve 162 and the second throttle valve 196. FIG. 3A to FIG. 3B In contrast to the separate mechanisms and controls of the illustrated exemplary PAI system 200 , the diverter valve 401 may provide a single mechanism for regulating flow through each of the first and second pathways of the PAI system 400 .

[0059] The diverter valve 401 divides the flow between the first conduit 450 and the second conduit 452 of the intake plenum 440, thereby acting as a replacement for two separate adjustable bodies (eg, FIG. 3A to FIG. 3B The diverter valve 401 may be a single proportional valve that is configured to control the flow of the first throttle valve 162 and the second throttle valve 196. Based on the position of the valve, the diverter valve 401 may enable flow only through the first conduit 450, flow only through the second conduit 452, or flow from a combination of the first conduit 450 and the second conduit 452. The flow from each of the first conduit 450 and the second conduit 452 relative to each other may be controlled by an actuator 402 of the diverter valve 401 based on a command signal received from an engine controller.

[0060] The outer portion 420 of the diverter valve 401 (eg, the portion located outside the intake plenum 440) may include a controller (eg, Figure 1The controller 12) of the actuator 402 in electronic communication with the arm 404. The actuator 402 can be arranged adjacent to the single channel 403 into which the first conduit 450 and the second conduit 452 merge. The actuator 402 is connected to the arm 404 at the first end 409 of the actuator 402, which is located upstream of the second end 411. The actuator 402 receives a signal that can be converted into movement of the arm 404.

[0061] The arm 404 extends across the second conduit 452 in a direction perpendicular to the air flow (as indicated by arrow 410) and can be fixed to the wall of the intake plenum 440 via a pin 414 in a saddle 412 where the first conduit 450 and the second conduit 452 converge. The pin 414 extends through the wall 418 of the intake plenum 440. The arm 404 includes a plurality of sections 406 connected by a hinge 408, and the plurality of sections 406 can pivot about the hinge 408. The pivoting of the plurality of sections 406 of the arm 404 can rotate a V-shaped flow divider 416 disposed inside the intake plenum 440, as shown in FIG. Figure 4B shown.

[0062] The V-shaped flow splitter 416 has a first wing 415 with a first center axis 405 located in the first conduit 450, and a second wing 417 with a second center axis 407 located in the second conduit 452. The first center axis 405 is arranged perpendicular to the second center axis 407. The first wing 415 and the second wing 417 can be connected to each other at a pivot point defined by the position of the pin 414. The pin 414 extending through the wall 418 can connect with the V-shaped flow splitter 416 at a pivot point in the intake boost chamber 146, thereby fixing the valve 416 to the saddle 412 at the V-shaped pivot point. Rotation of the pin 414 can also cause the V-shaped flow splitter 416 to rotate through the arm 404.

[0063] The first wing 415 and the second wing 417 may be at a fixed angle 419 relative to each other. The fixed angle 419 may be greater than 90 degrees or less than 90 degrees, but not 90 degrees, so as to allow more airflow to reach the engine manifold through the first duct 450 rather than the second duct 452 or more airflow to reach the engine manifold through the second duct 452 rather than the first duct 450 by pivoting the V-shaped splitter 416 via the pin 414. When the first wing 415 or the second wing 417 is arranged at 90 degrees within the first duct 450 and the second duct 452, respectively, the ducts are sealed.

[0064] As an example, during conditions where more airflow is desired through the first duct 450 rather than the second duct 452, such as at low loads, the V-shaped splitter 416 may be pivoted so that the second flap 417 is at a slightly greater or lesser angle than perpendicular to the second central axis 407. The smaller opening in the second duct 452 due to the nearly vertical positioning of the second flap 417 (compared to the first flap 415 which is more offset from perpendicular) allows more airflow through the first duct 450 rather than the second duct 452. In another example, if airflow is desired only through the first duct 450, adjusting the V-shaped splitter 416 so that the second flap 417 is perpendicular to the second central axis 407 may completely close the second duct 452 while allowing the first flap 415 to remain open, thereby enabling airflow only through the first duct 450. To enable more airflow through the second duct 452 than through the first duct 450 during higher engine loads and speeds, the V-shaped splitter 416 may be pivoted so that the first flap is at a slightly greater or lesser angle than perpendicular to the first central axis 405. This results in a larger opening in the second duct 452 than in the first duct 450. For flow from only the second duct 452, the V-shaped splitter 416 may be adjusted so that the first flap 415 is perpendicular to the first central axis 405. Thus, the first duct 450 is closed and air is delivered to the intake plenum 440 through the second duct 452.

[0065] Now go to Figure 5 , describing an exemplary routine 500 for providing ambient air or cooled charge air to an engine. In response to an increase in torque demand and engine operation in a higher engine speed load region (such as after an operator tip-in event), charge air may be exhausted from a reservoir of the PAI system, thereby requesting additional engine torque and / or an accelerator pedal release (e.g., releasing the pedal). By adjusting airflow from a first path and / or a second path of the PAI system, cooled charge air may be stored in the PAI system and supplied to the engine as needed. Instructions for executing method 500 and the remaining methods included herein may be executed by a controller based on instructions stored on a memory of the controller and in combination with information from sensors of the engine system (such as those described above with reference to FIG. 1 ). Figure 1 According to the method described below, the controller may use engine actuators of the engine system to adjust engine operation.

[0066] At 502, operating conditions of the engine may be estimated and / or measured. These operating conditions may include, for example, engine speed and load, torque demand, engine coolant temperature, barometric pressure, ambient humidity, ambient temperature, MAP, MAF, etc. At 504, it may be determined whether the operator torque demand has increased. For example, it may be determined whether a tip-in is detected. In one example, an accelerator pedal depression may be measured via a pedal position sensor. If a tip-in is not detected, then at 506, the method includes operating at nominal settings based on the estimated engine parameters.

[0067] In one example, with the engine operating at a low to medium speed load, operating under nominal conditions includes supplying fresh air at ambient temperature, pressure, and humidity to the engine cylinders via a first path of the PAI system while keeping a second path including a compressor and a CAC closed. This includes opening the first path by actuating a first throttle valve disposed in the first path proximate to an intake plenum chamber coupled to an intake manifold of the engine to a fully open position or a partially open position. Partially opening the first throttle valve may include adjusting the opening of the first throttle valve to a certain percentage of the opening when fully open. For example, the opening of the partially opened first throttle valve may be 20%, 50%, 70%, or a percentage between 1% and 99% of the opening of the first throttle valve when the first throttle valve is fully open.

[0068] If the accelerator pedal is detected, the method proceeds to 508, where the controller may send a signal to reduce the flow through the first path and increase the flow through the second path of the PAI system so that a larger portion of the air delivered to the engine intake is cooled boost air. The program includes directing ambient air from the intake passage through the compressor of the turbocharger, and then cooling the air through the CAC so that the air is cooled and compressed when it reaches the engine intake. In an example where the PAI system has a first throttle valve connected to the first path and a second throttle valve connected to the second path, directing a larger portion of the air to the engine as boost air includes opening the second throttle valve and closing the first throttle valve. As inferred from the pedal position, the degree of opening of the second throttle valve is based on the amount of torque requested. The more the pedal is depressed, the greater the torque required, resulting in a higher degree of opening of the second throttle valve. When the pedal is slightly depressed, the second throttle valve may open a smaller amount, or when the pedal is depressed to the maximum, the second throttle valve may be fully opened. While the second valve is opening, the opening of the first valve is reduced because the input from the pedal indicates an increased demand for charge air. The first valve opening may be reduced to an extent proportional to the amount the second valve is opened, or the first valve may be completely closed to avoid potential changes in the pressure and / or temperature of the charge air due to mixing with ambient air.

[0069] In another example, the PAI system has a diverter valve disposed in an area where the first path and the second path merge with a first flap disposed in the first path and a second flap disposed in the second path, and operation under nominal conditions at 506 as described above includes adjusting the diverter valve so that the second flap is perpendicular to the flow path in the second path. Thus, the second path is closed and the first path is opened, thereby delivering ambient air to the engine via the first path of the PAI system.

[0070] In the case of stepping on the accelerator pedal, the method at 508 directs a larger portion of the air to the engine as charge air. The diverter valve can be tilted so that the second wing forms an opening in the second path, which is larger than the opening formed by the first wing in the first path. The angle of the diverter valve is based on the requested torque amount obtained by sensing the pedal position, for example. The more the pedal is pressed, the greater the torque required, resulting in the adjustment of the diverter valve so that the first wing is closer to vertical than the second valve in the first path. The closer the first wing is to vertical, the smaller the opening in the first path is relative to the opening in the second path. If it is detected that the pedal position is slightly depressed, the diverter valve can be tilted so that the first wing is slightly closer to vertical in the first path than the second wing in the second path. As a result, a smaller opening is formed in the first path than in the second path. If the pedal is pressed to the maximum position, the first wing can be precisely positioned vertically so that the first path is blocked, and the air delivered to the engine is entirely from the air in the second path.

[0071] At 510, the air is taken from the intake passage (such as Figure 2 Air is drawn into the intake passage 142 of the PAI system, pressurized by the compressor, and then cooled as it passes through the CAC. At 512, the method may determine whether a tip-out is detected, for example, whether the accelerator pedal is released as inferred by a pedal position sensor. If a tip-out is not detected, engine operation continues to 514, where the second path is opened and the first path is closed while the torque demand remains elevated. If a tip-out is detected, the method proceeds to 516, where the controller may send a signal to increase flow through the first path and decrease flow through the second path of the PAI system so that a larger portion of the air delivered to the engine intake is ambient air.

[0072] In an example where the PAI system has a first throttle valve coupled to a first path and a second throttle valve coupled to a second path, directing a larger portion of air to the engine as ambient air includes opening the first throttle valve and closing the second throttle valve. The degree of opening of the first throttle valve and closing of the second throttle valve is based on torque demand. The more the pedal is released (e.g., the less it is pressed), the lower the torque demand is, resulting in a further reduction in the opening of the second throttle valve. The lower torque demand (as inferred by the pedal position) and the resulting reduction in the opening of the second throttle valve result in an increase in the opening of the first throttle valve. When the pedal is fully released, the first throttle valve may be fully opened, while the second throttle valve is fully closed.

[0073] In another example of a PAI system having a diverter valve, the diverter valve is arranged in a region where the first path and the second path merge with a first wing plate arranged in the first path and a second wing plate arranged in the second path. At 516, the diverter valve can be tilted so that the first wing plate forms an opening in the first path, and the opening is larger than the opening formed by the second wing plate in the second path. The angle of the diverter valve is based on the increase of torque demand inferred by the pedal position. The less the pedal is pressed, the smaller the torque required, resulting in the adjustment of the diverter valve so that the second wing plate is closer to vertical than the first valve in the second path. The closer the second wing plate is to vertical, the smaller the opening in the second path is relative to the opening in the first path. If the pedal is released to, for example, an incompletely depressed position, the diverter valve can be tilted so that the second wing plate is slightly closer to vertical than the first wing plate in the first path in the second path. As a result, a smaller opening is formed in the second path than in the first path. If the pedal is fully released, the second wing plate can be precisely positioned vertically so that the second path is blocked, and the air delivered to the engine is completely ambient air from the first path.

[0074] At 518, ambient air flows to the engine intake at atmospheric pressure, thereby bypassing the compressor and CAC. As ambient air is drawn into the engine, flow through the second path is blocked by closing the second flap of the second throttle or diverter valve. At 519, air contained within the second path is trapped by a PRV located at the upstream end (such as a Figure 2 The second path is closed between the PRV 164 and a second throttle or second flap at the downstream end of the second path. In the closed second path, the air trapped upstream of the CAC may be pressurized and brought to ambient temperature, and the air trapped downstream of the CAC may be pressurized and cooled. At 520, the state of the charge air stored in the second path is estimated by inferring the heat transferred to the stored air and calculating the rate of temperature rise.

[0075] For example, data from an intake air humidity sensor and an IAT sensor (such as Figure 2The controller may be configured to estimate the ambient humidity and ambient temperature of the trapped air using data from sensors 230 and 232 of the second path. The data is used to calculate the amount of heat transferred from ambient air outside the second path to the trapped air based on information stored in the controller regarding the conductivity of the material forming the walls of the second path and the temperature difference between the ambient air and the trapped charge air. The temperature of the trapped air may be determined using heat transfer, which is compared to a preset non-zero temperature threshold. The threshold may be a temperature at or above which the boost potential of the trapped air is reduced to the extent that the boost performance of the engine may be degraded if the trapped air is exhausted. In addition to the temperature threshold, a time threshold may also be used to assess the boost potential of the stored air.

[0076] The temperature rise rate of the trapped air can be inferred based on the estimated heat transfer, such as joules / second. The time threshold can be calculated based on a lookup table stored in the memory of the controller, thereby providing a time threshold that varies with ambient conditions and the estimated temperature rise rate. For example, low ambient temperature or low ambient humidity can result in a slower temperature rise rate, a longer time threshold, and a longer time period before the temperature of the trapped air reaches or exceeds the temperature threshold. Conversely, high ambient temperature or high ambient humidity can shorten the time threshold due to a faster expected temperature rise rate. Both the preset temperature threshold and the time threshold can be used to evaluate the state of the pressurized air trapped in the second path of the PAI system.

[0077] At 522 of method 500, the inferred temperature of the stored air and the duration since the second path was closed to trap the charge air may be compared to a preset threshold stored in the memory of the controller. If the estimated temperature is not above the temperature threshold or the duration does not exceed the calculated time threshold, the air is kept trapped in the second path. At 526, the method then determines whether a tip-in is detected. In the event that a tip-in is not detected, the method returns to 520 and the state of the trapped air is evaluated based on ambient temperature and humidity as described above, and then compared to a preset threshold at 522. Alternatively, if a tip-in is detected, the method returns to 508, where the opening of the first path is reduced and the opening of the second path is increased based on the detected pedal position and the inferred torque demand. Ambient air is delivered to the engine while minimizing or blocking the flow of charge air.

[0078] Returning to 522 of method 500, if the heat transfer exceeds the threshold, the method proceeds to 530. At 530, the second path is opened to allow the heated charge air to be discharged to the engine intake manifold. However, in addition to delivering air to the engine intake manifold via the first path, the release of heated charge air may also result in boosting the engine above the desired torque level. Therefore, the controller may send a signal to reduce the flow of ambient air from the first path.

[0079] In one example where the PAI system has a first throttle valve coupled to a first path and a second throttle valve coupled to a second path, opening the second path to exhaust the stored pressurized air includes opening the second throttle valve and closing the first throttle valve. The degree of opening of the second throttle valve and closing of the first throttle valve is based on the amount of torque requested as inferred from the pedal position. For example, if the pedal is slightly depressed, the first throttle valve may be completely closed and the second throttle valve may be partially opened to prevent the engine from becoming overloaded. If the pedal is not fully depressed, the opening of the first throttle valve may be reduced but still partially open, while the second throttle valve is partially opened to exhaust the stored air.

[0080] In another example of a PAI system having a diverter valve, the diverter valve is disposed in an area where a first path and a second path merge with a first wing disposed in the first path and a second wing disposed in the second path, and opening the second path to discharge the stored pressurized air includes tilting the diverter valve so that an opening formed by the second wing in the second path is increased while reducing an opening formed by the first wing in the first path. The angle of the diverter valve is based on the amount of torque requested as inferred from the pedal position. For example, if the pedal is slightly depressed, the diverter valve may be tilted so that the opening in the second path is smaller than the first path. If the pedal is not fully depressed, the diverter valve may be adjusted so that the openings in the first path and the second path are approximately equal.

[0081] If reducing flow from the first path is insufficient to compensate for the boost provided by the heated charge air, then at 532, one or more engine actuators may be adjusted. If a torque transient is anticipated, other engine operating parameters may also be changed. For example, spark timing may be retarded, fuel injection and valve timing may be changed, or the ratio of fuel delivered via direct injection to port injection may be adjusted. By changing engine operation in response to excess boost relative to engine load, misfires at multiple cylinders of the engine may be avoided.

[0082] In one example, the degree to which the spark timing is retarded is based on the difference between the amount of torque requested and the amount of torque supplied. When the heated boost air is discharged to the engine through the second path, the flow from the first path is reduced, and the boost air can still provide the engine with a boost pressure that exceeds the requested amount inferred by the pedal position. Therefore, the spark can be retarded from the maximum brake torque (MBT) to avoid engine knock. For example, the greater the difference between the requested boost and the provided boost (where the provided boost is too high), the longer the spark timing can be retarded in order to allow the pressure in the combustion chamber of the engine to dissipate a certain amount before ignition. In other words, the more the opening of the second path increases during the discharge of the heated stored air, the more the spark timing is retarded from MBT. When the torque supply is reduced to match the torque demand, the spark timing returns to MBT.

[0083] After adjusting the engine operating parameters, the method returns to 526 to determine whether a tip-in is detected. If a tip-in is not detected, the method returns to 520 and the state of the trapped air is evaluated based on ambient temperature and humidity as described above, and then compared with a preset threshold at 522. Alternatively, if a tip-in is detected, the method returns to 508, where the opening of the first path is reduced and the opening of the second path is increased based on the detected pedal position and the inferred torque demand. Ambient air is delivered to the engine while minimizing or blocking the boost air flow. Therefore, after initial startup, by exhausting the stored boost air through the second path and reducing the flow through the first path, boost air can be easily supplied to the engine when a tip-in is detected. In the event of a tip-in, the second path is bypassed, thereby providing a shortened ambient air delivery path to the engine, thereby avoiding unnecessary use of boost air. During a tip-in, if the temperature of the stored air exceeds a temperature threshold or a time period that exceeds a time threshold has passed, making the stored air less effective in providing boost, the stored air is released.

[0084] Reference Figure 6 Discuss the PAI system (ref. FIG. 3A to FIG. 3B Example operation of the PAI system). Figure 7 Shown is suitable for FIG. 4A to FIG. 4B An example of a PAI system with a diverter valve is shown. Based on a request for engine torque and heat exchange with charge air stored in the PAI system, airflow through a first path supplying fresh air and a second path supplying charge air is adjusted.

[0085] Figure 6An exemplary operation of a PAI system adapted with a first throttle valve and a second throttle valve is shown, wherein the first throttle valve controls the fresh air flow and the second throttle valve controls the boost air flow. As described in detail in the mapping diagram 600, the detection of the accelerator pedal being pressed or released by the pedal position is depicted at curve 602. The opening and closing of the first throttle valve and the second throttle valve are respectively shown at curve 604 and curve 606. The temperature of the boost air in the second path is shown at curve 608, and the boost pressure of the air supplied to the engine intake is shown at curve 610. The spark timing that varies according to the operating conditions shown is depicted at curve 612.

[0086] Prior to t1, the engine is operating at a low speed with the first throttle valve open, thereby enabling fresh air flow to the engine through the first path. The second throttle valve is closed, thereby blocking flow from the second path into the engine, because boost air is not required, the CAC is not operating, and the air temperature in the second path is close to ambient temperature and above a preset non-zero temperature threshold 609. As a result of the low torque demand, boost pressure is also low and spark timing is at or near MBT.

[0087] At t1, a tip-in is detected as indicated by depression of the accelerator pedal. The tip-in activates an adjustment of the airflow to the engine: the first throttle valve is fully closed, and the second throttle valve is fully opened. As the air flows through the second path, the air is continuously cooled, resulting in a gradual decrease in the air temperature of the second path. The boost pressure in the second path is increased to meet the request for increased torque, while the spark timing is maintained at MBT.

[0088] At t2, a tip-out detected by reduced pedal depression occurs. In response to the tip-out, the first throttle is opened and the second throttle is closed, thereby alternately supplying air to the engine to flow fresh air rather than boost air. Due to the closure of the second throttle, the boost air is stored in the second path. Between t2 and t3, the stored air gradually heats up due to heat transfer between the ambient air around the second path and the air stored in the second path. When the temperature of the second path exceeds a temperature threshold 609, the boost pressure of the stored air remains relatively constant until t3. The threshold may be a value above which the boost provided by the air is degraded. In addition, a time threshold may elapse to t3, which is based on a temperature rise rate calculated based on the inferred heat transfer, and determines when the temperature of the stored air exceeds the temperature threshold 609. In response to detecting that the above temperature and time thresholds are exceeded, a gradual adjustment of the opening of the second throttle is performed. The opening of the second throttle increases the airflow to the engine, resulting in an undesirable increase in torque. Thus, the first throttle is adjusted such that its opening is less correlated to the opening of the second throttle. However, the charge air in the second path is pressurized so that more air can flow out of the second path with each incremental opening of the second throttle compared to an equivalent incremental closing of the first throttle. Thus, as shown by curves 604 and 606 in the map 600, each opening step of the second throttle is accompanied by a larger step of the first throttle to accommodate the different densities of fresh air and charge air. As an example, for every 5% opening of the second throttle, the first throttle is closed by an estimated 15%.

[0089] Adjustments to the first throttle and the second throttle may not be able to fully compensate for the increase in airflow to the engine via the second path. Therefore, torque transients may occur in the event of excessive torque being produced. To address this issue, one or more engine operating parameters may be adjusted. For example, the spark timing may be retarded from MBT. At t3, as the second throttle opening increases, the spark ignition timing is retarded more from MBT. As the boost air is released from the second path to the engine while the air temperature in the second path remains relatively constant and above the temperature threshold 609, a simultaneous decrease in boost pressure is observed.

[0090] At t4, a second tip-in is detected, and the first throttle is closed when the second throttle is open. As air flows through the compressor and CAC operation in the second path is enabled, the air is cooled and the temperature of the charge air in the second path is reduced to below threshold 609. The boost pressure at t4 is lower than the boost pressure after the first tip-in between t2 and t3, but higher than the boost pressure for the initial period up to t1. The distance between the dashed line of t1 and the dashed line of t2 indicates the time, or turbo lag, for the boost pressure to increase from the pre-tip-in pressure at t1 to the maximum boost pressure at t2. Similarly, the distance between the dashed line of t4 and the dashed line of t5 indicates the turbo lag before the boost pressure increases to the maximum boost pressure after the tip-in at t4. The turbo lag after the second tip-in at t4 is shorter than the turbo lag after the first tip-in at t1. This indicates that by keeping the boost air from the reservoir stored in the second path of the PAI system, a quicker increase to maximum boost pressure is possible.After t4, the spark timing returns to MBT as the air supply to the engine is now appropriate relative to the torque demand.

[0091] exist Figure 7 , a device for adapting a diverter valve (such as Figure 1 The PAI system of the diverter valve 401 is similar to Figure 6 A set of operations described. The detection of stepping on the accelerator pedal or releasing the accelerator pedal by the pedal position is depicted at curve 702. The position of the V-shaped valve of the diverter valve is shown at curve 704. The V-shaped valve can be pivoted to allow more ambient air from the first path to be delivered to the engine rather than the pressurized air from the second path, or the V-shaped valve can be adjusted to allow more pressurized air to be delivered rather than ambient air. The intermediate position where the airflow to the engine includes equal amounts of ambient air from the first path and pressurized air from the second path is represented by the short dashed line 705. The V-shaped valve can also be positioned so that air flows only from the first path or the second path. The temperature of the pressurized air in the second path is shown at curve 706, and the pressure of the pressurized air supplied to the engine intake is shown at curve 708. The spark timing that changes according to the operating conditions shown is depicted at curve 710.

[0092] Prior to t1, the engine is operating at low speed with the diverter valve tilted so that the first flap forms an opening in the first path, thereby enabling fresh air flow to reach the engine through the first path. The second flap of the diverter valve is positioned vertically in the second path, thereby blocking flow from the second path into the engine because boost air is not required. The CAC is not operating and the air temperature in the second path is close to ambient temperature and above a preset non-zero temperature threshold 709. As a result of the low torque demand, boost pressure is also low and spark timing is at or near MBT.

[0093] At t1, a tip-in is detected as indicated by depression of the accelerator pedal. The tip-in activates an adjustment of the airflow to the engine: the first flap is made vertical, thereby blocking the flow through the first path, and the second path is opened. As the air flows through the second path, the air is continuously cooled, resulting in a gradual decrease in the air temperature of the second path. The boost pressure in the second path is increased to meet the request for increased torque, while the spark timing is maintained at MBT.

[0094] At t2, a tip-out detected by reduced pedal depression occurs. In response to a tip-out, the diverter valve tilts so that the first path is opened and the second path is closed, thereby alternately supplying air to the engine to flow fresh air rather than boost air. Due to the closure of the second path, the boost air is stored in the second path. Between t2 and t3, the stored air gradually heats up due to heat transfer between the ambient air around the second path and the air stored in the second path. When the temperature of the second path exceeds the temperature threshold 709, the boost pressure of the stored air remains relatively constant until t3.

[0095] The threshold may be a value above which the boost provided by the air is degraded. Additionally, a time threshold may elapse to t3, which is based on a temperature rise rate calculated from the inferred heat transfer, and determines when the temperature of the stored air exceeds a temperature threshold 709. In response to detecting that the temperature and time thresholds are exceeded, a gradual adjustment of the position of the diverter valve is performed. When the flow through the first path decreases, the opening of the second path increases, resulting in an undesirable increase in torque. Therefore, the diverter valve is adjusted so that the opening in the first path is larger than the opening in the second path in order to regulate the amount of additional air delivered to the engine. For example, the diverter valve may be tilted so that 80% of the airflow reaching the engine is ambient air from the first path, and 20% of the airflow is boost air from the second path. As shown by curves 704 and 706 in the map 700, the diverter valve position is biased toward the first path immediately after t3 and gradually adjusted toward an intermediate position indicated by a dashed line 705 until t4, where the first path is slightly more open than the second path.

[0096] Adjustment of the diverter valve may not be able to fully compensate for the increase in airflow to the engine via the second path. Therefore, torque transients may occur where excessive torque is produced. To address this issue, one or more engine operating parameters may be adjusted. For example, the spark timing may be retarded from MBT. At t3, as the flow through the second path increases, the spark timing is retarded more from MBT. As the charge air is released from the second path to the engine while the air temperature in the second path remains relatively constant and above the temperature threshold 609, a simultaneous decrease in boost pressure is observed.

[0097] At t4, a second tip-in is detected, and the diverter valve is tilted so that the first path is closed when the second path is open. When air flows through the compressor and CAC operation in the second path is enabled, the air is cooled and the temperature of the charge air in the second path is reduced to below the threshold 709. The boost pressure at t4 is lower than the boost pressure after the first tip-in between t2 and t3, but higher than the boost pressure for the initial period up to t1. The distance between the dashed line of t1 and the dashed line of t2 indicates the time, or turbo lag, for the boost pressure to increase from the pre-tip-in pressure at t1 to the maximum boost pressure at t2. Similarly, the distance between the dashed line of t4 and the dashed line of t5 indicates the turbo lag before the boost pressure increases to the maximum boost pressure after the tip-in at t4. The turbo lag after the second tip-in at t4 is shorter than the turbo lag after the first tip-in at t1. This indicates that by keeping the boost air from the reservoir stored in the second path of the PAI system, a quicker increase to maximum boost pressure is possible.After t4, the spark timing returns to MBT as the air supply to the engine is now appropriate relative to the torque demand.

[0098] In this way, boost air can be stored in the PAI system so that boost is readily available during periods of increased engine load. By discharging the stored air while the compressor is accelerating during a tip-in, turbo lag is reduced. By including an air path that bypasses the compressor and CAC, ambient air can be quickly provided to the engine at low loads. In addition, the stored air can be discharged when it is heated above a threshold but has a lower boost capacity. A technical effect of coupling the PAI system to the engine is that turbo lag is minimized when higher engine torque is requested by maintaining a cooled boost air supply in the duct.

[0099] As an embodiment, a supercharged engine method includes: at a higher engine load, drawing cooled compressed air into the engine via an intake passage; at a lower engine load, drawing ambient air into the engine via a duct while maintaining the cooled compressed air in the intake passage; and releasing the compressed air from the intake passage based on the amount of heat transferred to the compressed air during the lower engine load. In a first example of the supercharged engine method, the amount of heat transferred to the compressed air maintained in the intake passage is estimated based on ambient conditions including ambient temperature and humidity, the amount of heat transferred increasing with increasing ambient temperature and / or increasing with decreasing ambient humidity. A second example of the supercharged engine method optionally includes the first example and further includes: wherein maintaining the cooled compressed air includes closing a throttle valve connected in the intake passage downstream of an intake compressor, and wherein the amount of heat transferred is determined based on an initial temperature of the cooled compressed air and a duration of time since the throttle valve was closed. The third example of the supercharged engine method optionally includes one or more of the first example and the second example, and further includes: wherein the compressed air is released in response to heat transfer above a threshold value at the lower engine load. The fourth example of the supercharged engine method optionally includes the first example to the third example, and further includes: in response to heat transfer below a threshold value at the lower engine load, the compressed air is released in response to an increase in operator torque demand. The fifth example of the supercharged engine method optionally includes the first example to the fourth example, and further includes: wherein the intake passage is coupled to the conduit at a position upstream of an intake compressor. The sixth example of the supercharged engine method optionally includes the first example to the fifth example, and further includes: wherein drawing cooled compressed air at the higher engine load includes increasing an opening of a boost throttle coupled in the intake passage so as to draw air via the intake compressor and allow it to enter the engine through a charge air cooler located downstream of the compressor, and wherein maintaining cooled compressed air in the intake passage at the lower engine load includes not allowing air to flow through the compressor and closing the boost throttle. A seventh example of the boosted engine method optionally includes the first to sixth examples, and further includes: reducing an opening of an air throttle coupled to the duct at the higher engine load, wherein reducing the opening of the air throttle is based on increasing the opening of the boost throttle.The eighth example of the supercharged engine method optionally includes the first to seventh examples, and further includes: wherein releasing the compressed air includes: increasing the opening of the boost throttle when at the lower engine load; reducing the opening of the air throttle based on the opening of the boost throttle; and retarding spark timing based on the engine torque increased by the opening of the boost throttle relative to the operator torque demand at the lower engine load. The ninth example of the supercharged engine method optionally includes the first to eighth examples, and further includes: wherein coolant is circulated through the charge air cooler while the cooled compressed air is drawn into the engine via the intake passage, and wherein coolant is not circulated through the charge air cooler while the compressed air is maintained in the intake passage.

[0100] As an embodiment, a method for supercharging an engine includes: in response to a tip-in, increasing a boost throttle opening to draw cooled compressed air into the engine from downstream of a charge air cooler (CAC) via a boost passage; in response to a tip-out, increasing an air throttle opening to draw ambient air into the engine from upstream of the CAC via an air passage while maintaining the compressed air in the boost passage; and opening the boost throttle after the tip-out based on heat transfer to the compressed air in the conduit relative to an operator torque demand. In a first example of the supercharging engine method, opening the boost throttle after the tip-out includes: opening the boost throttle in response to heat transfer to the compressed air in the conduit being above a threshold amount when the operator torque demand is below a threshold demand; and opening the boost throttle in response to an increase in the operator torque demand above the threshold demand when the heat transfer to the compressed air in the conduit is below the threshold amount. A second example of the supercharged engine method optionally includes the first example and further includes: in response to opening the boost throttle when the operator torque demand is below the threshold demand, adjusting one or more engine operating parameters to reduce engine torque output, the adjustment including retarding spark timing, adjusting fuel injection timing, adjusting valve timing, and adjusting the split ratio of fuel delivered via direct injection relative to port injection. A third example of the supercharged engine method optionally includes one or more of the first example and the second example, and further includes: wherein the boost passage includes a pressure relief valve located upstream of the compressor, the boost passage is coupled to an air passage located upstream of the pressure relief valve, increasing the boost throttle opening includes reducing the air throttle opening, and increasing the air throttle opening includes reducing the boost throttle opening. A fourth example of the supercharged engine method optionally includes the first example to the third example, and further includes: estimating the heat transfer to the compressed air based on each of an ambient temperature and an ambient humidity, the heat transfer increasing with increasing ambient temperature and decreasing ambient humidity.As one embodiment, a supercharged engine system includes: an engine; a first intake passage, the first intake passage is connected to the engine via a first throttle; a second intake passage, the second intake passage accommodating a pressure relief valve, a compressor located downstream of the valve, and a charge air cooler located downstream of the compressor, the second intake passage is connected to the engine via a second throttle, the first intake passage is connected to the second intake passage upstream of the pressure relief valve; an ambient temperature sensor and an ambient humidity sensor, the ambient temperature sensor and the ambient humidity sensor are connected to the first intake passage; an accelerator pedal, the accelerator pedal is used to receive an operator torque demand; and a controller, the controller having computer-readable instructions stored on a non-transitory memory, the computer-readable instructions are used to: adjust the opening of the first throttle relative to the second throttle based on the operator torque demand; and when operating with the second throttle fully closed, adjust the timing of opening the second throttle based on the temperature rise rate of the compressed air trapped in the second intake passage. In the first example of the boosted engine system, the adjusting the opening of the first throttle relative to the second throttle includes: when the operator torque demand exceeds a threshold demand, increasing the opening of the second throttle relative to the first throttle; and when the operator torque demand drops below the threshold demand, increasing the opening of the first throttle relative to the second throttle and retaining a certain amount of air in the second intake passage. A second example of the boosted engine method optionally includes the first example and further includes: wherein the controller includes additional instructions, the additional instructions are used to: estimate the temperature rise rate of the compressed air retained in the second intake passage based on each of the following items: measured ambient temperature, measured ambient humidity, initial temperature of the compressed air when the second throttle is fully closed, and the duration elapsed since the second throttle was fully closed, the transferred heat increases with one or more of the following items: the ambient temperature increases, the ambient humidity decreases, the initial temperature increases, and the elapsed duration increases. A third example of the boosted engine system optionally includes one or more of the first example and the second example, and further includes: wherein adjusting the timing of opening the second throttle valve includes: when the operator torque demand is lower than the threshold demand, when the temperature rise rate of the trapped compressed air is higher than a threshold amount, instantaneously opening the second throttle valve to release the trapped compressed air; and when the operator torque demand exceeds the threshold demand, when the temperature rise rate of the trapped compressed air is lower than the threshold amount, opening the second throttle valve while accelerating the compressor.A fourth example of the boosted engine system optionally includes the first to third examples, and further includes: wherein the controller includes additional instructions, the additional instructions being used to: retard the spark timing from MBT while momentarily opening the second throttle; and maintain the spark timing at MBT while opening the second throttle and accelerating the compressor.

[0101] It should be noted that the exemplary control and estimation procedures included herein can be used with various engine and / or vehicle system configurations. The control methods and procedures disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in combination with various sensors, actuators and other engine hardware. The specific procedures described herein may represent one or more of any number of processing strategies (such as event-driven, intermittently driven, multi-tasking, multi-threading, etc.). In this way, the various actions, operations and / or functions shown can be performed in the order shown, can be performed in parallel, or can be omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations and / or functions shown can be repeatedly performed according to the specific strategy used. In addition, the described actions, operations and / or functions can graphically represent the code in the non-transitory memory of the computer-readable storage medium to be programmed into the engine control system, wherein the described actions are performed by executing instructions in a system including various engine hardware components combined with an electronic controller.

[0102] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments should not be considered limiting, as many variations are possible. For example, the above techniques can be applied to V6, inline 4, inline 6, V12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0103] The following claims specifically point out certain combinations and subcombinations that are considered novel and not self-explanatory. These claims may refer to "an" element or a "first" element or the equivalent thereof. Such claims should be understood to include the incorporation of 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 characteristics may be claimed by amending the present claims or by presenting new claims in this or a related application. Such claims are also considered to be included in the subject matter of the present disclosure, whether broader, narrower, the same, or different in scope than the original claims.

[0104] According to the present invention, a supercharged engine method is provided, comprising: at higher engine loads, drawing cooled compressed air into the engine via an intake passage; at lower engine loads, drawing ambient air into the engine via a duct while maintaining the cooled compressed air in the intake passage; and releasing the compressed air from the intake passage based on heat transferred to the compressed air during the lower engine load.

[0105] According to one embodiment, the present invention is further characterized in that the heat transferred to the compressed air maintained in the intake passage is estimated based on environmental conditions including ambient temperature and humidity, and the transferred heat increases with increasing ambient temperature and / or increases with decreasing ambient humidity.

[0106] According to one embodiment, maintaining the cooled compressed air comprises closing a throttle valve coupled in the intake passage downstream of an intake compressor, and wherein the transferred heat is determined based on an initial temperature of the cooled compressed air and a duration elapsed since the throttle valve was closed.

[0107] According to one embodiment, said compressed air is released in response to a heat transfer above a threshold at said lower engine load.

[0108] According to one embodiment, the invention is further characterized by releasing said compressed air in response to an increase in operator torque demand in response to heat transfer below a threshold at said lower engine load.

[0109] According to one embodiment, the intake passage is coupled to the duct at a location upstream of an intake compressor.

[0110] According to one embodiment, drawing in cooled compressed air at the higher engine load comprises increasing an opening of a boost throttle coupled in the intake passage to draw air via the intake compressor and into the engine through a charge air cooler located downstream of the compressor, and wherein maintaining cooled compressed air in the intake passage at the lower engine load comprises not flowing air through the compressor and closing the boost throttle.

[0111] According to one embodiment, the invention is further characterized by reducing the opening of an air throttle valve coupled in said duct at said higher engine load, said reducing said opening of said air throttle valve being based on said increasing said opening of said boost throttle valve.

[0112] According to one embodiment, releasing the compressed air includes: increasing the opening of the boost throttle when at the lower engine load; decreasing the opening of the air throttle based on the opening of the boost throttle; and retarding spark timing based on the engine torque increased by the opening of the boost throttle relative to the operator torque demand at the lower engine load.

[0113] According to one embodiment, coolant is circulated through the charge air cooler while cooled compressed air is drawn into the engine via the intake passage, and wherein coolant is not circulated through the charge air cooler while the compressed air is retained in the intake passage.

[0114] According to the present invention, a method for supercharging an engine is provided, comprising: in response to a tip-in, increasing a boost throttle opening so as to draw cooled compressed air from downstream of a charge air cooler (CAC) into the engine via a boost passage; in response to a tip-out, increasing an air throttle opening so as to draw ambient air from upstream of the CAC into the engine via an air passage while maintaining the compressed air in the boost passage; and opening the boost throttle after the tip-out based on heat transfer to the compressed air in the duct relative to an operator torque demand.

[0115] According to one embodiment, opening the boost throttle after the tip-out includes: opening the boost throttle in response to heat transfer to the compressed air in the conduit being above a threshold amount when the operator torque demand is below a threshold demand; and opening the boost throttle in response to the operator torque demand increasing above the threshold demand when the heat transfer to the compressed air in the conduit is below the threshold amount.

[0116] According to one embodiment, the present invention is further characterized by, in response to opening the boost throttle when the operator torque demand is below the threshold demand, adjusting one or more engine operating parameters to reduce engine torque output, the adjustments including retarding spark timing, adjusting fuel injection timing, adjusting valve timing, and adjusting a split ratio of fuel delivered via direct injection relative to port injection.

[0117] According to one embodiment, the boost passage comprises a pressure relief valve located upstream of the compressor, the boost passage is coupled to an air passage located upstream of the pressure relief valve, increasing the boost throttle opening comprises decreasing the air throttle opening, and increasing the air throttle opening comprises decreasing the boost throttle opening.

[0118] According to one embodiment, the invention is further characterized in that the heat transfer to the compressed air is estimated based on each of an ambient temperature and an ambient humidity, the heat transfer increasing with an increase in the ambient temperature and a decrease in the ambient humidity.

[0119] According to the present invention, a supercharged engine system is provided, which has: an engine; a first intake passage, the first intake passage is connected to the engine via a first throttle valve; a second intake passage, the second intake passage accommodates a pressure relief valve, a compressor located downstream of the valve, and a charge air cooler located downstream of the compressor, the second intake passage is connected to the engine via a second throttle valve, the first intake passage is connected to the second intake passage upstream of the pressure relief valve; an ambient temperature sensor and an ambient humidity sensor, the ambient temperature sensor and the ambient humidity sensor are connected to the first intake passage; an accelerator pedal, the accelerator pedal is used to receive an operator torque demand; and a controller, the controller having computer-readable instructions stored on a non-transitory memory, the computer-readable instructions are used to: adjust the opening of the first throttle valve relative to the second throttle valve based on the operator torque demand; and when operating with the second throttle valve fully closed, adjust the timing of opening the second throttle valve based on the temperature rise rate of the compressed air trapped in the second intake passage.

[0120] According to one embodiment, adjusting the opening of the first throttle valve relative to the second throttle valve includes: when the operator torque demand exceeds a threshold demand, increasing the opening of the second throttle valve relative to the first throttle valve; and when the operator torque demand drops below the threshold demand, increasing the opening of the first throttle valve relative to the second throttle valve and retaining a certain amount of air in the second intake passage.

[0121] According to one embodiment, the controller includes additional instructions for estimating the rate of temperature rise of the compressed air trapped in the second intake passage based on each of the following items: the measured ambient temperature, the measured ambient humidity, the initial temperature of the compressed air when the second throttle valve is fully closed, and the duration elapsed since the second throttle valve was fully closed, the transferred heat increasing with one or more of the following items: the ambient temperature increases, the ambient humidity decreases, the initial temperature increases, and the elapsed duration increases.

[0122] According to one embodiment, adjusting the timing of opening the second throttle valve includes: when the operator torque demand is lower than the threshold demand, when the temperature rise rate of the trapped compressed air is higher than a threshold amount, momentarily opening the second throttle valve to release the trapped compressed air; and when the operator torque demand exceeds the threshold demand, when the temperature rise rate of the trapped compressed air is lower than the threshold amount, opening the second throttle valve while accelerating the compressor.

[0123] According to one embodiment, the controller includes further instructions for: retarding spark timing from MBT while momentarily opening the second throttle valve; and maintaining spark timing at MBT while opening the second throttle valve and accelerating the compressor.

Claims

1. A method for supercharging an engine, comprising: drawing cooled compressed air into the engine via an intake passage at a first engine load greater than a second engine load; at the second engine load that is lower than the first engine load, drawing ambient air into the engine via a duct while maintaining cooled compressed air in the intake passage; as well as The compressed air is released from the intake passage based on an amount of heat transferred to the compressed air exceeding a threshold during the second engine load.

2. The method of claim 1, further comprising: The amount of heat transferred to the compressed air held in the intake passage is estimated based on ambient conditions including ambient temperature and ambient humidity, the amount of heat transferred increasing as the ambient temperature increases and / or increasing as the ambient humidity decreases.

3. The method of claim 1 , wherein maintaining the cooled compressed air comprises closing a throttle valve coupled in the intake passage downstream of an intake compressor, and wherein the amount of heat transferred is determined based on an initial temperature of the cooled compressed air and a duration that has elapsed since the throttle valve was closed. 4 . The method of claim 1 , wherein the compressed air is released in response to heat transfer above a threshold at the second engine load.

5. The method of claim 4, further comprising: In response to heat transfer being below a threshold at the second engine load, the compressed air is released in response to an increase in operator torque demand.

6. The method of claim 1, wherein the intake passage is coupled to the conduit at a location upstream of an intake compressor.

7. The method of claim 6, wherein drawing cooled compressed air at the first engine load includes increasing an opening of a boost throttle coupled in the intake passage to draw air via the intake compressor and into the engine through a charge air cooler located downstream of the intake compressor, and wherein maintaining cooled compressed air in the intake passage at the second engine load includes not flowing air through the intake compressor and closing the boost throttle.

8. The method of claim 7, further comprising: An opening of an air throttle valve coupled to the duct is reduced at the first engine load, the reducing the opening of the air throttle valve being based on increasing the opening of the boost throttle valve.

9. The method of claim 7, wherein releasing the compressed air comprises: increasing an opening of the boost throttle valve at the second engine load; reducing an opening of an air throttle in the duct based on an opening of the boost throttle; as well as Spark timing is retarded based on an opening of the boost throttle relative to the increased engine torque of the operator torque demand at the second engine load.

10. The method of claim 7, wherein coolant is circulated through the charge air cooler while cooled compressed air is drawn into the engine via the intake passage, and wherein coolant is not circulated through the charge air cooler while the compressed air is maintained in the intake passage.

11. A supercharged engine system, comprising: engine; a first intake passage coupled to the engine via a first throttle valve; a second intake passage accommodating a pressure relief valve, a compressor downstream of the valve, and a charge air cooler downstream of the compressor, the second intake passage being coupled to the engine via a second throttle valve, the first intake passage being coupled to the second intake passage upstream of the pressure relief valve; an ambient temperature sensor and an ambient humidity sensor, the ambient temperature sensor and the ambient humidity sensor being coupled to the first intake passage; an accelerator pedal for receiving an operator torque request; as well as A controller having computer readable instructions stored on a non-transitory memory, the computer readable instructions for: adjusting an opening of the first throttle valve relative to the second throttle valve based on the operator torque request; and When operating with the second throttle valve fully closed, the timing of opening the second throttle valve is adjusted based on a rate of increase in temperature of the compressed air stagnating in the second intake passage.

12. The system of claim 11, wherein said adjusting an opening of said first throttle valve relative to said second throttle valve comprises: increasing an opening of the second throttle valve relative to the first throttle valve when the operator torque request exceeds a threshold request; as well as When the operator torque demand drops below the threshold demand, the opening of the first throttle valve is increased relative to the second throttle valve and an amount of air is trapped in the second intake passage.

13. The system of claim 11, wherein the controller includes further instructions for: The rate of temperature rise of the compressed air trapped in the second intake passage is estimated based on each of the following items: the measured ambient temperature, the measured ambient humidity, the initial temperature of the compressed air when the second throttle valve is fully closed, and the duration since the second throttle valve was fully closed, the amount of heat transferred increases with one or more of the following items: the ambient temperature increases, the ambient humidity decreases, the initial temperature increases, and the elapsed duration increases.

14. The system of claim 12, wherein adjusting the timing of opening the second throttle valve comprises: when the operator torque demand is less than the threshold demand, momentarily opening the second throttle valve to release trapped compressed air if the rate of increase in temperature of the trapped compressed air is greater than a threshold amount; as well as When the operator torque demand exceeds the threshold demand, the second throttle valve is opened while accelerating the compressor while the rate of temperature rise of trapped compressed air is less than the threshold amount.

15. The system of claim 14, wherein the controller includes further instructions for: retarding spark timing from MBT while momentarily opening the second throttle valve; and Spark timing is maintained at MBT while opening the second throttle valve and accelerating the compressor.

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