Method and system for operating an engine

Abstract

Methods and systems are described for operating an engine including four compressors for two cylinder groups. In one example, the output of two compressors and the position of a valve are adjusted in response to engine gas flow to prevent backflow of air through the compressors. For higher engine gas flow, the output from the two compressors can be combined.

Description

TECHNICAL FIELD

[0001] The present description relates to a method and system for controlling airflow through an internal combustion engine. The method and system can be implemented via an engine that includes multiple engine intake compression devices.

[0002] BACKGROUND AND SUMMARY

[0003] The engine can include one or more compression devices for each cylinder group. The compression devices can achieve increased engine performance by increasing the amount of air that can enter the engine cylinders. In one example, a first compressor can supply a first amount of air to the engine and a second compressor can supply a second amount of air to the engine. The first amount of air can be equal to the second amount of air, or the first amount of air can be different than the second amount of air. If the first amount of air is different than the second amount of air, then different pressure ratios can be created across the first and second compressors. As a result, air can have the potential to flow backwards through one of the engines, thereby reducing compressor efficiency and engine airflow. Although it can be possible to close loop control each of the two engines so that both compressors provide substantially the same amount of air to the engine, close loop control can be difficult to apply and it can increase system cost more than desired.

[0004] The inventors herein have recognized the above-mentioned shortcomings and have developed a method for operating an engine, the method comprising: adjusting a speed of a third compressor and a position of a valve in response to an engine airflow, the third compressor and the valve being positioned in an intake device of the engine upstream of an engine throttle, the third compressor being positioned in the intake device downstream of a first compressor and a second compressor.

[0005] By adjusting the speed of the third compressor and the position of the valve in the engine intake device, it can be possible to provide the desired airflow to the engine without causing backflow through a compressor that has a lower pressure ratio than the third compressor and is positioned in parallel with the third compressor. For example, at a medium level of engine airflow, all of the air entering the engine can flow through the third compressor, and airflow through a path in the engine intake device that is parallel to the third compressor can stop because the third engine has the capacity to meet the requested boost and engine airflow. As a result, air can not backflow through a fourth compressor that is positioned in the parallel path, thereby avoiding backflow of air in the fourth compressor at the medium level of engine airflow. As such, it can be possible to avoid close loop control of the third compressor and the fourth compressor at the medium engine airflow. If the engine airflow increases to a higher level, then the valve can be opened so that the fourth compressor can further increase the engine airflow, and because the flow rate through the third compressor and the fourth compressor is higher, it can be possible to reduce the likelihood of backflow through one of the third compressor and the fourth compressor.

[0006] The present description can provide several advantages. In particular, the method can simplify compressor control of an engine and improve system response. Additionally, the method can reduce system power consumption when the engine compressor is electrically driven. Moreover, the method can be applied to systems in which the compressor is mechanically or electrically driven.

[0007] The above advantages and other advantages and features of the present description will be apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are understood to represent illustrative embodiments of principles of the present description.

[0008] It should be understood that the foregoing summary is intended merely to introduce some of the concepts of the concepts further described in the DETAILED DESCRIPTION. This summary is not intended to neither identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter to implementations that address any or all of the disadvantages noted in the background section or any part of this disclosure. Furthermore, the claimed subject matter is not limited to implementations that solve any or all of the problems noted in the background section or any part of this disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0009] The advantages described herein will be more fully understood from the following detailed description, taken in conjunction with the Examples (which are referred to herein as the DETAILED DESCRIPTION), when it is read in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a schematic diagram of a first example engine.

[0011] Figure 2 is a schematic diagram of a second example engine.

[0012] Figure 3 and Figure 4 are example methods for controlling airflow through the first and second example engines.

[0013] Figure 5 and Figure 6 are example engine operation sequences according to Figure 3 and Figure 4 the methods. DETAILED DESCRIPTION

[0014] The present description relates to operating an engine that includes multiple compression devices. In one example, the engine includes four compressors for supplying air to an internal combustion engine, as shown in Figure 1 and Figure 2 The engine can also include one or two intake port control valves and a throttle. The compressors can be electrically or mechanically driven. The engine and its associated compressors can be controlled according to the methods described via state machines in Figure 3 and Figure 4 The engine system and compressors can be as shown in Figure 5 andFigure 6 as shown by the sequence of FIGS. 1-4.

[0015] Reference Figure 1 , Figure 1 An internal combustion engine 10 is shown in FIG. 1, which includes a plurality of cylinders 30. The engine 10 is controlled by an electronic engine controller 12. The engine 10 includes a plurality of cylinders, each cylinder including a piston (not shown) positioned therein and connected to a crankshaft (not shown). The engine 10 can be rotated via a starter motor (not shown) to start the engine and begin combustion of air and fuel within the engine 10. The cylinders 30 are shown in pneumatic communication with an intake manifold 44, a left exhaust manifold 48a associated with a first cylinder group 13, and a right exhaust manifold 48b associated with a second cylinder group 14. The cylinders 30 are shown in communication with the intake manifold 44 and the exhaust manifolds 48a and 48b via respective intake and exhaust poppet valves 52 and 54. Each intake and exhaust valve can be operated by an intake cam (not shown) and an exhaust cam (not shown).

[0016] Exhaust gases can flow from the left exhaust manifold 48a to the left turbocharger 33 via the passage 49a. The exhaust gases can cause the turbine 33b of the left turbocharger 33 to rotate, causing the compressor 33a of the left turbocharger 33 to rotate. The controller 12 can regulate the speed and airflow through the left turbocharger 33 by adjusting the position of the wastegate 33c. Similarly, exhaust gases can flow from the right exhaust manifold 48b to the right turbocharger 30 via the passage 49b. The exhaust gases can cause the turbine 30b of the right turbocharger 30 to rotate, causing the compressor 30a of the right turbocharger 30 to rotate. The controller 12 can regulate the speed and airflow through the right turbocharger 30 by adjusting the position of the wastegate 30c. The left compressor 33a and the right compressor 30a draw air from the air inlet 71 through the air cleaner 8 and the air intake 70. In addition, the left compressor 33a and the right compressor 30a supply pressurized air to the left electric drive compressor 43, the right electric drive compressor 40, and the valve 60 in the air intake 70. The compressor 43b is driven via the motor 43a and the right compressor 40b is driven via the motor 40a. The engine air intake 70 includes a first air path 70a through the left compressor 43b, a second air path 70b through the valve 60, and a third air path 70c through the right compressor 40b. The passages 70a, 70b, and 70c are arranged in parallel and recombine to form a single passage 70 just prior to the charge air cooler 12. Thus, the compressors 33a and 30a can provide compressed air to the compressors 43b and 40b. The compressors 43b and 40b can supply compressed air to the engine 10 via the throttle 62. Air flows from the air cleaner 8 to the throttle 62. Thus, depending on the direction of airflow into the engine 10, the air cleaner is upstream of the compressors 33a and 30a. In addition, depending on the direction of airflow into the engine 10, the compressors 33a and 30a are upstream of the compressors 43b and 40b. Similarly, depending on the direction of airflow into the engine 10, the compressors 43b and 40b are upstream of the throttle 62. In alternative examples, the compressors 43b and 40b can be mechanically driven via exhaust gases or the engine crankshaft. Forward airflow through the compressors 43b and 40b is indicated by the arrows 72a. Backward airflow or recirculation through the compressors 43b and 40b is indicated by the arrows 72b.

[0017] A fuel injector 66 is shown positioned to inject fuel into the cylinder 30. Fuel can be injected directly or port injected. The fuel injector 66 delivers liquid fuel in proportion to the pulse width of a signal from the controller 12. Fuel is delivered to the fuel injector 66 by a fuel system (not shown) that includes a fuel tank, a fuel pump, and a fuel rail (not shown). In one example, a high pressure two-stage fuel system can be used to generate higher fuel pressures. Additionally, the intake manifold 44 is shown in communication with an electronic throttle 62 that adjusts the position of a throttle plate 64 to control airflow from an engine air intake 70 to the intake manifold 44.

[0018] The engine 10 can be a compression ignition engine or it can include a non- distributor ignition system (not shown) to provide ignition spark to the cylinders 30 via a spark plug (not shown) in response to the controller 12. A universal exhaust gas oxygen (UEGO) sensor 126 is coupled to the exhaust manifold 48 upstream of the catalytic converter 70.

[0019] In one example, the converter 70 can include a plurality of catalyst bricks. In another example, a plurality of emission control mechanisms can be used, each having a plurality of bricks. In one example, the converter 70 can be a three-way catalyst.

[0020] Figure 1 The controller 12 is shown as a conventional microcomputer including a microprocessor unit 102, input / output ports 104, read only memory 106 (e.g., non-transitory memory), random access memory 108, a keep-alive memory 110, and a conventional data bus. In addition to those signals previously discussed, the controller 12 is shown receiving various signals from sensors coupled to the engine 10, including engine coolant temperature (ECT) from a temperature sensor 112, a position sensor 134 coupled to an accelerator pedal 130 for sensing the force applied by a human driver 132, engine manifold pressure measurements (MAP) from a pressure sensor 115 coupled to the intake manifold 44, mass of air entering the engine from a sensor 117, brake pedal position from a brake pedal position sensor 154 when the human driver 132 applies the brake pedal 150, and throttle position measurements from the sensor 58.

[0021] In some examples, the driver demand torque can be provided via an autonomous vehicle controller 189. The autonomous vehicle controller can determine the driver demand torque in response to sensors 188. The sensors 188 can include, but are not limited to, cameras, laser ranging sensors (e.g., lidar), global positioning system sensors (GPS), and radar.

[0022] The controller 12 can also interact with the vehicle occupants via a human / machine interface 133. The human / machine interface 133 can include a visual display that provides visual feedback to the vehicle occupants and receives input from the vehicle occupants.

[0023] During operation, each cylinder within the engine 10 typically undergoes a four stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, typically the exhaust valve 54 is closed and the intake valve 52 is open. Air is introduced into the cylinder 30 via the intake manifold 44 and the piston (not shown) moves to the bottom of the cylinder to increase the volume within the cylinder 30. The position where the piston is near the bottom of the cylinder and at the end of its stroke (e.g., when the cylinder 30 is at its maximum volume) is commonly referred to by those skilled in the art as the bottom dead center (BDC). During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston (not shown) moves toward the cylinder head to compress the air within the cylinder 30. The point where the piston is at the end of its stroke and closest to the cylinder head (e.g., when the cylinder 30 is at its minimum volume) is commonly referred to by those skilled in the art as the top dead center (TDC). During a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. During a process hereinafter referred to as ignition, the injected fuel is ignited by a known ignition means such as a spark plug or compression, causing combustion. During the expansion stroke, the expanding gases push the piston back to the BDC. The crankshaft (not shown) converts the piston movement into rotational torque of the rotational shaft. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the combusted air-fuel mixture to the exhaust manifold 48a and 48b as the piston returns to the TDC. It should be noted that the above is shown merely as an example and the intake and exhaust valve opening and / or closing times can vary, such as to provide positive valve overlap or negative valve overlap, late intake valve closing, or various other examples.

[0024] Reference is now made to Figure 2 , showing a schematic view of a second example engine. Figure 2 The engine shown in Figure 1 includes components and devices that are identical to and operate in the same manner as the devices and components shown in Figure 1 . Components and devices of Figure 1 are identified by the same numerical labels as used in Figure 2 . Accordingly, for the sake of brevity, the description of identical components is omitted.

[0025] In this engine configuration, the engine 10 includes a second valve 61 positioned in the passage 70c. The second valve 61 can completely seal the passage 70c so that air cannot flow backwards through the compressor 40b (e.g., in the direction from the valve 61 to 40b) by means of compressed air supplied via the compressor 43a. The positions of the valves 60 and 61 are adjusted via the controller 12. Thus, the valves 60 and 61 can be adjusted as described in greater detail in the methods of Figure 3 and Figure 4 to reduce the likelihood of backflow through one or more compressors.

[0026] Figure 1 and Figure 2 may provide a vehicle system comprising: an engine comprising two cylinder banks and four compressors, a first compressor and a second compressor of the four compressors positioned upstream of a third compressor and a fourth compressor included in the four compressors, the third compressor positioned in a first intake passage, the fourth compressor positioned in a third intake passage; and a first valve positioned in a second intake passage, the first intake passage, the second intake passage, and the third intake passage arranged in parallel. The vehicle system further comprises a second valve positioned in the third intake passage, the first intake passage, the second intake passage, and the third intake passage arranged upstream of an engine throttle. The vehicle system includes where the third compressor and the fourth compressor are electrically driven compressors. The vehicle system further comprises a controller comprising executable instructions stored in a non-transitory memory for adjusting a position of the first valve in response to engine air flow. The vehicle system further comprises additional instructions for adjusting a position of the second valve in response to engine air flow. The vehicle system further comprises instructions for operating the third compressor and the fourth compressor at different speeds in response to engine air flow.

[0027] Referring now to Figure 3 , a first example method of a system control engine air flow for Figure 1 is shown. Figure 3 The method of Figure 1 may be incorporated into and can cooperate with the system of Figure 3 . Further, at least portions of the method of may be incorporated as executable instructions stored in a non-transitory memory, while other portions of the method can be executed via a controller, transforming the operational state of devices and actuators in the physical world.

[0028] The method of Figure 3Methods. Method 300 can move between operating states via paths 310, 312, 314, 316, 318, and 320. The paths can be negotiated when conditions requirements are met.

[0029] Method 300 begins by entering operating state 302, in which compressors 43b and 40b are deactivated (e.g., no mechanical or electrical energy is supplied). If the compressors are electrically driven, power can be withheld to cause the compressors to rotate. Also, in some examples, electric motors 43a and 40a can be operated in a generator mode to resist forces that can be applied to compressors 43b and 40b via air pressurized by compressors 33a and 30a to the compressors 43b and 40b so that air flow through the compressors 43b and 40b can be resisted. In other examples, compressors 43b and 40b can be rotated at a predetermined low speed (e.g., less than 100 RPM) via electric motors 43a and 40a. If compressors 43b and 40b are mechanically driven, clutches can be disengaged to prevent them from moving. Valve 60 is also opened to provide a low resistance air flow path between compressors 33a and 30b and the charge air cooler 12. By opening valve 60 and deactivating compressors 43b and 40b, electrical energy consumption can be reduced. Engine 10 can operate in state 302 when engine airflow is less than a first threshold amount (e.g., less than 1 kg / min). State 304 can be entered from state 302 via path 312 when engine airflow or desired engine airflow is less than the first threshold amount. Alternatively, state 306 can be entered from state 302 via path 318 when engine airflow or desired engine airflow is less than the first threshold amount.

[0030] Engine airflow can be determined via an airflow sensor, and desired engine airflow can be determined from driver demand torque. Driver demand torque can be determined from an accelerator pedal position via a table or function that references empirically determined torque values for accelerator pedal positions. Alternatively, driver demand torque can be provided via a controller, such as an autonomous vehicle controller. Torque amounts can then be converted to engine air amounts via a table or function that references outputs of empirically determined engine air amounts in response to engine torque amounts.

[0031] In state 304, method 300 activates both compressors 43b and 40b (e.g., supplying electrical or mechanical energy) to increase airflow to engine 10. Valve 60 is closed so that air does not return to the inlet sides of compressors 43b and 40b. Compressors 43b and 40b are commanded to the same speed to balance the airflow through both compressors, and the compressor speed can be determined by retrieving the speed from a lookup table. The compressor speed values ​​in the table can be empirically determined and referenced via engine airflow or desired engine airflow and engine speed. In one example, desired engine airflow can be determined from accelerator pedal position and engine speed. When the engine airflow or desired engine airflow exceeds a second threshold amount (e.g., 3.5 kg / min), state 304 can be transitioned from state 302 via path 310. Alternatively, state 304 can be transitioned from state 306 via path 314 when the engine airflow or desired engine airflow exceeds the second threshold amount.

[0032] In state 306, method 300 activates compressor 43b and operates compressor 40b at low speed to increase airflow to engine 10 and reduce the likelihood of backflow through compressor 40b (e.g., air flowing backward in the direction of 72b). Additionally, valve 60 is closed so that air does not return to the inlet sides of compressors 43b and 40b. Compressor 43b is adjusted to provide the desired engine airflow. Compressor 43b is commanded to a speed determined by retrieving a speed from a lookup table. The compressor speed values ​​in the table may be empirically determined and referenced via engine airflow or desired engine airflow and engine speed. In one example, desired engine airflow may be determined from accelerator pedal position or virtual driver torque demand (e.g., torque request provided via an autonomous vehicle controller) and engine speed. When the engine airflow or desired engine airflow exceeds a first threshold amount but is less than a second threshold amount, state 306 may be transitioned from state 302 via path 320. Alternatively, when the engine airflow or desired engine airflow is less than the second threshold amount but greater than the first threshold amount, state 306 may be transitioned from state 304 via path 316.

[0033] Therefore, in Figure 1 In the system shown, the likelihood of air flowing backward through compressors 43b and 40b can be reduced by installing valve 60 in the engine air intake duct 70 parallel to compressors 43b and 40b. Furthermore, by controlling the energy flow to compressors 43b and 40b, it is possible to reduce energy consumption by allowing compressor 43b to provide total boost in the operating region where a total boost request is likely to be provided and by allowing compressor 40b to rotate at a low-speed threshold to prevent backflow through compressor 43b.

[0034] Now for reference Figure 4, showing the use of Figure 2 This is a second example method for system-controlled engine airflow. Figure 4 The method can be merged into Figure 1 And it can collaborate with the system. Furthermore, Figure 4 At least a portion of the method can be incorporated into executable instructions stored in non-transitory memory, while other portions of the method can be executed via a controller to change the operating state of devices and actuators in the physical world.

[0035] Described in the form of a state machine including three different operating states 402, 404 and 406 Figure 4 The method 400 can move between operating states via paths 410, 412, 414, 416, 418, and 420. These paths can be negotiated when certain conditions are met.

[0036] Method 400 begins by entering operating state 402, in which compressors 43b and 40b are deactivated (e.g., no mechanical or electrical energy is supplied). If the compressors are electrically driven, then electricity may not be allowed to rotate the compressors. Furthermore, in some examples, motors 43a and 40a may operate in generator mode to resist forces that can be applied to compressors 43b and 40b via air pressurized by compressors 33a and 30a, so that airflow through compressors 43b and 40b can be resisted. In other examples, compressors 43b and 40b may rotate at a predetermined low speed (e.g., less than 100 RPM) via motors 43a and 40a. If compressors 43b and 40b are mechanically driven, then the clutch may be disengaged to prevent them from moving. Valve 60 is also opened to provide a low-resistance airflow path between compressors 33a and 30b and the booster air cooler 12. By opening valve 60 and disabling compressors 43b and 40b, power consumption can be reduced, while backflow through compressors 43b and 40b can be reduced or eliminated. In one example, valve 61 is opened to allow compressor 40b to provide boost, or valve 61 is closed to prevent backflow through compressor 40b. The engine can operate in state 402 when the engine airflow is less than a first threshold amount (e.g., less than 1 kg / min). State 402 can be transitioned from state 404 via path 412 when the engine airflow or desired engine airflow is less than the first threshold amount. Alternatively, state 402 can be transitioned from state 406 via path 418 when the engine airflow or desired engine airflow is less than the first threshold amount.

[0037] In state 404, method 400 activates both compressors 43b and 40b (e.g., supplying electrical or mechanical energy) to increase airflow to engine 10. Valve 60 is closed so that air does not return to the inlet side of compressors 43b and 40b, and valve 61 is opened to allow airflow through compressor 40b. Compressors 43b and 40b are commanded to the same speed to balance the airflow through both compressors, and the compressor speed can be determined by retrieving the speed from a lookup table. The compressor speed values ​​in the table can be empirically determined and referenced via engine airflow or desired engine airflow and engine speed. In one example, desired engine airflow can be determined from accelerator pedal position and engine speed. When the engine airflow or desired engine airflow exceeds a second threshold amount (e.g., 3.5 kg / min), state 404 can be transitioned from state 402 via path 410. Alternatively, state 404 can be transitioned from state 406 via path 414 when the engine airflow or desired engine airflow exceeds the second threshold amount.

[0038] In state 406, method 400 activates compressor 43b and deactivates compressor 40b to increase airflow to engine 10 and reduce the likelihood of backflow through compressor 40b (e.g., air flowing backward in the direction of 72b). Additionally, valves 60 and 61 are closed so that air does not return to the inlet sides of compressors 43b and 40b. Compressor 43b is adjusted to provide the desired engine airflow. Compressor 43b is commanded to a speed determined by retrieving a speed from a lookup table. The compressor speed values ​​in the table can be empirically determined and referenced via engine airflow or desired engine airflow and engine speed. In one example, the desired engine airflow can be determined from the accelerator pedal position and engine speed. When the engine airflow or desired engine airflow exceeds a first threshold amount but is less than a second threshold amount, state 406 can be transitioned from state 402 via path 420. Alternatively, when the engine airflow or desired engine airflow is less than the second threshold amount but greater than the first threshold amount, state 406 can be transitioned from state 404 via path 416.

[0039] Therefore, in Figure 2 In the system shown, the likelihood of air flowing backward through compressors 43b and 40b can be reduced by installing valve 60 in the engine air intake duct 70, which is parallel to compressors 43b and 40b. Valve 61 is connected in series with compressor 40b and positioned parallel to compressor 43b. Furthermore, by controlling the energy flow to compressors 43b and 40b, it is possible to reduce energy consumption by closing valve 61 to allow compressor 43b to deliver the total desired boost when it is in an operating state where compressor 43b is capable of providing total boost (e.g., under low boost demand conditions).

[0040] Figure 3 and Figure 4 The method provides a method for operating an engine, the method comprising: adjusting the speed of a third compressor and the position of a valve in response to engine airflow, the third compressor and the valve being positioned in the engine's intake system upstream of the engine throttle valve, the third compressor being positioned in the intake system downstream of a first compressor and a second compressor. The method further includes the following: wherein the first compressor and the second compressor are compressors of a turbocharger. Furthermore, Figure 1 and Figure 2 The compressor shown may be a turbocharged compressor (e.g., exhaust-driven), a supercharger compressor (e.g., mechanically driven via an engine crankshaft or camshaft), or an electrically driven compressor. The method includes: adjusting the position of the valve includes closing the valve in response to the engine airflow exceeding a second threshold amount, and opening the valve in response to the engine airflow being less than the second amount. The method includes: closing the valve closes an air passage parallel to an air passage including the third compressor. The method includes: wherein the air passage is parallel to an air passage including a fourth compressor. The method further includes adjusting the speed of the fourth compressor in response to the engine airflow exceeding the second threshold level. The method further includes adjusting the engine airflow in response to accelerator pedal position or torque demand from an autonomous vehicle controller.

[0041] Figure 3 and Figure 4A method provides a method for operating an engine, the method comprising: adjusting the speed of a third compressor and the position of a first valve and a second valve in response to engine airflow, the third compressor being positioned in a first air intake passage and the first valve being positioned in a second air intake passage of the engine upstream of an engine throttle valve, the third compressor being positioned in the first air intake passage downstream of the first compressor and the second compressor. The method further comprises: wherein the second valve is positioned in a third air intake passage parallel to the first air intake passage and the second air intake passage. The method further comprises a fourth compressor positioned in the third air intake passage. The method includes: wherein adjusting the position of the first valve and the position of the second valve includes closing the first valve and closing the second valve in response to the engine airflow exceeding the first threshold level. The method includes: wherein adjusting the position of the first valve and the position of the second valve includes opening the first valve and opening the second valve in response to the engine airflow being less than the first threshold level. The method includes: wherein adjusting the position of the first valve and the position of the second valve includes closing the first valve and opening the second valve in response to the engine airflow exceeding the second threshold level. The method further includes adjusting the speed of the fourth compressor to match the speed of the third compressor in response to the engine air flow exceeding the second threshold level.

[0042] Now for reference Figure 5 The first example engine operation sequence is shown. Figure 5 The sequence can be transmitted via Figure 1 The system and Figure 3 The methods are coordinated to execute this. The graph shown is arranged chronologically and occurs at the same time. The vertical lines at times t1 to t2 represent the time of interest during the sequence.

[0043] since Figure 5 The first curve at the top is a curve of engine airflow or desired engine airflow versus time. Trace 502 represents engine airflow. The vertical axis represents engine airflow, and the engine airflow increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side. Horizontal line 520 represents the first threshold engine airflow, and horizontal line 522 represents the second threshold engine airflow.

[0044] since Figure 5The second graph from the top is a graph of valve 60 state versus time. Trace 504 represents the state of valve 60. The vertical axis represents the state of valve 60, and when trace 504 is at a higher level near the open label, valve 60 is open to allow airflow through the valve. When trace 504 is at a lower level near the closed label, valve 60 is closed to prevent airflow through the valve. The horizontal axis represents time, and time increases from the left to the right of the graph.

[0045] since Figure 5 The third graph from the top is a graph of the state of electric compressor 43 versus time. Trace 506 represents the state of electric compressor 43. The vertical axis represents the state of compressor 43, and when trace 506 is at a higher level near the open label, compressor 43 is activated (e.g., supplied with electrical or mechanical power). When trace 506 is at a lower level near the closed label, compressor 43 is deactivated (e.g., not supplied with electrical or mechanical power). The horizontal axis represents time, and time increases from the left to the right of the graph.

[0046] since Figure 5 The fourth graph from the top is a graph of the state of electric compressor 40 versus time. Trace 508 represents the state of electric compressor 40. The vertical axis represents the state of compressor 40, and when trace 508 is at a higher level near the open label, compressor 40 is activated (e.g., supplied with electrical or mechanical power). When trace 508 is at a lower level near the closed label, compressor 40 is deactivated (e.g., not supplied with electrical or mechanical power). The horizontal axis represents time, and time increases from the left to the right of the graph.

[0047] since Figure 5 The fifth graph from the top is a graph of compressor 43 versus time. Trace 510 represents the airflow to compressor 43. The vertical axis represents the airflow to compressor 43, and the airflow rate of compressor 43 increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0048] since Figure 5 The sixth graph from the top is a graph of compressor 40 versus time. Trace 512 represents the airflow to compressor 40. The vertical axis represents the airflow to compressor 40, and the airflow rate to compressor 40 increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0049] At time t0, the engine airflow is less than the first threshold 520. In response to the engine airflow, valve 60 opens and compressors 43 and 40 are deactivated. Because the compressors are deactivated, very little airflow passes through compressors 43 and 40. By opening valve 60, compressors 33 and 30 can supply air to engine 10 via low-resistance air passages.

[0050] Between time t0 and time t1, the engine airflow remains constant, but near time t1, the engine airflow begins to increase. The engine airflow increases in response to the increase in the driver's demand torque (not shown). Compressors 43 and 40 remain inactive, and the airflow through compressors 43 and 40 remains minimal.

[0051] At time t1, the engine airflow exceeds the first threshold 520. Valve 60 remains closed, and compressors 40 and 43 are activated. The speed of compressor 43 is adjusted to provide the desired engine airflow, and the speed of compressor 40 is adjusted to the minimum compressor speed that prevents air backflow through compressor 40, while compressor 40 does not provide boost or increase the airflow to the engine. Therefore, compressor 40 can operate with a lower amount of electrical energy.

[0052] Between time t1 and time t2, the engine airflow remains constant, but near time t2, the engine airflow begins to increase. The engine airflow increases in response to the increase in the driver's demand torque (not shown). Near time t2, compressors 43 and 40 remain active, and the airflow through compressor 43 increases to provide the desired engine airflow.

[0053] At time t2, the engine airflow exceeds the second threshold 522. Valve 60 closes in response to the engine airflow exceeding threshold 522. Compressors 43 and 40 remain active, and their outputs increase to meet the increased engine air volume. Compressors 43 and 40 operate at the same speed to provide equal flow through the compressors and reduce the likelihood of backflow through the compressors. Although not shown, the flow through compressor 43 may briefly decrease when the flow through compressor 40 increases to meet the desired engine airflow.

[0054] In this way, the compressor and valves can be operated to reduce the likelihood of air backflow through the compressor. Furthermore, the electrical energy supplied to the compressor can be reduced while supplying the desired engine airflow.

[0055] Now for reference Figure 6 This shows the alternative engine operation sequence. Figure 6 The sequence can be transmitted via Figure 2 The system and Figure 4 The method is provided collaboratively. The graph shown is arranged chronologically and occurs at the same time. The vertical lines at times t10 to t12 represent the time of interest during the sequence.

[0056] since Figure 6The first curve at the top is a graph of engine airflow or desired engine airflow versus time. Trace 602 represents engine airflow. The vertical axis represents engine airflow, and the engine airflow increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side. Horizontal line 620 represents the first threshold engine airflow, and horizontal line 622 represents the second threshold engine airflow.

[0057] since Figure 6 The second graph from the top is a graph of valve 60 state versus time. Trace 604 represents the state of valve 60. The vertical axis represents the state of valve 60, and when trace 604 is at a higher level near the open label, valve 60 is open to allow airflow through the valve. When trace 604 is at a lower level near the closed label, valve 60 is closed to prevent airflow through the valve. The horizontal axis represents time, and time increases from the left to the right of the graph.

[0058] since Figure 6 The third graph from the top is a graph of valve 61 state versus time. Trace 606 represents the state of valve 61. The vertical axis represents the state of valve 61, and when trace 606 is at a higher level near the open label, valve 61 is open to allow airflow through the valve. When trace 606 is at a lower level near the closed label, valve 61 is closed to prevent airflow through the valve. The horizontal axis represents time, and time increases from the left to the right of the graph.

[0059] since Figure 6 The fourth graph from the top is a graph of the state of electric compressor 43 versus time. Trace 608 represents the state of electric compressor 43. The vertical axis represents the state of compressor 43, and when trace 608 is at a higher level near the open label, compressor 43 is activated (e.g., supplied with electrical or mechanical power). When trace 608 is at a lower level near the closed label, compressor 43 is deactivated (e.g., not supplied with electrical or mechanical power). The horizontal axis represents time, and time increases from the left to the right of the graph.

[0060] since Figure 6 The fifth graph from the top is a graph of the state of electric compressor 40 versus time. Trace 610 represents the state of electric compressor 40. The vertical axis represents the state of compressor 40, and when trace 610 is at a higher level near the open label, compressor 40 is activated (e.g., supplied with electrical or mechanical power). When trace 610 is at a lower level near the closed label, compressor 40 is deactivated (e.g., not supplied with electrical or mechanical power). The horizontal axis represents time, and time increases from the left to the right of the graph.

[0061] since Figure 6The sixth graph from the top is a graph of compressor 43 versus time. Trace 612 represents the airflow to compressor 43. The vertical axis represents the airflow to compressor 43, and the airflow rate of compressor 43 increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0062] since Figure 6 The seventh graph from the top is a graph of compressor 40 versus time. Trace 614 represents the airflow to compressor 40. The vertical axis represents the airflow to compressor 40, and the airflow rate of compressor 40 increases in the direction of the arrow on the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side.

[0063] At time t10, the engine airflow is less than the first threshold 620. In response to the engine airflow, valves 60 and 61 open and compressors 43 and 40 deactivate. Because the compressors are deactivated, very little airflow passes through compressors 43 and 40. By opening valve 60, compressors 33 and 30 can supply air to engine 10 via a low-resistance air passage. Furthermore, opening valve 61 is equivalent to allowing even a small amount of air to pass through compressors 43 and 40.

[0064] Between time t10 and time t11, the engine airflow remains constant, but near time t11, the engine airflow begins to increase. The engine airflow increases in response to the increase in the driver's demand torque (not shown). Compressors 43 and 40 remain inactive, and the airflow through compressors 43 and 40 remains minimal.

[0065] At time t11, the engine airflow exceeds a first threshold 620. In response to the engine airflow exceeding the first threshold 620, valves 60 and 61 close, compressor 40 is deactivated, and compressor 43 is activated. The speed of compressor 43 is adjusted to provide the desired engine airflow. Closing valve 61 prevents air from flowing back through compressor 40, thus saving energy by deactivating compressor 40.

[0066] Between time t11 and time t12, the engine airflow remains constant, but near time t12, the engine airflow begins to increase. The engine airflow increases in response to an increase in the driver's demand torque (not shown). Compressor 43 remains active and compressor 40 remains deactivated. Near time t12, the airflow through compressor 43 increases to provide the desired engine airflow. Valves 60 and 61 remain closed.

[0067] At time t12, the engine airflow exceeds the second threshold 622. Valve 60 remains closed, and valve 61 opens in response to the engine airflow exceeding threshold 622. Compressor 43 remains active, and compressor 40 is activated in response to the engine airflow exceeding threshold 622. Furthermore, the output of compressors 43 and 40 increases to meet the increased engine air volume. Compressors 43 and 40 operate at the same speed to provide equal flow through the compressors and reduce the possibility of backflow through the compressors. Although not shown, the flow through compressor 43 may be briefly reduced when the flow of compressor 40 increases to meet the desired engine airflow.

[0068] In this way, the compressor and valves can be operated to reduce the likelihood of air backflow through the compressor. Furthermore, the electrical energy supplied to the compressor can be reduced while supplying the desired engine airflow.

[0069] As those skilled in the art will understand, the methods described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, etc. Accordingly, the various steps and functions shown can be performed in the sequence shown, in parallel, or omitted in some cases. Similarly, the order of processing is not necessarily required to achieve the goals, features, and advantages described herein, but is provided for ease of illustration and description. Although not explicitly shown, those skilled in the art will recognize that one or more of the steps or functions shown can be performed repeatedly, depending on the specific strategy used.

[0070] This concludes the description. Many changes and modifications will be apparent to those skilled in the art upon reading this description without departing from its spirit and scope. For example, this description can be effectively utilized in vehicles incorporating electric propulsion systems, hybrid propulsion systems, or internal combustion engine propulsion systems.

[0071] According to the present invention, a method for operating an engine includes: adjusting the speed of a third compressor and the position of a valve in response to engine air flow, the third compressor and the valve being positioned in an intake device of the engine upstream of the engine throttle valve, the third compressor being positioned in the intake device downstream of a first compressor and a second compressor.

[0072] According to an embodiment, the first compressor and the second compressor are compressors of a turbocharger.

[0073] According to an embodiment, adjusting the position of the valve includes closing the valve in response to the engine air flow exceeding a second threshold amount, and opening the valve in response to the engine air flow being less than the second threshold amount.

[0074] According to an embodiment, closing the valve will close the air passage parallel to the air passage including the third compressor.

[0075] According to an embodiment, the air passage is parallel to the air passage including the fourth compressor.

[0076] According to an embodiment, the invention is further characterized in that the speed of the fourth compressor is adjusted in response to the engine air flow exceeding a second threshold level.

[0077] According to an embodiment, the invention is further characterized in that the engine airflow is adjusted in response to the position of the accelerator pedal.

[0078] According to the present invention, a method for operating an engine includes: adjusting the speed of a third compressor and the position of a first valve and a second valve in response to engine air flow, the third compressor being positioned in a first air intake passage and the first valve being positioned in a second air intake passage of the engine located upstream of the engine throttle valve, the third compressor being positioned in the first air intake passage downstream of the first compressor and the second compressor.

[0079] According to an embodiment, the second valve is positioned in a third air intake duct parallel to the first air intake duct and the second air intake duct.

[0080] According to an embodiment, the invention is further characterized by a fourth compressor located in the third air intake duct.

[0081] According to an embodiment, adjusting the position of the first valve and the position of the second valve includes closing the first valve and closing the second valve in response to the engine air flow exceeding a first threshold level.

[0082] According to an embodiment, adjusting the position of the first valve and the position of the second valve includes opening the first valve and opening the second valve in response to the engine air flow being less than a first threshold level.

[0083] According to an embodiment, adjusting the positions of the first valve and the second valve includes closing the first valve and opening the second valve in response to the engine air flow exceeding a second threshold level.

[0084] According to an embodiment, the invention is further characterized in that the speed of the fourth compressor is adjusted to match the speed of the third compressor in response to the engine air flow exceeding the second threshold level.

[0085] According to the present invention, a vehicle system is provided, the vehicle system comprising: an engine including two cylinder banks and four compressors, a first compressor and a second compressor of the four compressors being positioned upstream of a third compressor and a fourth compressor included in the four compressors, the third compressor being positioned in a first air intake manifold, and the fourth compressor being positioned in a third air intake manifold; and a first valve being positioned in a second air intake manifold, the first air intake manifold, the second air intake manifold, and the third air intake manifold being arranged in parallel.

[0086] According to an embodiment, the invention is further characterized by a second valve, which is positioned in the third intake passage, wherein the first intake passage, the second intake passage, and the third intake passage are arranged upstream of the engine throttle valve.

[0087] According to an embodiment, the third compressor and the fourth compressor are electrically driven compressors.

[0088] According to an embodiment, the invention is further characterized by a controller, the controller including executable instructions stored in a non-transitory memory, the executable instructions being used to adjust the position of the first valve in response to engine airflow.

[0089] According to an embodiment, the invention is further characterized by an additional command for adjusting the position of the second valve in response to engine airflow.

[0090] According to an embodiment, the invention is further characterized by instructions for operating the third compressor and the fourth compressor at different speeds in response to engine airflow.

Claims

1. A method for operating an engine, the method comprising: In response to an engine airflow rate greater than a first threshold and less than a second threshold, a first valve is closed and a third and fourth compressor are activated, the third compressor, the fourth compressor, and the first valve being located in the engine's intake system upstream of the engine throttle valve and in the intake system downstream of the first and second compressors; as well as Adjust the speed of the third compressor to provide the desired engine airflow; as well as The speed of the fourth compressor is adjusted to the minimum speed to prevent backflow through the fourth compressor. The intake ducts of the first valve, the third compressor, and the fourth compressor are arranged in parallel.

2. The method of claim 1, wherein the first compressor and the second compressor are compressors of a turbocharger.

3. The method of claim 1, wherein the method further comprises closing the first valve in response to the engine air flow exceeding the second threshold amount, and opening the first valve in response to the engine air flow being less than the first threshold amount.

4. The method of claim 3, wherein closing the first valve closes the intake passage parallel to the intake passage including the third compressor.

5. The method of claim 4, further comprising adjusting the speed of the fourth compressor in response to the engine air flow exceeding the second threshold amount.

6. The method of claim 1, further comprising adjusting the engine airflow in response to the accelerator pedal position.

7. A vehicle system, the vehicle system comprising: An engine comprising two cylinder banks and four compressors, wherein a first compressor and a second compressor of the four compressors are positioned upstream of a third compressor and a fourth compressor of the four compressors, the third compressor being positioned in a first intake manifold, and the fourth compressor being positioned in a third intake manifold. And a first valve, the first valve being positioned in the second air intake, the first air intake, the second air intake, and the third air intake being arranged in parallel; as well as The controller includes executable instructions and additional instructions stored in a non-transitory memory. The executable instructions are configured to adjust the speed of the third compressor to provide a desired engine air flow and adjust the speed of the fourth compressor to a minimum speed to prevent backflow through the fourth compressor in response to an engine air flow rate greater than a first threshold amount and less than a second threshold amount. The additional instructions are configured to cause the third compressor and the fourth compressor to operate at the same speed to make the flow rates through the compressors equal in response to an engine air flow rate greater than the second threshold amount.

8. The vehicle system of claim 7, further comprising a second valve positioned in the third air intake passage, wherein the first air intake passage, the second air intake passage, and the third air intake passage are arranged upstream of the engine throttle valve.

9. The vehicle system of claim 8, wherein the third compressor and the fourth compressor are electrically driven compressors.

10. The vehicle system of claim 9, wherein the controller includes executable instructions stored in the non-transitory memory for adjusting the position of the first valve in response to the engine airflow.

11. The vehicle system of claim 10, wherein the controller further includes additional instructions for adjusting the position of the second valve in response to the engine airflow.

12. The vehicle system of claim 11, wherein the controller further includes instructions for operating the third compressor and the fourth compressor at different speeds in response to the engine airflow.

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