Internal combustion engine control system, internal combustion engine control method, and internal combustion engine control program

Abstract

To provide an internal combustion engine control system that prohibits closing control of a waste gate valve all the time in a low load region and in a steady state.SOLUTION: An internal combustion engine control system includes an internal combustion engine, a supercharger, a waste gate valve and a controller. In the internal combustion engine control system, the controller includes: a load measurement section (201) that measures load to be applied to the internal combustion engine; a load determination section (202) that determines whether a change of the load is within a predetermined range for a predetermined period; and a waste gate valve control section (203) that determines a steady state when the change of the load is within the predetermined range for the predetermined period to prohibit closing control of the waste gate valve and performs the closing control of the waste gate valve when the change of the load is not within the predetermined range for the predetermined period.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine control system, a control method for an internal combustion engine, and a control program for an internal combustion engine. [Background technology]

[0002] Vehicles have been developed that include internal combustion engines equipped with a wastegate valve (WGV) provided in a passage that bypasses a turbocharger. Patent Document 1 discloses an internal combustion engine for vehicle operation that opens the WGV when the vehicle is in a low-load state where turbocharging by a turbocharger is not required. In this internal combustion engine for vehicle operation, the WGV is prohibited from opening when the vehicle speed V is greater than a predetermined speed V1 and the turn signal is on, indicating a high probability of the vehicle accelerating. At this time, the WGV is forcibly closed regardless of whether the vehicle is in a low-load state or not. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-14289 Summary of the Invention [Problem to be solved by the invention]

[0004] However, closing the WGV in the low load range (Natural Aspiration (NA) range) as in Patent Document 1 increases back pressure, increasing pumping loss and worsening fuel economy. Furthermore, when compared under conditions where the torque generated by the internal combustion engine is the same, the air volume increases to compensate for the torque equivalent to the pumping loss, which reduces the intake manifold negative pressure and worsens the PCV ventilation rate. Therefore, the objective of this disclosure is to provide an internal combustion engine control system that always prohibits wastegate valve closing control in the low load range and steady state. [Means for solving the problem]

[0005] The internal combustion engine control system of the present disclosure comprises: an internal combustion engine to which a load is applied by an accelerator operation or a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, The controller a load measuring unit that measures the load applied to the internal combustion engine; a load determining unit that determines whether a load is low for a predetermined period of time and whether a change in the load is within a predetermined range; When the load is low for the predetermined period and the change in the load is within the predetermined range, it is determined that the engine is in a low load region and in a steady state, and the closing control of the wastegate valve is prohibited; a wastegate valve control unit that controls to close the wastegate valve when the load is not low during the predetermined period or when the change in the load is not within the predetermined range.

[0006] The internal combustion engine control system described above always prohibits the closing control of the wastegate valve when the engine is in a low load region and in a steady state, thereby improving fuel economy.

[0007] Further, the internal combustion engine control system of the present disclosure includes: It has a high load mode that prioritizes high load over low fuel consumption. When the steady state is determined, if the driver sets the high load mode, the wastegate valve control unit controls the wastegate valve to close.

[0008] According to the above configuration, when the driver selects a high load mode such as POWER mode or SPORT mode, it is determined that the driver intends to prioritize acceleration over fuel economy, and the steady state can be disabled.

[0009] Further, the internal combustion engine control system of the present disclosure includes: When the steady state is determined, the load measurement unit measures the load and the load determination unit determines that the load has exceeded a predetermined threshold, and the wastegate valve control unit controls the wastegate valve to close.

[0010] According to the above configuration, when the driver quickly depresses the accelerator pedal, for example, and the accelerator opening degree changes at a rate equal to or greater than a predetermined rate, it is determined that the driver intends to accelerate strongly, and the steady state can be invalidated.

[0011] The control method for an internal combustion engine according to the present disclosure includes: A control method for an internal combustion engine including: an internal combustion engine to which a load is applied by an accelerator operation or a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, measuring the load applied to the internal combustion engine; determining whether there is a low load for a predetermined period of time and whether the change in the load is within a predetermined range; determining that the engine is in a low load region and in a steady state when the load is low for the predetermined period and the change in the load is within the predetermined range, and prohibiting control to close the wastegate valve; and controlling the wastegate valve to close when the load is not low during the predetermined period or when the change in the load is not within the predetermined range.

[0012] According to the control method for an internal combustion engine of the present disclosure, the closing control of the wastegate valve is always prohibited when the engine is in a low load region and in a steady state, thereby improving fuel economy.

[0013] The control program for an internal combustion engine according to the present disclosure comprises: A control program for an internal combustion engine including: an internal combustion engine to which a load is applied by an accelerator operation or a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, measuring the load applied to the internal combustion engine; determining whether there is a low load for a predetermined period of time and whether the change in the load is within a predetermined range; determining that the engine is in a low load region and in a steady state when the load is low for the predetermined period and the change in the load is within the predetermined range, and prohibiting control to close the wastegate valve; and controlling the wastegate valve to close when the load is not low during the predetermined period or when the change in the load is not within the predetermined range.

[0014] The control program for an internal combustion engine according to the present disclosure always prohibits the closing control of the wastegate valve when the engine is in a low load region and in a steady state, thereby improving fuel economy. [Effects of the Invention]

[0015] The present disclosure makes it possible to provide an internal combustion engine control system that always prohibits the closing control of the wastegate valve when the engine is in a low load region and in a steady state, thereby improving fuel economy. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an example of an internal combustion engine control system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing an example of an internal configuration of a controller according to the present embodiment. [Figure 3] 5 is a flowchart showing an example of an operation of the controller according to the present embodiment. [Figure 4]10 is a flowchart showing another example of the operation of the controller according to the present embodiment. [Figure 5] 10 is a flowchart showing yet another example of the operation of the controller according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] This embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0018] (Description of the internal combustion engine control system according to this embodiment) Fig. 1 is a schematic diagram showing an example of an internal combustion engine control system according to this embodiment. Fig. 2 is a block diagram showing an example of the internal configuration of a controller according to this embodiment. The internal combustion engine control system according to this embodiment will be described with reference to Figs. 1 and 2.

[0019] As shown in FIG. 1, the internal combustion engine control system 10 includes an internal combustion engine 100, an intake passage 101, an exhaust passage 102, an air flow meter 103, an intake temperature sensor 104, a turbocharger 105, a throttle valve 106, a throttle position sensor 107, an exhaust bypass passage 108, a wastegate valve (WGV) 109, a blow-by gas passage 110, a PCV (Positive Crankcase Ventilation) valve 111, and a controller (ECU (Electronic Control Unit)) 112.

[0020] An intake passage 101 and an exhaust passage 102 communicate with each cylinder of the internal combustion engine 100. The turbocharger 105 includes a compressor 151 and a turbine 152. Furthermore, the blow-by gas passage 110 includes a light load blow-by gas passage 113 and a high load blow-by gas passage 114.

[0021] The internal combustion engine 100 is a device that burns fuel such as gasoline in a cylinder and obtains power using the generated combustion gas.

[0022] The intake passage 101 is a passage that introduces air into the internal combustion engine 100. Near the entrance of the intake passage 101, an air flow meter 103 and an intake air temperature sensor 104 are provided.

[0023] The exhaust passage 102 is a passage through which exhaust gas emitted from the internal combustion engine 100 is released into the atmosphere. In addition, an exhaust bypass passage 108 that bypasses the turbine 152 is connected to the exhaust passage 102.

[0024] The air flow meter 103 outputs a signal to the controller 112 according to the flow rate of air taken into the intake passage 101 .

[0025] The intake air temperature sensor 104 outputs a signal corresponding to the temperature of the air taken into the intake passage 101 (intake air temperature or outside air temperature) to the controller 112. Downstream of the air flow meter 103 and the intake air temperature sensor 104, a compressor 151 of the turbocharger 105 is installed.

[0026] The turbocharger 105 is a device that uses the flow of exhaust gas to increase the density of the air taken in by the internal combustion engine 100. The turbocharger 105 includes a compressor 151, a turbine 152, and a connecting shaft 153.

[0027] The compressor 151 is integrally connected to the turbine 152 via a connecting shaft 153. The turbine 152 is disposed in the exhaust passage 102. The compressor 151 increases the density of the air using the power transmitted from the turbine 152. A throttle valve 106 is provided downstream of the compressor 151 to adjust the amount of air taken into the internal combustion engine 100.

[0028] The turbine 152 rotates using the flow of exhaust gas, and transmits the rotational power to the compressor 151 via a connecting shaft 153.

[0029] The throttle valve 106 is an electronically controlled valve that is driven by a throttle motor (not shown) based on the accelerator opening. A throttle position sensor 107 is provided near the throttle valve 106.

[0030] The throttle position sensor 107 is a sensor that detects the throttle opening and outputs a signal corresponding to the detected throttle opening to the controller 112.

[0031] The exhaust bypass passage 108 is a passage that releases exhaust gas into the atmosphere, bypassing the turbine 152. A wastegate valve (WGV) 109 is provided midway along the exhaust bypass passage 108.

[0032] The WGV 109 is a valve that opens and closes the exhaust bypass passage 108. Specifically, the WGV 109 is connected inside the crankcase of the internal combustion engine 100, and opens to allow ventilation in only one direction when the internal pressure of the intake manifold is lower than that of the crankcase. The WGV 109 can be adjusted to any opening angle by a pressure-regulating or electric actuator (not shown). When the WGV 109 is open, the exhaust passes through the exhaust bypass passage 108, improving fuel economy but reducing acceleration. Conversely, when the WGV 109 is closed, fuel economy decreases but acceleration improves.

[0033] The blow-by gas passage 110 is a passage that connects the internal combustion engine 100 and the intake passage 101 in order to process blow-by gas generated inside the internal combustion engine 100. More specifically, one end of the blow-by gas passage 110 is connected to the internal combustion engine 100. The blow-by gas passage 110 branches into a light load blow-by gas passage 113 and a high load blow-by gas passage 114 midway.

[0034] Here, the passage that is connected to the intake passage 101 downstream of the throttle valve 106 after branching is referred to as a light load blow-by gas passage 113. Also, the passage that is connected to the intake passage 101 upstream of the compressor 151 after branching is referred to as a high load blow-by gas passage 114.

[0035] The PCV valve 111 is a valve that operates in response to intake negative pressure. The PCV valve 111 is provided in the light load blow-by gas passage 113. Under a light load, the PCV valve 111 opens. Therefore, blow-by gas in an amount corresponding to the intake manifold negative pressure downstream of the throttle valve 106 is introduced into the intake passage 101 via the light load blow-by gas passage 113. This blow-by gas is introduced into the intake passage 101 downstream of the throttle valve 106. On the other hand, under a high load (supercharging), the PCV valve 111 closes. Therefore, the blow-by gas is introduced into the intake passage 101 upstream of the compressor 151 via the high load blow-by gas passage 114.

[0036] The controller 112 is a device that controls the internal combustion engine control system 10. The controller 112 also functions as a device that controls the WGV 109.

[0037] As shown in FIG. 2, the controller 112 includes a load measuring unit 201, a load determining unit 202, and a wastegate valve control unit 203 as internal components.

[0038] The load measurement unit 201 has a function of measuring the load applied to the internal combustion engine 100. The load measurement unit 201 is electrically connected to the accelerator opening signal and brake signal of the vehicle. That is, the load changes depending on the accelerator operation or brake operation. When the load is high, the accelerator opening becomes larger, and when the load is low, the accelerator opening becomes smaller. Furthermore, when the load is high, the brakes are applied suddenly, and when the load is low, the brakes are applied gently. When the load is high, the rotation speed of the internal combustion engine 100 increases, and when the load is low, the rotation speed of the internal combustion engine 100 decreases. Similarly, when the load is high, the acceleration of the vehicle equipped with the internal combustion engine 100 increases, and when the load is low, the acceleration of the vehicle equipped with the internal combustion engine 100 decreases.

[0039] The load determining unit 202 has a function of determining whether or not the load is low for a predetermined period of time and whether or not the change in the load is within a predetermined range. The load determining unit 202 is connected to the load measuring unit 201. The load determining unit 202 determines whether or not the load measured by the load measuring unit 201 is low. For example, a threshold indicating the upper limit of the low load region is set in advance in the load determining unit 202. The load determining unit 202 compares the measured load with the threshold to determine whether or not the load is low. In other words, if the measured load is equal to or less than the threshold, the load determining unit 202 determines that the load is in the low load region, and if the measured load is greater than the threshold, the load determining unit 202 determines that the load is not in the low load region.

[0040] Furthermore, the load determination unit 202 determines a change in the load measured by the load measurement unit 201. The predetermined period is a certain period during which the vehicle equipped with the internal combustion engine 100 is traveling. In other words, the predetermined period is a certain period during which the internal combustion engine 100 is operating. The predetermined periods may be set consecutively, at intervals, or overlapping. The change in load is a change in the driver's accelerator work and brake work. The change in load being within a predetermined range means that the accelerator work and brake work fall within a certain range.

[0041] That is, the load determining unit 202 determines whether the driver's acceleration and deceleration are within a certain range during a certain period while the vehicle is running. When the acceleration and deceleration are within this range, the vehicle is said to be in a steady state.

[0042] The wastegate valve control unit 203 is connected to the load determination unit 202. The wastegate valve control unit 203 has a function of prohibiting the closing control of the wastegate valve 109 when the load is in the low load region and in the steady state, according to the determination of the load determination unit 202. The wastegate valve control unit 203 also has a function of controlling the wastegate valve 109 to close when the load is not in the low load region or the steady state, according to the determination of the load determination unit 202. The closing control means that the wastegate valve 109 may be completely closed or partially closed.

[0043] By using this internal combustion engine control system 10, the closing control of the wastegate valve 109 is always prohibited when the engine is in a low load region and in a steady state, thereby improving fuel economy.

[0044] In addition, the driver may set a high load mode, such as SPORT mode or POWER mode, which prioritizes acceleration over fuel economy. When the driver sets the high load mode, the wastegate valve control unit 203 controls the wastegate valve 109 to close even in the low load region and steady state.

[0045] When the driver selects a high-load mode such as POWER mode or SPORT mode, the internal combustion engine control system 10 determines that the driver intends to prioritize acceleration over fuel economy, and the wastegate valve control unit 203 controls the wastegate valve 109 to close.

[0046] Furthermore, the load determination unit 202 determines the load measured by the load measurement unit 201 in the low load region and in the steady state. When the load determination unit 202 determines that the load exceeds a predetermined threshold, the wastegate valve control unit 203 controls the wastegate valve 109 to close.

[0047] When the driver depresses the accelerator pedal quickly, for example, and the accelerator opening degree changes at a rate equal to or greater than a predetermined rate, the internal combustion engine control system 10 determines that the driver intends to accelerate strongly, and controls the wastegate valve 109 to close.

[0048] (Description of the control method for the internal combustion engine according to this embodiment) Fig. 3 is a flowchart showing an example of the operation of the controller according to this embodiment. Fig. 4 is a flowchart showing another example of the operation of the controller according to this embodiment. Fig. 5 is a flowchart showing yet another example of the operation of the controller according to this embodiment. A control method for an internal combustion engine according to this embodiment will be described with reference to Figs. 3 to 5.

[0049] The process starts with the internal combustion engine in operation, and the following steps are executed. Referring to Fig. 3, first, the load measurement unit 201 measures the load applied to the internal combustion engine 100 (S301). Next, the load determination unit 202 determines whether the load is low (S302). If the load is not low (NO in S302), the wastegate valve control unit 203 controls the WGV 109 to close and ends the process (S305). If the load is low (YES in S302), the load determination unit 202 determines whether the change in load is within a predetermined range for a predetermined period of time (S303).

[0050] If the load change is within a predetermined range (YES in S303), the wastegate valve control unit 203 determines that the load is in the low load region and in a steady state, and prohibits the wastegate valve (WGV) 109 from closing, and ends the process (S304). If the load change is not within the predetermined range (NO in S303), the wastegate valve control unit 203 closes the WGV 109, and ends the process (S305).

[0051] By doing so, the closing control of the wastegate valve 109 is always prohibited in the low load region and in the steady state, thereby improving fuel economy.

[0052] 4, the process begins with the internal combustion engine 100 operating and the vehicle in a low load region and in a steady state (S401). Next, the controller 112 determines whether the vehicle is set to a high load mode such as SPORT mode or POWER mode (S402).

[0053] If the high load mode is set (YES in S402), the wastegate valve control unit 203 closes the WGV (S403). If the high load mode is not set (NO in S402), the wastegate valve control unit 203 determines that the engine is in the low load region and in a steady state, and prohibits the closing control of the WGV 109 and ends the process.

[0054] By doing this, when the driver selects a high load mode such as POWER mode or SPORT mode, it is determined that the driver intends to prioritize acceleration over fuel economy, and the wastegate valve control unit 203 controls the WGV 109 to close.

[0055] 5, the process starts with the internal combustion engine 100 operating and the vehicle being in a low load region and in a steady state (S501). Next, the load determination unit 202 determines whether the load measured by the load measurement unit 201 exceeds a predetermined threshold value (S502).

[0056] If the load exceeds a predetermined threshold (YES in S502), the wastegate valve control unit 203 controls the WGV 109 to close and ends the process (S503). That is, because the load determination unit 202 determines that the load is not in the low load region, the wastegate valve control unit 203 controls the WGV 109 to close. If the load does not exceed the threshold (NO in S502), the load is in the low load region and in a steady state, and the wastegate valve control unit 203 ends the process while prohibiting the WGV 109 from closing.

[0057] In this way, if the driver depresses the accelerator pedal quickly, for example, and the accelerator opening degree changes at a rate equal to or greater than a predetermined rate, it is determined that the driver intends to accelerate strongly, and the wastegate valve control unit 203 performs control to close the WGV 109.

[0058] Furthermore, some or all of the processes in the controller 112 described above can be implemented as a computer program. Such a program can be stored and provided to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible recording media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be provided to a computer by various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable media can provide the program to a computer via a wired communication path such as an electric wire or optical fiber, or via a wireless communication path.

[0059] By having the controller 112 execute such a control program for the internal combustion engine, the closing control of the wastegate valve 109 is always prohibited when the engine is in a low load region and in a steady state, thereby improving fuel economy.

[0060] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0061] 10 Internal combustion engine control system 100 Internal combustion engine 101 Intake passage 102 Exhaust passage 103 Air flow meter 104 Intake air temperature sensor 105 Turbocharger 106 Throttle valve 107 Throttle position sensor 108 Exhaust bypass passage 109 Wastegate valve 110 Blow-by gas passage 111 PCV valve 112 Controller 113 Blow-by gas passage under light load 114 Blow-by gas passage under high load 152 Turbine 151 Compressor 153 Connecting shaft 201 Load measurement section 202 Load judgment section 203 Wastegate valve control unit

Claims

1. an internal combustion engine to which a load is applied by a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, The brake operation is such that a high load is applied during sudden braking and a low load is applied during gentle braking. The controller a load measuring unit that measures the load applied to the internal combustion engine; a load determining unit that determines whether a load is low for a predetermined period of time and whether a change in the load is within a predetermined range; When the load is low for the predetermined period and the change in the load is within the predetermined range, it is determined that the engine is in a low load region and a steady state, and the closing control of the wastegate valve is prohibited; a wastegate valve control unit that controls to close the wastegate valve when the load is not low during the predetermined period or when the change in the load is not within the predetermined range.

2. It has a high load mode that prioritizes high load over low fuel consumption.

2. The internal combustion engine control system according to claim 1, wherein when the steady state is determined and the driver sets the high load mode, the wastegate valve control unit controls the wastegate valve to close.

3. 3. The internal combustion engine control system according to claim 1, wherein, when the steady state is determined, the load measurement unit measures the load and the load determination unit determines that the load exceeds a predetermined threshold, the wastegate valve control unit controls to close the wastegate valve.

4. A control method for an internal combustion engine including: an internal combustion engine to which a load is applied by a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, The brake operation is such that a high load is applied during sudden braking and a low load is applied during gentle braking. measuring the load applied to the internal combustion engine; determining whether there is a low load for a predetermined period of time and whether the change in the load is within a predetermined range; determining that the engine is in a low load region and in a steady state when the load is low for the predetermined period and the change in the load is within the predetermined range, and prohibiting control to close the wastegate valve; and controlling the wastegate valve to close when the load is not low during the predetermined period or when the change in the load is not within the predetermined range.

5. A control program for an internal combustion engine including: an internal combustion engine to which a load is applied by a brake operation by a driver; a supercharger connected to an exhaust passage of the internal combustion engine; a wastegate valve provided in a passage of the exhaust passage that bypasses the supercharger; and a controller that controls the internal combustion engine, the supercharger, and the wastegate valve, The brake operation is such that a high load is applied during sudden braking and a low load is applied during gentle braking. measuring the load applied to the internal combustion engine; determining whether there is a low load for a predetermined period of time and whether the change in the load is within a predetermined range; determining that the engine is in a low load region and in a steady state when the load is low for the predetermined period and the change in the load is within the predetermined range, and prohibiting control to close the wastegate valve; and controlling the wastegate valve to close when the load is not low during the predetermined period or when a change in the load is not within the predetermined range.

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