Control device for internal combustion engine

Abstract

To improve fuel economy in an internal combustion engine performing torque reserve control.SOLUTION: The control device 90 for an internal combustion engine according to the present invention includes the torque reserve control unit 97 that executes the torque reserve control of securing the reserve torque by increasing the intake air amount adjusted by the throttle valve 34 and the fuel injection amount injected by the fuel injector 51 in advance in preparation for an increase in the required torque required as the output torque, and reducing the output torque increased by the secured reserve torque by the reduction means. When the driver monitoring system 91 detects the switching operation of the electric load by the driver, the torque reserve control unit 97 can improve the fuel efficiency by executing the torque reserve control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device for an internal combustion engine. [Background technology]

[0002] 2. Description of the Related Art Internal combustion engines that perform torque reserve control are known. Patent Document 1 discloses a torque control device for an internal combustion engine that is equipped with torque control means that performs torque reserve control to realize the required torque by offsetting an intake air amount control value set in accordance with the required torque in the torque increasing direction by a predetermined torque margin value and canceling the torque increase due to this offset of the intake air amount control value by offsetting the ignition timing in the retarding direction.In this torque control device for an internal combustion engine, when an idle speed control execution condition is met, the throttle opening is controlled to feedback control the intake air amount so that the engine speed matches a target idle speed, and torque reserve control is also performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-138300 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the torque control device for an internal combustion engine in Patent Document 1 has a problem in that while the conditions for executing idle rotation speed control are met, torque reserve control is performed, which increases the fuel injection amount and worsens fuel economy. The present invention has been made in view of the above-mentioned problems, and has as its object to improve fuel economy in an internal combustion engine that performs torque reserve control. [Means for solving the problem]

[0005] The present invention is a control device for an internal combustion engine that has a throttle valve that adjusts the amount of intake air supplied and a fuel injector that injects fuel, and generates output torque by burning a mixture of intake air and fuel, and has a control unit that, in preparation for an increase in the required torque required as output torque, secures reserve torque by increasing in advance the amount of intake air adjusted by the throttle valve and the amount of fuel injected by the fuel injector, and performs torque reserve control that reduces the output torque that increases due to the secured reserve torque by a reduction means, and is characterized in that the control unit executes the torque reserve control when a driver monitoring system detects an operation of switching an electrical load by the driver. [Effects of the Invention]

[0006] According to the present invention, it is possible to improve fuel economy in an internal combustion engine that performs torque reserve control. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing a schematic configuration of a vehicle equipped with a control device for an internal combustion engine. [Figure 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a control device. [Figure 3] 10 is a flowchart illustrating an example of processing by a control device. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment according to the present invention is a control device 90 for an internal combustion engine that includes a throttle valve 34 that adjusts the amount of intake air supplied and a fuel injector 51 that injects fuel, and that generates output torque by burning a mixture of intake air and fuel. The control device 90 has a torque reserve control unit 97 that, in preparation for an increase in the torque required as output torque, ensures reserve torque by increasing the intake air amount adjusted by the throttle valve 34 and the fuel injection amount injected by the fuel injector 51 in advance, and performs torque reserve control to reduce the output torque that increases due to the ensured reserve torque using a reduction unit. The torque reserve control unit 97 performs torque reserve control when a driver monitoring system 91 detects an operation of switching an electric load by the driver, thereby improving fuel efficiency in an internal combustion engine that performs torque reserve control. [Example]

[0009] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a diagram showing a schematic configuration of a vehicle 1 equipped with a control device for an internal combustion engine (hereinafter referred to as the control device) according to this embodiment. Note that Fig. 1 is simplified for the sake of convenience in explaining this embodiment, and components that are normally included in a vehicle are assumed to be included even if they are not shown in the figure.

[0010] The vehicle 1 of this embodiment includes an engine 10 as an internal combustion engine, a sensor section 60, an electrical equipment section 70, a driver monitor camera 80, a control device 90, and the like. The engine 10 has an engine body 11, an intake system 30 that takes in intake air for combustion in the engine body 11, an exhaust system 40 that discharges exhaust gas from the engine body 11 to the outside, and a fuel system 50 that supplies fuel to the engine body 11.

[0011] Engine body 11 performs a series of strokes consisting of an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. Engine body 11 has a combustion chamber 13 in which a piston 12 is housed so that it can reciprocate, a crank chamber 15 in which a crankshaft 14 is rotatably housed, an intake port 16 which is an inlet for intake air for combustion, and an exhaust port 17 which is an outlet for exhaust gas. Engine body 11 also has an ignition plug 18 positioned so that its tip is located within combustion chamber 13, an intake valve 19 located between combustion chamber 13 and intake port 16, and an exhaust valve 20 located between combustion chamber 13 and exhaust port 17. The ignition timing of spark plug 18 is controlled by a control device 90.

[0012] During the intake stroke, the piston 12 descends from top dead center to bottom dead center, the intake valve 19 opens, and the exhaust valve 20 closes. As the piston 12 descends, a mixture of intake air and fuel flows from the intake system 30 into the combustion chamber 13. During the compression stroke, the piston 12 moves upward from the bottom dead center toward the top dead center, and the intake valve 19 and the exhaust valve 20 close. As the piston 12 moves upward, the air-fuel mixture is compressed.

[0013] During the combustion stroke, the compressed air-fuel mixture is ignited by the spark plug 18 and combusted, pushing the piston 12 downward from top dead center to bottom dead center. During the exhaust stroke, the piston 12 rises from bottom dead center to top dead center, the intake valve 19 closes, and the exhaust valve 20 opens. As the piston 12 rises, exhaust gases generated during the combustion stroke are discharged into the exhaust system 40.

[0014] As the engine body 11 repeats a series of processes, output torque is transmitted from the engine body 11 to the drive wheels via the crankshaft 14, causing the vehicle 1 to run. The configuration of the engine body 11 is not particularly limited, and various known engines can be applied. Furthermore, the engine body 11 may be either a gasoline engine or a diesel engine.

[0015] The intake system 30 includes an intake passage 31, an air cleaner 33, and a throttle valve 34. The intake passage 31 is a passage that guides intake air taken in from outside the vehicle 1 to the combustion chamber 13 via the intake port 16. The intake passage 31 is mainly composed of an intake pipe 32. The air cleaner 33 is disposed in the intake passage 31 and purifies the intake air by removing foreign matter such as dust and dirt contained in the intake air. The throttle valve 34 is disposed in the intake passage 31 and adjusts the amount of intake air by opening and closing it. The opening and closing of the throttle valve 34 is controlled by a control device 90.

[0016] The exhaust system 40 includes an exhaust passage 41 and a catalyst (catalytic converter) 43. The exhaust passage 41 is a passage through which exhaust gas burned in the combustion chamber 13 is exhausted to the outside of the vehicle 1 via the exhaust port 17. The exhaust passage 41 is mainly composed of an exhaust pipe 42. The catalyst 43 purifies harmful substances contained in the exhaust gas.

[0017] The fuel system 50 supplies fuel to the engine body 11. The fuel system 50 includes a fuel tank, a fuel pump, and a fuel injector 51. The fuel pump supplies fuel stored in the fuel tank to the fuel injector 51. The fuel injector 51 injects the fuel supplied from the fuel tank into the intake passage 31. The fuel injector 51 adjusts the fuel injection amount based on the control of the control device 90. Furthermore, the fuel injector 51 is not limited to injecting fuel into the intake passage 31, and may be configured to inject fuel into the combustion chamber 13 or the intake port 16.

[0018] The sensor unit 60 detects the state of the vehicle 1 or operations by the driver, and transmits the detected results to the control device 90. As shown in Fig. 2, the sensor unit 60 includes an accelerator opening sensor 61, a crank angle sensor 62, a throttle opening sensor 63, an intake pressure sensor 64, an illuminance sensor 65, an interior temperature sensor 66, an exterior temperature sensor 67, and the like. The accelerator pedal position sensor 61 detects the stroke of the accelerator pedal operated by the driver. The crank angle sensor 62 detects the crank angle of the crankshaft 14 . The throttle opening sensor 63 detects the throttle opening of the throttle valve 34 . The intake pressure sensor 64 detects the intake pressure of the intake air flowing through the intake passage 31 . The illuminance sensor 65 detects the illuminance outside the vehicle. The interior temperature sensor 66 detects the temperature inside the vehicle. The outside temperature sensor 67 detects the temperature outside the vehicle.

[0019] The electrical equipment unit 70 is a device that generates an electrical load when activated. Here, the electrical equipment unit 70 is activated by switching from a non-activated state (off) to an activated state (on) when the driver accesses a physical switch (including a button) or an electronically displayed switch (including a button). When the electrical equipment unit 70 switches to the activated state, an electrical load switching signal is sent from the electrical equipment unit 70 to the control device 90.

[0020] Here, the electrical equipment unit 70 includes an air conditioner, a headlight unit, a power window unit, and the like. The air conditioner unit operates when an alternator generates electricity using the output torque of the engine body 11 and the generated electricity drives a compressor. The air conditioner unit is activated, for example, by the driver operating a switch located on the instrument panel in front of the driver's seat. The headlight unit and the power window unit operate using electricity from the battery, which generates electricity using the output torque of the engine body 11 and stores the generated electricity in a battery. The headlight unit is activated (turned on) by the driver operating a switch located at the tip of a lever located in front of the steering wheel, for example. The power window unit is activated by the driver operating a switch located on the front door of the driver's seat, for example. Regardless of the type of electrical equipment 70, when the electrical equipment 70 is in a driven state, the electrical load increases, and therefore an alternator is required to generate electricity. Therefore, when the electrical equipment 70 is in a driven state, more output torque is required to drive the alternator than when the electrical equipment 70 is in a non-driven state.

[0021] The driver monitor camera 80 captures the driver's condition. The driver monitor camera 80 of this embodiment is set in a shooting direction and angle of view so that it can capture not only the driver's face but also the operation of the driver's hands. The video signal captured by the driver monitor camera 80 is transmitted to the control device 90.

[0022] The control device 90 controls the entire vehicle 1. The control device 90 can be, for example, an ECU (Electronic Control Unit). The control device 90 has a CPU, ROM, RAM, etc. as a hardware configuration. The ROM stores, in advance, for example, programs and predetermined information for controlling the engine 10, the electrical equipment unit 70, etc. The RAM is a work memory that temporarily stores programs and data. The CPU reads out programs stored in the ROM, expands them in the RAM, and executes them to control the engine 10, the electrical equipment unit 70, etc. Note that the control device 90 may be configured with one ECU or multiple ECUs.

[0023] FIG. 2 is a diagram showing an example of the internal configuration of the control device 90. As shown in FIG. The control device 90 includes a driver monitoring system (DMS) 91, an engine ECU (ECM), and the like. The driver monitoring system 91 is a system that detects the driver's state based on the video signal from the driver monitor camera 80 and issues an alert when the detected driver's state is a predetermined state. For example, when the driver monitoring system 91 detects that the driver is dozing, drowsy, or looking away, it can emit an alarm from a speaker or display an alarm on a display.

[0024] The driver monitoring system 91 of this embodiment includes a motion detection unit 92 and a signal transmission unit 93 . The operation detection unit 92 detects, based on the video signal from the driver monitor camera 80, an operation (electric load switching operation) of the driver that is a precursor to switching the electrical component 70 from a non-operating state to an operating state. When the operation detection unit 92 detects the driver's switching operation of the electric load, the signal transmission unit 93 transmits a switching operation signal to the engine ECU 95 at a timing earlier than the timing when the driver actually switches the electrical equipment unit 70 from a non-operating state to an operating state.

[0025] The engine ECU 95 calculates the required torque required as the output torque based on information such as the amount of accelerator pedal stroke detected by the accelerator opening sensor 61, the crank angle detected by the crank angle sensor 62, the throttle opening detected by the throttle opening sensor 63, and the intake pressure detected by the intake pressure sensor 64. The engine ECU 95 drives the engine 10 by controlling the intake amount via the throttle valve 34, controlling the ignition timing for igniting the air-fuel mixture via the spark plug 18, and controlling the timing and amount of fuel injection from the fuel injector 51 so as to output the calculated required torque. Furthermore, when the electrical equipment unit 70 is in a driven state, the engine ECU 95 calculates a required torque that is increased by an amount corresponding to the alternator being driven compared to when the electrical equipment unit 70 is not driven.

[0026] The engine ECU 95 of this embodiment includes an idle control unit 96 and a torque reserve control unit 97 . When the idle control execution condition is met in an idle operating state or an operating state close to the idle operating state, the idle control unit 96 executes idle rotation speed control to adjust the intake amount by controlling the throttle opening of the throttle valve 34 so that the engine rotation speed becomes a target idle engine rotation speed.

[0027] The torque reserve control unit 97 executes torque reserve control when the idle speed control is being executed by the idle control unit 96. The torque reserve control unit 97 receives information on the required torque calculated by the engine ECU 95. Here, torque reserve control is broadly divided into two types of control. The first control is a control that prepares for an increase in the required torque required as output torque by increasing the intake amount adjusted by the throttle valve 34 in advance and the fuel injection amount injected by the fuel injector 51 to ensure reserve torque, and reduces the output torque that increases due to the ensured reserve torque by retarding the ignition timing of the spark plug 18. The second control is a control in which, when the required torque actually increases, the ignition timing of the spark plug 18 that has been retarded is advanced to quickly make the output torque follow the required torque.

[0028] Generally, since the driver's operation of switching the electric load cannot be predicted, when the idle speed control is being executed, the torque reserve control (first control) is always executed in preparation for the driver's operation of switching the electric load. However, while the torque reserve control (first control) is being executed, the fuel injection amount increases, which deteriorates fuel efficiency. Therefore, in order to improve fuel efficiency, the control device 90 of this embodiment does not always execute torque reserve control (first control) while executing idle speed control, but executes torque reserve control (first control) when the driver monitoring system 91 detects an electrical load switching operation by the driver.

[0029] An example of specific processing by the control device 90 will be described below with reference to the flowchart in Fig. 3. The flowchart in Fig. 3 begins when the engine 10 is started and the idle control unit 96 executes idle speed control. Note that torque reserve control is not being executed when the flowchart in Fig. 3 begins.

[0030] In S10, the behavior detector 92 of the driver monitoring system 91 executes a process of detecting the behavior of the driver based on the video signal from the driver monitor camera 80.

[0031] In S11, the operation detection unit 92 determines, based on the detection result, whether or not the driver's operation is an operation to switch an electric load on the electrical component unit 70. Note that the determination of whether or not the operation is an operation to switch an electric load is not limited to the video signal from the driver monitor camera 80, but may also refer to information detected by the illuminance sensor 65, the interior temperature sensor 66, or the exterior temperature sensor 67. If the operation is an operation to switch an electric load, the process proceeds to S12, and if not, the process returns to S10.

[0032] Here, the determination of the switching operation of the electric load differs depending on the type of the electrical component 70 (air conditioner unit, headlight unit, power window unit), as follows. (1) When the electrical equipment unit 70 is an air conditioner, the driver operates the air conditioner when the inside of the vehicle is hot or cold, and the following operation corresponds to the switching operation of the electrical load. Driver frequently wipes his face Driver frequently exhales Driver adjusting clothing (e.g. pulling on collar or opening neckline) Driver reaching for the air conditioning switch It may also be determined that an electric load switching operation has occurred when any of the above operations has occurred and the temperature detected by the vehicle interior temperature sensor 66 or the temperature detected by the vehicle exterior temperature sensor 67 is equal to or higher than a threshold (or equal to or lower than a threshold). It may also be determined that an electric load switching operation has occurred when several of the above four operations have occurred consecutively.

[0033] (2) When the electrical equipment unit 70 is a headlight device, the driver operates the headlight device when it is dark outside the vehicle and driving is difficult. Therefore, the following operation corresponds to the switching operation of the electrical load. Driver frowning or squinting The driver leans forward towards the windshield and stares out The driver's movement to reach for the headlight switch It may also be determined that an electric load switching operation has occurred when any of the above operations has occurred and the illuminance detected by the illuminance sensor 65 is equal to or lower than a threshold value. It may also be determined that an electric load switching operation has occurred when several of the above three operations have occurred consecutively.

[0034] (3) When the electrical equipment unit 70 is a power window device, the driver operates the power window device when he or she wants to relieve stress or ventilate the air inside the vehicle, and therefore the following operations correspond to the switching operation of the electrical load. - The driver shakes their head from side to side multiple times within a certain period of time. - Drivers shaking their bodies back and forth or their shoulders up and down multiple times within a certain period of time The driver's movement to reach for the power window switch It may also be determined that an electrical load switching operation has occurred when several of the above three operations occur consecutively.

[0035] If the operation detection unit 92 detects an electric load switching operation in S11 and the process proceeds to S12, the signal transmission unit 93 of the driver monitoring system 91 transmits an electric load switching operation signal to the torque reserve control unit 97. The electric load switching operation signal includes information on the type of the electrical component 70 (air conditioner unit, headlight unit, power window unit).

[0036] In S12, the torque reserve control unit 97 executes torque reserve control. Specifically, as a first control of the torque reserve control, the torque reserve control unit 97 executes a process of securing reserve torque by increasing the intake amount adjusted by the throttle valve 34 and the fuel injection amount injected by the fuel injector 51 in preparation for an increase in the required torque required as output torque, and of retarding the ignition timing of the spark plug 18 to reduce the output torque that is increased by the secured reserve torque.

[0037] The torque reserve control unit 97 secures reserve torque according to the type of electrical component 70 contained in the electrical load switching operation signal transmitted from the driver monitoring system 91. For example, when the torque reserve control unit 97 receives a switching operation signal based on the switching operation of the electrical load for the air conditioner, it secures reserve torque necessary to drive the air conditioner. Information on the reserve torque necessary for each type of electrical component 70 (information on the increase in intake amount, information on the increase in fuel injection amount, etc.) is stored in the engine ECU 95.

[0038] In S13, the torque reserve control unit 97 determines whether a predetermined time has elapsed since the driver monitoring system 91 detected the driver's operation to switch the electric load. Specifically, the torque reserve control unit 97 determines whether a predetermined time has elapsed since the torque reserve control unit 97 received an electric load switching operation signal from the driver monitoring system 91. Information about the predetermined time is stored in the engine ECU 95. If the predetermined time has elapsed, the process proceeds to S14, and if the predetermined time has not elapsed, the process returns to S13.

[0039] In S14, the torque reserve control unit 97 determines whether or not an electrical load has actually been switched. Specifically, if an electrical load has actually been switched, the electrical equipment unit 70 sends an electrical load switching signal to the engine ECU 95, which causes the engine ECU 95 to calculate and increase the required torque by an amount corresponding to driving the alternator, and sends information about the increased required torque to the torque reserve control unit 97. Therefore, the torque reserve control unit 97 can determine that an electrical load has been switched when it receives information about the increased required torque. If an electrical load has been switched, the process proceeds to S15.

[0040] In S15, the torque reserve control unit 97 continues the torque reserve control. Specifically, as a second control of the torque reserve control, the torque reserve control unit 97 executes a process of advancing the ignition timing of the spark plug 18, which had been retarded in advance, in response to an actual increase in the required torque, thereby causing the output torque to follow the required torque.

[0041] If there is no switching of the electric load in S14, the process proceeds to S16. In S16, the torque reserve control unit 97 stops the torque reserve control. Specifically, the torque reserve control unit 97 restores the intake air amount that had been increased by the throttle valve 34 and the fuel injection amount that had been increased by the fuel injector 51, thereby canceling the reserve torque. Therefore, the engine body 11 transitions to a state in which the idle speed control is being executed but the torque reserve control is not being executed.

[0042] After the processing of S15 and the processing of S16, the flow chart of Fig. 3 ends. While the idle speed control is being executed, the flow chart of Fig. 3 is repeatedly executed until the driving of the engine 10 is stopped.

[0043] As described above, according to this embodiment, the torque reserve control unit 97 executes torque reserve control when the driver monitoring system 91 detects an operation to switch the electric load by the driver. Therefore, until an operation to switch the electric load is detected, the torque reserve control is not executed and the amount of fuel injected by the fuel injector 51 does not increase, thereby improving fuel economy.

[0044] Furthermore, according to this embodiment, the torque reserve control unit 97 suspends the torque reserve control if the electric load is not switched within a predetermined time after the driver monitoring system 91 detects a switching operation by the driver. Even if the electric load switching operation is detected, if the torque reserve control is continued when the electric load is not actually switched, fuel economy will deteriorate. Therefore, by suspending the torque reserve control when the electric load is not actually switched within a predetermined time after the driver's switching operation is detected, fuel economy can be improved.

[0045] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and modifications and the like are possible within the scope of the present invention. In the above-described embodiment, the torque reserve control is described as a control for reducing the output torque that is increased by the ensured reserve torque by retarding the ignition timing of the spark plug 18. However, the reduction of the output torque is not limited to retarding the ignition timing of the spark plug 18, and other torque reduction means may be used. As other torque reduction means, for example, a means for controlling the fuel injection timing or a means for controlling the opening and closing timing of the intake and exhaust valves by a variable valve timing mechanism may be used.

[0046] In the above-described embodiment, the driver monitor camera 80 is described as being set in a shooting direction and angle of view so that it can capture not only the driver's face but also the operation at hand, but it may also be installed in a position where it can focus on the operation at hand. Also, the driver monitor camera 80 may be configured with multiple cameras, including a camera that captures the driver's face and a camera that captures the operation at hand. [Explanation of symbols]

[0047] 1: Vehicle 10: Engine 11: Engine body 12: Piston 13: Combustion chamber 18: Spark plug 34: Throttle valve 51: Fuel injector 60: Sensor section 70: Electrical section 80: Driver monitor camera 90: Control device 91: Driver monitoring system 92: Operation detection section 93: Signal transmission section 95: Engine ECU 96: Idle control section 97: Torque reserve control section

Claims

1. A control device for an internal combustion engine that is equipped with a throttle valve that adjusts the amount of intake air supplied and a fuel injector that injects fuel, and that generates output torque by burning a mixture of intake air and fuel, a control unit that executes torque reserve control in which, in preparation for an increase in torque required as output torque, the intake amount adjusted by the throttle valve and the fuel injection amount injected by the fuel injector are increased in advance to ensure reserve torque, and the output torque that increases due to the ensured reserve torque is reduced by a reducing means; The control unit 10. A control device for an internal combustion engine, comprising: a driver monitoring system that executes the torque reserve control when the driver has detected an operation of switching an electric load by the driver;

2. The control unit 2. The control device for an internal combustion engine according to claim 1, wherein the torque reserve control is stopped if the electric load is not switched within a predetermined time after the driver monitoring system detects the electric load switching operation by the driver.

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