Control device for internal combustion engine

Abstract

To provide a control device of an internal combustion engine capable of improving fuel consumption and suppressing the deterioration of emission performance, by suppressing the generation of unburned gas.SOLUTION: A control device of an internal combustion engine is equipped with a temperature sensor 34 that detects the temperature of an engine 2, a fuel amount calculating portion 31 that calculates the maximum fuel amount capable of evaporating in a combustion chamber 7 of the engine 2 from the temperature of the engine 2, a torque calculating portion 32 that calculates the estimated maximum torque that is torque that can be outputted by the engine 2 according to the maximum fuel amount, and a control portion 33 that performs torque limit for limiting fuel injection amount to the maximum fuel amount so that the output of the engine 2 becomes the estimated maximum torque when a driver demand torque becomes larger than the estimated maximum torque.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 aims to provide a control device for an internal combustion engine that can enhance the effect of reducing HC (hydrocarbon) and PN (particulate number) in exhaust gas in accordance with the combustion state in the cylinder of the internal combustion engine, and describes that when the ECU determines that the engine is in a wet condition, it controls the opening and closing timing using the variable valve device to reduce the amount of intake air, and when it determines that the engine is in a suspended droplet condition, it controls the opening and closing timing using the variable valve device to increase the in-cylinder temperature. Note that both the wet condition and the suspended droplet condition are conditions in which fuel is not vaporized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-79580 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the control described in Patent Document 1 is a control for starting the engine, and it is thought that during normal driving, the amount of fuel injected corresponds to the torque requested by the driver and the requested torque is output. Even during normal driving, there is a concern that unvaporized fuel may generate unburned gas, resulting in a deterioration in emission performance.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can suppress the generation of unburned gas, improve fuel efficiency, and suppress deterioration of emission performance. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: A control device for an internal combustion engine that injects fuel into an intake port, Internal combustion engine The intake port a temperature sensor for detecting a temperature of the internal combustion engine; The intake port The system comprises a fuel quantity calculation unit that calculates the maximum amount of fuel that can be vaporized in the combustion chamber of the internal combustion engine from the temperature, a torque calculation unit that calculates an estimated maximum torque that can be output by the internal combustion engine based on the maximum fuel quantity, and a control unit that performs torque limitation by limiting the fuel injection quantity to the maximum fuel quantity when the torque required by the driver becomes greater than the estimated maximum torque so that the output of the internal combustion engine becomes the estimated maximum torque. [Effects of the Invention]

[0007] As described above, according to the present invention, it is possible to suppress the generation of unburned gas, improve fuel economy, and suppress the deterioration of emission performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a control device for an internal combustion engine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the procedure of torque control processing in the control device for an internal combustion engine according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A control device for an internal combustion engine according to one embodiment of the present invention is configured to include a temperature sensor that detects the temperature of the internal combustion engine, a fuel amount calculation unit that calculates the maximum amount of fuel that can be vaporized in the combustion chamber of the internal combustion engine from the temperature of the internal combustion engine, a torque calculation unit that calculates an estimated maximum torque, which is the torque that can be output by the internal combustion engine based on the maximum fuel amount, and a control unit that performs torque limitation by limiting the fuel injection amount to the maximum fuel amount so that the output of the internal combustion engine becomes the estimated maximum torque when the driver's requested torque becomes greater than the estimated maximum torque.

[0010] As a result, the control device for an internal combustion engine according to one embodiment of the present invention can suppress the generation of unburned gas, improve fuel economy, and suppress deterioration of emission performance. [Example]

[0011] Hereinafter, a control device for an internal combustion engine according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0012] In FIG. 1, a vehicle 1 equipped with an internal combustion engine control device according to one embodiment of the present invention includes an internal combustion engine 2 and an ECU (Electronic Control Unit) 3.

[0013] The engine 2 is formed with a cylinder 5 as a cylinder. A piston 6 that can reciprocate up and down within the cylinder 5 is housed in the cylinder 5. A combustion chamber 7 is provided above the cylinder 5.

[0014] The engine 2 is a so-called four-stroke gasoline engine in which a piston 6 performs a series of four strokes, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, during two reciprocating motions of the piston 6 in the cylinder 5.

[0015] The piston 6 is connected to the crankshaft via a connecting rod, which converts the reciprocating motion of the piston 6 into the rotational motion of the crankshaft.

[0016] Further, an ignition plug 8 is provided in the combustion chamber 7. The ignition plug 8 is disposed with an electrode protruding into the combustion chamber 7, and the ignition timing thereof is controlled by the ECU 3.

[0017] The engine 2 is provided with an intake port 11 and an exhaust port 21. The intake port 11 communicates with the combustion chamber 7 and an intake passage (not shown). The intake port 11 is provided with an intake valve 12.

[0018] The intake valve 12 opens and closes to connect or block the intake passage and the combustion chamber 7 .

[0019] An injector 9 is provided in the intake port 11. The injector 9 injects fuel into the intake port 11, the fuel being supplied from a fuel tank (not shown) by a fuel pump.

[0020] Furthermore, a temperature sensor 34 is provided in the intake port 11. The temperature sensor 34 detects the temperature of the engine 2. The temperature sensor 34 may be provided in the cylinder 5.

[0021] On the other hand, an exhaust valve 22 is provided in the exhaust port 21. The exhaust valve 22 opens and closes to connect or block an exhaust passage (not shown) and the combustion chamber 7.

[0022] The ECU 3 is configured by a computer unit that includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

[0023] The ROM of this computer unit stores various control constants, various maps, etc., as well as a program for causing the computer unit to function as the ECU 3. That is, the computer unit functions as the ECU 3 when the CPU executes the program stored in the ROM.

[0024] In addition to the temperature sensor 34 described above, various sensors and switches such as an accelerator opening sensor 35 and a torque limit release switch 36 are connected to the input port of the ECU 3.

[0025] The accelerator position sensor 35 detects the accelerator position, which indicates the amount of operation of an accelerator pedal (not shown) operated by the driver. The torque limit release switch 36 is a switch for selecting whether to release the torque limit that limits the output torque of the engine 2, which will be described later.

[0026] On the other hand, various control targets such as the spark plug 8, the injector 9, and the notification unit 37 are connected to the output port of the ECU 3.

[0027] The notification unit 37 is composed of, for example, a monitor device, a speaker, a lamp, a meter, a buzzer, etc., and notifies the driver of various information visually, audibly, etc.

[0028] The ECU 3 calculates the torque required by the driver based on the accelerator opening detected by the accelerator opening sensor 35, and then calculates the ignition timing, fuel injection amount, and intake air amount of the engine 2 according to the required torque.The ECU 3 then controls the operating state of the engine 2 by controlling the spark plugs 8, the injectors 9, and a throttle valve (not shown) so that the calculated ignition timing, fuel injection amount, and intake air amount are achieved.

[0029] In this embodiment, the ECU 3 calculates the estimated maximum torque, which is the torque that can be output by the engine 2, based on the maximum amount of fuel that can be vaporized in the combustion chamber 7 of the engine 2, and performs torque limitation to limit the output torque of the engine 2 to the estimated maximum torque even if the torque required by the driver is greater than or equal to the estimated maximum torque.

[0030] For this purpose, the ECU 3 includes a fuel amount calculation unit 31, a torque calculation unit 32, and a control unit 33.

[0031] The fuel amount calculation unit 31 calculates the maximum amount of fuel that can be vaporized in the combustion chamber 7 of the engine 2 based on, for example, the temperature of the intake port 11 detected by the temperature sensor 34. The temperature of the intake port 11 may be estimated from the temperature of the cooling water of the engine 2 or the temperature of the intake air.

[0032] Furthermore, a sensor for detecting the temperature inside the combustion chamber 7 may be provided, and the maximum amount of fuel that can be vaporized inside the combustion chamber 7 may be calculated taking that temperature into consideration. The temperature inside the combustion chamber 7 may also be estimated from the temperature of the cooling water of the engine 2 or the temperature of the intake air.

[0033] Furthermore, if the engine 2 is a direct injection engine that injects fuel directly into the combustion chamber 7, the maximum amount of fuel that can be vaporized in the combustion chamber 7 can be calculated by detecting the temperature inside the combustion chamber 7 or estimating it from the temperature of the engine 2's cooling water or the temperature of the intake air.

[0034] Based on the maximum fuel amount calculated by the fuel amount calculation section 31, the torque calculation section 32 calculates an estimated maximum torque that can be output by the engine 2 with the maximum fuel amount.

[0035] When the torque required by the driver becomes greater than the estimated maximum torque, the control unit 33 limits the output torque of the engine 2 to the estimated maximum torque, for example, by limiting the fuel injection amount to the maximum fuel amount calculated by the fuel amount calculation unit 31 so that the output of the engine 2 becomes the estimated maximum torque.

[0036] The control unit 33 notifies the driver by the notification unit 37 that the torque of the engine 2 is being limited to the estimated maximum torque. The notification unit 37 may, for example, light an indicator provided on the instrument panel. Alternatively, the notification may be made by sound, an image, or the like.

[0037] When the torque limit release switch 36 is set to release the torque limit, the control unit 33 releases the torque limit on the engine 2 and controls the engine 2 to output the torque requested by the driver.

[0038] In addition, if the vehicle 1 is equipped with a motor or an ISG (Integrated Starter Generator) as a rotating electric machine that assists the driving force of the engine 2, the control unit 33 may adjust the output of the engine 2 to the estimated maximum torque when the driver's requested torque becomes greater than the estimated maximum torque, and may compensate for the difference between the requested torque and the estimated maximum torque with the torque of the rotating electric machine.

[0039] In addition, in the case of a vehicle that does not have a rotating electric machine, if the torque required by the driver becomes greater than the estimated maximum torque, the control unit 33 may temporarily cut off air conditioning operation and power generation to reduce the torque used for purposes other than driving.

[0040] The torque control process performed by the control device for an internal combustion engine according to this embodiment configured as described above will be described with reference to Fig. 2. The torque control process described below is started when the ECU 3 starts operating, and is executed at preset time intervals.

[0041] In step S1, the ECU 3 determines whether the engine 2 is running. If it is determined that the engine 2 is operating, the ECU 3 executes the process of step S2. If it is determined that the engine 2 is not operating, the ECU 3 executes the process of step S9.

[0042] In step S2, the ECU 3 calculates the maximum amount of fuel that can be vaporized in the combustion chamber 7 from information from the temperature sensor 34. After executing the process of step S2, the ECU 3 executes the process of step S3.

[0043] In step S3, the ECU 3 calculates the estimated maximum torque from the maximum amount of fuel that can be vaporized. After executing the process of step S3, the ECU 3 executes the process of step S4.

[0044] In step S4, the ECU 3 determines whether the torque required by the driver is greater than the estimated maximum torque.

[0045] If it is determined that the torque required by the driver is greater than the estimated maximum torque, the ECU 3 executes the process of step S5. If it is determined that the torque required by the driver is not greater than the estimated maximum torque, the ECU 3 executes the process of step S7.

[0046] In step S5, the ECU 3 limits the output of the engine 2 to the estimated maximum torque. After executing the process of step S5, the ECU 3 executes the process of step S6.

[0047] In step S6, the ECU 3 notifies the driver that the torque is being limited by the notification unit 37. After executing the process of step S6, the ECU 3 executes the process of step S1.

[0048] In step S7, the ECU 3 controls the output of the engine 2 so as to achieve the torque required by the driver. After executing the process of step S7, the ECU 3 executes the process of step S8.

[0049] In step S8, the ECU 3 ends the notification of the torque limitation by the notification unit 37. After executing the process of step S8, the ECU 3 executes the process of step S1.

[0050] In step S9, if the notification unit 37 is currently notifying that torque is being limited, the ECU 3 ends the notification. After executing the process of step S9, the ECU 3 ends the torque control process.

[0051] As described above, this embodiment includes a fuel quantity calculation unit 31 that calculates the maximum amount of fuel that can be vaporized in the combustion chamber 7 of the engine 2 based on the temperature detected by the temperature sensor 34, a torque calculation unit 32 that calculates the estimated maximum torque, which is the torque that can be output by the engine 2 with the maximum fuel quantity, based on the maximum fuel quantity calculated by the fuel quantity calculation unit 31, and a control unit 33 that limits the fuel injection quantity to the maximum fuel quantity so that the output of the engine 2 becomes the estimated maximum torque when the torque required by the driver becomes greater than the estimated maximum torque.

[0052] As a result, the output of the engine 2 is limited to the estimated maximum torque calculated from the maximum amount of fuel that can be vaporized in the combustion chamber 7. In other words, when the engine 2 is used under conditions that would deteriorate emissions performance in response to a driver's request, the amount of fuel injection is limited, thereby limiting the output of the engine 2. This makes it possible to suppress the generation of unburned gas, and further improve fuel efficiency and suppress deterioration of emissions performance.

[0053] Furthermore, the control unit 33 notifies the driver by the notification unit 37 that the torque is being limited so that the output of the engine 2 becomes the estimated maximum torque.

[0054] This notifies the driver that the output torque of the engine 2 is being limited, thereby making it possible to suppress the driver's sense of discomfort regarding the torque limit.

[0055] Furthermore, when torque limit release switch 36 is used to select release of torque limit, control unit 33 releases the torque limit on engine 2 and controls engine 2 to output the torque requested by the driver.

[0056] As a result, when torque limit release switch 36 is used to select release of the torque limit, engine 2 is controlled to output the torque requested by the driver. Therefore, in situations where the driver requires more torque than is limited, such as when climbing a slope or accelerating, torque limit release switch 36 allows the driver to release the limit at his or her will, thereby meeting the driver's request.

[0057] Furthermore, if the vehicle 1 is equipped with a rotating electric machine that assists the driving force of the engine 2, when the torque requested by the driver becomes greater than the estimated maximum torque, the control unit 33 adjusts the output of the engine 2 to the estimated maximum torque, and compensates for the difference between the requested torque and the estimated maximum torque with the torque of the rotating electric machine.

[0058] As a result, in a vehicle equipped with a rotating electric machine, when the torque required by the driver becomes greater than the estimated maximum torque, the difference between the required torque and the estimated maximum torque is compensated for by the torque of the rotating electric machine, which makes it possible to suppress the generation of unburned gas while suppressing the driver's discomfort, and further improve fuel efficiency and suppress deterioration of emission performance.

[0059] In this embodiment, an example has been described in which ECU 3 performs various determinations and calculations based on various sensor information, but this is not limited to this. Vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various determinations and calculations may be performed by the external device based on the detection information of various sensors transmitted from the communication unit. The determination results and calculation results may be received by the communication unit, and various controls may be performed using the received determination results and calculation results.

[0060] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0061] 1 vehicle 2. Engine (internal combustion engine) 3 ECU 7. Combustion chamber 9 Injectors 31 Fuel amount calculation section 32 Torque calculation section 33 Control Unit 34 Temperature Sensor 36 Torque limit release switch 37 Information Department

Claims

1. A control device for an internal combustion engine that injects fuel into an intake port, comprising: a temperature sensor for detecting a temperature of the intake port of the internal combustion engine; a fuel amount calculation unit that calculates a maximum amount of fuel that can be vaporized in a combustion chamber of the internal combustion engine based on a temperature of the intake port of the internal combustion engine; a torque calculation unit that calculates an estimated maximum torque that can be output by the internal combustion engine using the maximum fuel amount; a control unit that, when a driver's requested torque becomes greater than the estimated maximum torque, performs torque limitation by limiting the fuel injection amount to the maximum fuel amount so that the output of the internal combustion engine becomes the estimated maximum torque.

2. 2. The control device for an internal combustion engine according to claim 1, wherein the control unit notifies a driver that the torque restriction is being performed.

3. 3. The control device for an internal combustion engine according to claim 1, further comprising a switch that allows a user to select whether to release the torque limit.

4. a rotating electric machine that assists the driving force of the internal combustion engine, 4. The control device for an internal combustion engine according to claim 1, wherein when a torque required by a driver becomes greater than the estimated maximum torque, the control unit controls the output of the internal combustion engine to become the estimated maximum torque, and compensates for a difference between the required torque and the estimated maximum torque with the torque of the rotating electric machine.

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