Controller of internal combustion engine

Abstract

To provide a controller of an internal combustion engine capable of satisfying torque required by a driver even when using alternate fuel.SOLUTION: A controller of an internal combustion engine comprises: a first fuel injection device 60 capable of injecting alternative fuel into an engine 2; a second fuel injection device 61 capable of injecting hydrogen into a combustion chamber 24 of the engine 2; and an ECU 3 that calculates a differential torque, which is the difference between a torque required of the engine 2 and an actual torque output by the engine 2, and adds hydrogen using the second fuel injection device 61 when the differential torque is equal to or larger than a predetermined value.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 describes that when fuel is combusted in the presence of ozone, the effect of improving combustion is enhanced by strengthening the airflow inside the cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-168802 A Summary of the Invention [Problem to be solved by the invention]

[0004] Gasoline has traditionally been used as fuel. Carbon neutral fuel (hereafter referred to as "CN fuel") is expected to become more common as an alternative to gasoline in the future. CN fuel is produced by synthesizing carbon dioxide and hydrogen.

[0005] CN fuels may have poor evaporation characteristics because the portion of the fuel specification that affects evaporation characteristics may be set close to the lower limit.

[0006] In addition, the fuel properties of CN fuel are not always consistent, resulting in variations in the combustion state. For this reason, the torque required by the driver may not be satisfied.

[0007] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can satisfy the torque required by the driver even when an alternative fuel is used. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a control device for an internal combustion engine that can be run using alternative fuel, comprising a first fuel injection device capable of injecting alternative fuel and a second fuel injection device capable of injecting hydrogen into a combustion chamber, and a control unit capable of adjusting the driving torque of the internal combustion engine, wherein the control unit calculates a differential torque, which is the difference between the required torque of the internal combustion engine and the actual torque output by the internal combustion engine, and when the differential torque is equal to or greater than a predetermined value, adds hydrogen via the second fuel injection device. Effect of the Invention

[0009] Thus, according to the present invention, the torque required by the driver can be met even when alternative fuels are used. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a control device for an internal combustion engine according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing a procedure of a combustion improvement control process of the internal combustion engine control device according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a time chart showing the timing of the combustion improvement control process of the internal combustion engine control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A control device for an internal combustion engine according to one embodiment of the present invention is a control device for an internal combustion engine that can be driven using alternative fuel, and is equipped with a first fuel injection device capable of injecting alternative fuel and a second fuel injection device capable of injecting hydrogen into the combustion chamber, and has a control unit capable of adjusting the driving torque of the internal combustion engine, and the control unit is configured to calculate a differential torque, which is the difference between the required torque of the internal combustion engine and the actual torque output by the internal combustion engine, and to add hydrogen using the second fuel injection device when the differential torque is greater than or equal to a predetermined value.

[0012] As a result, the control device for an internal combustion engine according to one embodiment of the present invention can satisfy the torque required by the driver even when alternative fuel is used. EXAMPLES

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An internal combustion engine control device according to an embodiment of the present invention will now be described in detail with reference to the drawings.

[0014] 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 as a control unit.

[0015] The engine 2 is a four-stroke engine in which a piston 20 performs a series of four strokes, consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, while the piston 20 reciprocates twice within the cylinder 21.

[0016] In this embodiment, the engine 2 is an in-line 4-cylinder engine, but in the present invention, the engine 2 may be an in-line 6-cylinder engine, a V6 engine, a V12 engine, a horizontally opposed 6-cylinder engine, or any other type of engine. The engine 2 shown in Fig. 1 has four in-line cylinders, of which only one cylinder 21 is shown.

[0017] A piston 20 housed in each cylinder 21 is connected to a crankshaft 23 via a connecting rod 22. The connecting rod 22 converts the reciprocating motion of the piston 20 into the rotational motion of the crankshaft 23.

[0018] Therefore, the engine 2 generates driving force for driving the vehicle 1 by burning a mixture of fuel and air in the combustion chamber 24 inside the cylinder 21 to cause the piston 20 to move back and forth and rotate the crankshaft 23 via the connecting rod 22.

[0019] An intake manifold 31 for introducing air into the combustion chamber 24 is provided at an intake port 30 of the engine 2. The intake manifold 31 is connected to an intake pipe 32 for drawing in outside air. That is, the intake manifold 31 communicates between the intake pipe 32 and the intake port 30 of each cylinder 21.

[0020] An exhaust manifold 41 is provided at an exhaust port 40 of the engine 2 to discharge exhaust gas generated by combustion of the air-fuel mixture in the combustion chamber 24 to the outside of the vehicle. The exhaust manifold 41 is connected to an exhaust pipe 42. That is, the exhaust manifold 41 communicates between the exhaust pipe 42 and the exhaust ports 40 of each cylinder 21. The exhaust pipe 42 is provided with a catalytic converter 43 that purifies the exhaust gas using a catalyst.

[0021] The engine 2 is also provided with an intake valve 50 for controlling the introduction of air from the intake manifold 31 to the combustion chamber 24, an exhaust valve 51 for controlling the discharge of exhaust gas from the combustion chamber 24 to the exhaust manifold 41, and an ignition plug 52 for igniting the air-fuel mixture in the combustion chamber 24.

[0022] The spark plug 52 is a known spark plug having an electrode made of platinum or an iridium alloy. The spark plug 52 discharges electricity when the electrode is energized by the ECU 3, and ignites the air-fuel mixture in the combustion chamber 24.

[0023] The intake valve 50 is adapted to open and close so as to establish or block communication between the intake port 30 and the combustion chamber 24. The opening and closing of the intake valve 50 is controlled by an intake camshaft (not shown).

[0024] The exhaust valve 51 is adapted to open and close so as to connect or block the exhaust port 40 and the combustion chamber 24. The exhaust valve 51 is opened and closed by an exhaust camshaft (not shown).

[0025] This engine 2 is supplied with CN fuel, an alternative fuel to gasoline, as the fuel to be injected into the combustion chamber 24. The engine 2 is equipped with a first fuel injection device 60 in the intake port 30, which supplies CN fuel stored in a fuel tank (not shown) into the combustion chamber 24. The first fuel injection device 60 is a so-called port injection type fuel injection device.

[0026] The alternative fuel may be e-Fuel, biomass fuel, or fuel with a large amount of ethanol added. The first fuel injection device 60 may be a direct injection type fuel injection device that directly injects CN fuel into the combustion chamber 24.

[0027] The engine 2 is capable of injecting hydrogen into the combustion chamber 24. The engine 2 is provided with a second fuel injection device 61 at the intake port 30, which supplies hydrogen stored in a hydrogen tank (not shown) into the combustion chamber 24. The second fuel injection device 61 is a so-called port injection type fuel injection device.

[0028] The second fuel injection device 61 may be a direct injection type fuel injection device that injects hydrogen directly into the combustion chamber 24 .

[0029] The ECU 3 is composed of a computer unit equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, etc., an input port, and an output port.

[0030] The ROM of this computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 3.

[0031] That is, the CPU executes the programs stored in the ROM using the RAM as a working area, whereby this computer unit functions as the ECU 3 in this embodiment.

[0032] An input port of the ECU 3 is connected to various sensors such as an air-fuel ratio sensor 11, an accelerator opening sensor 12, an engine speed sensor 14, a fuel remaining amount sensor 15, an intake air temperature sensor 16, a water temperature sensor 17, and a vehicle speed sensor 18.

[0033] The air-fuel ratio sensor 11 is a sensor that detects the air-fuel ratio (A / F) in the exhaust gas introduced into the catalytic converter 43. The accelerator opening sensor 12 detects the opening of an accelerator pedal 13 operated by the driver.

[0034] The engine speed sensor 14 detects the engine speed, which is the engine speed of the engine 2. The remaining fuel sensor 15 detects the remaining amount of CN fuel in the fuel tank. The intake air temperature sensor 16 detects the intake air temperature, which is the temperature of the intake air introduced into the combustion chamber 24 through the intake pipe 32. The water temperature sensor 17 detects the engine water temperature, which is the temperature of the cooling water for the engine 2. The vehicle speed sensor 18 detects the vehicle speed, which is the speed of the vehicle 1.

[0035] To an output port of the ECU 3, various control targets such as the above-mentioned ignition plug 52, the first fuel injector 60, the second fuel injector 61, etc. are connected.

[0036] In this embodiment, the ECU 3 calculates the differential torque, which is the difference between the required torque of the engine 2 and the actual torque output by the engine 2, and when the differential torque is greater than or equal to a predetermined value, hydrogen is injected by the second fuel injection device 61.

[0037] The ECU 3 obtains a required torque from, for example, an accelerator opening and an engine speed, and calculates an actual torque from, for example, a vehicle speed and an engine speed.

[0038] The ECU 3 may use a map that determines a threshold torque, which is the threshold value of the actual torque at which the differential torque becomes equal to or greater than a predetermined value, based on, for example, engine speed, accelerator opening, vehicle speed, engine water temperature, etc., and may inject hydrogen when the actual torque is less than the threshold torque. The threshold torque corresponds to the torque when gasoline is used as the fuel.

[0039] The ECU 3 stores the amount of hydrogen injected by the second fuel injection device 61 when the differential torque becomes less than a predetermined value as a basic hydrogen injection amount, injects the basic hydrogen injection amount through the second fuel injection device 61 when the engine 2 is in a cold state, and stops hydrogen injection when the engine 2 is in a warm state.

[0040] For example, when ECU 3 determines that the temperature of the engine 2 coolant is below the water temperature threshold, it determines that engine 2 is in a cold state, and when ECU 3 determines that the temperature of the engine 2 coolant is above the water temperature threshold, it determines that engine 2 is in a warm state.

[0041] The ECU 3 determines that a state in which the temperature of the engine 2 coolant is below the water temperature threshold value is within the combustion improvement control range, and injects hydrogen from the second fuel injection device 61 when the differential torque is equal to or greater than a predetermined value.

[0042] The ECU 3 learns and stores the basic hydrogen injection amount on the condition that the vehicle 1 has been refueled with CN fuel. If the vehicle 1 has not been refueled with CN fuel, the ECU 3 injects the basic hydrogen injection amount of hydrogen from the second fuel injection device 61 when the engine 2 is in a cold state. On the other hand, if the vehicle 1 has been refueled with CN fuel, the ECU 3 learns the hydrogen injection amount that makes the differential torque less than a predetermined value, and stores that value as the basic hydrogen injection amount.

[0043] For example, when the ECU 3 determines that the remaining amount of CN fuel has increased, it determines that CN fuel has been replenished.

[0044] The combustion improvement control process performed by the control device for an internal combustion engine according to this embodiment configured as above will be described with reference to Fig. 2. The combustion improvement control process described below is started when the ECU 3 starts operating, and is executed at preset time intervals.

[0045] In step S1, the ECU 3 determines whether or not the remaining amount of CN fuel has increased.

[0046] If it is determined that the remaining amount of CN fuel has increased, the ECU 3 executes the process of step S2. If it is determined that the remaining amount of CN fuel has not increased, the ECU 3 executes the process of step S12.

[0047] In step S2, the ECU 3 determines whether the engine water temperature is within the combustion improvement control range.

[0048] If it is determined that the engine water temperature is within the combustion improvement control range, the ECU 3 executes the process of step S3. If it is determined that the engine water temperature is not within the combustion improvement control range, the ECU 3 executes the process of step S12.

[0049] In step S3, the ECU 3 determines whether the actual torque is lower than the threshold torque.

[0050] If the ECU 3 determines that the actual torque is lower than the threshold torque, the ECU 3 executes the process of step S4. If the ECU 3 determines that the actual torque is not lower than the threshold torque, the ECU 3 executes the process of step S12.

[0051] In step S4, the ECU 3 performs hydrogen addition by injecting a predetermined amount of hydrogen from the second fuel injection device 61. After executing the process of step S4, the ECU 3 executes the process of step S5.

[0052] In step S5, the ECU 3 determines whether the actual torque is equal to or greater than a threshold torque.

[0053] If it is determined that the actual torque is equal to or greater than the threshold torque, the ECU 3 executes the process of step S9. If it is determined that the actual torque is not equal to or greater than the threshold torque, the ECU 3 executes the process of step S6.

[0054] In step S6, the ECU 3 increases the amount of hydrogen injected by the second fuel injection device 61 to increase the amount of hydrogen added. After executing the process of step S6, the ECU 3 executes the process of step S7.

[0055] In step S7, the ECU 3 determines whether the actual torque is equal to or greater than a threshold torque.

[0056] If it is determined that the actual torque is equal to or greater than the threshold torque, the ECU 3 executes the process of step S9. If it is determined that the actual torque is not equal to or greater than the threshold torque, the ECU 3 executes the process of step S8.

[0057] In step S8, the ECU 3 determines whether or not the amount of injected hydrogen has reached the upper limit of the hydrogen addition amount and whether or not hydrogen has been added up to the upper limit of the hydrogen addition amount.

[0058] If it is determined that hydrogen has been added up to the upper limit of the hydrogen addition amount, the ECU 3 executes the process of step S9. If it is determined that hydrogen has not been added up to the upper limit of the hydrogen addition amount, the ECU 3 executes the process of step S6.

[0059] In step S9, the ECU 3 fixes the amount of hydrogen injection to fix the amount of hydrogen added, and stores the injection amount as a basic hydrogen injection amount. After executing the process of step S9, the ECU 3 executes the process of step S10.

[0060] In step S10, the ECU 3 determines whether the engine water temperature is within the combustion improvement control range.

[0061] If it is determined that the engine water temperature is within the combustion improvement control range, the ECU 3 executes the process of step S10. If it is determined that the engine water temperature is not within the combustion improvement control range, the ECU 3 executes the process of step S11.

[0062] In step S11, the ECU 3 stops the injection of hydrogen and stops the addition of hydrogen. After executing the process of step S11, the ECU 3 executes the process of step S12.

[0063] In step S12, the ECU 3 performs normal fuel injection control. After executing the process of step S12, the ECU 3 ends the combustion improvement control process.

[0064] In the normal fuel injection control of step S12, when it is determined that the engine water temperature is within the combustion improvement control range and that the actual torque is lower than the threshold torque, the ECU 3 injects the basic hydrogen injection amount of hydrogen from the second fuel injection device 61 and performs hydrogen addition.

[0065] The operation based on such combustion improvement control processing will be described with reference to FIG. At time t1, CN fuel is replenished, the remaining fuel amount increases, and the engine water temperature is less than the water temperature threshold value, so the hydrogen addition control flag is turned on and hydrogen addition begins.

[0066] Thereafter, the engine water temperature gradually increases, and at time t2, when the engine water temperature reaches the water temperature threshold value, the hydrogen addition control flag is turned off and the addition of hydrogen is terminated.

[0067] Thus, in this embodiment, the ECU 3 calculates the differential torque, which is the difference between the required torque of the engine 2 and the actual torque output by the engine 2, and when the differential torque is greater than or equal to a predetermined value, injects hydrogen through the second fuel injection device 61.

[0068] As a result, when the differential torque is equal to or greater than a predetermined value, hydrogen is injected by the second fuel injection device 61. Therefore, the torque shortage caused by the deterioration of combustion due to the fuel properties of the CN fuel can be compensated for by adding hydrogen, which has good ignition properties, to satisfy the driver's request.

[0069] CN fuel has poor fuel properties, which means that atomization is not promoted and not all of the injected fuel is burned, resulting in insufficient torque. With port injection, the torque is even more insufficient because the fuel required for torque cannot be delivered to the combustion chamber 24. Adding hydrogen improves combustion and increases the torque.

[0070] In addition, the ECU 3 stores the amount of hydrogen injected by the second fuel injection device 61 when the differential torque becomes less than a predetermined value as a basic hydrogen injection amount, injects the basic hydrogen injection amount from the second fuel injection device 61 when the engine 2 is in a cold state, and stops hydrogen injection when the engine 2 is in a warm state.

[0071] This allows the amount of correction to be obtained from the torque deficiency and stored, and hydrogen to be added in a cold engine state when the fuel properties have a large effect, making it possible to satisfy the driver's request immediately after the cold engine start.

[0072] Furthermore, the ECU 3 learns and stores the basic hydrogen injection amount on the condition that the vehicle 1 has been refueled with CN fuel.

[0073] Because the fuel properties of the CN fuel in the tank change with each refueling, the basic hydrogen injection amount is changed with each refueling. In this way, the driver's requirements can be met even with CN fuel, whose fuel properties are unstable.

[0074] In this embodiment, an example has been described in which the ECU 3 performs various determinations and calculations based on various sensor information, but the present invention is not limited to this. The 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 the 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.

[0075] Although an embodiment of the invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made therein without departing from the spirit and scope of the invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0076] 1 vehicle 2. Engine (internal combustion engine) 3 ECU (control unit) 11 Air-fuel ratio sensor 12 Accelerator opening sensor 14 Engine speed sensor 15 Fuel level sensor 16 Intake Air Temperature Sensor 17 Water Temperature Sensor 18 Vehicle speed sensor 60 First fuel injector 61 Second fuel injector

Claims

1. A control device for an internal combustion engine that can be driven using alternative fuel, comprising: a first fuel injection device capable of injecting an alternative fuel; a second fuel injection device capable of injecting hydrogen into the combustion chamber; a control unit capable of adjusting a drive torque of the internal combustion engine, The control unit calculates a differential torque, which is the difference between the required torque of the internal combustion engine and the actual torque output by the internal combustion engine, and when the differential torque is equal to or greater than a predetermined value, adds hydrogen using the second fuel injection device.

2. 2. The control device for an internal combustion engine as described in claim 1, wherein the control unit stores the hydrogen injection amount when the differential torque becomes less than a predetermined value as a basic hydrogen injection amount, injects the basic hydrogen injection amount of hydrogen when the internal combustion engine is in a cold state, and stops hydrogen injection when the internal combustion engine is in a warm state.

3. 3. The control device for an internal combustion engine according to claim 2, wherein the control unit learns and stores the basic hydrogen injection amount on condition that the vehicle on which the internal combustion engine is mounted has been refueled with alternative fuel.

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