WO2018030222A1

WO2018030222A1 - Internal combustion engine control device

Info

Publication number: WO2018030222A1
Application number: PCT/JP2017/027926
Authority: WO
Inventors: 哲志市橋; 智巳米丸
Original assignee: 株式会社ケーヒン
Priority date: 2016-08-08
Filing date: 2017-08-01
Publication date: 2018-02-15
Also published as: DE112017003958T5; JP2018025115A; DE112017003958B4; JP6684680B2

Abstract

In an internal combustion engine control device (100), a control unit (102) calculates a differential temperature that is the differential between a first temperature, which is the temperature of the combustion chamber (9)-side of a wall that defines a combustion chamber (9) in an internal combustion engine (1) and is in contact with a coolant, and a representative temperature for the internal combustion engine (1); calculates a reference target differential temperature on the basis of parameters related to the operating state; calculates a second temperature, which is the temperature of the coolant-side of the wall; calculates a target differential temperature by correcting the reference target differential temperature in accordance with the second temperature; and controls the operating state in accordance with the deviation between the target differential temperature and the differential temperature.

Description

Internal combustion engine control device

The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device applied to an internal combustion engine of a vehicle such as a two-wheeled vehicle.

In recent years, for an internal combustion engine of a vehicle such as a two-wheeled motor vehicle, the operation of the internal combustion engine is performed using a controller in cooperation with the fuel supply to the internal combustion engine, the supply of air, and the ignition of the mixture comprising fuel and air. An electronically controlled internal combustion engine controller that electronically controls the state is employed.

Specifically, such an internal combustion engine control device includes an intake air amount and a crank angle sensor for an internal combustion engine obtained by using respective detection signals from sensors such as an air flow sensor, a throttle opening sensor, and an intake manifold negative pressure sensor. The fuel injection amount for realizing an appropriate air-fuel ratio in the internal combustion engine is calculated based on the rotational speed of the internal combustion engine obtained using this detection signal, and the fuel injection amount is injected into the internal combustion engine with this fuel injection amount. And the ignition is performed on the mixture of intake air and injected fuel at a predetermined ignition timing. Further, at this time, in the internal combustion engine control device, the limit values for the fuel injection amount and the ignition timing are set in consideration of the characteristics related to MBT (Minimum Advance for the Best Torque) and knock in the internal combustion engine. There is also. Further, in such an internal combustion engine control device, the fuel to the air-fuel mixture corresponding to the combustion state in the combustion chamber is detected by using detection signals from sensors such as an in-cylinder pressure sensor, a knock sensor, and an ion current sensor. Some have a configuration in which the injection amount and the ignition timing are each adjusted.

Under such circumstances, Patent Document 1 relates to an ignition timing control device for a spark ignition type internal combustion engine, and relates to the actual temperature of the combustion chamber wall portion of the internal combustion engine and the combustion chamber wall corresponding to the operation state of the internal combustion engine stored in advance. The temperature data in the steady state of a part is compared, The structure which calculates | requires the correction amount for correct | amending the ignition timing of an internal combustion engine according to the deviation is disclosed.

Patent Document 2 relates to an internal combustion engine control device, and relates to a first temperature corresponding to the temperature of a first portion in a wall portion defining a combustion chamber of the internal combustion engine and an outer wall surface than the first portion in the wall portion. The structure which controls the operating state of an internal combustion engine based on the difference with 2nd temperature corresponding to the temperature of the 2nd site | part which is a side is disclosed.

Japanese Patent Laid-Open No. 2-223677 International Publication WO2016 / 104186

However, according to the study of the present inventor, in the configuration of Patent Document 1, the ignition timing of the internal combustion engine is prevented from being retarded more than necessary, and the output and efficiency of the internal combustion engine are improved. Although it is intended to improve the acceleration performance of a vehicle equipped with an engine, paying attention to the fact that the temperature of the combustion chamber wall of the internal combustion engine has a correlation with the in-cylinder pressure of the internal combustion engine, only the temperature of the combustion chamber wall Therefore, there is a certain limit in improving the accuracy of control of the operating state of the internal combustion engine, and there is room for improvement in this respect.

Further, in the configuration of Patent Document 2 in which a part of the inventor is common, in addition to the temperature of the combustion chamber wall portion of the internal combustion engine, the cooling capacity of the cooling system of the internal combustion engine has a correlation with the in-cylinder pressure of the internal combustion engine. In consideration of the cooling capacity of the cooling system, the first temperature corresponding to the temperature of the first part in the wall part defining the combustion chamber of the internal combustion engine and the first part in the wall part are outside the first part. By using a difference temperature from the second temperature corresponding to the temperature of the second part on the wall surface side and comparing it with a predetermined threshold value, the ignition timing is set to a limit advance timing at which knock does not occur. For example, when the coolant is a coolant, the water jacket in which the coolant passage is formed is used for the internal combustion engine. On some cylinder blocks, etc. Because kicked by a change in temperature of the wall surface of the coolant passage due to heat generated in the combustion chamber is heat transfer, so that the thermal conductivity of the coolant will also vary changed cooling capacity of the cooling system. Thus, since the change in the cooling capacity of the cooling system may affect the accuracy of the predetermined threshold, the internal combustion engine may not be able to operate at the best efficiency. There is room.

In other words, at present, it is a simple configuration that can be suitably applied to a vehicle such as a two-wheeled vehicle that is particularly required to be lightweight and small, and is determined in consideration of fluctuations in the cooling capacity of the internal combustion engine. It can be said that there is a long-awaited situation for realizing an internal combustion engine control apparatus that can improve the accuracy of the control target value including the threshold value and control the operation state of the internal combustion engine with more optimal efficiency.

The present invention has been made through the above-described studies. With a simple configuration, the accuracy of the control target value is improved in consideration of fluctuations in the cooling capacity of the internal combustion engine, and the operation of the internal combustion engine is performed with more optimal efficiency. An object of the present invention is to provide an internal combustion engine control device capable of controlling the state.

In order to achieve the above object, the present invention defines a combustion chamber of an internal combustion engine and a difference between a first temperature, which is a temperature on the combustion chamber side of a wall portion in contact with a coolant, and a representative temperature of the internal combustion engine In the internal combustion engine control device including a control unit that calculates a differential temperature that is a value and controls an operating state of the internal combustion engine based on the differential temperature, the control unit calculates a reference target differential temperature from a parameter related to the operating state. Calculating a second temperature which is a temperature on the coolant side of the wall, calculating a target differential temperature by correcting the reference target differential temperature according to the second temperature, and calculating the target differential temperature. It is a first aspect to control the operation state according to a deviation between the difference temperature and the difference temperature.

In addition to the first aspect, the second aspect of the present invention includes that the parameters include the rotational speed of the internal combustion engine and the torque output by the internal combustion engine.

In the present invention, in addition to the first or second aspect, the control unit further corrects the reference target differential temperature in consideration of a heat transfer time delay reflecting the heat transfer characteristics of the wall. The calculation of the target differential temperature is a third aspect.

According to the internal combustion engine control apparatus according to the first aspect of the present invention described above, the control unit defines the combustion chamber of the internal combustion engine and is the first temperature that is the temperature on the combustion chamber side of the wall portion that contacts the coolant. A differential temperature that is a differential value between the engine and the representative temperature of the internal combustion engine, a reference target differential temperature is calculated from a parameter relating to the operating state, a second temperature that is a coolant side temperature of the wall is calculated, and a reference target By correcting the difference temperature according to the second temperature, the target difference temperature is calculated, and the operation state is controlled according to the deviation between the target difference temperature and the difference temperature. It is possible to improve the accuracy of the control target value in consideration of fluctuations in the cooling capacity of the engine, and to control the operating state of the internal combustion engine with more optimal efficiency.

Further, according to the internal combustion engine control apparatus according to the second aspect of the present invention, since the parameter relating to the operating state used by the control unit includes the rotational speed of the internal combustion engine and the torque output by the internal combustion engine, An accurate reference target differential temperature can be calculated, and based on this, the target differential temperature can be calculated, and the operating state of the internal combustion engine can be controlled with more optimal efficiency.

Moreover, according to the internal combustion engine control device according to the third aspect of the present invention, the control unit further corrects the reference target differential temperature in consideration of the heat transfer time delay reflecting the heat transfer characteristics of the wall. Therefore, the target differential temperature can be calculated with higher accuracy, and the operating state of the internal combustion engine can be controlled with more optimal efficiency.

FIG. 1A schematically shows the configuration of a water-cooled internal combustion engine and an internal combustion engine control device applied thereto in an embodiment of the present invention, and the amount of heat generated in the internal combustion engine is output while being transferred to a cooling system or an exhaust system. It is a fragmentary sectional view which shows a mode that it is consumed with the system | strain typically. FIG. 1B is a schematic plan view of the combustion chamber shown in FIG. 1A, and also shows the temperature measurement position in the combustion chamber during the experiment in the present embodiment. FIG. 2 shows the experimental results in the present embodiment. Each of the inner surfaces of the combustion chamber when the ignition timing in the advance direction is changed with the rotational speed of the water-cooled internal combustion engine set to 5000 rpm and the opening degree of the throttle valve set to 48 degrees. It is a graph which shows the temperature in a position with the output torque and knock level of an internal combustion engine. FIG. 3 shows the temperature distribution in the combustion chamber of the internal combustion engine when the air-fuel mixture is combusted when the internal combustion engine is air-cooled and has one intake valve and one exhaust valve. Specifically, (a) and (b) in FIG. 3 are when the rotational speed of the internal combustion engine is fixed at 2000 rpm and the carbon monoxide concentration in the exhaust gas is 0.5% and 0.7%. 3 shows the temperature distribution of the inner surface of the combustion chamber in order, and (c) to (g) in FIG. 3 fix the carbon monoxide concentration in the exhaust gas of the internal combustion engine to 0.5%, And the temperature distribution of the inner surface of a combustion chamber when rotation speed is 1400 rpm, 1800 rpm, 2000 rpm, 2200 rpm, and 2400 rpm is shown correspondingly in order. FIG. 4 is a block diagram showing a configuration of an internal combustion engine control device applied to the water-cooled internal combustion engine in the present embodiment. FIG. 5 shows the experimental results in this embodiment. The differential temperature when the ignition timing in the advance direction is changed with the rotational speed of the water-cooled internal combustion engine set at 5000 rpm and the throttle valve opening set at 40 degrees is shown in FIG. It is a graph shown with an output torque and a knock level. FIG. 6 is a graph showing experimental results in the present embodiment, in which the differential temperature is compared with the peak in-cylinder pressure when the rotational speed of the water-cooled internal combustion engine is 5000 rpm and the opening of the throttle valve is 40 degrees. is there. FIG. 7 is a schematic cross-sectional view of the water-cooled internal combustion engine in the present embodiment, and is a schematic diagram conceptually showing the content of correction of the reference target differential temperature in the internal combustion engine control device applied thereto. FIG. 8 is a schematic diagram showing table data of differential temperature correction values used for correcting the reference target differential temperature in the internal combustion engine control apparatus applied to the water-cooled internal combustion engine in the present embodiment. FIG. 9 is a schematic diagram showing a comparison between the target differential temperature before the filter process and the target differential temperature after the filter process in the internal combustion engine control apparatus applied to the water-cooled internal combustion engine in the present embodiment. FIG. 10 is an experimental result when the compression ratio of the water-cooled internal combustion engine in the present embodiment varies when mass production is assumed, and the internal combustion engine has a predetermined rotational speed and a throttle valve opening degree. 10 is a graph showing the output torque and knock level of the internal combustion engine by the internal combustion engine operating state control process of the comparative example. Specifically, FIG. (B) in the middle is a graph showing the output torque and knock level of the internal combustion engine by the internal combustion engine operating state control process of the present embodiment. FIG. 11 shows the experimental results when various fuel types are used in the present embodiment, and the advance direction of the internal combustion engine with the rotation speed of the water-cooled internal combustion engine as the predetermined rotation speed and the throttle valve opening as the predetermined opening degree. 6 is a graph showing a target differential temperature, an output torque of the internal combustion engine, and a knock level when the ignition timing is changed. 12 is a flowchart illustrating the flow of target difference temperature calculation processing executed by the internal combustion engine control device applied to the water-cooled internal combustion engine in the present embodiment.

Hereinafter, an internal combustion engine control apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Configuration of internal combustion engine]
First, a configuration of an internal combustion engine to which the internal combustion engine control device according to the present embodiment is applied will be described with reference to FIGS. 1A to 3.

FIG. 1A schematically shows a configuration of a water-cooled internal combustion engine and an internal combustion engine control device applied thereto in the present embodiment, and an output system while heat generated in the internal combustion engine is transferred to a cooling system or an exhaust system. FIG. 1B is a schematic plan view of the combustion chamber shown in FIG. 1A, and shows the temperature measurement position in the combustion chamber at the time of the experiment in this embodiment. Also shown. FIG. 2 shows the experimental results in this embodiment. The temperature at each position on the inner surface of the combustion chamber when the ignition timing in the advance direction is changed with the rotational speed of the internal combustion engine set to 5000 rpm and the opening degree of the throttle valve set to 48 degrees. Is a graph showing the output torque and knock level of the internal combustion engine. FIG. 3 shows the temperature distribution in the combustion chamber of the internal combustion engine when the air-fuel mixture is combusted when the internal combustion engine is air-cooled and has one intake valve and one exhaust valve. Specifically, (a) in FIG. 3 and (b) in FIG. 3 fix the rotational speed of the internal combustion engine at 2000 rpm, and the carbon monoxide concentration in the exhaust gas is 0.5% and 0.7%. 3 shows the temperature distribution on the inner surface of the combustion chamber in order, and (g) in FIG. 3 to (g) in FIG. 3 indicate the carbon monoxide concentration in the exhaust gas of the internal combustion engine. The temperature distribution of the inner surface of the combustion chamber when the rotation number is fixed to 0.5% and the rotation speed is 1400 rpm, 1800 rpm, 2000 rpm, 2200 rpm, and 2400 rpm is shown in order. In FIG. 2, for the sake of convenience, the torque and the knock level are shown on the same vertical axis.

As shown in FIG. 1A, the internal combustion engine 1 includes a cylinder block 2 that is mounted on a vehicle such as a two-wheeled vehicle (not shown) and has one or a plurality of cylinders 2a. A coolant passage 3 is formed in a side wall of a portion of the cylinder block 2 corresponding to the cylinder 2a through which a coolant that is a coolant for cooling the cylinder block 2 flows. FIG. 1A shows an example in which the number of cylinders 2a is only one for convenience. Further, the internal combustion engine 1 is not limited to such a water-cooled type, and is an air-cooled type that does not have the coolant passage 3 and uses the surrounding air as a coolant for cooling the cylinder block 2. Also good.

Piston 4 is arranged inside cylinder 2a. The piston 4 is connected to the crankshaft 6 via a connecting rod 5. The crankshaft 6 is provided with a rotor 7 that rotates coaxially therewith. On the outer peripheral surface of the rotor 7, a plurality of tooth portions (retractors) 7 a juxtaposed in a predetermined pattern in the circumferential direction are provided upright.

The cylinder head 8 is assembled to the upper part of the cylinder block 2. The inner wall surface of the cylinder block 2, the upper surface of the piston 4, and the inner wall surface of the cylinder head 8 cooperate to define the combustion chamber 9 of the cylinder 2a. The coolant passage 3 may be formed in the cylinder head 8 in addition to the cylinder block 2.

The cylinder head 8 is provided with a spark plug 10 that ignites a mixture of fuel and air in the combustion chamber 9. There may be a plurality of spark plugs 10 for each combustion chamber 9.

The cylinder head 8 is assembled with an intake pipe 11 that communicates with the combustion chamber 9. In the cylinder head 8, an intake passage 11 a that communicates the combustion chamber 9 and the intake pipe 11 is formed. An intake valve 12 is provided at a corresponding connection portion between the combustion chamber 9 and the intake passage 11a. The intake pipe 11 may be a manifold according to the number of cylinders 2a, and the number of intake passages 11a is equal to the number of cylinders 2a. The number of intake valves 12 for each combustion chamber 9 is assumed to be two in the case of the water-cooled internal combustion engine 1, and is assumed to be one in the case of the air-cooled internal combustion engine 1. May be the number.

The intake pipe 11 is provided with an injector 13 for injecting fuel therein. The intake pipe 11 is provided with a throttle valve 14 on the upstream side of the injector 13. The throttle valve 14 is a component of a throttle device (not shown), and the main body of the throttle device is assembled to the intake pipe 11. The injector 13 may inject fuel directly into the corresponding combustion chamber 9. The number of injectors 13 and throttle valves 14 may be plural.

Further, an exhaust pipe 15 communicating with the combustion chamber 9 corresponding to the cylinder head 8 is assembled to the cylinder head 8. An exhaust passage 15a is formed in the cylinder head 8 to communicate the combustion chamber 9 and the exhaust passage 15a. An exhaust valve 16 is provided at a corresponding connection portion between the combustion chamber 9 and the exhaust pipe 15. The exhaust pipe 15 may be a manifold according to the number of cylinders 2a, and the number of exhaust passages 15a is equal to the number of cylinders 2a and exhaust pipes 15. The number of exhaust valves 16 for each combustion chamber 9 is assumed to be two in the case of the water-cooled internal combustion engine 1 and one in the case of the air-cooled internal combustion engine 1. May be any other number.

Here, considering the case where the internal combustion engine 1 is a water-cooled type, the total amount of heat generated in the internal combustion engine 1 is assumed as shown in the following formula (Equation 1) on the assumption that the cooling function of the cooling system of the internal combustion engine 1 does not fail. QT is equal to the sum of the amount of heat Qtq converted to the torque output from the internal combustion engine 1, the amount of heat Qw cooled by the internal combustion engine 1, and the amount of heat Qex discharged by the exhaust of the internal combustion engine 1. The amount of heat Qtq converted into the torque output from the engine 1 and the amount of heat Qw of cooling of the internal combustion engine 1 are in a proportional relationship. Further, the cooling heat quantity Qw can be expressed by h representing the heat transfer coefficient of the heat passage portion from the combustion chamber 9 to the coolant, h representing the cooling surface area of the combustion chamber 9, and t representing the time. With respect to the difference temperature TCCD between the temperature of the wall surface on the combustion chamber 9 side of the wall portion of the cylinder block 2 or the cylinder head 8 that defines the above and the temperature of the coolant flowing through the coolant passage 3 of the internal combustion engine 1, There is a relationship as shown by the following formula (Equation 2). The heat transfer coefficient h in the equation (Equation 2) is expressed by the following equation (Equation 3) which is Eichenberg's equation, the third root of the piston 4 speed (piston speed) Cm, the internal pressure of the cylinder 2a ( The in-cylinder pressure increases in proportion to the square root of p and the square root of the combustion gas temperature (combustion gas temperature) Tg of the internal combustion engine 1. Therefore, a positive correlation is established between the differential temperature TCCD and the torque in an arbitrary operation state of the internal combustion engine 1. Note that, in principle, this argument holds even when the internal combustion engine 1 is an air-cooled type.

Further, from the experimental results shown in FIG. 2 regarding the temperature measurement position shown in FIG. 1B, when the ignition timing is advanced, the torque output from the water-cooled internal combustion engine 1 increases, and the ignition timing reaches MBT. After that, it can be seen that an increase in temperature appears at each position on the inner surface of the combustion chamber 9 with the start of knocking of the internal combustion engine 1. Here, the position of the inner surface of the combustion chamber 9 is indicated by the squish region 1 to the squish region 5 in FIG. 2. The squish region 1 is the intake side squish region and the squish region 2 that are separated from the center of the combustion chamber 9. The intake side squish area approaching the center of the combustion chamber 9, the squish area 3 is the exhaust side squish area, the squish area 4 is the center of the combustion chamber 9 and the squish area away from the spark plug, and the squish area 5 is the combustion chamber 9. Each squish area is shown spaced apart from the center and approaching the spark plug 10. In FIG. 2, the region where the temperature rise is most prominent among the squish region 1 to the squish region 5 is the squish region 2, which is the intake side squish region approaching the center of the combustion chamber 9. It can be seen that the temperature increase in the squish area on the side appears more sharply than the temperature increase in the squish area on the exhaust side. This is generally considered to be caused by the knocking starting from the suction side region in the combustion chamber 9 of the internal combustion engine 1. Further, regarding the increase in the torque of the internal combustion engine 1 before reaching the MBT, the reaction in the intake side region appears more sharply than the reaction on the exhaust side, so that the temperature distribution in the combustion chamber 9 is a combustion state including the knock of the internal combustion engine 1. It is understood that it is preferable to install a combustion chamber temperature sensor on the intake side of the combustion chamber 9 in consideration of this index. Furthermore, in consideration of the mass production conditions of the internal combustion engine 1, when a general thermistor type temperature sensor was installed in the vicinity of the squish region 1, the temperature detection value shown in FIG. 2 could be obtained with this temperature sensor.

Further, in order to confirm the characteristics of the temperature distribution in the combustion chamber 9, an experimental result shown in FIG. 3 showing the temperature distribution in the combustion chamber 9 was obtained using the air-cooled internal combustion engine 1 having a simple cooling system configuration. In the experimental results of (a) in FIG. 3 and (b) in FIG. 3, the combustion chamber 9 due to the difference in fuel tone (carbon monoxide concentration) even in the no-load operation state in which the internal combustion engine 1 generates a small amount of heat. The temperature distribution showed a temperature difference of about 40 ° C. between the intake side (intake valve 12 side) and the exhaust side (exhaust valve 16 side). Further, in the other experimental results from (c) in FIG. 3 to (g) in FIG. 3, even if the rotational speed of the internal combustion engine 1 changes, the tendency of the temperature distribution does not change, and the rotational speed is The result showed that the temperature increased as the temperature increased. For this reason, it is understood that parameters for determining the combustion state can be extracted and used even in an air-cooled internal combustion engine with one intake / exhaust valve. In addition, the code | symbol A to the code | symbol K in FIG. 3 shows the temperature range in each area | region, Specifically, the code | symbol A is 165 degreeC or more and less than 170 degreeC, and the code | symbol B is 160 degreeC. The temperature range of 165 ° C. or lower, the symbol C is a temperature range of 155 ° C. or higher and lower than 160 ° C., the symbol D is a temperature range of 150 ° C. or higher and lower than 155 ° C., and the symbol E is a temperature range of 145 ° C. or higher and lower than 150 ° C. Symbol F is a temperature range of 140 ° C. or more and less than 145 ° C., Symbol G is a temperature range of 135 ° C. or more and less than 140 ° C., Symbol H is a temperature range of 130 ° C. or more and less than 135 ° C., and Symbol I is 125 ° C. or more and 130 ° C. A temperature range of less than ° C., symbol J represents a temperature range of 120 ° C. or more and less than 125 ° C., and symbol K represents a temperature range of 115 ° C. or more and less than 120 ° C., respectively.

[Configuration of internal combustion engine controller]
Next, the configuration of the internal combustion engine control apparatus according to this embodiment will be described with reference to FIGS. 4 to 11 in addition to FIGS. 1A and 1B.

FIG. 4 is a block diagram showing a configuration of an internal combustion engine control device applied to the water-cooled internal combustion engine in the present embodiment. FIG. 5 shows the experimental results in this embodiment. The differential temperature when the ignition timing in the advance direction is changed with the rotational speed of the water-cooled internal combustion engine set at 5000 rpm and the throttle valve opening set at 40 degrees is shown in FIG. It is a graph shown with an output torque and a knock level. FIG. 6 is a graph showing experimental results in the present embodiment, in which the differential temperature is compared with the peak in-cylinder pressure when the rotational speed of the water-cooled internal combustion engine is 5000 rpm and the opening of the throttle valve is 40 degrees. is there. FIG. 7 is a schematic cross-sectional view of the water-cooled internal combustion engine in the present embodiment, and is a schematic diagram conceptually showing the content of correction of the reference target differential temperature in the internal combustion engine control device applied thereto. FIG. 8 is a schematic diagram showing table data of differential temperature correction values used for correcting the reference target differential temperature in the internal combustion engine control apparatus applied to the water-cooled internal combustion engine in the present embodiment. FIG. 9 is a schematic diagram showing a comparison between the target differential temperature before the filter process and the target differential temperature after the filter process in the internal combustion engine control apparatus applied to the water-cooled internal combustion engine in the present embodiment. FIG. 10 is an experimental result when the compression ratio of the water-cooled internal combustion engine in the present embodiment varies when mass production is assumed, and the internal combustion engine has a predetermined rotational speed and a throttle valve opening degree. 10 is a graph showing the output torque and knock level of the internal combustion engine by the internal combustion engine operating state control process of the comparative example. Specifically, FIG. (B) in the middle is a graph showing the output torque and knock level of the internal combustion engine by the internal combustion engine operating state control process of the present embodiment. FIG. 11 shows experimental results when various fuel types are used in the present embodiment. The progress of the internal combustion engine is determined by setting the rotation speed of the water-cooled internal combustion engine to a predetermined rotation speed and the opening of the throttle valve to a predetermined opening. It is a graph which shows the target differential temperature, the output torque of an internal combustion engine, and a knock level when changing the ignition timing in the angular direction. In FIG. 5, for convenience, the differential temperature and the knock level are shown on the same vertical axis, and in FIG. 11, the target differential temperature and torque are shown on the same vertical axis for convenience.

As shown in FIG. 4, the internal combustion engine control apparatus 100 in this embodiment is electrically connected to a coolant temperature sensor 21, a crank angle sensor 22, an intake air temperature sensor 23, a throttle opening sensor 24, and a wall temperature sensor 25. ECU (Electronic Control Unit) 102 is provided.

The cooling water temperature sensor 21 is attached to the cylinder block 2 in a state of entering the coolant passage 3, detects the temperature of the coolant flowing in the coolant passage 3 (coolant temperature), and an electric signal indicating the detected coolant temperature. Is input to the ECU 102. The coolant temperature is used as the representative temperature of the internal combustion engine 1 (internal combustion engine representative temperature). As the internal combustion engine representative temperature, the oil temperature of the lubricating oil of the internal combustion engine 1 and the like may be used as necessary. It is possible to use the oil temperature or the like detected by an oil temperature sensor or the like. Further, when the internal combustion engine 1 is air-cooled, the representative temperature of the internal combustion engine may be the oil temperature or the like of the lubricating oil of the internal combustion engine 1 detected by an oil temperature sensor or the like.

The crank angle sensor 22 is attached to a lower case or the like (not shown) assembled to the lower part of the cylinder block 2 so as to face the tooth portion 7 a formed on the outer peripheral surface of the rotor 7, and with the rotation of the crankshaft 6. The angular velocity of the crankshaft 6 is detected by detecting the rotating tooth portion 7a. The crank angle sensor 22 inputs an electrical signal indicating the detected angular velocity to the ECU 102.

The intake air temperature sensor 23 is attached to the intake pipe 11 so as to enter the intake pipe 11, detects the temperature of the air flowing into the intake pipe 11, and outputs an electric signal indicating the detected temperature of the ECU 102 to the ECU 102. To enter.

The throttle opening sensor 24 is attached to the main body of the throttle device, detects the opening of the throttle valve 14, and inputs an electric signal indicating the detected opening to the ECU 102.

The wall temperature sensor 25 is a member defining the combustion chamber 9, that is, a wall surface of the cylinder block 2 or the cylinder head 8, and a heat receiving portion is mounted on the combustion chamber 9 side. And an electric signal indicating the detected temperature of the wall portion on the combustion chamber 9 side is input to the ECU 102. Specifically, the wall temperature sensor 25 is a portion of the wall surface on the intake valve 12 side, which is a portion where a flame generated when the air-fuel mixture in the combustion chamber 9 is ignited by the spark plug 10 and ignited is difficult to propagate. Attached to the cylinder block 2 or the cylinder head 8 on the combustion chamber 9 side of the wall so as to detect the temperature (the temperature of the inner wall surface of the cylinder block 2 or the cylinder head 8 on the side of the intake valve 12 and on the side of the combustion chamber 9). Is done. Here, the temperature of the wall portion corresponding to the wall surface temperature on the intake valve 12 side is a temperature at a portion where the flame generated by the ignition of the air-fuel mixture in the combustion chamber 9 is difficult to propagate. This temperature is sensitive to the combustion state of the air-fuel mixture in the chamber 9. In FIG. 1A, the wall temperature sensor 25 shows an example in which a heat receiving portion is mounted on the combustion chamber 9 side in the wall portion of the cylinder head 8 as a member defining the combustion chamber 9. This corresponds to a configuration in which the portion is disposed in the vicinity of the squish region 1 on the intake side that is separated from the center of the combustion chamber 9 in FIG. If the temperature is sensitive to the combustion state of the air-fuel mixture in the combustion chamber 9, the wall surface temperature of the cylinder block 2 or the like detected by a temperature sensor other than the wall temperature sensor 25 is used as the wall temperature. It is also possible to adopt as.

The ECU 102 operates using electric power from a battery provided in the vehicle, and includes a microcomputer 104, A / D (Analog to Digil) conversion circuits 201a and 201b, a waveform shaping circuit 202, and a drive circuit 301.

The microcomputer 104 includes a memory 106 and a CPU (Central Processing Unit) 108.

The memory 106 is configured by various nonvolatile and volatile storage devices, and stores a control program for the operation state control processing of the internal combustion engine and various control data. The non-volatile storage device functions as a working area that temporarily stores control data (such as the fuel injection amount instruction value and ignition timing) used when the ECU 102 executes the internal combustion engine operating state control process.

The CPU 108 controls the overall operation of the ECU 102 using electrical signals from the coolant temperature sensor 21, the crank angle sensor 22, the intake air temperature sensor 23, the throttle opening sensor 24, and the wall temperature sensor 25. Calculation unit 203, torque calculation unit 204, wall temperature calculation unit 205, cooling water temperature calculation unit 206, differential temperature calculation unit 207, reference target differential temperature calculation unit 208, correction term calculation unit 209, target differential temperature calculation unit 210, operation A state control unit 211, a comparison unit 212, and an ignition timing calculation unit 213 are provided. The rotation speed calculation unit 203, the torque calculation unit 204, the wall temperature calculation unit 205, the cooling water temperature calculation unit 206, the differential temperature calculation unit 207, the reference target differential temperature calculation unit 208, the correction term calculation unit 209, and the target differential temperature calculation Unit 210, operation state control unit 211, comparison unit 212, and ignition timing calculation unit 213 are functional blocks when the CPU 108 reads out necessary control programs and control data from the memory 106 and executes internal combustion engine operation state control processing and the like. As shown.

The A / D conversion circuit 201a converts the analog electrical signal input from the wall temperature sensor 25 into a digital format and inputs it to the wall temperature calculation unit 205.

The A / D conversion circuit 201 b converts the analog electrical signal input from the cooling water temperature sensor 21 into a digital format and inputs it to the cooling water temperature calculation unit 206.

The waveform shaping circuit 202 performs a shaping process such as a smoothing process on the electric signal input from the crank angle sensor 22, and then inputs the electric signal to the rotation speed calculation unit 203 and the torque calculation unit 204.

The rotation speed calculation unit 203 calculates the rotation speed of the internal combustion engine 1 using the electrical signal input from the waveform shaping circuit 202. The rotation speed of the internal combustion engine 1 calculated by the rotation speed calculation unit 203 in this way is the reference Used by the target differential temperature calculation unit 208.

The torque calculation unit 204 calculates the output torque (torque) of the internal combustion engine 1 using the electrical signal input from the waveform shaping circuit 202. The torque of the internal combustion engine 1 calculated by the torque calculation unit 204 in this way is the reference Used by the target differential temperature calculation unit 208. The torque calculation unit 204 may perform a predetermined filtering process so that the calculated torque value of the internal combustion engine 1 changes smoothly.

The wall temperature calculation unit 205 uses the electric signal input from the A / D conversion circuit 201a to define the combustion chamber 9 of the internal combustion engine 1 on the combustion chamber 9 side of the wall of the cylinder block 2 or the cylinder head 8. The temperature (wall surface temperature) is calculated, and the temperature on the combustion chamber 9 side of the wall calculated by the wall temperature calculating unit 205 in this way is used by the differential temperature calculating unit 207 and the correction term calculating unit 209. The temperature of the wall portion on the combustion chamber 9 side is the temperature of the internal combustion engine 1 that directly reflects the combustion state of the air-fuel mixture in the combustion chamber 9 of the internal combustion engine 1, and as described above, 9 is a temperature that reacts sensitively to a combustion state such as combustion disturbance of the air-fuel mixture in the fuel tank 9, that is, a heat receiving state on the wall surface of the combustion chamber 9. Here, the heat receiving state of the wall surface of the combustion chamber 9 is affected by the internal pressure level of the cylinder of the internal combustion engine 1 and the occurrence of knocking. The internal pressure level of the cylinder and the occurrence of knocking are determined by the internal combustion engine. It is influenced by the ignition timing of the engine 1. Note that the wall temperature calculation unit 205 may perform a predetermined filtering process so that the calculated temperature value of the wall on the combustion chamber 9 side changes smoothly. In addition, since the temperature on the combustion chamber 9 side of the wall portion can be evaluated as a temperature that directly reflects the amount of generated heat generated in the cylinder of the internal combustion engine 1, such a wall portion. The temperature on the combustion chamber 9 side of the internal combustion engine 1 and the fuel injection amount supplied to the combustion chamber 9 in the cylinder of the internal combustion engine 1 are also generally correlated with each other. The temperature on the side can be used not only for controlling the ignition timing but also for controlling the fuel injection amount.

The cooling water temperature calculation unit 206 calculates the coolant temperature flowing through the coolant passage 3 as the representative temperature of the internal combustion engine using the electric signal input from the A / D conversion circuit 201b, and the cooling water temperature calculation unit 206 calculates in this way. The coolant temperature thus used is used in the differential temperature calculation unit 207 and the correction term calculation unit 209. Here, the coolant temperature is a representative temperature of the internal combustion engine 1 representatively showing the temperature of the internal combustion engine, that is, a representative temperature of the internal combustion engine, and a temperature reflecting a cooling heat amount for cooling the cylinder of the internal combustion engine 1. It can be evaluated. Further, the coolant temperature is a temperature that does not react sensitively to the combustion state of the air-fuel mixture in the combustion chamber 9 as compared with the temperature of the wall portion on the combustion chamber 9 side calculated by the wall temperature calculation unit 205. Note that the coolant temperature calculation unit 206 may perform a predetermined filtering process on the coolant temperature so calculated so that the coolant temperature value changes smoothly. In addition to the coolant temperature, the temperature of the lubricating oil of the internal combustion engine 1 may be used as the representative internal combustion engine temperature. Even when the internal combustion engine 1 is air-cooled, the temperature of the lubricating oil of the internal combustion engine 1 can be used as the representative internal combustion engine temperature.

The difference temperature calculation unit 207 calculates a difference temperature that is a difference value between the temperature on the combustion chamber 9 side of the wall calculated by the wall temperature calculation unit 205 and the coolant temperature calculated by the cooling water temperature calculation unit 206. The difference temperature calculated by the difference temperature calculation unit 207 is used in the internal combustion engine operation state control process of the operation state control unit 211. Here, the temperature on the combustion chamber 9 side of the wall calculated by the wall temperature calculation unit 205 is a temperature that reacts sensitively to the combustion state of the air-fuel mixture in the combustion chamber 9 of the internal combustion engine 1, and the cooling water temperature calculation unit Since the coolant temperature calculated by 206 is a temperature that does not react sensitively to the combustion state of the air-fuel mixture in the combustion chamber 9, the difference temperature is large when the combustion state in the combustion chamber 9 is good. On the other hand, when the ignition timing is retarded and the output of the internal combustion engine 1 is low, a small value is shown. Therefore, the differential temperature is an index indicating whether the combustion state in the combustion chamber 9 is good or bad, and also reflects the cooling capacity of the cooling system of the internal combustion engine 1. In particular, the ignition timing of the internal combustion engine 1 affects the internal pressure level of the cylinder of the internal combustion engine 1 and the occurrence of knocking. The internal pressure level of the cylinder and the occurrence of knocking occur on the wall surface of the combustion chamber 9 of the internal combustion engine 1. The difference temperature that affects the state of heat reception and that is the difference between the temperature on the combustion chamber 9 side of the wall of the combustion chamber 9 and the internal combustion engine representative temperature such as the coolant temperature of the internal combustion engine is the combustion chamber 9 Therefore, the differential temperature can be applied to the ignition timing control when the operation state control unit 211 controls the operation state of the internal combustion engine 1. . Note that the differential temperature can be applied to the control of the fuel injection amount when the operation state control unit 211 controls the operation state of the internal combustion engine 1 as necessary.

Here, from the experimental results shown in FIG. 5, as the ignition timing is advanced, the torque of the internal combustion engine 1 increases, and the differential temperature also increases until the torque reaches its peak. It can be seen that there is a range in which the differential temperature becomes a constant value after the torque reaches the peak and before the knock level starts to rise, and then the differential temperature shows a steep rising trend as the knock level starts to rise.

Also, the experimental results shown in FIG. 6 show that there is a very good positive correlation between the difference temperature and the peak in-cylinder pressure. If the ignition timing is fixed, there is a positive correlation between the peak in-cylinder pressure and the average effective pressure, so there is a positive correlation between the torque of the internal combustion engine 1 and the differential temperature at MBT. Thus, if there is a positive correlation between the torque of the internal combustion engine 1 and the differential temperature, the internal combustion engine is controlled by setting the differential temperature as the target differential temperature so that the differential temperature of the actual machine becomes the target differential temperature. 1 can be operated in the best torque state. Further, when the relationship between the torque and the differential temperature was measured at various rotational speeds and load conditions in the internal combustion engine 1, the rotational speed was in the range of 1900 rpm to 5000 rpm, and the throttle opening was in the range from the idle opening to the fully opened opening. Such a positive correlation was observed.

The reference target difference temperature calculation unit 208 calculates the reference target difference temperature from the parameters related to the operating state of the internal combustion engine 1, and the reference target difference temperature calculated by the reference target difference temperature calculation unit 208 in this way is the correction term calculation unit 209. And the target differential temperature calculation unit 210. Here, the reference target differential temperature is a reference value of the target differential temperature that is the target value of the differential temperature calculated by the differential temperature calculation unit 207, and is a level that the internal combustion engine 1 can ignore the knock level. Thus, it is calculated as an ideal value of the differential temperature when in an operating state in which the best torque is output. Further, as a parameter relating to the operating state of the internal combustion engine 1, a reference target differential temperature that is an ideal value when the internal combustion engine 1 is in an operating state in which the internal combustion engine 1 outputs the best torque is obtained. Therefore, it is necessary to set the extracted parameter as indicating the actual operating state of the internal combustion engine 1. From this point of view, it is preferable to set the rotational speed of the internal combustion engine 1 and the torque output by the internal combustion engine 1 at the rotational speed as parameters relating to the operating state of the internal combustion engine 1.

Specifically, the reference target differential temperature calculation unit 208 defines the reference target differential temperature value corresponding to the data stored in advance in the memory 106, that is, the parameter value relating to the operating state of the internal combustion engine 1. The table data and the map data are read from the memory 106, and the parameter values relating to the operating state of the internal combustion engine 1 that is actually operated are compared with the data read from the memory 106. The value of the reference target differential temperature corresponding to the value of the parameter relating to the operating state of the internal combustion engine 1 that is being operated is calculated. For example, when the rotational speed of the internal combustion engine 1 and the torque output by the internal combustion engine 1 at the rotational speed are set as parameters relating to the operating state of the internal combustion engine 1, the data stored in advance in the memory 106 is , Defining the value of the rotational speed of the internal combustion engine 1 and the value of the torque output by the internal combustion engine 1 at the rotational speed corresponding to the two axes orthogonal to each other, and the third axis orthogonal to the two axes, It becomes the form of map data in which the value of the reference target differential temperature is defined corresponding to the value of the rotation speed and the value of the torque. In such a case, the reference target differential temperature calculation unit 208 reads the map data from the memory 106 and refers to the map data, and the torque calculation unit 204 calculates the rotation number of the internal combustion engine 1 calculated by the rotation number calculation unit 203. The reference target differential temperature corresponding to the torque of the internal combustion engine 1 is calculated.

The correction term calculation unit 209 uses the coolant temperature calculated by the cooling water temperature calculation unit 206 and the reference target difference temperature calculated by the reference target difference temperature calculation unit 208 to correct the correction value in the correction term for correcting the reference target difference temperature. The correction value calculated by the correction term calculation unit 209 in this way is used by the target differential temperature calculation unit 210. This correction value is mainly for adjusting the reference target differential temperature in consideration of the time variation of the cooling capacity of the cooling system so that the amount of heat exceeding the allowable heat amount of the internal combustion engine 1 does not occur in the correction value. . Here, when the output of the internal combustion engine 1 is increased, the temperature of the wall surface on the side of the coolant passage 3 typically formed in the wall portion of the cylinder block 2 defining the combustion chamber 9 is the coolant. When approaching the nucleate boiling point, the disturbance of the flow field of the coolant passage 3 or the surrounding coolant increases and the thermal conductivity of the coolant increases, while the temperature of the wall surface on the coolant passage 3 side further increases. When the film boiling point is approached, the phenomenon that the thermal conductivity of the coolant decreases occurs in a short time, and the amount of heat that can be received by the cooling system of the internal combustion engine 1 fluctuates in a short time. It is only necessary to calculate a correction value for adjusting the reference target differential temperature from this temperature.

Specifically, the correction term calculation unit 209 reads from the memory 106 data stored in advance in the memory 106, that is, table data in which the value of the temperature correlation coefficient is defined corresponding to the value of the coolant temperature. The coolant temperature value calculated by the coolant temperature calculation unit 206 is compared with the table data read from the memory 106, and the temperature phase relationship corresponding to the coolant temperature value calculated by the coolant temperature calculation unit 206 from the data is compared. Calculate the value of the number. Next, the correction term calculation unit 209 multiplies the temperature correlation coefficient by the reference target difference temperature calculated by the reference target difference temperature calculation unit 208, and the temperature of the wall portion on the combustion chamber 9 side and the coolant passage 3 of the wall portion. Calculate the temperature drop between the side temperatures. Next, the correction term calculation unit 209 calculates the temperature of the wall portion on the coolant passage 3 side by subtracting the temperature drop from the temperature of the wall portion on the combustion chamber 9 side calculated by the wall portion temperature calculation unit 205. Next, the correction term calculation unit 209 reads from the memory 106 data stored in advance in the memory 106, that is, table data in which a differential temperature correction value is defined corresponding to the temperature value of the wall on the coolant passage 3 side. The temperature on the coolant passage 3 side of the wall portion calculated by the correction term calculation unit 209 is compared with the table data read from the memory 106, and the wall portion calculated by the correction term calculation unit 209 is calculated from the data. A differential temperature correction value corresponding to the temperature value on the coolant passage 3 side is calculated. When the internal combustion engine 1 is air-cooled, the cooling capacity of the cooling system includes the speed of the vehicle on which the internal combustion engine 1 is mounted, the representative temperature of the internal combustion engine 1, the intake air temperature, the oil temperature, and the cylinder. Since the temperature depends on the surface temperature of the outer skin of the block or the like, the temperature corresponding to the temperature on the coolant passage 3 side of the wall portion in the water-cooled internal combustion engine 1 is detected as the representative temperature of the internal combustion engine 1. It can be calculated by correcting the position and multiplying this by a correlation coefficient corresponding to the vehicle speed and the intake air temperature.

The target difference temperature calculation unit 210 uses the difference temperature correction value calculated by the correction term calculation unit 209 to correct the reference target difference temperature calculated by the reference target difference temperature calculation unit 208 to calculate the target difference temperature. As described above, the target difference temperature calculated by the target difference temperature calculation unit 210 is used by the operation state control unit 211. Specifically, the target difference temperature calculation unit 210 adds the difference temperature correction value calculated by the correction term calculation unit 209 to the value of the reference target difference temperature calculated by the reference target difference temperature calculation unit 208, so that the target difference temperature Will be calculated. At this time, the target differential temperature calculation unit 210 takes into account the time delay of heat transfer from the combustion chamber 9 to the wall portion reflecting the heat transfer characteristics of the wall portion defining the combustion chamber 9 of the internal combustion engine 1. The reference target differential temperature may be further corrected. In such a case, specifically, the target differential temperature calculation unit 210 calculates a filtering coefficient corresponding to when the output of the internal combustion engine 1 increases and decreases, and a standard obtained by correcting the filtering coefficient using the differential temperature correction value. The target differential temperature is calculated by multiplying the target differential temperature.

Here, as shown in FIG. 7, the difference temperature TCCD is a difference value between the temperature TCC on the combustion chamber 9 side of the wall calculated by the wall temperature calculation unit 205 and the coolant temperature TW calculated by the cooling water temperature calculation unit 206. Therefore, the amount of heat generated by the combustion of the internal combustion engine 1 corresponds to the amount of heat transmitted to the cooling system. That is, the differential temperature TCCD changes depending on whether the internal combustion engine 1 is knocked or the level of the in-cylinder pressure. Therefore, the differential temperature TCCD can be evaluated as a parameter directly indicating the soundness of combustion of the internal combustion engine 1. However, since the amount of heat transferred to the cooling system itself depends on the thermal conductivity of the coolant, the difference temperature TCCD is an increase / decrease in the temperature TCCR on the coolant passage 3 side of the wall (TCCR ′ in FIG. 7). When the thermal conductivity of the coolant increases or decreases in correspondence with (indicated by TCCR ″ and TCCR ″), it increases or decreases like TCCD ′ or TCCD ″. Therefore, the target difference temperature calculation unit 210 corrects the reference target difference temperature TCCBPM calculated by the reference target difference temperature calculation unit 208 using the difference temperature correction value DTCCR calculated by the correction term calculation unit 209 (FIG. 7, indicated as TCCBPM ′ and TCCBPM ″).

The table data shown in FIG. 8 is an example of table data used when the correction term calculation unit 209 calculates a differential temperature correction value for correcting the reference target differential temperature by the target differential temperature calculation unit 210. FIG. The mode of change of the differential temperature correction value on the right side in the middle corresponds to the nucleate boiling point and the film boiling point of the coolant.

In addition, as shown in FIG. 9, the target differential temperature calculation unit 210 has a time delay of heat transfer from the combustion chamber 9 to the wall portion reflecting the heat transfer characteristics of the wall portion defining the combustion chamber 9 of the internal combustion engine 1. When the reference target differential temperature is further corrected in consideration of the above, the post-filter target differential temperature that is smoothly and remarkably changed from the pre-filter target differential temperature is obtained.

The operating state control unit 211 controls the operation of the internal combustion engine control device 100 as a whole. Specifically, the operating state control unit 211 uses the electrical signal input from the intake air temperature sensor 23 to the ECU 102 to calculate the opening of the throttle valve 14 calculated by the CPU 108, and the electrical signal input from the intake air temperature sensor 23 to the ECU 102. On the basis of the temperature of the air flowing into the intake pipe 11 calculated by the CPU 108, the differential temperature calculated by the differential temperature calculation unit 207, the target differential temperature calculated by the target differential temperature calculation unit 210, and the like. An indication value of the fuel injection amount is calculated. Then, the operation state control unit 211 executes the internal combustion engine operation state control process for controlling the operation state by applying the ignition timing and the fuel injection amount instruction value calculated in this way to the internal combustion engine 1. The operating state control unit 211 includes a comparison unit 212 and an ignition timing calculation unit 213 as functional blocks for calculating an instruction value of the ignition timing, focusing on the control of the ignition timing in the internal combustion engine operation state control process. .

The comparison unit 212 compares the difference temperature value calculated by the difference temperature calculation unit 207 with the target difference temperature value calculated by the target difference temperature calculation unit 210, and determines the magnitude relationship between them. The magnitude relationship determined by the comparison unit 212 is used by the ignition timing calculation unit 213.

The ignition timing calculation unit 213 determines that the difference temperature value calculated by the difference temperature calculation unit 207 is larger than the target difference temperature value calculated by the target difference temperature calculation unit 210 based on the magnitude relationship determined by the comparison unit 212. Calculates the ignition timing instruction value obtained by retarding the currently applied ignition timing instruction value by a predetermined amount, and the difference temperature value calculated by the difference temperature calculation unit 207 is calculated by the target difference temperature calculation unit 210. If it is smaller than the value of the differential temperature, the ignition timing command value is calculated by advancing the command value of the currently applied ignition timing by a predetermined amount.

In order to apply the indicated value of the ignition timing calculated by the ignition timing calculation unit 213 to the ignition operation of the spark plug 10, the drive circuit 301 uses an ignition coil or the like in accordance with a control signal input from the operation state control unit 211. The ignition timing of the internal combustion engine 1 is controlled by driving the spark plug 10.

Here, in the experimental results shown in FIG. 10, when it is assumed that the compression ratio of each internal combustion engine varies within the range of −0.2 to +0.5, the target difference as shown in FIG. The variation width W1 of the torque of the internal combustion engine by the internal combustion engine operating state control process with a general fixed ignition timing that does not use the temperature is about 3.6% FS ratio. The variation width W2 of the torque of the internal combustion engine 1 by the internal combustion engine operating state control process with the ignition timing control using the comparative target differential temperature of this embodiment as shown in (b) is shown in (a) of FIG. It can be seen that when the target differential temperature for comparison exhibiting the knock level equivalent to the knock level at the fixed ignition timing is set, it is improved to about 1.6% FS ratio.

Further, from the experimental results shown in FIG. 11, when high-octane (so-called high-octane class) gasoline, low-octane (so-called regular class) gasoline, and ethanol are used as fuel for the internal combustion engine 1, the target difference is obtained. It has been found that there is no difference in temperature behavior, and as knocking occurs, the target differential temperature starts to rise, and the state of knocking above a certain level can be similarly judged for each fuel type. In FIG. 11, the advance angle limit of high octane gasoline is indicated by L1, the advance angle limit of low octane gasoline is indicated by L2, and the advance angle limit of ethanol is indicated by L3.

The internal combustion engine control apparatus 100 having the above-described configuration substantially performs the individual difference of the internal combustion engine 1 by executing the target difference temperature calculation process shown below when executing the internal combustion engine operating state control process. A target differential temperature that realizes the operating state of the internal combustion engine 1 with the optimum efficiency is calculated in an unaffected manner. Hereinafter, the operation of the internal combustion engine control apparatus 100 when executing the target differential temperature calculation process will be described with further reference to FIG.

[Target differential temperature calculation processing]
FIG. 12 is a flowchart illustrating the flow of target difference temperature calculation processing executed by the internal combustion engine control device 100 according to this embodiment.

The flowchart of the target difference temperature calculation process shown in FIG. 12 is in accordance with the timing at which the internal combustion engine control apparatus 100 is operated when the ignition switch of the vehicle is switched from the OFF state to the ON state and the internal combustion engine operation state control process is executed. The target differential temperature calculation process proceeds to step S1. The target differential temperature calculation process is the internal combustion engine operation state control process in which a necessary control program and control data are read from the memory 106 while the internal combustion engine control apparatus 100 is in an operating state and the internal combustion engine operation state control process is being executed. It is repeatedly executed every predetermined control cycle.

In the process of step S1, the torque calculation unit 204 calculates the torque DCBCPFLT output from the internal combustion engine 1 using the electrical signal input from the waveform shaping circuit 202. Here, the torque calculation unit 204 performs a filtering process of multiplying the torque DCBCP once calculated by a predetermined filtering coefficient CDCBPREF so that the torque value of the internal combustion engine 1 calculated by the torque calculation unit 204 changes smoothly. Torque DCBCPFLT is calculated. As the value of the filtering coefficient CDCBPREF, the value read from the memory 106 by the torque calculation unit 204 is used. Thereby, the process of step S1 is completed and the target difference temperature calculation process proceeds to the process of step S2.

In the process of step S2, the target differential temperature calculation unit 210 takes into account the time delay of heat transfer from the combustion chamber 9 to the wall portion that reflects the heat transfer characteristics of the wall portion that defines the combustion chamber 9 of the internal combustion engine 1. A filtering coefficient CDBPREF is calculated. Here, the target differential temperature calculation unit 210 reads out the table data of the filtering coefficient CDBPREF reflecting the time delay of heat transfer according to the increase and decrease of the output of the internal combustion engine 1 from the memory 106, and refers to this. The value of the filtering coefficient CDBPREF corresponding to when the output of the internal combustion engine 1 increases or decreases is calculated. Thereby, the process of step S2 is completed and the target difference temperature calculation process proceeds to the process of step S3.

In the process of step S3, the reference target difference temperature calculation unit 208 reads out map data in which the value of the reference target difference temperature TCCBPM is defined from the memory 106 in correspondence with the value of the parameter relating to the operating state of the internal combustion engine 1, The value of the parameter relating to the operating state of the internal combustion engine 1 that is being operated at the same time is compared with the data read from the memory 106, and from this data, the reference target differential temperature corresponding to the value of the parameter relating to the operating state of the internal combustion engine 1 Calculate the value of TCCBPM. Here, the reference target differential temperature calculation unit 208 uses the rotation speed of the internal combustion engine 1 and the torque output from the internal combustion engine 1 as parameters relating to the operating state of the internal combustion engine 1, and the data referred to by the map data is map data. It is a form. At this time, the reference target differential temperature calculation unit 208 sets the rotation speed NE of the internal combustion engine 1 calculated by the rotation speed calculation unit 203 in the process of the step not shown in the present process as the value of the rotation speed of the internal combustion engine 1. As the value of the torque output from the internal combustion engine 1, the value of the torque DCBCPFLT of the internal combustion engine 1 calculated by the torque calculation unit 204 in step S1 in the current process is used. Thereby, the process of step S3 is completed and the target difference temperature calculation process proceeds to the process of step S4.

In the process of step S4, the correction term calculation unit 209 reads out the table data in which the value of the temperature correlation coefficient MTCCR is defined corresponding to the value of the coolant temperature from the memory 106, and is a step in which illustration is omitted in the current process The coolant temperature value calculated by the cooling water temperature calculation unit 206 in the process of the above and the table data read from the memory 106 are collated, and the temperature corresponding to the coolant temperature value calculated by the cooling water temperature calculation unit 206 from the data is compared. The value of the correlation coefficient MTCCR is calculated. Here, the correction term calculation unit 209 uses the coolant temperature TWTCDFLT value calculated by the cooling water temperature calculation unit 206 by performing a predetermined filtering process as the coolant temperature value. Thereby, the process of step S4 is completed and the target difference temperature calculation process proceeds to the process of step S5.

In the process of step S5, the correction term calculation unit 209 uses the value of the temperature correlation coefficient MTCCR calculated by the correction term calculation unit 209 in the process of step S4 in the current process as the reference target in the process of step S3 in the current process. By multiplying the value of the reference target differential temperature TCCBPM calculated by the differential temperature calculation unit 208, a temperature drop MTCBPF between the temperature of the wall portion on the combustion chamber 9 side and the temperature of the wall portion on the coolant passage 3 side is calculated. Thereby, the process of step S5 is completed and the target difference temperature calculation process proceeds to the process of step S6.

In the process of step S6, the correction term calculation unit 209 determines the value of the drop temperature MTCBPF calculated by the correction term calculation unit 209 in the process of step S5 in the current process as a wall in the process of step not shown in the current process. The temperature TCCR of the wall portion on the side of the coolant passage 3 is calculated by subtracting from the temperature value of the wall portion on the side of the combustion chamber 9 calculated by the portion temperature calculation unit 205. Here, the correction term calculation unit 209 calculates the temperature TCCFLT on the combustion chamber 9 side of the wall calculated by the wall temperature calculation unit 205 by performing a predetermined filtering process as the temperature value on the combustion chamber 9 side of the wall. The value is used. Thereby, the process of step S6 is completed and the target difference temperature calculation process proceeds to the process of step S7.

In the process of step S7, the correction term calculation unit 209 reads out the table data in which the differential temperature correction value is defined corresponding to the temperature value on the coolant passage 3 side of the wall from the memory 106, and the step in this process The temperature TCCR on the coolant passage 3 side of the wall calculated by the correction term calculation unit 209 in the process of S6 is compared with the table data read from the memory 106, and the wall calculated by the correction term calculation unit 209 from the data is compared. The temperature difference correction value DTCCR corresponding to the value of the temperature TCCR on the coolant passage 3 side of the part is calculated. Thereby, the process of step S7 is completed and the target difference temperature calculation process proceeds to the process of step S8.

In the process of step S8, the target difference temperature calculation unit 210 uses the difference temperature correction value DTCCR calculated by the correction term calculation unit 209 in the process of step S7 in the current process as the reference target difference in the process of step S3 in the current process. The target difference temperature TCCDBP0 is calculated by adding to the value of the reference target difference temperature TCCBPM calculated by the temperature calculation unit 208. Thereby, the process of step S8 is completed and the target difference temperature calculation process proceeds to the process of step S9.

In the process of step S9, the target differential temperature calculation unit 210 calculates the filtering coefficient CDBPREF according to the increase and decrease of the output of the internal combustion engine 1 calculated by the target differential temperature calculation unit 210 in the process of step S2 in the current process. The target differential temperature TCCDBP0 is calculated by multiplying the value by the target differential temperature TCCDBP0 calculated by the target differential temperature calculation unit 210 in step S8 of the current process. Thereby, the process of step S9 is completed, and the current series of target difference temperature calculation processes ends.

As is apparent from the above description, in the internal combustion engine control apparatus 100 according to the present embodiment, the control unit 102 defines the combustion chamber 9 of the internal combustion engine 1 and at the temperature on the combustion chamber 9 side of the wall portion that contacts the coolant. A differential temperature that is a differential value between a certain first temperature and a representative temperature of the internal combustion engine 1 is calculated, a reference target differential temperature is calculated from a parameter relating to the operating state, and a second temperature that is a temperature on the coolant side of the wall portion. Since the target difference temperature is calculated by correcting the reference target difference temperature according to the second temperature and the operation state is controlled according to the deviation between the target difference temperature and the difference temperature, With a simple configuration, it is possible to improve the accuracy of the control target value in consideration of fluctuations in the cooling capacity of the internal combustion engine 1, and to control the operating state of the internal combustion engine with more optimal efficiency.

Further, in the internal combustion engine control apparatus 100 according to the present embodiment, the parameters relating to the operating state used by the control unit 102 include the rotational speed of the internal combustion engine 1 and the torque output by the internal combustion engine, and therefore a more accurate reference. The target differential temperature is calculated, and based on this, the target differential temperature can be calculated, and the operating state of the internal combustion engine 1 can be controlled with more optimal efficiency.

Further, in the internal combustion engine control apparatus 100 in the present embodiment, the control unit 102 further corrects the reference target differential temperature by taking into account the heat transfer time delay reflecting the heat transfer characteristics of the wall portion, thereby obtaining the target differential temperature. Therefore, the target differential temperature can be calculated with higher accuracy, and the operating state of the internal combustion engine 1 can be controlled with more optimal efficiency.

In the present invention, the type, shape, arrangement, number, and the like of the members are not limited to the above-described embodiment, and the gist of the invention is appropriately replaced such that the constituent elements are appropriately replaced with those having the same operational effects. Of course, it can be changed as appropriate without departing from the scope.

As described above, the present invention improves the accuracy of the control target value by taking into account the fluctuation of the cooling capacity of the internal combustion engine with a simple configuration, and can control the operating state of the internal combustion engine with more optimum efficiency. The present invention provides an engine control device, and is expected to be widely applicable to internal combustion engine control devices such as vehicles because of its general-purpose universal character.

Claims

Calculating a differential temperature that is a differential value between a first temperature that is a temperature on the combustion chamber side of a wall portion that is in contact with coolant and that defines a combustion chamber of the internal combustion engine, and a representative temperature of the internal combustion engine; In the internal combustion engine control device provided with a control unit for controlling the operating state of the internal combustion engine based on
The controller is
Calculate a reference target differential temperature from the parameters related to the operating state,
Calculating a second temperature which is a temperature on the coolant side of the wall,
Calculating the target differential temperature by correcting the reference target differential temperature according to the second temperature;
An internal combustion engine control device that controls the operating state according to a deviation between the target differential temperature and the differential temperature.
2. The internal combustion engine control device according to claim 1, wherein the parameter includes a rotational speed of the internal combustion engine and a torque output from the internal combustion engine.
The control unit calculates the target differential temperature by further correcting the reference target differential temperature in consideration of a heat transfer time delay reflecting the heat transfer characteristics of the wall. Or the internal combustion engine control apparatus of 2.