JP6684680B2 - Internal combustion engine controller - Google Patents

Description

  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 motorcycle.

  In recent years, for an internal combustion engine of a vehicle such as a two-wheeled vehicle, a controller is used to operate the internal combustion engine while cooperating with the supply of fuel to the internal combustion engine, the supply of air, and the ignition of a mixture of fuel and air. An electronically controlled internal combustion engine controller that electronically controls the state is adopted.

  Specifically, such an internal combustion engine control device uses 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. Based on the internal combustion engine speed, etc. obtained by using the detection signal of, the fuel injection amount for realizing an appropriate air-fuel ratio in the internal combustion engine is calculated, and the fuel injection amount is used to inject fuel into the internal combustion engine. In addition to executing the ignition, ignition is performed on a mixture of intake air and injected fuel at a predetermined ignition timing. Further, at this time, in the internal combustion engine control device, when the fuel injection amount and the ignition timing are set to respective limit values in consideration of characteristics such as 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, by using respective detection signals from sensors such as an in-cylinder pressure sensor, a knock sensor and an ion current sensor, the fuel to the air-fuel mixture according to the combustion state in the combustion chamber is used. There is also a configuration in which the injection amount and the ignition timing are respectively 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 an actual temperature of a combustion chamber wall of the internal combustion engine and a combustion chamber wall corresponding to an operating state of the internal combustion engine stored in advance. Disclosed is a configuration in which temperature data in a steady state of the engine portion is compared with and a correction amount for correcting the ignition timing of the internal combustion engine is obtained according to the deviation.

  Further, Patent Document 2 relates to an internal combustion engine controller, and a first temperature corresponding to a temperature of a first portion of a wall portion that defines a combustion chamber of the internal combustion engine and an outer wall surface of the first portion of the wall portion. A configuration for controlling the operating state of the internal combustion engine based on the difference from the second temperature corresponding to the temperature of the second portion on the side is disclosed.

JP-A-2-223677 International publication WO2016 / 104186

  However, according to the study by the present inventor, in the configuration of Patent Document 1, it is possible to prevent the ignition timing of the internal combustion engine from being retarded more than necessary, to improve the output and efficiency of the internal combustion engine, and Although it is intended to improve the acceleration performance of a vehicle equipped with an engine, only the temperature of the combustion chamber wall is considered, considering that the temperature of the combustion chamber wall of the internal combustion engine has a correlation with the cylinder pressure of the internal combustion engine. Is used as a control parameter, 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 shared by some of the present inventors, the cooling capacity of the cooling system of the internal combustion engine has a correlation with the cylinder pressure of the internal combustion engine in addition to the temperature of the combustion chamber wall 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 portion of the wall defining the combustion chamber of the internal combustion engine and the temperature outside the first portion of the wall By using the difference temperature from the second temperature corresponding to the temperature of the second portion on the wall surface side and comparing it with a predetermined threshold value, the ignition timing is set to a critical advance timing at which knock does not occur. It is possible to set the temperature and the like to improve the accuracy of control of the operating state of the internal combustion engine. For example, when the coolant is a coolant, the water jacket in which the coolant passage through which the coolant flows is formed is the internal combustion engine. Installed in a part of the cylinder block It is because, by the 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. In this way, the change in the cooling capacity of the cooling system may affect the accuracy of the predetermined threshold value, and therefore the internal combustion engine may not be able to operate at the best efficiency. There is room.

  In other words, at present, with a simple configuration that can be suitably applied to a vehicle such as a motorcycle that is particularly required to be lightweight and small, the predetermined value is taken into consideration in consideration of the fluctuation of the cooling capacity of the internal combustion engine. It can be said that there is a long-awaited situation of realizing an internal combustion engine control device capable of improving the accuracy of the control target value including the threshold value and controlling the operating state of the internal combustion engine with more optimal efficiency.

  The present invention has been made through the above studies, has a simple structure, improves the accuracy of the control target value in consideration of the fluctuation of the cooling capacity of the internal combustion engine, and operates the internal combustion engine 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 first temperature which is a temperature on the combustion chamber side of a wall portion which is in contact with a coolant flowing through the internal combustion engine and the coolant . In the internal combustion engine control device including a control unit that calculates a difference temperature that is a difference value with the temperature and controls the operating state of the internal combustion engine based on the difference temperature, the control unit is a reference from the parameters related to the operating state. calculates a target differential temperature, the Ri temperature der of the coolant side of the wall portion, and calculates the second temperature Ru temperature der obtained from the first temperature, said reference target differential temperature the second A first aspect is to calculate a target difference temperature by correcting the temperature according to the temperature and control the operating state according to a deviation between the target difference temperature and the difference temperature. In the present invention, in addition to the first aspect, the second temperature is a drop temperature calculated by multiplying the reference target difference temperature by a temperature correlation coefficient calculated corresponding to the temperature of the coolant. The second phase is calculated by subtracting from the first temperature.

The present invention, in addition to the first or second aspect, as the parameter, as a third aspect that the rotational speed and the engine of the internal combustion engine include torque output.

According to the present invention, in addition to any one of the first to third aspects, the control unit further corrects the reference target difference temperature by adding a heat transfer time delay reflecting the heat transfer characteristic of the wall. A fourth aspect is to calculate the target difference temperature by doing so.

According to the internal combustion engine controller according to the first aspect of the present invention described above, the controller controls the temperature on the combustion chamber side of the wall portion that defines the combustion chamber of the internal combustion engine and that is in contact with the coolant flowing through the internal combustion engine. calculating a differential temperature which is a difference value between the temperature of the coolant of a first temperature and the internal combustion engine, calculates a reference target differential temperature from the parameter related to the operating state, Ri temperature der coolant side of the wall portion, and the calculating a second temperature Ru temperature der determined from first temperature, a reference target differential temperature calculating the target differential temperature by correcting depending on the second temperature, the deviation between the target differential temperature and differential temperature Accordingly, since the operation state is controlled, the accuracy of the control target value is improved in consideration of the fluctuation of the cooling capacity of the internal combustion engine with a simple configuration, and the operating state of the internal combustion engine is more efficiently adjusted. Can be controlled. Further, the internal combustion engine control device according to the second aspect of the present invention also exerts such an effect.

Further, according to the internal combustion engine control device in the third aspect of the present invention, 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, It is possible to calculate an accurate reference target difference temperature and calculate the target difference temperature based on this, and it is possible to control the operating state of the internal combustion engine with more optimal efficiency.

Further, according to the internal combustion engine control device of the fourth aspect of the present invention, the control unit further corrects the reference target differential temperature by taking into account the heat transfer time delay that reflects the heat transfer characteristics of the wall. Since the target difference temperature is calculated by the above, the target difference temperature can be calculated with higher accuracy, and the operating state of the internal combustion engine can be controlled with more optimum efficiency.

FIG. 1 is a schematic diagram showing a configuration of an internal combustion engine and an internal combustion engine control device applied to the same in an embodiment of the present invention, and FIG. 1A is a water-cooled internal combustion engine according to the present embodiment and its application. 1 is a partial cross-sectional view schematically showing a configuration of an internal combustion engine control device according to the present invention and showing how heat generated in an internal combustion engine is consumed in an output system while being transferred to a cooling system and an exhaust system. 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 is a result of an experiment in the present embodiment, showing each inner surface 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 being 5000 rpm and the opening of the throttle valve being 48 degrees. 6 is a graph showing the temperature at the position together with 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 at the time of combustion of the air-fuel mixture when the internal combustion engine is an air-cooled type and one intake valve and one exhaust valve are provided, as experimental results in the present embodiment. Specifically, FIGS. 3 (a) and 3 (b) show when the rotation 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%. The temperature distribution of the inner surface of the combustion chamber of Fig. 3 is shown in order, and Figs. 3 (c) to 3 (g) show that the carbon monoxide concentration in the exhaust gas of the internal combustion engine is fixed at 0.5%, In addition, the temperature distribution of the inner surface of the combustion chamber when the number of rotations is 1400 rpm, 1800 rpm, 2000 rpm, 2200 rpm, and 2400 rpm is shown in order. FIG. 4 is a block diagram showing the configuration of the internal combustion engine control device applied to the water-cooled internal combustion engine in this embodiment. FIG. 5 is a result of an experiment in the present embodiment, and shows the difference temperature of the internal combustion engine when the ignition timing in the advance direction is changed with the rotational speed of the water-cooled internal combustion engine being 5000 rpm and the opening of the throttle valve being 40 degrees. It is a graph shown with an output torque and a knock level. FIG. 6 is a graph showing, as an experimental result in the present embodiment, the differential temperature and the peak in-cylinder pressure in comparison 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 contents of correction of the reference target difference temperature in the internal combustion engine control device applied thereto. FIG. 8 is a schematic diagram showing table data of difference temperature correction values used for correction of the reference target difference temperature in the internal combustion engine control device applied to the water-cooled internal combustion engine in the present embodiment. FIG. 9 is a schematic diagram showing a comparison of the target difference temperature before filter processing and the target difference temperature after filter processing in the internal combustion engine control device 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 according to the present embodiment varies when mass production is assumed. The internal combustion engine has a predetermined rotation speed of the internal combustion engine and a predetermined opening degree of the throttle valve. 10 (a) is a graph showing the output torque and knock level of the internal combustion engine according to the internal combustion engine operating state control process of the comparative example, and FIG. 10] is a graph showing an output torque and a knock level of the internal combustion engine by the internal combustion engine operating state control processing of the present embodiment. FIG. 11 is an experimental result when various fuel types in the present embodiment are used, and shows the advancing direction of the internal combustion engine when the rotational speed of the water-cooled internal combustion engine is a predetermined rotational speed and the opening of the throttle valve is a predetermined opening. 6 is a graph showing a target difference temperature, an output torque of the internal combustion engine, and a knock level when the ignition timing of is changed. 12 is a flowchart illustrating the flow of the target difference temperature calculation process 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 device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[Structure of internal combustion engine]
First, the 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. 1 to 3.

  FIG. 1 is a schematic diagram showing a configuration of an internal combustion engine and an internal combustion engine control device applied to the same in an embodiment of the present invention, and FIG. 1A is a water-cooled internal combustion engine according to the present embodiment and its application. 1 is a partial cross-sectional view schematically showing a configuration of an internal combustion engine control device according to the present invention and showing how heat generated in an internal combustion engine is consumed in an output system while being transferred to a cooling system and an exhaust system. 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 is a result of an experiment in the present embodiment, showing 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 rotation speed of the internal combustion engine being 5000 rpm and the opening of the throttle valve being 48 degrees. 2 is a graph showing the output torque of an internal combustion engine and a knock level. FIG. 3 shows the temperature distribution in the combustion chamber of the internal combustion engine at the time of combustion of the air-fuel mixture when the internal combustion engine is an air-cooled type and one intake valve and one exhaust valve are provided, as experimental results in the present embodiment. Specifically, FIGS. 3 (a) and 3 (b) show when the rotation 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%. The temperature distribution of the inner surface of the combustion chamber of Fig. 3 is shown in order, and Figs. 3 (c) to 3 (g) show that the carbon monoxide concentration in the exhaust gas of the internal combustion engine is fixed at 0.5%, In addition, the temperature distribution of the inner surface of the combustion chamber when the number of rotations is 1400 rpm, 1800 rpm, 2000 rpm, 2200 rpm, and 2400 rpm is shown in order. Note that, in FIG. 2, for convenience, the torque and the knock level are shown on the same vertical axis.

  As shown in FIG. 1, an internal combustion engine 1 is mounted on a vehicle such as a motorcycle (not shown) and includes a cylinder block 2 having 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 serving as a cooling liquid for cooling the cylinder block 2 flows. Note that FIG. 1 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 cooling type, and is an air cooling type that does not have the coolant passage 3 and uses the surrounding air as a coolant for cooling the cylinder block 2. Good.

  A piston 4 is arranged inside the cylinder 2a. The piston 4 is connected to the crankshaft 6 via the 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 (reactors) 7a are arranged upright in the circumferential direction in a predetermined pattern.

  A cylinder head 8 is attached 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 for igniting a mixture of fuel and air in the combustion chamber 9. A plurality of spark plugs 10 may be provided for each combustion chamber 9.

  An intake pipe 11 that communicates with the combustion chamber 9 is attached to the cylinder head 8. An intake passage 11 a is formed in the cylinder head 8 to connect the combustion chamber 9 and the intake pipe 11 to each other. 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 corresponding 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 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 into the intake pipe 11. The intake pipe 11 is provided with a throttle valve 14 upstream of the injector 13. The throttle valve 14 is a component of a throttle device (not shown), and the body of the throttle device is assembled to the intake pipe 11. The injector 13 may directly inject the fuel into the corresponding combustion chamber 9. The number of injectors 13 and the number of throttle valves 14 may be plural.

  In addition, an exhaust pipe 15 is attached to the cylinder head 8 so as to communicate with the combustion chamber 9. An exhaust passage 15a is formed in the cylinder head 8 to connect the combustion chamber 9 and the exhaust passage 15a to each other. 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 corresponding to the number of the cylinders 2a, and the number of the exhaust passages 15a is equal to the number of the cylinders 2a and the 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 other numbers.

  Here, considering the case where the internal combustion engine 1 is a water-cooled type, on the assumption that the cooling function of the cooling system of the internal combustion engine 1 does not fail, the total amount of heat generated in the internal combustion engine 1 as shown by the following mathematical formula (Equation 1). QT is equal to the sum of the heat quantity Qtq converted into the torque output by the internal combustion engine 1, the cooling heat quantity Qw of the internal combustion engine 1, and the heat quantity Qex discharged by the exhaust gas of the internal combustion engine 1. At this time, The heat quantity Qtq converted into the torque output by the engine 1 and the cooling heat quantity Qw of the internal combustion engine 1 are in a proportional relationship. Further, the cooling heat quantity Qw is expressed as follows: h is the heat transfer coefficient of the heat passage portion from the combustion chamber 9 to the coolant, A is the cooling surface area of the combustion chamber 9, and t is the time. To the temperature difference between the temperature of the wall surface of the wall portion of the cylinder block 2 or the cylinder head 8 on the side of the combustion chamber 9 and the temperature of the coolant flowing in the coolant passage 3 of the internal combustion engine 1, There is a relationship as shown by the following mathematical formula (Equation 2). The heat transfer coefficient h in this equation (Equation 2) is represented by the following equation (Equation 3), which is the Eichelberg equation, and the cube root of the velocity (piston velocity) Cm of the piston 4 and the internal pressure of the cylinder 2a ( It increases in proportion to the square root of (cylinder pressure) p and the square root of the temperature of the combustion gas (combustion gas temperature) Tg of the internal combustion engine 1. Therefore, in an arbitrary operating state of the internal combustion engine 1, a positive correlation is established between the temperature difference TCCD and the torque. It should be noted that, in principle, such an argument holds even in the case where the internal combustion engine 1 is of the air cooling type.

  Further, from the experimental result shown in FIG. 2 regarding the temperature measurement position shown in FIG. 1B, as the ignition timing is advanced, the torque output from the water-cooled internal combustion engine 1 increases and the ignition timing changes. It can be seen that, after reaching the MBT, the temperature rise 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 shown as squish region 1 to squish region 5 in FIG. 2, and the squish region 1 is an intake side squish region separated from the center of the combustion chamber 9 and a squish region 2 is The intake side squish region near the center of the combustion chamber 9, the squish region 3 is the exhaust side squish region, the squish region 4 is the squish region separated from the center of the combustion chamber 9 and the spark plug, and the squish region 5 is the combustion chamber 9 Each of the squish regions spaced from the center and close to the spark plug 10 is shown. In FIG. 2, the squish region 1 to the squish region 5 where the temperature rise is most prominent is the squish region 2 which is the intake side squish region close to the center of the combustion chamber 9. It can be seen that the temperature increase in the squish region on the side appears more sharply than the temperature increase in the squish region on the exhaust side. This is generally considered to be due to knocking starting from the intake 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 on the intake side region is more sensitive than the reaction on the exhaust side. Therefore, the temperature distribution of the combustion chamber 9 is changed to the combustion state including knock of the internal combustion engine 1. It can be seen that it is preferable to install a combustion chamber temperature sensor on the intake side of the combustion chamber 9 in consideration of the use of the above as an index. Further, in consideration of the mass production conditions of the internal combustion engine 1, a general thermistor type temperature sensor was installed in the vicinity of the squish region 1, and the temperature detection value shown in FIG. 2 could be obtained by this temperature sensor.

  Further, in order to confirm the characteristics of the temperature distribution in the combustion chamber 9, an air-cooled internal combustion engine 1 having a simple cooling system configuration was used to obtain the experimental results shown in FIG. 3 showing the temperature distribution in the combustion chamber 9. In the experimental results shown in FIGS. 3A and 3B, the temperature distribution in the combustion chamber 9 due to the difference in fuel control (carbon monoxide concentration) is obtained even in the no-load operation state where the heat generation amount of the internal combustion engine 1 is small. It was found that the temperature difference between the intake side (intake valve 12 side) and the exhaust side (exhaust valve 16 side) was about 40 ° C. Further, in the other experimental results of FIG. 3 (c) to FIG. 3 (g), the tendency of the temperature distribution does not change even if the rotation speed of the internal combustion engine 1 changes, and the temperature increases as the rotation speed increases. The result was rising. Therefore, it is understood that the parameters for determining the combustion state can be extracted and used even in the air-cooled internal combustion engine having one intake / exhaust valve. It should be noted that reference numerals A to K in FIG. 3 indicate temperature ranges in the respective regions, specifically, the reference numeral A is a temperature range of 165 ° C. or higher and lower than 170 ° C., and the reference numeral B is 160 ° C. A temperature range of 165 ° C. or more and less than 165 ° C., a code C of 155 ° C. or more and less than 160 ° C., a code D of 150 ° C. or more and less than 155 ° C., and a code E of 145 ° C. or more and less than 150 ° C. Reference symbol F is a temperature range of 140 ° C. or higher and lower than 145 ° C., reference symbol G is a temperature range of 135 ° C. or higher and lower than 140 ° C., reference symbol H is a temperature range of 130 ° C. or higher and lower than 135 ° C., and reference symbol I is 125 ° C. or higher and 130 ° C. A temperature range of less than 0 ° C., a symbol J indicates a temperature range of 120 ° C. or more and less than 125 ° C., and a symbol K indicates a temperature range of 115 ° C. or more and less than 120 ° C., respectively.

[Configuration of internal combustion engine controller]
Next, with reference to FIG. 4 to FIG. 11 in addition to FIG. 1, the configuration of the internal combustion engine controller in the present embodiment will be described.

FIG. 4 is a block diagram showing the configuration of the internal combustion engine control device applied to the water-cooled internal combustion engine in this embodiment. FIG. 5 is a result of an experiment in the present embodiment, and shows the difference temperature of the internal combustion engine when the ignition timing in the advance direction is changed with the rotational speed of the water-cooled internal combustion engine being 5000 rpm and the opening of the throttle valve being 40 degrees. It is a graph shown with an output torque and a knock level. FIG. 6 is a graph showing, as an experimental result in the present embodiment, the differential temperature and the peak in-cylinder pressure in comparison 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 contents of correction of the reference target difference temperature in the internal combustion engine control device applied thereto. FIG. 8 is a schematic diagram showing table data of difference temperature correction values used for correction of the reference target difference temperature in the internal combustion engine control device applied to the water-cooled internal combustion engine in the present embodiment. FIG. 9 is a schematic diagram showing a comparison of the target difference temperature before filter processing and the target difference temperature after filter processing in the internal combustion engine control device 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 according to the present embodiment varies when mass production is assumed. The internal combustion engine has a predetermined rotation speed of the internal combustion engine and a predetermined opening degree of the throttle valve. 10 (a) is a graph showing the output torque and knock level of the internal combustion engine according to the internal combustion engine operating state control process of the comparative example, and FIG. 10] is a graph showing an output torque and a knock level of the internal combustion engine by the internal combustion engine operating state control processing of the present embodiment. Further, FIG. 11 is an experimental result when various fuel types in the present embodiment are used. The engine speed of the water-cooled internal combustion engine is set to a predetermined rotation speed and the opening degree of the throttle valve is set to a predetermined opening degree. 6 is a graph showing a target difference temperature, an output torque of the internal combustion engine, and a knock level when the ignition timing in the angular direction is changed. In FIG. 5, the difference temperature and the knock level are shown on the same vertical axis for convenience, and in FIG. 11, the target difference temperature and the torque are shown on the same vertical axis for convenience.

  As shown in FIG. 4, the internal combustion engine controller 100 according to the present embodiment is electrically connected to the cooling water 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. An ECU (Electronic Control Unit) 102 is provided.

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

  The crank angle sensor 22 is attached to a lower case or the like (not shown) that is assembled to the lower portion of the cylinder block 2 in such a manner as to face the tooth portion 7a formed on the outer peripheral surface of the rotor 7, and the crank angle sensor 22 rotates as the crankshaft 6 rotates. The angular velocity of the crankshaft 6 is detected by detecting the rotating tooth portion 7a. The crank angle sensor 22 inputs an electric signal indicating the angular velocity thus detected 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 air temperature to the ECU 102. To enter.

  The throttle opening sensor 24 is mounted on 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 portion temperature sensor 25 is a member that defines the combustion chamber 9, that is, a wall surface of the wall portion of the cylinder block 2 or the cylinder head 8 on which the heat receiving portion is mounted on the combustion chamber 9 side and the wall surface on the combustion chamber 9 side. Is detected, and an electric signal indicating the temperature on the combustion chamber 9 side of the wall portion thus detected is input to the ECU 102. Specifically, the wall temperature sensor 25 is a wall surface on the intake valve 12 side, which is a portion where the flame generated by igniting and igniting the air-fuel mixture in the combustion chamber 9 is difficult to propagate. Attached to the cylinder block 2 or cylinder head 8 on the side of the combustion chamber 9 of the wall portion so as to detect the temperature (inner wall surface temperature on the intake valve 12 side of the cylinder block 2 or the cylinder head 8 on the side of the combustion chamber 9). To be done. Here, the temperature of the wall portion, which corresponds to the wall surface temperature on the intake valve 12 side, is the temperature of the portion where the flame generated by the ignition of the air-fuel mixture in the combustion chamber 9 does not easily propagate, The temperature is a temperature at which the air-fuel mixture in the chamber 9 reacts sensitively to the combustion state. In addition, in FIG. 1, the wall temperature sensor 25 shows an example in which a heat receiving portion is attached to the combustion chamber 9 side in the wall portion of the cylinder head 8 as a member that defines the combustion chamber 9. This corresponds to the configuration in which the portion is arranged in the vicinity of the squish region 1 on the intake side, which is separated from the center of the combustion chamber 9 in FIG. Further, if the temperature is a temperature that 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 included 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 composed of various nonvolatile and volatile storage devices, and stores control programs for internal combustion engine operating state control processing and various control data. The nonvolatile storage device functions as a working area that temporarily stores control data (instruction value of fuel injection amount, ignition timing, etc.) 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 cooling water 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, difference temperature calculation unit 207, reference target difference temperature calculation unit 208, correction term calculation unit 209, target difference temperature calculation unit 210, operation The state control part 211, the comparison part 212, and the ignition timing calculation part 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 difference temperature calculation unit 207, the reference target difference temperature calculation unit 208, the correction term calculation unit 209, and the target difference temperature calculation. The unit 210, the operation state control unit 211, the comparison unit 212, and the ignition timing calculation unit 213 are functional blocks when the CPU 108 reads out a necessary control program and control data from the memory 106 and executes an internal combustion engine operation state control process and the like. Is shown as.

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

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

  The waveform shaping circuit 202 performs shaping processing such as smoothing processing 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 electric signal input from the waveform shaping circuit 202, and the rotation speed of the internal combustion engine 1 calculated by the rotation speed calculation unit 203 in this way is a reference value. It is used by the target difference temperature calculation unit 208.

  The torque calculation unit 204 calculates the output torque (torque) of the internal combustion engine 1 using the electric signal input from the waveform shaping circuit 202, and the torque of the internal combustion engine 1 calculated by the torque calculation unit 204 in this way is a reference value. It is used by the target difference temperature calculation unit 208. The torque calculation unit 204 may perform a predetermined filtering process on the torque value of the internal combustion engine 1 calculated in this way so that the torque value 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 or the wall of the cylinder head 8 on the combustion chamber 9 side of the cylinder head 2. The temperature (wall surface temperature) is calculated, and the temperature of the wall portion on the combustion chamber 9 side calculated by the wall portion temperature calculation unit 205 is used by the difference temperature calculation unit 207 and the correction term calculation 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, The temperature is a temperature that is sensitive to the combustion state such as the turbulence of the combustion of the air-fuel mixture in 9, that is, the state of heat reception on the wall surface of the combustion chamber 9. Here, the state of heat reception on 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 knock generation state, and the internal pressure level of the cylinder and the knock generation state are This is affected by the ignition timing of the engine 1. The wall portion temperature calculation unit 205 may perform a predetermined filtering process on the wall portion so that the calculated temperature value of the wall portion on the combustion chamber 9 side changes smoothly. In addition, in addition, since the temperature of the wall on the side of the combustion chamber 9 can be evaluated to be a temperature that directly reflects the amount of heat generated in the cylinder of the internal combustion engine 1, the temperature of the wall may be evaluated. The temperature on the side of the combustion chamber 9 and the fuel injection amount supplied to the cylinder of the internal combustion engine 1, that is, the combustion chamber 9 are also roughly related to 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 calculating unit 206 calculates the temperature of the coolant flowing through the coolant passage 3 as the internal combustion engine representative temperature using the electric signal input from the A / D conversion circuit 201b, and the cooling water temperature calculating unit 206 calculates in this way. The calculated coolant temperature is used by the difference 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 is a temperature that reflects the amount of cooling heat 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. The cooling water temperature calculation unit 206 may perform a predetermined filtering process on the coolant temperature calculated in this way so that the coolant temperature 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 temperature of the internal combustion engine. Even when the internal combustion engine 1 is an air-cooled type, it is possible to use the temperature of the lubricating oil of the internal combustion engine 1 as the internal combustion engine representative temperature.

  The difference temperature calculation unit 207 calculates a difference temperature which is a difference value between the temperature of the wall on the combustion chamber 9 side calculated by the wall temperature calculation unit 205 and the coolant temperature calculated by the cooling water temperature calculation unit 206. The differential temperature calculated by the differential temperature calculating unit 207 is used in the internal combustion engine operating state control process of the operating state control unit 211. Here, the temperature of the wall on the combustion chamber 9 side calculated by the wall temperature calculation unit 205 is a temperature that is sensitive 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, this difference temperature is large when the combustion state in the combustion chamber 9 is good. On the other hand, when the ignition timing is in the retarded state and the output of the internal combustion engine 1 is low, the value is small compared to the value. Therefore, the difference temperature serves as 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 knock generation state, and the internal pressure level of the cylinder and the knock generation state of the cylinder surface of the combustion chamber 9 of the internal combustion engine 1 The difference temperature that affects the state of heat reception and is the difference value between the temperature on the combustion chamber 9 side of the wall portion of the combustion chamber 9 and the internal combustion engine representative temperature such as the coolant temperature of the internal combustion engine is the difference temperature. The differential temperature can be applied to control of ignition timing when the operating state control unit 211 controls the operating state of the internal combustion engine 1, since it is sensitive to the heat receiving state of the wall surface of the internal combustion engine 1. . It should be noted that, if necessary, such a difference temperature can also be applied to control of the fuel injection amount when the operating state control unit 211 controls the operating state of the internal combustion engine 1.

  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 begins to rise, and after that the knock level begins to rise and the differential temperature shows a steep rising tendency.

  Further, from the experimental results shown in FIG. 6, it is found that the relationship between the differential temperature and the peak in-cylinder pressure has a very good positive correlation. If the ignition timing is fixed, the relationship between the peak in-cylinder pressure and the average effective pressure has a positive correlation, so that there is a positive correlation between the torque of the internal combustion engine 1 at the MBT and the differential temperature. In this way, if there is a positive correlation between the torque of the internal combustion engine 1 and the differential temperature, the internal temperature of the internal combustion engine is controlled by controlling the differential temperature of the actual machine to be the target differential temperature by using this differential temperature as the target differential temperature. It is possible to operate the No. 1 in the state of the best torque. Further, when the relationship between the torque and the differential temperature is measured under various rotation speeds and load conditions in the internal combustion engine 1, the rotation speed is in the range of 1900 rpm to 5000 rpm, and the throttle opening is in the range of the idle opening to the full opening. , Such a positive correlation was observed.

  The reference target difference temperature calculation unit 208 calculates the reference target difference temperature from the parameter 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 difference temperature calculation unit 210. Here, the reference target difference temperature is a reference value of the target difference temperature that is the target value of the difference temperature calculated by the difference temperature calculation unit 207, and the knock level of the internal combustion engine 1 is a level that can be ignored. It is calculated as an ideal value of the differential temperature in the operating state in which the best torque is output. Further, as a parameter related to the operating state of the internal combustion engine 1, in the actually operating internal combustion engine 1, a reference target difference temperature that is an ideal value when the internal combustion engine 1 is in an operating state that outputs the best torque is obtained. Therefore, it is necessary to set the extracted parameters that represent 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 the parameter related to the operating state of the internal combustion engine 1.

  Specifically, the reference target difference temperature calculation unit 208 defines the value of the reference target difference temperature corresponding to the data stored in advance in the memory 106, that is, the value of the parameter related to the operating state of the internal combustion engine 1. The table data and the map data are read out from the memory 106, and the values of the parameters relating to the operating state of the internal combustion engine 1 that is actually operating are compared with the data read out from the memory 106. The value of the reference target difference temperature corresponding to the value of the parameter related 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 , 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 are correspondingly defined on the two axes orthogonal to each other, and on the third axis orthogonal to the two axes, The map data has a form in which the value of the reference target difference temperature is defined in correspondence with the value of the rotational speed and the value of the torque. In such a case, the reference target difference temperature calculation unit 208 reads the map data from the memory 106 and refers to the map data to calculate the rotation speed of the internal combustion engine 1 calculated by the rotation speed calculation unit 203 and the torque calculation unit 204. The reference target difference 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. And the correction value calculated by the correction term calculation unit 209 in this way is used by the target difference temperature calculation unit 210. The 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 heat amount exceeding the allowable heat amount of the internal combustion engine 1 is not generated in it. . Here, when the output of the internal combustion engine 1 is increased, the temperature of the wall surface on the coolant passage 3 side that is typically formed in the wall portion of the cylinder block 2 that defines the combustion chamber 9 is the coolant that is the coolant. When approaching the nucleate boiling point, the turbulence of the coolant flow field of the coolant passage 3 or its surroundings 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 approaching the film boiling point, the phenomenon that the thermal conductivity of the coolant decreases decreases 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 suffices to calculate the correction value for adjusting the reference target difference temperature from the temperature.

  Specifically, the correction term calculation unit 209 reads out from the memory 106 the data stored in advance in the memory 106, that is, the 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 cooling water temperature calculation unit 206 is compared with the table data read from the memory 106, and from this data, the temperature phase relationship corresponding to the value of the coolant temperature calculated by the cooling water temperature calculation unit 206. Calculate the value of a number. Then, the correction term calculation unit 209 multiplies the reference target difference temperature calculated by the reference target difference temperature calculation unit 208 by the temperature correlation coefficient to obtain the temperature of the wall on the combustion chamber 9 side and the coolant passage 3 of the wall. Calculate the temperature drop between the two temperatures. Next, the correction term calculation unit 209 subtracts the drop temperature from the temperature of the wall portion on the combustion chamber 9 side calculated by the wall portion temperature calculation unit 205 to calculate the temperature of the wall portion on the coolant passage 3 side. Next, the correction term calculation unit 209 stores, from the memory 106, the data stored in advance in the memory 106, that is, 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 portion. The temperature on the coolant passage 3 side of the wall portion, which is read out and calculated by the correction term calculation unit 209, is compared with the table data read out from the memory 106, and the data of the wall portion calculated by the correction term calculation unit 209 is calculated from this data. A difference temperature correction value corresponding to the temperature value on the coolant passage 3 side is calculated. When the internal combustion engine 1 is an air-cooled type, the cooling capacity of the cooling system depends on the speed of the vehicle in which the internal combustion engine 1 is mounted, the representative temperature of the internal combustion engine 1, its intake air temperature, its oil temperature, and its 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 of the water-cooled internal combustion engine 1 is detected as the representative temperature of the internal combustion engine 1. The calculated position can be calculated by correcting the position and multiplying it by a correlation coefficient corresponding to the vehicle speed or the intake air temperature.

  The target difference temperature calculation unit 210 corrects the reference target difference temperature calculated by the reference target difference temperature calculation unit 208 using the difference temperature correction value calculated by the correction term calculation unit 209 to calculate the target difference temperature. The target difference temperature calculated by the target difference temperature calculation unit 210 is used by the operating 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 to obtain the target difference temperature. Will be calculated. Further, at this time, the target difference temperature calculation unit 210 takes into consideration the time delay of the 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. The reference target difference temperature may be further corrected. In such a case, specifically, the target difference temperature calculation unit 210 calculates a filtering coefficient according to the increase and decrease of the output of the internal combustion engine 1, and a reference obtained by correcting the filtering coefficient using the difference temperature correction value. The target difference temperature is multiplied to calculate the target difference 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 combustion of the internal combustion engine 1 corresponds to the amount of heat transferred to the cooling system. That is, since the difference temperature TCCD changes depending on the presence or absence of knocking of the internal combustion engine 1 and the level of the in-cylinder pressure, it can be evaluated as a parameter that directly indicates 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 differential temperature TCCD increases or decreases the temperature TCCR on the coolant passage 3 side of the wall (TCCR ′ in FIG. 7). And TCCR ″), the thermal conductivity of the coolant increases / decreases like TCCD ′ and TCCD ″. Therefore, the target difference temperature calculation unit 210 corrects the reference target difference temperature TCCDBPM 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, TCCDBPM 'and TCCDBPM' ').

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

  In addition, as shown in FIG. 9, the target difference temperature calculation unit 210 causes the time delay of the 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. In consideration of the above, when the reference target difference temperature is further corrected, the target difference temperature after the filter processing that smoothly and remarkably changes as compared with the target difference temperature before the filter processing is obtained.

  The operating state control unit 211 controls the operation of the entire internal combustion engine control device 100. Specifically, the operating state control unit 211 uses the electric 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 electric signal input from the intake air temperature sensor 23 to the ECU 102. Based on the temperature of the air flowing into the intake pipe 11 calculated by the CPU 108, the difference temperature calculated by the difference temperature calculation unit 207, the target difference temperature calculated by the target difference temperature calculation unit 210, and the like, the ignition timing and An instruction value or the like of the fuel injection amount is calculated. Then, the operating state control unit 211 executes the internal combustion engine operating state control process for controlling the operating state by applying the ignition timing, the instruction value of the fuel injection amount, and the like thus calculated to the internal combustion engine 1. Further, when focusing on the control of the ignition timing in the internal combustion engine operating state control processing, the operating state control unit 211 includes a comparing unit 212 and an ignition timing calculating unit 213 as functional blocks for calculating an instruction value of the ignition timing. .

  The comparison unit 212 compares the value of the difference temperature calculated by the difference temperature calculation unit 207 and the value of the target difference temperature calculated by the target difference temperature calculation unit 210, determines the magnitude relationship between them, and 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 whether 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. Is the target value calculated by the target difference temperature calculation unit 210 by calculating the ignition timing command value obtained by delaying the currently applied ignition timing command value by a predetermined amount, and calculating the difference temperature value calculated by the difference temperature calculation unit 207. If it is smaller than the value of the differential temperature, the ignition timing instruction value obtained by advancing the currently applied ignition timing instruction value by a predetermined amount is calculated.

  The drive circuit 301 applies the instruction value of the ignition timing calculated by the ignition timing calculation unit 213 to the ignition operation of the spark plug 10 in accordance with a control signal input from the operating state control unit 211 via an ignition coil or the like. 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, assuming that the compression ratio of each internal combustion engine varies within the range of −0.2 to +0.5, the target difference temperature as shown in FIG. The variation width W1 of the torque of the internal combustion engine due to the internal combustion engine operating state control process with a general fixed ignition timing that is not used is about 3.6% FS ratio, but as shown in FIG. As shown in FIG. 10A, the variation width W2 of the torque of the internal combustion engine 1 by the internal combustion engine operating state control process involving the ignition timing control using the comparative target difference temperature of the present embodiment is the knock at the fixed ignition timing of FIG. It can be seen that when the comparison target difference temperature exhibiting a knock level equivalent to the level 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 were used as the fuel of the internal combustion engine 1, the target difference It was found that there is no difference in temperature behavior, and the target differential temperature starts to rise with the occurrence of knock, and the knock state above a certain level can be similarly determined for each fuel type. In FIG. 11, the advance limit of high octane gasoline is indicated by L1, the advance limit of low octane gasoline is indicated by L2, and the advance limit of ethanol is indicated by L3.

  The internal combustion engine control device 100 having the above-described configuration substantially eliminates the individual difference of the internal combustion engine 1 by executing the following target difference temperature calculation process when executing the internal combustion engine operating state control process. The target differential temperature that achieves the operating state of the internal combustion engine 1 with optimum efficiency is calculated in a manner that is not affected. Hereinafter, with further reference to FIG. 12, the operation of the internal combustion engine control device 100 when executing the target difference temperature calculation process will be described.

[Target difference temperature calculation process]
FIG. 12 is a flowchart exemplifying the flow of the target difference temperature calculation process executed by the internal combustion engine controller 100 according to this embodiment.

  The flowchart of the target difference temperature calculation process shown in FIG. 12 is adjusted to the timing at which the internal combustion engine control device 100 is operated by switching the ignition switch of the vehicle from the off state to the on state and the internal combustion engine operating state control process is executed. Then, the target difference temperature calculation process proceeds to step S1. The target difference temperature calculation process is performed by reading a necessary control program and control data from the memory 106 while the internal combustion engine control device 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 by the internal combustion engine 1 using the electric signal input from the waveform shaping circuit 202. Here, the torque calculation unit 204 performs a filtering process of multiplying the once calculated torque DCBCP by a predetermined filtering coefficient CDCBPREF so that the value of the torque of the internal combustion engine 1 calculated by the torque calculation unit 204 smoothly changes. The torque DCBCPFLT of 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. As a result, the process of step S1 is completed, and the target difference temperature calculation process proceeds to step S2.

  In the process of step S2, the target difference temperature calculation unit 210 takes into consideration the time delay of the heat transfer from the combustion chamber 9 to the wall that reflects the heat transfer characteristics of the wall that defines the combustion chamber 9 of the internal combustion engine 1. The filtering coefficient CDBPREF is calculated. Here, the target difference temperature calculation unit 210 reads the table data of the filtering coefficient CDBPREF, which reflects the time delay of the heat transfer depending on the increase and decrease of the output of the internal combustion engine 1, from the memory 106 and refers to it. The value of the filtering coefficient CDBPREF corresponding to the increase and decrease of the output of the internal combustion engine 1 is calculated. As a result, the process of step S2 is completed, and the target difference temperature calculation process proceeds to step S3.

  In the process of step S3, the reference target difference temperature calculation unit 208 reads out from the memory 106 the map data in which the value of the reference target difference temperature TCCDBPM is defined corresponding to the value of the parameter related to the operating state of the internal combustion engine 1, and actually The value of the parameter related to the operating state of the internal combustion engine 1 that is being driven is compared with the data read from the memory 106, and from this data, the reference target difference temperature corresponding to the value of the parameter related to the operating state of the internal combustion engine 1 Calculate the value of TCCDBPM. Here, the reference target difference temperature calculation unit 208 uses the rotational speed of the internal combustion engine 1 and the torque output by the internal combustion engine 1 as parameters regarding the operating state of the internal combustion engine 1, and the data referred to by the reference data is map data. It is in the form of. At this time, the reference target difference temperature calculation unit 208 determines, as the value of the rotation speed of the internal combustion engine 1, 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. The value of the torque DCBCPFLT of the internal combustion engine 1 calculated by the torque calculation unit 204 in step S1 in the present process is used as the value of the torque output by the internal combustion engine 1. As a result, the process of step S3 is completed, and the target difference temperature calculation process proceeds to 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 the step of which illustration is omitted in this process is omitted. The value of the coolant temperature calculated by the cooling water temperature calculation unit 206 in the processing of step 1 is compared with the table data read from the memory 106, and from this data, the temperature corresponding to the value of the coolant temperature calculated by the cooling water temperature calculation unit 206. The value of the correlation coefficient MTCCR is calculated. Here, the correction term calculation unit 209 uses the value of the coolant temperature TWTCDFLT calculated by the cooling water temperature calculation unit 206 by performing a predetermined filtering process as the value of the coolant temperature. As a result, the process of step S4 is completed, and the target difference temperature calculation process proceeds to step S5.

  In the process of step S5, the correction term calculation unit 209 sets the value of the temperature correlation coefficient MTCCR calculated by the correction term calculation unit 209 in the process of step S4 in this process to the reference target in the process of step S3 in this process. The temperature difference MTCBPF between the temperature of the combustion chamber 9 side of the wall and the temperature of the coolant passage 3 side of the wall is calculated by multiplying the value of the reference target difference temperature TCCDBPM calculated by the difference temperature calculation unit 208. As a result, the process of step S5 is completed, and the target difference temperature calculation process proceeds to step S6.

  In the process of step S6, the correction term calculation unit 209 sets the value of the temperature drop MTCBPF calculated by the correction term calculation unit 209 in the process of step S5 in this process to the wall in the process of the step not shown in this process. The temperature TCCR on the side of the coolant passage 3 of the wall is calculated by subtracting from the value of the temperature on the side of the combustion chamber 9 of the wall calculated by the section temperature calculation unit 205. Here, the correction term calculation unit 209 calculates, as the temperature value of the combustion chamber 9 side of the wall, the temperature TCCFLT of the wall combustion chamber 9 side calculated by the wall temperature calculation unit 205 performing a predetermined filtering process. The value is used. As a result, the process of step S6 is completed, and the target difference temperature calculation process proceeds to 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 of 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 portion calculated by the correction term calculation unit 209 in the process of S6 is collated with the table data read from the memory 106, and the wall calculated by the correction term calculation unit 209 from the data. The difference temperature correction value DTCCR corresponding to the value of the temperature TCCR on the coolant passage 3 side of the part is calculated. As a result, the process of step S7 is completed, and the target difference temperature calculation process proceeds to 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 this process as the reference target difference in the process of step S3 in this process. The target difference temperature TCCDBP0 is calculated by adding it to the value of the reference target difference temperature TCCDBPM calculated by the temperature calculation unit 208. As a result, the process of step S8 is completed, and the target difference temperature calculation process proceeds to step S9.

  In the process of step S9, the target difference temperature calculation unit 210 determines the filtering coefficient CDBPREF according to the increase and decrease of the output of the internal combustion engine 1 calculated by the target difference temperature calculation unit 210 in the process of step S2 in the present process. The target difference temperature TCCDBP0 is calculated by multiplying the value by the value of the target difference temperature TCCDBP0 calculated by the target difference temperature calculation unit 210 in the process of step S8 in the present process. As a result, the process of step S9 is completed, and this series of target difference temperature calculation processes is completed.

  As is clear from the above description, in the internal combustion engine control device 100 according to the present embodiment, the control unit 102 defines the combustion chamber 9 of the internal combustion engine 1 and controls the temperature of the wall portion in contact with the coolant on the combustion chamber 9 side. A difference temperature, which is a difference value between a certain first temperature and a representative temperature of the internal combustion engine 1, is calculated, a reference target difference temperature is calculated from a parameter related to an operating state, and a second temperature is a temperature on the coolant side of the wall portion. Is calculated and the target difference temperature is calculated by correcting the reference target difference temperature according to the second temperature, and the operating state is controlled according to the deviation between the target difference temperature and the difference temperature. With a simple configuration, the accuracy of the control target value can be improved in consideration of the fluctuation of the cooling capacity of the internal combustion engine 1, and the operating state of the internal combustion engine can be controlled with more optimal efficiency.

  Further, in the internal combustion engine control device 100 according to the present embodiment, the rotation speed of the internal combustion engine 1 and the torque output by the internal combustion engine are included as the parameters related to the operating state used by the control unit 102, and therefore a more accurate reference is provided. The target difference temperature can be calculated and the target difference temperature can be calculated based on this, and the operating state of the internal combustion engine 1 can be controlled with more optimal efficiency.

  Further, in the internal combustion engine control device 100 according to the present embodiment, the control unit 102 adds the heat transfer time delay that reflects the heat transfer characteristics of the wall portion, and further corrects the reference target difference temperature to obtain the target difference temperature. Since it is calculated, the target difference temperature can be calculated with higher accuracy, and the operating state of the internal combustion engine 1 can be controlled with more optimum efficiency.

  It should be noted that the present invention is not limited to the type, shape, arrangement, number, etc. of the members described above in the embodiment, and appropriately replaces the constituent elements with those having the same operational effect. Of course, it is possible to make appropriate changes without departing from the scope.

  INDUSTRIAL APPLICABILITY As described above, the present invention is an internal combustion engine that has a simple structure, improves the accuracy of the control target value in consideration of the fluctuation of the cooling capacity of the internal combustion engine, and can control the operating state of the internal combustion engine with more optimal efficiency. An engine control device is provided, and it is expected that the engine control device can be widely applied to an internal combustion engine control device of a vehicle or the like because of its general and universal nature.

DESCRIPTION OF SYMBOLS 1 ... Internal-combustion engine 2 ... Cylinder block 2a ... Cylinder 3 ... Coolant passage 4 ... Piston 5 ... Connecting rod 6 ... Crankshaft 7 ... Rotor 7a ... Tooth part (retractor)
8 ... Cylinder head 9 ... Combustion chamber 10 ... Spark plug 11 ... Intake pipe 11a ... Intake passage 12 ... Intake valve 13 ... Injector 14 ... Throttle valve 15 ... Exhaust pipe 15a ... Exhaust passage 16 ... Exhaust valve 21 ... Cooling water temperature sensor 22 ... Crank angle sensor 23 ... Intake air temperature sensor 24 ... Throttle opening sensor 25 ... Wall temperature sensor 100 ... Internal combustion engine control device 102 ... ECU
104 ... Microcomputer 106 ... Memory 108 ... CPU
201a, 201b ... A / D conversion circuit 202 ... Waveform shaping circuit 203 ... Rotation speed calculation unit 204 ... Torque calculation unit 205 ... Wall temperature calculation unit 206 ... Cooling water temperature calculation unit 207 ... Difference temperature calculation unit 208 ... Reference target difference temperature Calculation unit 209 ... Correction term calculation unit 210 ... Target difference temperature calculation unit 211 ... Operating state control unit 212 ... Comparison unit 213 ... Ignition timing calculation unit 301 ... Drive circuit

Claims (4)

A difference temperature that is a difference value between a temperature of the coolant and a first temperature that is a temperature on the combustion chamber side of a wall portion that defines a combustion chamber of the internal combustion engine and that is in contact with a coolant that flows in the internal combustion engine is calculated. In an internal combustion engine control device including a control unit that controls the operating state of the internal combustion engine based on the differential temperature,
The control unit is
Calculate the reference target differential temperature from the parameters related to the operating state,
Ri temperature der of said coolant side of said wall portion, and calculates the second temperature Ru temperature der obtained from the first temperature,
A target difference temperature is calculated by correcting the reference target difference temperature according to the second temperature,
An internal combustion engine controller, wherein the operating state is controlled according to a deviation between the target difference temperature and the difference temperature. The second temperature is calculated by subtracting, from the first temperature, a drop temperature calculated by multiplying the reference target difference temperature by a temperature correlation coefficient calculated corresponding to the coolant temperature. The internal combustion engine controller according to claim 1, wherein The internal combustion engine control device according to claim 1 or 2 , wherein the parameters include a rotation speed of the internal combustion engine and a torque output by the internal combustion engine. The control unit calculates the target difference temperature by further correcting the reference target difference temperature in consideration of a heat transfer time delay reflecting the heat transfer characteristic of the wall. 4. The internal combustion engine controller according to any one of 1 to 3 .

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