On-vehicle control device and internal combustion engine control method

Abstract

To provide an on-vehicle control device which can reduce cooling loss and friction loss while effectively suppressing knocking.SOLUTION: An on-vehicle control device mounted on an automobile with an internal combustion engine having a combustion chamber as a drive source, comprises: a cooling-timing setting unit that sets a timing which is earlier than a start timing of a predicted knock occurrence period by a prescribed time as an increase timing of a cooling volume of the combustion chamber, and also setting a timing which is earlier than a finish timing of the predicted knock occurrence period by a prescribed time as a decrease timing of the cooling volume of the combustion chamber; and a cooling volume change unit that changes the cooling volume of the combustion chamber with a cooling mechanism on the basis of the set increase timing, the decrease timing and a target cooling volume which is set by a target cooling volume setting unit.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an in-vehicle control device mounted on a vehicle and a method for controlling an internal combustion engine.

Background Art

[0002] In order to meet the increasingly stringent fuel consumption regulations for automobiles year by year, technologies for promoting the downsizing, supercharging, and high compression ratio of internal combustion engines have been adopted. When these technologies are adopted, the load factor of the internal combustion engine increases, and the pressure and temperature in the combustion chamber increase. Therefore, when meeting the fuel consumption regulations of automobiles, the occurrence of knocking has become an issue.

[0003] To suppress knocking, it is effective to cool the internal combustion engine. On the other hand, cooling the internal combustion engine may lead to an increase in cooling loss and friction loss. Therefore, when suppressing knocking by cooling the internal combustion engine, it is necessary to optimize the cooling amount and cooling timing according to the driving conditions of the vehicle.

[0004] Therefore, Patent Document 1 discloses a technique for controlling the temperature and cooling timing of the coolant of an internal combustion engine based on the predicted result of future engine output (output of the internal combustion engine). More specifically, Patent Document 1 relates to a control device including a target coolant temperature determination unit that determines a target temperature of the coolant based on the predicted output of the internal combustion engine, and a change timing setting unit that sets a change timing for changing the temperature of the coolant to the target temperature based on the predicted output of the internal combustion engine. The change timing setting unit discloses a technique for setting, as the change timing, the timing at which the predicted output of the internal combustion engine switches from low output to high output, or the timing at which the predicted output of the internal combustion engine switches from high output to low output.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] When an internal combustion engine is cooled, a temperature response delay occurs due to the heat capacity of the internal combustion engine. This temperature response delay is the time delay between when the cooling mechanism starts cooling the internal combustion engine and when the temperature of the internal combustion engine actually drops to a target temperature. Therefore, if the cooling timing is not set taking into account the temperature response delay when the output of the internal combustion engine changes significantly over time, such as when accelerating a vehicle, that is, under transient operating conditions, the knocking suppression effect of the cooling may not be sufficient, or cooling loss and friction loss may increase, which may result in a deterioration in the fuel efficiency of the internal combustion engine.

[0007] However, the technology disclosed in Patent Document 1 does not take into consideration the temperature response delay that occurs with the heat capacity when cooling the internal combustion engine, and therefore there is a risk that the fuel efficiency of the internal combustion engine will deteriorate.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide an on-board control device and an internal combustion engine control method that can effectively suppress knocking while reducing cooling loss and friction loss. [Means for solving the problem]

[0009] In order to solve the above problem, one aspect of the present invention provides an on-board control device that is mounted on an automobile powered by an internal combustion engine having a combustion chamber, and that includes: a cooling mechanism that cools the combustion chamber; an engine output prediction unit that predicts an engine output, which is a future output of the internal combustion engine; a knock intensity prediction unit that predicts a future knock intensity based on the engine output predicted by the engine output prediction unit; a knock occurrence period prediction unit that predicts a future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit; a target cooling amount setting unit that sets a target cooling amount for the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit; a cooling time setting unit that sets a timing that precedes a start timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing for increasing the cooling amount for the combustion chamber, and sets a timing that precedes an end timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing for decreasing the cooling amount for the combustion chamber; and a cooling amount change unit that changes the cooling amount for the combustion chamber by the cooling mechanism, based on the increase timing and decrease timing set by the cooling time setting unit and the target cooling amount set by the target cooling amount setting unit. In the on-board control device of the first aspect of the present invention, the cooling mechanism is an oil jet mechanism that cools a piston of the internal combustion engine with an oil jet, the target cooling amount setting unit is a target oil jet flow rate setting unit that sets a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted by the knock intensity prediction unit, and the cooling timing setting unit sets a timing that precedes the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing to increase the oil jet flow rate of the oil jet mechanism, and sets a timing that precedes the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing to decrease the oil jet flow rate of the oil jet mechanism. The oil jet flow rate change timing setting unit is an oil jet flow rate change unit that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and decrease timing set by the oil jet flow rate change timing setting unit and the target oil jet flow rate set by the target oil jet flow rate setting unit, and further includes a piston temperature prediction unit that predicts the piston temperature before the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit, and when the piston temperature predicted by the piston temperature prediction unit is lower than a predetermined temperature, the oil jet flow rate change timing setting unit delays the increase timing of the oil jet flow rate compared to when the piston temperature predicted by the piston temperature prediction unit is higher than the predetermined temperature. In a second aspect of the on-board control device of the present invention, the cooling mechanism is an oil jet mechanism that cools a piston of the internal combustion engine by an oil jet, the target cooling amount setting unit is a target oil jet flow rate setting unit that sets a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted by the knock intensity prediction unit, the cooling timing setting unit is an oil jet flow rate change timing setting unit that sets a timing that precedes the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing to increase the oil jet flow rate in the oil jet mechanism, and sets a timing that precedes the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit by a predetermined time as the timing to decrease the oil jet flow rate in the oil jet mechanism, and the cooling amount change unit is an oil jet flow rate change unit that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and decrease timing set by the oil jet flow rate change timing setting unit and the target oil jet flow rate set by the target oil jet flow rate setting unit, and the predetermined time is determined by the step response time of the piston temperature of the internal combustion engine. In the on-board control device of the third aspect of the present invention, the cooling amount change unit further changes the cooling amount of the combustion chamber based on the actual engine output, or the actual ignition retard amount, or the actual knock intensity, when the difference between the engine output predicted by the engine output prediction unit and the actual engine output becomes equal to or greater than a predetermined value. In the on-board control device of a fourth aspect of the present invention, the cooling amount change unit further changes the cooling amount of the combustion chamber based on the actual engine output, or the actual ignition timing retard amount, or the actual knock intensity, when the ignition retard amount exceeds a predetermined ignition retard amount, or when the knock intensity exceeds a predetermined intensity, or when at least one of the water temperature, oil temperature, internal combustion engine wall temperature, and intake air temperature exceeds a predetermined temperature, before the timing for increasing the cooling amount set by the cooling timing setting unit. In the on-board control device of a fifth aspect of the present invention, the cooling amount change unit further changes the cooling amount of the combustion chamber based on the actual engine output, or the actual ignition timing retard amount, or the actual knock intensity, when, at the timing of decreasing the cooling amount set by the cooling timing setting unit, the ignition retard amount exceeds a predetermined ignition retard amount, or the knock intensity exceeds a predetermined intensity, or at least one of the water temperature, the oil temperature, the wall temperature of the internal combustion engine, and the temperature of the intake air exceeds a predetermined temperature.

[0010] Moreover, a control method for an internal combustion engine according to an aspect of the present invention is a control method for an internal combustion engine in an automobile including an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber, the method including: an engine output prediction step of predicting an engine output which is a future output of the internal combustion engine; a knock intensity prediction step of predicting a future knock intensity based on the engine output predicted in the engine output prediction step; a knock occurrence period prediction step of predicting a future knock occurrence period based on the knock intensity predicted in the knock intensity prediction step; a target cooling amount setting step of setting a target cooling amount of the cooling mechanism based on the knock intensity predicted in the knock intensity prediction step; a cooling timing setting step of setting a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted in the knock occurrence period prediction step as the increase timing of the cooling amount of the combustion chamber, and setting a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted in the knock occurrence period prediction step as the decrease timing of the cooling amount of the combustion chamber; and a cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step. The control method for an internal combustion engine of the first aspect of the present invention further includes the steps of: the cooling mechanism is an oil jet mechanism that cools a piston of the internal combustion engine by an oil jet; the target cooling amount setting step is a target oil jet flow rate setting step of setting a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted in the knock intensity prediction step; and the cooling timing setting step is an oil jet flow rate setting step of setting a timing that precedes the start timing of the knock occurrence period predicted in the knock occurrence period prediction step by a predetermined time as the timing to increase the oil jet flow rate of the oil jet mechanism, and setting a timing that precedes the end timing of the knock occurrence period predicted in the knock occurrence period prediction step by a predetermined time as the timing to decrease the oil jet flow rate of the oil jet mechanism. The oil jet flow rate change timing setting step is an oil jet flow rate change step that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and decrease timing set in the oil jet flow rate change timing setting step and the target oil jet flow rate set in the target oil jet flow rate setting step, and further includes a piston temperature prediction step that predicts the piston temperature before the start timing of the knock occurrence period predicted in the knock occurrence period prediction step, and the oil jet flow rate change timing setting step delays the increase timing of the oil jet flow rate when the piston temperature predicted in the piston temperature prediction step is lower than a predetermined temperature compared to when the piston temperature predicted in the piston temperature prediction step is higher than the predetermined temperature. In a second aspect of the internal combustion engine control method of the present invention, the cooling mechanism is an oil jet mechanism that cools a piston of the internal combustion engine by an oil jet, the target cooling amount setting step is a target oil jet flow rate setting step that sets a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted in the knock intensity prediction step, the cooling timing setting step is an oil jet flow rate change timing setting step that sets a timing that precedes the start timing of the knock occurrence period predicted in the knock occurrence period prediction step by a predetermined time as the timing to increase the oil jet flow rate in the oil jet mechanism, and sets a timing that precedes the end timing of the knock occurrence period predicted in the knock occurrence period prediction step by a predetermined time as the timing to decrease the oil jet flow rate in the oil jet mechanism, and the cooling amount changing step is an oil jet flow rate changing step that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and decrease timing set in the oil jet flow rate change timing setting step and the target oil jet flow rate set in the target oil jet flow rate setting step, and the predetermined time is determined by the step response time of the piston temperature of the internal combustion engine. In the third aspect of the internal combustion engine control method of the present invention, the cooling amount change step further changes the amount of cooling of the combustion chamber based on the actual engine output, or the actual ignition retard amount, or the actual knock intensity, when the difference between the engine output predicted in the engine output prediction step and the actual engine output becomes equal to or greater than a predetermined value. In the fourth aspect of the internal combustion engine control method of the present invention, the cooling amount change step further changes the cooling amount of the combustion chamber based on the actual engine output, or the actual ignition timing retard amount, or the actual knock intensity when the ignition retard amount exceeds a predetermined ignition retard amount, or when the knock intensity exceeds a predetermined intensity, or when at least one of the water temperature, oil temperature, internal combustion engine wall temperature, and intake air temperature exceeds a predetermined temperature, before the timing of increasing the cooling amount set in the cooling timing setting step. The control method for an internal combustion engine according to the fifth aspect of the present invention further includes, in the cooling amount change step, when the ignition retard amount exceeds a predetermined ignition retard amount, or when the knock intensity exceeds a predetermined intensity, or when at least one of the water temperature, oil temperature, wall temperature of the internal combustion engine, and temperature of the intake air exceeds a predetermined temperature, at the timing of the decrease in the cooling amount set in the cooling timing setting step, the cooling amount of the combustion chamber is changed based on the actual engine output, or the actual ignition timing retard amount, or the actual knock intensity.

Advantages of the Invention

[0011] According to at least one aspect of the present invention, it is possible to effectively suppress knocking while reducing cooling loss and friction loss.

Brief Description of the Drawings

[0012]

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[0013] Hereinafter, examples of embodiments of the present invention will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, components having substantially the same functions or configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0014] First Embodiment FIG. 1 is a schematic configuration diagram showing an example of an automobile equipped with an on-board control device according to the first embodiment. As shown in FIG. 1, the automobile 100 includes a VCU (Vehicle Control Unit) 1, an ECU (Engine Control Unit) 2, a transmission 5, an accelerator opening sensor 6, a brake switch 7, an automobile speed sensor 8, a crank angle sensor 10, a navigation device 11a, an on-board camera 11b, an on-board radar 11c, an internal combustion engine 13, a differential gear 19, and a variable displacement oil pump 57.

[0015] The VCU 1 is an automobile device that controls the automobile 100. The ECU 2 is an internal combustion engine control device that controls the internal combustion engine 13. The transmission 5 is a mechanism for switching the gear ratio according to the rotational speed of the internal combustion engine 13. The accelerator position sensor 6 is a sensor for detecting the depression amount of the accelerator pedal, i.e., the accelerator position. The brake switch 7 is a sensor for detecting whether the brake pedal is depressed or not. The accelerator position sensor 6 and the brake switch 7 are provided in the cabin of the automobile 100. The automobile speed sensor 8 is a sensor for detecting the traveling speed of the automobile 100. The automobile speed sensor 8 is provided on the drive shaft of the wheels 20. The crank angle sensor 10 is a sensor for detecting the rotation angle of the crankshaft of the internal combustion engine 13. The crank angle sensor 10 is provided on the crankshaft of the internal combustion engine 13. The signals output from the automobile speed sensor 8 and the crank angle sensor 10 are input to the VCU 1. In addition, the signals output from the accelerator opening sensor 6 and the brake switch 7 are also taken into the VCU 1.

[0016] The navigation device 11a determines the current position of the automobile 100, which is driven by an internal combustion engine 13, by receiving GPS (Global Positioning System) signals transmitted via satellite radio waves from multiple GPS satellites in the sky above the automobile 100. The current position of the automobile 100 determined by the navigation device 11a can be displayed superimposed on a map displayed on a display device inside the automobile 100. The navigation device 11a may also use mobile phone base stations, Wi-Fi (registered trademark) access points, etc. to determine the current position. Information about the current position of the automobile 100 determined by the navigation device 11a, and map information including the surrounding area where the automobile 100 is traveling and the route to the destination, are imported into the VCU1.

[0017] The in-vehicle camera 11b is a camera that captures images of vehicles, road surfaces, obstacles, traffic signs, and the like around the automobile 100. The in-vehicle radar 11c is, for example, a laser or millimeter-wave radar, and measures the relative distances to stationary and moving objects around the automobile 100. The video signal captured by the in-vehicle camera 11b is input to the VCU1. The measurement signal of the in-vehicle radar 11c is also input to the VCU1.

[0018] The internal combustion engine 13 is, for example, a three-cylinder gasoline internal combustion engine for an automobile that uses spark ignition combustion, and is an example of an internal combustion engine. A crank angle sensor 10 is provided on the crankshaft of the internal combustion engine 13, and the other end of the crankshaft is connected to a transmission 5. The power of the internal combustion engine 13 is transmitted to wheels 20 via the transmission 5 and a differential gear 19.

[0019] Based on the output signal of the accelerator opening sensor 6, VCU1 calculates the driver's required torque. That is, the accelerator opening sensor 6 is used as a required torque detection sensor for detecting the required torque for the internal combustion engine 13. Also, based on the output signal of the brake switch 7, VCU1 determines the presence or absence of the driver's deceleration request. Further, based on the output signal of the crank angle sensor 10, VCU1 calculates the rotational speed of the internal combustion engine 13. Then, based on the driver request obtained from the output signals of the above-mentioned various sensors and the driving state of the vehicle 100, VCU1 calculates the optimal operation amount of the internal combustion engine required output. The internal combustion engine required output is the engine output (target output) required for the internal combustion engine by the driver's operation. Also, the driver's operation is, for example, an accelerator operation or a brake operation, and the operation amount is, for example, the operation amounts of the fuel injection unit, the ignition unit, the throttle valve, the hydraulic pump, etc.

[0020] The internal combustion engine required output calculated by VCU1 is sent to ECU2. Based on the internal combustion engine required output sent from VCU1, ECU2 controls the internal combustion engine 13. Specifically, in addition to the above-mentioned fuel injection unit, ignition unit, and throttle valve, ECU2 controls the variable displacement oil pump 57. The variable displacement oil pump 57 is provided as an example of a hydraulic pump that discharges engine oil (hereinafter simply referred to as "oil") at a predetermined pressure.

[0021] Next, the configuration of the internal combustion engine in the first embodiment will be described with reference to FIG. 2. FIG. 2 is a schematic configuration diagram of the internal combustion engine in the first embodiment. In FIG. 2, the internal combustion engine 13 is a spark ignition four-cycle gasoline internal combustion engine. The internal combustion engine 13 includes a cylinder block 23, a cylinder head 24, a piston 25, an intake valve 26, and an exhaust valve 27, and a combustion chamber 28 is formed by these components.

[0022] An ignition plug 21 and an ignition coil 22 are installed in the cylinder head 24. Air for combustion is taken into the combustion chamber 28 through an air cleaner 30, a throttle valve 31, and an intake port 32. An air flow sensor 36 is disposed between the air cleaner 30 and the throttle valve 31. The air flow sensor 36 is a sensor for detecting the amount of air taken into the combustion chamber 28 from the air cleaner 30 through the throttle valve 31 and the intake port 32.

[0023] Meanwhile, the burned gas discharged from the combustion chamber 28, i.e., the exhaust gas, is discharged into the atmosphere through an exhaust port 33 and a catalytic converter 34. An air-fuel ratio sensor 37 is disposed upstream of the catalytic converter 34. The air-fuel ratio sensor 37 is a sensor for detecting the air-fuel ratio of the exhaust gas discharged through the exhaust port 33. Furthermore, fuel is supplied into the intake port 32 by a fuel injection valve 35.

[0024] The amount of air taken into the combustion chamber 28 is detected by the ECU 2 reading the output of the air flow sensor 36. A temperature sensor and a humidity sensor (not shown) are also provided inside the air flow sensor 36. The ECU 2 detects the temperature and humidity of the air taken in through the air cleaner 30 by reading the outputs of the temperature sensor and humidity sensor.

[0025] On the other hand, the air-fuel ratio of the gas (exhaust gas) discharged from the combustion chamber 28 is detected by the ECU 2 reading the output of the air-fuel ratio sensor 37. Also, a knock sensor 38 is provided in the cylinder block 23. The knock sensor 38 is a sensor for detecting knocking (hereinafter also referred to as "knock") in the combustion chamber 28 of the internal combustion engine 13. The ECU 2 detects the strength of knock in the combustion chamber 28 by reading the output of the knock sensor 38.

[0026] The opening of the throttle valve 31, the amount and timing of fuel injection by the fuel injection valve 35, and the ignition timing by the ignition coil 22 are all changed by control values from the ECU 2.

[0027] A water jacket 42 is provided in the cylinder block 23. Cooling water flows through the water jacket 42 by a cooling water pump (not shown). Thereby, the cylinder block 23 is cooled. The heat of the cooling water is released into the atmosphere by a radiator (not shown). A water temperature sensor 41 is installed in the water jacket 42. The water temperature sensor 41 is a sensor for detecting the temperature of the cooling water (hereinafter also referred to as "water temperature"). The ECU 2 detects the temperature of the cooling water by reading the output of the water temperature sensor 41.

[0028] On the other hand, an oil pan 40 for storing oil is provided at the lower part of the cylinder block 23. An oil temperature sensor 39 is provided in the oil pan 40. The oil temperature sensor 39 is a sensor for detecting the temperature of the oil (hereinafter referred to as "oil temperature"). The ECU 2 detects the oil temperature by reading the output of the oil temperature sensor 39.

[0029] Also, an oil jet part 53 is attached to the cylinder block 23. The oil jet part 53 cools the piston 25 by injecting oil toward the back surface side of the piston 25. The oil jet part 53 is fastened and fixed to the mounting surface 54 of the cylinder block 23 using fixing bolts 55 so as to avoid interference with the connecting rod 50, the crankshaft, etc.

[0030] The amount of oil injected per unit time by the oil jet part 53 (hereinafter also referred to as "oil jet flow rate") changes according to the oil discharge pressure of a variable displacement oil pump 57 connected to the oil jet part 53. Also, the oil jet flow rate changes depending on the opening degree of a valve mechanism built into the oil jet part 53. The oil discharge pressure of the variable displacement oil pump 57 and the opening degree of the valve mechanism built into the oil jet part 53 are changed by control values respectively sent from the ECU 2. The oil discharge pressure is the pressure at which the variable displacement oil pump 57 discharges oil.

[0031] An oil supply passage 56 is provided in the cylinder block 23. The oil supply passage 56 is a passage for supplying oil to oil supply parts including the oil jet unit 53. The oil stored in the oil pan 40 is pressurized by a variable displacement oil pump 57. The oil pressurized by the variable displacement oil pump 57 is supplied to the oil jet unit 53 via the oil supply passage 56, as well as to lubrication parts, hydraulically operated equipment, etc.

[0032] Representative structures of the oil jet unit 53 include a die-cast type, a brazed two-piece type, and a brazed one-piece type. When the oil jet unit 53 has a die-cast type or a brazed two-piece type structure, the oil jet unit 53 is typically fastened to the cylinder block 23 with a fixing bolt 55 that has a built-in check ball. When the oil jet unit 53 has a brazed one-piece type structure and has a built-in valve mechanism, the oil jet unit 53 is fastened to the cylinder block 23 with a general fixing bolt that does not have a built-in check ball.

[0033] If the fixing bolt 55 that fixes the oil jet unit 53 has a built-in check ball, the check ball is urged by a spring in a direction that blocks the oil supply passage 56. Oil pressurized by the variable displacement oil pump 57 is supplied to the oil jet unit 53 when the oil pressure in the oil supply passage 56 (main gallery), i.e., the oil pressure, exceeds the set load of the spring. In other words, the oil jet unit 53 is configured to spontaneously inject oil when the pressure of the oil supplied to the oil supply passage 56 of the internal combustion engine 13 reaches or exceeds a predetermined value.

[0034] On the other hand, if the oil jet unit 53 has a built-in valve mechanism, the valve mechanism may be a solenoid type, for example. The opening of the valve mechanism may be adjusted by the solenoid to stop the oil jet unit 53 from spraying oil or adjust the oil jet flow rate.

[0035] FIG. 3 is an explanatory diagram showing the general relationship between oil pressure and oil jet flow rate in an oil jet unit of the type in which a check ball is built into the fixing bolt. As shown in Figure 3, when the oil pressure exceeds the set load of the spring, oil injection begins, and the oil jet flow rate increases as the oil pressure rises.

[0036] FIG. 4 is a characteristic diagram showing the general relationship between the valve opening and the oil jet flow rate in an oil jet unit with a built-in valve mechanism. As shown in Figure 4, when the oil pressure is constant, the oil jet flow rate increases as the valve opening increases.

[0037] FIG. 5 is a block diagram showing the functional configuration of the on-board control device according to the first embodiment. As shown in FIG. 5 , the on-board control device 101 includes an engine output prediction unit 58, a knock intensity prediction unit 59, a knock risk period prediction unit 60, an oil pressure change timing setting unit 61, a target oil pressure setting unit 62, an oil supply passage 56, a variable displacement oil pump 57, and an oil jet mechanism 530. The knock risk period prediction unit 60 predicts a future knock occurrence period as a knock risk period and functions as a knock occurrence period prediction unit. The oil jet mechanism 530 includes the oil jet unit 53 and a fixing bolt 55 described above. In the first embodiment, as an example, the oil jet unit 53 is fixed to the cylinder block 23 by a fixing bolt 55 incorporating a check ball.

[0038] Among the components of the in-vehicle control device 101 described above, the engine output prediction unit 58 is mounted on the VCU1, and the knock intensity prediction unit 59, the knock risk period prediction unit 60, the hydraulic pressure change timing setting unit 61, and the target hydraulic pressure setting unit 62 are mounted on the ECU2. Further, the variable displacement oil pump 57, the oil supply passage 56, and the oil jet mechanism 530 are mounted on the internal combustion engine 13. However, the components mounted on the VCU1 and the ECU2 are not limited to the example shown in FIG. 5. For example, the engine output prediction unit 58 may be mounted on the ECU2. Further, the knock intensity prediction unit 59, the knock risk period prediction unit 60, the hydraulic pressure change timing setting unit 61, and the target hydraulic pressure setting unit 62 may be mounted on the VCU1.

[0039] The engine output prediction unit 58 in the VCU1 predicts the output of the internal combustion engine 13 in a future prediction period based on the position information of the automobile 100 acquired from the navigation device 11a (see FIG. 1) that measures the current position of the automobile 100, the traffic information related to the route to the destination, the information obtained by the in-vehicle camera 11b and the in-vehicle radar 11c mounted on the automobile 100, and the control information of the internal combustion engine 13. The future prediction period is, for example, a period up to 30 seconds from the present. The period up to which the prediction is made from the present can be arbitrarily changed. The output of the internal combustion engine 13 is defined by, for example, the torque and the rotational speed of the internal combustion engine 13. In the following description, the output of the internal combustion engine 13 is also referred to as "engine output". Further, the torque of the internal combustion engine 13 is also referred to as "engine torque", and the rotational speed of the internal combustion engine 13 is also referred to as "engine rotational speed".

[0040] The engine output prediction unit 58 predicts the engine output, which is the future output of the internal combustion engine 13. For example, if an uphill road is predicted 10 seconds from now, the engine output prediction unit 58 predicts high engine torque and high engine speed as the engine output 10 seconds from now in order to increase the output of the internal combustion engine 13 10 seconds from now. Furthermore, if a downhill road is predicted 20 seconds from now, the engine output prediction unit 58 predicts low engine torque and low engine speed as the engine output 20 seconds from now in order to decrease the output of the internal combustion engine 13 20 seconds from now. These combinations of engine torque and engine speed are determined as combinations that, for example, provide the best fuel efficiency for the predicted engine output. The future engine output during the prediction period is determined by the engine output prediction unit 58 as time-series discrete data, for example, every 0.1 seconds. Furthermore, the combination that provides the best fuel efficiency is determined, for example, by a lookup table or correlation equation pre-stored in the ECU 2. The reference table or correlation equation is created by a calibration test of the internal combustion engine 13 and stored in the ECU 2 .

[0041] Knock intensity prediction unit 59 predicts future knock intensity based on the engine output predicted by engine output prediction unit 58. Knock intensity prediction unit 59 calculates knock intensity during the prediction period for each time-series discrete data point of the future engine output based on the future engine output during the prediction period described above. Here, the knock intensity is calculated, for example, by referencing a map that uses future engine torque and engine speed during the prediction period as indexes. In other words, knock intensity prediction unit 59 predicts future knock intensity based on engine torque and engine speed, which are the engine output predicted by engine output prediction unit 58. This allows for accurate prediction of knock intensity by taking into account differences in knock intensity at engine operating points (combinations of engine torque and engine speed).

[0042] The knock risk period prediction unit 60 predicts a knock risk period, which is a future knock occurrence period, based on the knock intensity predicted by the knock intensity prediction unit 59. The knock risk period is a period during which future knocking may occur. The knock risk period prediction unit 60 predicts, as the knock risk period (knock occurrence period), a period during which the knock intensity predicted by the knock intensity prediction unit 59 is equal to or greater than a predetermined knock threshold value. Thereby, the knock risk period can be accurately predicted.

[0043] The hydraulic pressure change timing setting unit 61 sets the change timing of the hydraulic pressure based on the knock risk period predicted by the knock risk period prediction unit 60. The hydraulic pressure is the discharge pressure of oil by the variable displacement oil pump 57. The change timing of the hydraulic pressure set by the hydraulic pressure change timing setting unit 61 includes the increase timing of the hydraulic pressure and the decrease timing of the hydraulic pressure. The hydraulic pressure change timing setting unit 61 corresponds to the oil jet flow rate change timing setting unit. The oil jet flow rate change timing setting unit sets the timing that is a predetermined time ahead of the start timing of the knock risk period (future knock occurrence period) predicted by the knock risk period prediction unit 60 as the increase timing of the oil jet flow rate in the oil jet mechanism 530. Further, the oil jet flow rate change timing setting unit sets the timing that is a predetermined time ahead of the end timing of the knock risk period predicted by the knock risk period prediction unit 60 as the decrease timing of the oil jet flow rate in the oil jet mechanism 530.

[0044] The above-described oil jet flow rate change timing setting unit corresponds to the cooling timing setting unit. The cooling timing setting unit sets the timing at which the oil jet mechanism 530 as a cooling mechanism changes the cooling amount of the internal combustion engine 13. Specifically, the cooling timing setting unit sets the timing that is a predetermined time ahead of the start timing of the knock risk period (future knock occurrence period) predicted by the knock risk period prediction unit 60 as the increase timing of the cooling amount of the internal combustion engine 13. Further, the cooling timing setting unit sets the timing that is a predetermined time ahead of the end timing of the knock risk period predicted by the knock risk period prediction unit 60 as the decrease timing of the cooling amount of the combustion chamber 28.

[0045] The target oil pressure setting unit 62 sets the target oil pressure of the oil jet mechanism 530 based on the knock intensity predicted by the knock intensity prediction unit 59. The target oil pressure setting unit 62 corresponds to the target oil jet flow rate setting unit. Further, the target oil jet flow rate setting unit corresponds to the target cooling amount setting unit. The target oil jet flow rate setting unit sets the target oil jet flow rate of the oil jet mechanism 530 based on the knock intensity predicted by the knock intensity prediction unit 59. The target cooling amount setting unit sets the target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit 59.

[0046] In the present embodiment, as an example, the cooling mechanism is constituted by the oil jet mechanism 530. The cooling mechanism is a mechanism for cooling the combustion chamber 28. The oil jet mechanism 530 is a mechanism for cooling the piston 25 of the internal combustion engine 13 by oil injection, that is, oil jet. The cooling amount of the piston 25 of the internal combustion engine 13 corresponds to the cooling amount of the combustion chamber 28. However, the cooling amount of the combustion chamber 28 is not limited to the cooling amount of the piston 25. For example, the cooling amount of the combustion chamber 28 includes the cooling amount of the cylinder block 23, the cooling amount of the cylinder head 24, and the like.

[0047] The amount of cooling of the piston 25 varies depending on the flow rate of oil injected from the oil jet portion 53 of the oil jet mechanism 530, i.e., the oil jet flow rate. Specifically, the amount of cooling of the piston 25 increases as the oil jet flow rate of the oil jet mechanism 530 increases. Furthermore, the oil jet flow rate of the oil jet mechanism 530 increases as the oil pressure of the oil jet mechanism 530 (the pressure of the oil supplied to the oil jet portion 53 by the variable displacement oil pump 57) increases. Therefore, the target oil pressure of the oil jet mechanism 530 corresponds to the target oil jet flow rate of the oil jet mechanism 530. Furthermore, the target oil jet flow rate of the oil jet mechanism 530 corresponds to the target cooling amount of the cooling mechanism.

[0048] The variable displacement oil pump 57 changes the pressure (oil pressure) of the oil delivered to the oil jet mechanism 530 based on the oil pressure change timing (oil pressure increase timing, oil pressure decrease timing) set by the oil pressure change timing setting unit 61 and the target oil pressure set by the target oil pressure setting unit 62. The pressure of the oil delivered to the oil jet mechanism 530 changes according to the oil discharge pressure of the variable displacement oil pump 57. Therefore, the variable displacement oil pump 57 changes the pressure of the oil delivered to the oil jet mechanism 530 by adjusting the oil discharge pressure.

[0049] In this embodiment, the variable displacement oil pump 57 corresponds to an oil jet flow rate change unit that changes the flow rate of the oil jet generated by the oil jet mechanism 530 based on the timing of increase and decrease of the oil flow rate set by the oil jet flow rate change timing setting unit and the target oil jet amount set by the target oil jet flow rate setting unit.

[0050] Oil supply passage 56 is a passage for supplying oil discharged from variable displacement oil pump 57 to oil jet mechanism 530. When the pressure (oil pressure) of the oil supplied from variable displacement oil pump 57 via oil supply passage 56 exceeds the spring set load of the check ball inside the fixing bolt, oil jet mechanism 530 injects oil at a flow rate corresponding to the oil pressure toward piston 25. Furthermore, when the oil pressure is lower than the spring set load of the check ball, oil jet mechanism 530 stops injecting oil.

[0051] Next, a control method for the internal combustion engine according to the first embodiment will be described with reference to FIGS. Fig. 6 is a flowchart showing the control procedure (control method) of the internal combustion engine according to the first embodiment. Fig. 7 is a diagram showing an example of the time history of the predicted torque, predicted rotation speed, predicted knock intensity, and target oil pressure to supplement the explanation of the control procedure of the internal combustion engine. In Fig. 7, the predicted torque and predicted rotation speed are the engine torque and engine rotation speed, which are the engine output predicted by engine output prediction unit 58. The predicted knock intensity is the knock intensity predicted by knock intensity prediction unit 59, and the prediction period is a future prediction period.

[0052] First, the engine output prediction unit 58 predicts the output of the internal combustion engine 13 in a future prediction period (for example, a period from the present to 30 seconds ahead), i.e., the future engine output of the internal combustion engine 13 (step S1). The future engine output predicted by the engine output prediction unit 58 includes engine torque and periodic rotation speed. The future engine output is predicted based on, for example, position information of the vehicle acquired from the navigation device 11a, traffic information related to the route to the destination, altitude information, traffic information around the vehicle acquired from the on-board camera 11b and the on-board radar 11c, past driving history information, current control information of the internal combustion engine 13, etc. Also, when the vehicle 100 travels on a predetermined route, for example, time-series data of the engine output assumed when the vehicle 100 travels on the predetermined route may be stored in advance in the storage device of the navigation device 11a as time history data, and the future engine output may be predicted using the time history data.

[0053] As described above, the torque and rotational speed of the internal combustion engine 13 predicted by the engine output prediction unit 58 are represented by time-series data within the prediction period, as shown in the graph of the predicted torque and predicted rotational speed in FIG. 7. This time-series data is discrete data, and the interval between each discrete data is, for example, 0.1 second. The time-series discrete data of the engine output predicted by the engine output prediction unit 58 is sent from the engine output prediction unit 58 to the knock intensity prediction unit 59.

[0054] Next, the knock intensity prediction unit 59 obtains the knock intensity for each time-series discrete data point of the engine output during the prediction period based on the engine output predicted by the engine output prediction unit 58 (step S2). The knock intensity is obtained, for example, by referring to a map using the torque and rotational speed of the future internal combustion engine 13 during the prediction period as indices. In that case, in the map, for example, the knock intensity expected when the ignition timing of the internal combustion engine 13 is set to MBT (maximum torque ignition timing) is stored as an index value in five steps from 0 (no knock occurrence) to 4 (maximum knock intensity) for each torque and rotational speed of the internal combustion engine 13.

[0055] The knock intensity index value is determined based on the results of tests of the internal combustion engine 13 conducted in advance, the results of simulations of the internal combustion engine 13, and the like. Furthermore, the knock intensity also varies depending on physical factors other than the torque and rotational speed of the internal combustion engine 13. Therefore, if the knock intensity index value obtained from the map is corrected taking into account the influence of the above physical factors, the knock intensity can be predicted more accurately. Examples of physical factors that affect the knock intensity include the octane number of the fuel, the temperature and humidity of the intake air (intake air temperature and intake air humidity), the temperature of the coolant (water temperature), the temperature of the oil (oil temperature), the intake pressure, the wall temperature of the internal combustion engine 13, the octane number of the fuel, the air-fuel ratio, and the EGR (exhaust gas recirculation) rate. Therefore, the knock intensity index value obtained from the map may be corrected based on at least one of the intake air temperature, intake air humidity, the water temperature, the oil temperature, the intake pressure, the wall temperature of the internal combustion engine 13, the octane number of the fuel, the air-fuel ratio, and the EGR rate. The wall temperature of the internal combustion engine 13 includes at least one of the wall temperature of the cylinder head 24 , the wall temperature of the cylinder block 23 , and the wall temperature of the piston 25 .

[0056] Specifically, the knock intensity tends to be higher when the intake air temperature, water temperature, oil temperature, intake pressure, wall temperature of the internal combustion engine 13, and air-fuel ratio are higher than when these factors are low. Therefore, the higher these physical factors are, the greater the knock intensity index value obtained from the map should be corrected to. Also, the knock intensity tends to be lower when the fuel octane number, intake air humidity, and EGR rate are higher than when these factors are low. Therefore, the higher these physical factors are, the greater the knock intensity index value obtained from the map should be corrected to. In this way, by correcting the knock intensity predicted by knock intensity prediction section 59 based on the above physical factors, it is possible to more accurately predict the knock intensity in the prediction period (future).

[0057] In addition to the method of referencing the map described above, the knock intensity during the prediction period may be calculated using a correlation equation that uses the multiple physical factors described above as explanatory variables or a physical model equation. Furthermore, current factor values detected by a sensor or the like may be used as the physical factors described above. Furthermore, future values of the physical factors may be predicted based on the engine output predicted by engine output prediction unit 58, and the knock intensity index value may be corrected using these future values. In particular, the EGR rate and intake pressure are changed by controlling the opening of the EGR valve and throttle valve of internal combustion engine 13, as well as the timing of opening and closing the intake and exhaust valves. Therefore, the knock intensity prediction accuracy can be further improved by estimating the control state of internal combustion engine 13 from the predicted engine output and predicting changes in the EGR rate and intake pressure during the prediction period.

[0058] Next, knock risk period prediction unit 60 predicts a knock risk period based on the knock intensity predicted by knock intensity prediction unit 59 (step S3). In this case, knock risk period prediction unit 60 receives the knock intensity index value as time-series discrete data from knock intensity prediction unit 59 and predicts a knock risk period using this time-series discrete data. Furthermore, knock risk period prediction unit 60 predicts, for example, a section where the knock intensity index value is 1 (a predetermined knock threshold value) or more as a section where a knock is predicted to occur in the future, i.e., a knock risk section.

[0059] Next, the target oil pressure setting unit 62 sets the target oil pressure of the oil jet mechanism 530 based on the knock intensity predicted by the knock intensity prediction unit 59 (step S4). The target oil pressure of the oil jet mechanism 530 is set based on the knock intensity in the knock risk period predicted by the knock risk period prediction unit 60.

[0060] FIG. 8 is an explanatory diagram showing an example of the relationship between the knock intensity during the knock risk period and the target oil pressure set by the target oil pressure setting unit 62. As shown in FIG. 8, the target hydraulic pressure setting unit 62 sets the target hydraulic pressure such that the higher the knocking intensity during the knock risk period, the higher the target hydraulic pressure during the knock risk period. However, the target hydraulic pressure during the knock risk period is set within the range of the maximum hydraulic pressure limited by the spring set load of the check ball in the fixed bolt 55, the boosting performance of the variable displacement oil pump 57, the pressure resistance of the internal combustion engine 13, etc. That is, the target hydraulic pressure during the knock risk period is set within the range exceeding the spring set load and below the maximum hydraulic pressure. Also, the target hydraulic pressure outside the knock risk period is set as the base hydraulic pressure required for devices other than the oil jet unit 53, for example, the drive of the variable valve mechanism and the lubrication of each part of the internal combustion engine 13. When controlling the internal combustion engine 13, it is necessary to set the oil discharge pressure of the variable displacement oil pump 57 to be equal to or higher than the base hydraulic pressure. Also, in order to prevent deterioration of the fuel consumption of the internal combustion engine 13 due to the driving force of the variable displacement oil pump 57, it is desirable that the base hydraulic pressure be as low as possible within the range that can cover the oil driving devices and lubrication. Generally, the base hydraulic pressure is lower than the spring set load of the check ball built into the fixed bolt 55.

[0061] The knocking intensity during the knock risk period is obtained, for example, as the average value of the index values of the knocking intensity during the knock risk period. Also, the knocking intensity during the knock risk period is obtained, for example, as the maximum value of the index values of the knocking intensity during the knock risk period.

[0062] Next, the hydraulic pressure change timing setting unit 61 sets the timing for changing the hydraulic pressure of the oil jet mechanism 530 determined by the oil discharge pressure of the variable displacement oil pump 57, that is, the hydraulic pressure change timing (Tr, Td) (step S5). The hydraulic pressure change timing setting unit 61 sets the hydraulic pressure increase timing Tr and the hydraulic pressure decrease timing Td as the hydraulic pressure change timing. The hydraulic pressure increase timing Tr is set as the timing obtained by subtracting a predetermined time Δt from the start timing ts of the knock risk period, as shown in the following formula (4). Tr = ts - Δt …(4) Further, the hydraulic pressure decrease timing Td is set as the timing obtained by subtracting a predetermined time Δt from the end timing te of the knock risk period, as shown in the following equation (5). Td = te - Δt …(5) That is, the hydraulic pressure change timing setting unit 61 sets the period from when the hydraulic pressure is increased until it is decreased as a period that precedes the knock risk period by a predetermined time Δt.

[0063] Next, the ECU 2 sends the hydraulic pressure change timing (Tr, Td) set by the hydraulic pressure change timing setting unit 61 in step S4 above and the target hydraulic pressure of the oil jet mechanism 530 set by the target hydraulic pressure setting unit 62 in step S5 above to the variable displacement oil pump 57 as hydraulic pressure control values, respectively (step S6). Thereby, the variable displacement oil pump 57 is controlled by the ECU 2 such that the oil discharge pressure of the variable displacement oil pump 57 becomes the target hydraulic pressure during the knock risk period from the time Tr which is the hydraulic pressure increase timing to the time Td which is the hydraulic pressure decrease timing. Further, the variable displacement oil pump 57 is controlled by the ECU 2 such that the oil discharge pressure of the variable displacement oil pump 57 becomes the base hydraulic pressure before the time Tr or after the time Td.

[0064] FIG. 9 is a diagram for explaining the effects of the first embodiment. FIG. 9A shows the change over time of the engine output, FIG. 9B shows the change over time of the knock intensity, and FIG. 9C shows the change over time of the hydraulic pressure. Further, FIG. 9D shows the change over time of the piston temperature, FIG. 9E shows the ignition timing, and FIG. 9F shows the net fuel improvement rate according to the first embodiment. In FIG. 9B, the period during which the knock intensity is equal to or greater than a predetermined value is defined as the knock risk period. In FIGS. 9C, 9D, and 9E, the case of the first embodiment is shown by a solid line, and the comparative form is shown by a broken line.

[0065] First, in the comparative form, the hydraulic pressure increase timing is the same as the start timing of the knock risk period (the timing when the engine output switches from low output to high output), and the hydraulic pressure decrease timing is the same as the end timing of the knock risk period (the timing when the engine output switches from high output to low output).

[0066] On the other hand, in the first embodiment, the hydraulic pressure increase timing is a timing that precedes the start timing of the knock risk period by a predetermined time Δt, and the hydraulic pressure decrease timing is a timing that precedes the end timing of the knock risk period by a predetermined time Δt. In this way, when the hydraulic pressure increase timing is advanced by a predetermined time Δt from the start timing of the knock risk period, the increment timing of the oil jet flow rate also precedes the start timing of the knock risk period by a predetermined time Δt. Also, when the hydraulic pressure decrease timing is advanced by a predetermined time Δt from the end timing of the knock risk period, the decrement timing of the oil jet flow rate also precedes the end timing of the knock risk period by a predetermined time Δt. As a result, before the temperature of the piston 25 starts to rise due to knock start (improvement of engine output), the cooling amount of the piston 25 by the oil jet mechanism 530 increases. Therefore, overheating of the piston 25 at the initial stage of the knock risk period can be suppressed. As a result, at the initial stage of the knock risk period, the ignition timing can be advanced compared to the comparative form. When the ignition timing is advanced, the combustion period advances accordingly, and the heat generation amount of the internal combustion engine 13 in the expansion stroke relatively decreases. Also, when the heat generation amount of the internal combustion engine 13 decreases, the temperature of the exhaust gas decreases. Therefore, by advancing the ignition timing as described above, the exhaust loss can be reduced.

[0067] Furthermore, according to the first embodiment, the amount of cooling of the piston 25 by the oil jet mechanism 530 is reduced before the end of the knock (before the engine output is reduced). This makes it possible to suppress overcooling of the piston 25 after the knock risk period. As a result, after the knock risk period (after the engine output is reduced), it is possible to reduce cooling loss compared to the comparative embodiment. Furthermore, by suppressing overcooling of the piston, an increase in oil viscosity is suppressed, making it possible to reduce friction loss occurring in the piston sliding parts.

[0068] In the first embodiment, the oil pressure increases before the start of the knock risk period, which raises concerns that net fuel economy will worsen compared to the comparative embodiment due to an increase in oil pump driving loss before the start of the knock risk period. However, in the first embodiment, the oil pressure decreases before the end of the knock risk period, which improves net fuel economy compared to the comparative embodiment due to a reduction in oil pump driving loss before the end of the knock risk period. Therefore, in the first embodiment, the deterioration in fuel economy (increase in pump driving loss) before the start of the knock risk period is offset by the improvement in fuel economy (reduction in pump driving loss) before the end of the knock risk period, so no deterioration in net fuel economy occurs.

[0069] Here, the above-mentioned predetermined time Δt will be described in detail. In the first embodiment, the predetermined time Δt is a time that defines how much the oil pressure increase timing Tr should precede the knock risk period start timing ts. The predetermined time Δt is also a time that defines how much the oil pressure decrease timing Td should precede the knock risk period end timing te. This predetermined time Δt is preferably set to the step response time τ of the piston temperature of the internal combustion engine 13. In other words, it is preferable to satisfy Δt ≒ τ. The reason for this is as follows.

[0070] For example, if a predetermined time Δt is made significantly longer than the step response time τ of the piston temperature, the cooling of the piston 25 becomes excessive from before the knock risk period to the initial stage of the knock risk period, and the cooling loss increases. Also, if the predetermined time Δt is made significantly longer than the step response time τ of the piston temperature, the cooling of the piston 25 before the end of the knock risk period is insufficient and the ignition retard amount increases.

[0071] On the other hand, if the predetermined time Δt is made significantly shorter than the step response time τ of the piston temperature, the cooling of the piston 25 at the initial stage of the knock risk period is insufficient and the ignition retard amount increases. Also, if the predetermined time Δt is made significantly shorter than the step response time τ of the piston temperature, the cooling of the piston 25 before the end of the knock risk period becomes excessive and the cooling loss increases.

[0072] In contrast, if the predetermined time Δt is set to the step response time τ of the piston temperature, overheating or overcooling of the piston around the start and end of the knock risk period is suppressed. Therefore, when the predetermined time Δt is set to the step response time τ of the piston temperature, the occurrence of knocking can be effectively suppressed, and at the same time, reduction of cooling loss and reduction of friction loss can be achieved.

[0073] The step response time τ of the piston temperature for determining the predetermined time Δt is obtained by solving the one-dimensional heat conduction equation shown in the following [Equation 1]. In this [Equation 1], T is the temperature of the piston (K), x is the distance in the piston thickness direction (m), ρ is the density of the piston (Kg / m 3 ), C is the specific heat of the piston (J / kg·K), and λ is the thermal conductivity of the piston (W / m·K).

[0074]

Equation

[0075] FIG. 10 is a diagram for explaining how to obtain the step response time of the piston temperature. FIG. 10A shows a model for piston temperature analysis, and FIG. 10B shows the analysis result of the temperature distribution within the piston. To obtain the step response time of the piston temperature, as shown in FIG. 10A, the piston is modeled as a homogeneous solid with a thickness d (mm) and an initial temperature TL. This model assumes the case where the piston reciprocates in the left - right direction in FIG. 10A. Also, in this model, the temperature of the wall of the piston located on the combustion chamber side (piston crown surface) is TH, and the temperature of the wall of the piston on the crank side (oil jet portion 53 side) is set to the same TL as the initial temperature (where TH > TL is satisfied). The step response time τ of the piston temperature is obtained by solving the above - mentioned [Equation 1] for the temperature change within the piston when TH and TL are defined as described above.

[0076] FIG. 10B is the analysis result of the temperature distribution within the piston in the piston thickness direction. In FIG. 10B, the temperature distributions at times t = 0, t1, t2, τ (where 0 < t1 < t2 < τ is satisfied) from the start of the analysis are shown respectively. The temperature distribution within the piston becomes a concave - shaped distribution with a strong curvature at the initial stage when the time from the start of the analysis is short, as can be seen from the temperature distribution at, for example, t = t1. However, as can be seen from the temperature distributions at, for example, t = t2 and t = t3, the curvature of the concave - shaped distribution becomes gentle as time elapses from the start of the analysis, and eventually becomes a linear equilibrium temperature distribution (t = τ). In this case, τ, which is the time required to reach the linear equilibrium temperature distribution from the start of the analysis, is obtained as the step response time of the piston temperature.

[0077] The inventor assumed the piston 25 of the currently - circulating internal combustion engine 13 and obtained the step response time τ of the piston temperature by the above - mentioned method. As a result, it was found that the step response time τ of the piston temperature takes the range from the time t1 (ms) defined by the following equations (1), (2), and (3) to the time t2 (ms).

[0078] t1 = 4.9d 2 …(1) t2 = 30 d 2 …(2) d = 4V / πB 2 …(3) In the formula, d is the thickness (mm) of the piston, V is Piston the volume (mm 3 ), B is the diameter (mm) of the piston, and π is the pi.

[0079] As described above, it is desirable to determine the predetermined time Δt by the step response time τ of the piston temperature. For this reason, it is desirable that the predetermined time Δt be within the range from the time t1 to the time t2 defined by the above formulas (1) to (3).

[0080] Also, when the lead time of the hydraulic pressure increase timing Tr with respect to the start timing ts of the knock risk period is Δtr, and the lead time of the hydraulic pressure decrease timing Td with respect to the end timing te of the knock risk period is Δtd, Δtr and Δtd do not necessarily have to be the same. For example, Δtr and Δtd may be set to different values corresponding to the distribution of the predicted knock intensity within the knock risk period. For example, when the knock intensity at the initial stage of the knock risk period is significantly larger than the knock intensity at the later stage of the knock risk period, it is desirable to set Δtr > Δtd and advance the increase timing of the piston cooling amount by the oil jet mechanism 530 to further suppress the overheating of the piston at the initial stage of the knock risk period. Also, for example, when the knock intensity at the later stage of the knock risk period is significantly larger than the knock intensity at the initial stage of the knock risk period, it is desirable to set Δtr < Δtd and delay the decrease timing of the piston cooling amount by the oil jet mechanism 530 to suppress the increase in knock at the later stage of the knock period.

[0081] <Second Embodiment> Next, an in-vehicle control device according to the second embodiment will be described. FIG. 11 is a block diagram showing the functional configuration of the in-vehicle control device according to the second embodiment. As shown in FIG. 11, the in-vehicle control device 102 is different in that the piston temperature prediction unit 63 is added as compared with the case of the first embodiment (FIG. 5) described above, and other components are the same as those in the case of the first embodiment.

[0082] The piston temperature prediction unit 63 predicts the piston temperature (hereinafter, also referred to as "pre-knock piston temperature") before the start timing of the knock risk period (future knock occurrence period) predicted by the knock risk period prediction unit 60. Further, the piston temperature prediction unit 63 predicts the pre-knock piston temperature based on the engine output (engine torque and engine rotational speed in the prediction period) predicted by the engine output prediction unit 58 and the like. Then, the hydraulic pressure change timing setting unit 61 that functions as an oil jet flow rate change timing setting unit sets the hydraulic pressure increase timing and the hydraulic pressure decrease timing based on the predicted knock risk period and the predicted piston temperature as described above. Specifically, when the piston temperature predicted by the piston temperature prediction unit 63 is lower than a predetermined temperature, the hydraulic pressure change timing setting unit 61 delays the hydraulic pressure increase timing compared to the case where the piston temperature predicted by the piston temperature prediction unit 63 is higher than the predetermined temperature. Stated by replacing it with the oil jet flow rate change timing setting unit, when the piston temperature predicted by the piston temperature prediction unit 63 is lower than a predetermined temperature, the oil jet flow rate change timing setting unit delays the increase timing of the oil jet flow rate compared to the case where the piston temperature predicted by the piston temperature prediction unit 63 is higher than the predetermined temperature. Note that the piston temperature prediction unit 63 may predict the pre-knock piston temperature based not only on the predicted engine output but also on, for example, the water temperature and the oil temperature in the prediction period, or the engine output, the water temperature, and the oil temperature before the prediction period.

[0083] Subsequently, a control method for an internal combustion engine according to the second embodiment will be described with reference to FIGS. 12 and 13. 12 is a flowchart showing the control procedure (control method) of the internal combustion engine according to the second embodiment. In this flowchart, steps S1 to S4 and step S6 are the same as steps S1 to S4 and step S6 in the control procedure of the internal combustion engine according to the first embodiment, and therefore a description thereof will be omitted here.

[0084] First, in step S7 after step S4, piston temperature prediction unit 63 predicts pre-knock piston temperature Tp. Here, "pre-knock" refers to any timing between the present and the start timing of the knock risk period. In other words, "pre-knock" refers to a timing after the present (current time) and before the start timing of the knock risk period. As an example, "pre-knock" refers to the same timing as the start timing of the knock risk period or a timing 5 seconds before the start timing of the knock risk period.

[0085] The pre-knock piston temperature Tp is predicted using a physical model equation, a correlation equation, map reference, or the like, which uses, as explanatory variables, for example, future engine output during the prediction period, the current water temperature and oil temperature, control information for the internal combustion engine 13, or the output history of the internal combustion engine 13 from the past to the present.

[0086] Next, the oil pressure change timing setting unit 61 compares the piston temperature Tp predicted by the piston temperature prediction unit 63 as described above with a predetermined temperature threshold Tc (for example, 100°C) (step S8). If this comparison shows that the predicted piston temperature Tp is higher than the temperature threshold Tc, the oil pressure change timing setting unit 61 sets the oil pressure increase timing Tr to be the timing obtained by subtracting a predetermined time Δt from the start timing ts of the knock risk period, and sets the oil pressure decrease timing Td to be the timing obtained by subtracting a predetermined time Δt from the end timing te of the knock risk period, as in the first embodiment described above (step S5).

[0087] On the other hand, when the predicted piston temperature Tp is equal to or lower than the temperature threshold Tc, the hydraulic pressure change timing setting unit 61 sets the hydraulic pressure increase timing Tr and the hydraulic pressure decrease timing Td as follows (step S9). First, regarding the hydraulic pressure increase timing Tr, as shown in the following equation (6), it is set as the timing obtained by subtracting a predetermined time Δt' from the start timing ts of the knock risk period. Tr = ts - Δt' …(6) In this equation (6), the predetermined time Δt' is shorter than the aforementioned predetermined time Δt. Also, regarding the hydraulic pressure decrease timing Td, as shown in the above equation (5), it is set as the timing obtained by subtracting a predetermined time Δt from the end timing te of the knock risk period.

[0088] Thus, in the control procedure of the internal combustion engine according to the second embodiment, when the pre-knock piston temperature is equal to or lower than the temperature threshold, the hydraulic pressure increase timing Tr is slower than when the pre-knock piston temperature is higher than the temperature threshold, which is different from the control procedure of the internal combustion engine according to the first embodiment.

[0089] The operation and effect of the second embodiment will be described below. First, at the initial stage of the knock risk period, the reaching temperature caused by piston overheating due to the temperature response delay of the piston is lower when the pre-knock piston temperature is sufficiently low than when the pre-knock piston temperature is high. Therefore, when the pre-knock piston temperature is sufficiently low (for example, lower than 100°C), even if the time from the hydraulic pressure increase timing to the start of the knock risk period is shorter than the step response time τ of the piston temperature, the increase in the ignition retard amount at the initial stage of the knock risk period is suppressed.

[0090] Therefore, in the control procedure for the internal combustion engine according to the second embodiment, when the pre-knock piston temperature is equal to or lower than the temperature threshold, the timing Tr for increasing the oil pressure is delayed compared to when the pre-knock piston temperature is higher than the temperature threshold. As a result, when the pre-knock piston temperature is equal to or lower than the temperature threshold, the period during which the oil pressure is increased is shorter compared to when the pre-knock piston temperature is higher than the temperature threshold. Therefore, according to the second embodiment, it is possible to reduce the work required to increase the oil pressure by the oil pump (the work of rotating the inner rotor of the pump), i.e., the loss due to the work of driving the oil pump. Furthermore, because the amount of cooling by the oil jet is suppressed before the knock risk period, it is possible to reduce both the cooling loss and the friction loss. The amount of cooling by the oil jet is the amount of heat removed from the piston by the oil jet.

[0091] When the pre-knock piston temperature Tp is equal to or lower than the temperature threshold value Tc, the predetermined time Δt′ by which the timing of increasing the oil pressure is advanced may be changed according to the pre-knock piston temperature Tp. Fig. 13 is an explanatory diagram showing an example of the relationship between the pre-knock piston temperature and the advance time of the oil pressure rise in the second embodiment. Fig. 13 shows an example of the relationship between the pre-knock piston temperature Tp and the predetermined time Δt' when the predetermined time Δt' is changed according to the pre-knock piston temperature Tp.

[0092] The piston overheat temperature at the beginning of the knock risk period decreases as the pre-knock piston temperature Tp decreases. Therefore, as shown in FIG. 13, by shortening the predetermined time Δt' as the pre-knock piston temperature Tp decreases, the driving loss, cooling loss, and friction loss of the oil pump can be further reduced. Furthermore, if the pre-knock piston temperature Tp is very low, the predetermined time Δt' may be set to a negative value, and the timing for increasing the oil pressure may be set to after the start of the knock risk period.

[0093] In this way, when pre-knock piston temperature Tp is lower than threshold temperature Tc, the predetermined time Δt' by which the timing of increasing the oil pressure is advanced is changed in accordance with pre-knock piston temperature Tp, thereby making it possible to finely set the timing of cooling the piston by the oil jet in accordance with the state of the internal combustion engine 13. Therefore, it is possible to further reduce the driving loss, cooling loss, and friction loss of the oil pump without increasing the amount of ignition retard due to knock.

[0094] <Third embodiment> In the first and second embodiments described above, a variable displacement oil pump 57 is used as the hydraulic pump, and an example is shown in which the oil jet flow rate is controlled by the level of the discharge pressure of the variable displacement oil pump 57. On the other hand, if the oil jet unit 53 has a built-in valve mechanism, it is possible to stop the oil jet from the oil jet unit 53 or adjust the oil jet flow rate by adjusting the opening of the valve mechanism without changing the discharge pressure (hydraulic pressure) of the hydraulic pump. Therefore, in the third embodiment, an example will be described in which the oil jet unit 53 has a built-in valve mechanism and a fixed displacement oil pump is used as the hydraulic pump.

[0095] FIG. 14 is a block diagram showing the functional configuration of the on-board control device according to the third embodiment. 14, the on-board control device 103 includes an engine output prediction unit 58, a knock intensity prediction unit 59, a knock risk period prediction unit 60, a valve opening change timing setting unit 61b, a target valve opening setting unit 62b, a valve opening change unit 64, an oil jet mechanism 530b, and a hydraulic pump 57b. The oil jet mechanism 530b includes an oil jet unit 53b. The oil jet unit 53b cools the piston 25 of the internal combustion engine 13 by spraying oil (oil jet). The oil jet unit 53b sprays oil, which is supplied from the hydraulic pump 57b via an oil supply passage 56, toward the piston 25 at a flow rate that depends on the opening of a valve mechanism built into the oil jet unit 53b.

[0096] Among the components of the in-vehicle control device 103 described above, the engine output prediction unit 58, the knock intensity prediction unit 59, the knock risk period prediction unit 60, and the oil supply passage 56 are the same as those in the first embodiment, and thus the description thereof will be omitted.

[0097] A valve mechanism (not shown) is incorporated in the oil jet portion 53b of the oil jet mechanism 530b. Therefore, the oil jet flow rate, which is the flow rate of the oil jetted by the oil jet portion 53b, varies depending on the opening degree of the valve mechanism. The hydraulic pump 57b is constituted by a constant displacement oil pump. In the present embodiment, the pressure (hydraulic pressure) of the oil determined by the discharge pressure of the hydraulic pump 57b is constant.

[0098] The valve opening degree change timing setting unit 61b sets the change timing for changing the opening degree (valve opening degree) of the valve mechanism incorporated in the oil jet portion 53b. The valve opening degree change timing setting unit 61b sets the valve opening timing and the valve closing timing of the valve mechanism respectively based on the knock risk period predicted as described above. Specifically, the valve opening degree change timing setting unit 61b sets the timing that is a predetermined time ahead of the start timing of the knock risk period (knock occurrence period) predicted by the knock risk period prediction unit 60 as the valve opening timing of the valve mechanism. Further, the valve opening degree change timing setting unit 61b sets the timing that is a predetermined time ahead of the end timing of the knock risk period predicted by the knock risk period prediction unit 60 as the valve closing timing of the valve mechanism. This valve opening degree change timing setting unit 61b corresponds to the oil jet flow rate change timing setting unit.

[0099] The target valve opening degree setting unit 62b sets the target valve opening degree of the valve mechanism based on the knock intensity predicted by the knock intensity prediction unit 59. The target valve opening degree setting unit 62b corresponds to the target oil jet flow rate setting unit.

[0100] The valve opening change unit 64 changes the opening of the valve mechanism based on the valve opening timing and the valve closing timing set by the valve opening change timing setting unit 61b and the target valve opening set by the target valve opening setting unit 62b. If a valve mechanism is built into the oil jet unit 53b, the valve opening change unit 64 changes the opening of the valve mechanism using a solenoid (see, for example, Japanese Patent Application Laid-Open No. 06-042346). The valve opening change unit 64 corresponds to the oil jet flow rate change unit.

[0101] Next, a control method for an internal combustion engine according to the third embodiment will be described with reference to FIGS. 15 is a flowchart showing the control procedure (control method) for the internal combustion engine according to the third embodiment. In this flowchart, steps S1 to S3 are the same as steps S1 to S3 in the control procedure for the internal combustion engine according to the first embodiment, and therefore, a description thereof will be omitted here.

[0102] First, in step S4b after step S3, target valve opening setting unit 62b sets a target valve opening of the valve mechanism in oil jet unit 53b based on the knock intensity prediction result in step S2. FIG. 16 is an explanatory diagram showing an example of the relationship between the target valve opening and the knock intensity in the knock risk period in the third embodiment. 16, the target valve opening setting unit 62b sets the target valve opening so that the higher the knock intensity during the knock risk period, the larger the target valve opening becomes. However, the target valve opening is set to be equal to or less than the maximum valve opening of the valve mechanism built into the oil jet unit 53b.

[0103] Next, the valve opening change timing setting unit 61b sets the timing for changing the oil jet flow rate in the oil jet mechanism 530b, that is, the valve opening change timing (Top, Tcl) of the valve mechanism (step S5b). The valve opening change timing setting unit 61b sets the valve opening timing Top and the valve closing timing Tcl of the valve mechanism as the valve opening change timing of the valve mechanism. The valve opening timing Top is set as the timing obtained by subtracting a predetermined time Δt from the start timing ts of the knock risk period, as shown in the following formula (7). Top = ts - Δt …(7) Also, the valve closing timing Tcl is set as the timing obtained by subtracting a predetermined time Δt from the end timing te of the knock risk period, as shown in the following formula (8). Tcl = te - Δt …(8) That is, the valve opening change timing setting unit 61b sets the period from when the valve mechanism opens to when it closes as a period that precedes the knock risk period by a predetermined time Δt.

[0104] Next, the ECU 2 sends the target valve opening set by the target valve opening setting unit 62b in step S4b above and the valve opening change timing (Top, Tcl) of the valve mechanism set by the valve opening change timing setting unit 61b in step S5b above to the valve opening change unit 64 as valve opening control values respectively (step S6b). Thereby, the valve opening change unit 64 changes the valve opening of the valve mechanism so that the valve opening of the valve mechanism becomes the target valve opening during the period from time Top to time Tcl. Also, the valve opening change unit 64 changes the valve opening of the valve mechanism so that the valve opening of the valve mechanism becomes zero (or below the maximum opening at which the oil injection stops) before time Top or after time Tcl.

[0105] In the third embodiment, the valve opening timing Top of the valve mechanism precedes the start timing ts of the knock risk period by a predetermined time Δt. Furthermore, the oil jet flow rate of the oil jet mechanism 530b increases as the valve mechanism of the oil jet unit 53b opens. Therefore, the timing of the increase in the oil jet flow rate precedes the start timing of the knock risk period by a predetermined time Δt. This increases the amount of cooling of the piston 25 by the oil jet mechanism 530b before the piston temperature begins to rise due to the start of knock. This makes it possible to suppress overheating of the piston 25 at the beginning of the knock risk period. As a result, the ignition timing can be advanced at the beginning of the knock risk period compared to the comparative example described above. Therefore, exhaust loss can be reduced.

[0106] Furthermore, in the third embodiment, the valve mechanism closing timing Tcl precedes the end timing te of the knock risk period by a predetermined time Δt. Furthermore, the oil jet flow rate of the oil jet mechanism 530b is reduced by the valve mechanism of the oil jet unit 53b closing. Therefore, the timing for reducing the oil jet flow rate precedes the end timing of the knock risk period by a predetermined time Δt. This makes it possible to suppress excessive cooling of the piston 25 after the knock risk period. As a result, cooling loss and friction loss can be reduced after the knock risk period compared to the comparative embodiment described above.

[0107] (Cooling other than oil jets) In the above-described embodiments, the control device and control method for an internal combustion engine are described, in which the piston 25 forming the combustion chamber 28 is cooled by an oil jet in order to suppress knocking. However, the cooling mechanism for cooling the combustion chamber 28 is not limited to the oil jet mechanism (530, 530b) that generates an oil jet. For example, the cooling mechanism may be configured to include a cooling water pump that flows cooling water through the water jacket 42. In that case, it is conceivable that the ECU 2 controls the temperature of the cooling water to cool the cylinder block 23 and the cylinder head 24.

[0108] The present invention is also applicable to the case where the combustion chamber 28 is cooled by coolant, as described above. For example, by configuring the coolant pump as an electric water pump and increasing the circulating flow rate of the coolant, which is determined by the discharge flow rate of the electric water pump, the amount of cooling of the combustion chamber 28 by the coolant can be increased, thereby suppressing knock. Therefore, by controlling the timing of increasing or decreasing the discharge flow rate of the electric water pump so that the period of increasing the circulating flow rate of the coolant (the period from the start to the end of the increase) precedes the predicted knock risk period by a predetermined time, it is possible to obtain an effect similar to that of cooling by the oil jet shown in the above-described embodiment. In this case, the predetermined time by which the period of increasing the circulating flow rate of the coolant precedes the knock risk period is preferably set to the step response time of the cylinder temperature, which is determined by the thermal capacity of the cylinder block 23, etc. and the coolant system.

[0109] Note that parameters for increasing or decreasing the amount of cooling in the combustion chamber 28 are not limited to the oil jet flow rate and the circulation flow rate of cooling water, but may also include, for example, the radiator fan rotation speed (cooling air volume) and the amount of oil flowing through the oil cooler.

[0110] (Regarding control when predictions are wrong) In the above-described embodiment, based on the predicted result of the future engine output, the future knock intensity is predicted, and further based on the predicted result of this knock intensity, the knock risk period, which is the future knock occurrence period, is predicted. Then, based on those predicted results, for example, the increase timing and decrease timing of the cooling amount of the combustion chamber 28 are advanced by a predetermined time with respect to the start timing and end timing of the knock risk period, respectively. On the other hand, due to the traffic conditions around the automobile 100 and the operations of unintended drivers, etc., there may be a large deviation between the predicted results of the future engine output and knock occurrence period, and the actual engine output and knock occurrence period during the prediction period. In particular, since the knock risk period is a period predicted based on the predicted result of the knock intensity, if the predicted result of the knock risk period deviates greatly from the actual knock occurrence period, there is a risk of damage to the internal combustion engine 13 caused by the occurrence of strong knocking, deterioration of drivability (noise and vibration of the internal combustion engine 13), deterioration of fuel efficiency, etc.

[0111] Therefore, as a preferable mode when the prediction is off, when the engine output predicted by the engine output prediction unit 58 deviates from the actual engine output by exceeding the allowable value, or when the knock risk period (knock occurrence period) predicted by the knock risk period prediction unit 60 deviates from the actual knock occurrence period by exceeding the allowable value, a mode of switching the control method of the internal combustion engine 13 from predictive control to normal control is conceivable.

[0112] As described above in each of the embodiments, predictive control is a method of controlling the internal combustion engine 13 so as to change the cooling amount of the combustion chamber 28 based on prediction results such as the engine output prediction unit 58, the engine output prediction unit 58, and the knock risk period prediction unit 60. On the other hand, normal control is a method of controlling the internal combustion engine 13 so as to change the cooling amount of the combustion chamber 28 based on the actual engine output, or the actual ignition timing retard amount, or the actual knock intensity detected by a knock sensor or the like. In any of the control methods, the main body for changing the cooling amount of the combustion chamber 28 is an oil jet flow rate change unit (variable displacement oil pump 57, valve opening degree change unit 64) that functions as a cooling amount change unit, or a cooling water flow rate change unit (electric water pump) that functions as a cooling amount change unit, etc.

[0113] For example, when the difference between the predicted engine output in the current prediction period and the actual engine output in the predicted engine becomes equal to or greater than a predetermined value, the ECU 2 stops the increase and decrease of the cooling amount at the increase timing and decrease timing of the cooling amount set based on the predicted engine output, and switches the control method of the internal combustion engine 13 from predictive control to normal control. Thereby, when the prediction is off, the internal combustion engine 13 is controlled by normal control instead of predictive control.

[0114] When the control method is switched from predictive control to normal control as described above, the ECU 2 controls the internal combustion engine 13 so as to change the cooling amount of the combustion chamber 28 (discharge pressure of the variable displacement oil pump 57, opening degree of the valve mechanism, discharge flow rate of the electric water pump, etc.) based on the actual engine output in the above prediction period, or the actual ignition timing retard amount, or the actual knock intensity detected by a knock sensor or the like.

[0115] The control method of the internal combustion engine 13 may be switched when the difference between the predicted engine output and the actual engine output is equal to or greater than a predetermined value. For example, if the ignition retard amount exceeds a predetermined value (ignition retard amount) before the timing for increasing the cooling amount of the combustion chamber 28 set based on the predicted engine output, or if the knock intensity detected by a knock sensor or the like exceeds a predetermined intensity, or if at least one of the water temperature, oil temperature, internal combustion engine wall temperature, and intake air temperature exceeds a predetermined temperature, the cooling amount change unit stops increasing the cooling amount of the combustion chamber 28 at the timing for increasing the cooling amount set based on the predicted engine output and switches the control method of the internal combustion engine 13 from predictive control to normal control. As a result, if the prediction is incorrect, the internal combustion engine 13 is controlled by normal control instead of predictive control.

[0116] Furthermore, for example, if the ignition retard amount exceeds a predetermined value at the timing for reducing the cooling amount of the combustion chamber 28 set based on the predicted engine output, or if the knock intensity detected by a knock sensor or the like exceeds a predetermined intensity, or if at least one of the coolant temperature, oil temperature, internal combustion engine wall temperature, and intake air temperature exceeds a predetermined temperature, the reduction of the cooling amount of the combustion chamber 28 at the timing for reducing the cooling amount set based on the predicted engine output is stopped, and the control method of the internal combustion engine 13 is switched from predictive control to normal control. As a result, if the prediction is incorrect, the internal combustion engine 13 is controlled by normal control rather than predictive control.

[0117] In this way, by switching the control method of the internal combustion engine 13 by the ECU 2, when the predicted results of the engine output or the knock risk period deviate significantly from the actual engine output or the knock occurrence period, i.e., when the predictions are incorrect, it is possible to suppress damage to the internal combustion engine 13, deterioration of drivability, and deterioration of fuel efficiency caused by the occurrence of strong knock. [Explanation of symbols]

[0118] 1...VCU, 2...ECU, 13...internal combustion engine, 25...piston, 28...combustion chamber, 53...oil jet unit, 57...variable displacement oil pump (oil jet flow rate change unit), 58...engine output prediction unit, 59...knock intensity prediction unit, 60...knock risk period prediction unit (knock occurrence period prediction unit), 61...oil pressure change timing setting unit (oil jet flow rate change time setting unit), 61b...valve opening change timing setting unit (oil jet flow rate change time setting unit), 62...target oil pressure setting unit (target oil jet flow rate setting unit), 62b...target valve opening setting unit (target oil jet flow rate setting unit), 63...piston temperature prediction unit, 64...valve opening change unit (oil jet flow rate change unit), 100...automobile, 101, 102, 103...on-board control device, 530...oil jet mechanism (cooling mechanism)

Claims

1. An in-vehicle control device mounted on an automobile having an internal combustion engine with a combustion chamber as a drive source, a cooling mechanism for cooling the combustion chamber, an engine output prediction unit for predicting an engine output which is a future output of the internal combustion engine, a knock intensity prediction unit for predicting a future knock intensity based on the engine output predicted by the engine output prediction unit, a knock occurrence period prediction unit for predicting a future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit, a target cooling amount setting unit for setting a target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit, a cooling timing setting unit that sets a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the cooling amount of the combustion chamber, and sets a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the cooling amount of the combustion chamber, a cooling amount change unit for changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set by the cooling timing setting unit and the target cooling amount set by the target cooling amount setting unit, comprising: the cooling mechanism is an oil jet mechanism for cooling a piston of the internal combustion engine by an oil jet, the target cooling amount setting unit is a target oil jet flow rate setting unit for setting a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted by the knock intensity prediction unit, the cooling timing setting unit is an oil jet flow rate change timing setting unit that sets a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the oil jet flow rate in the oil jet mechanism, and sets a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the oil jet flow rate in the oil jet mechanism, The cooling amount changing unit is an oil jet flow rate changing unit that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and the decrease timing set by the oil jet flow rate change timing setting unit and the target oil jet flow rate set by the target oil jet flow rate setting unit. It further includes a piston temperature prediction unit that predicts the piston temperature before the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit. When the piston temperature predicted by the piston temperature prediction unit is lower than a predetermined temperature, the oil jet flow rate change timing setting unit delays the increase timing of the oil jet flow rate compared to when the piston temperature predicted by the piston temperature prediction unit is higher than the predetermined temperature. In-vehicle control device.

2. An in-vehicle control device mounted on an automobile having an internal combustion engine with a combustion chamber as a drive source, a cooling mechanism for cooling the combustion chamber; an engine output prediction unit that predicts the engine output, which is the future output of the internal combustion engine; a knock intensity prediction unit that predicts the future knock intensity based on the engine output predicted by the engine output prediction unit; a knock occurrence period prediction unit that predicts the future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit; a target cooling amount setting unit that sets the target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit; a cooling timing setting unit that sets the timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the cooling amount of the combustion chamber, and sets the timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the cooling amount of the combustion chamber; a cooling amount changing unit that changes the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set by the cooling timing setting unit and the target cooling amount set by the target cooling amount setting unit; and includes the cooling mechanism is an oil jet mechanism that cools the piston of the internal combustion engine by an oil jet. The target cooling amount setting unit is a target oil jet flow rate setting unit that sets a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted by the knock intensity prediction unit. The cooling timing setting unit is an oil jet flow rate change timing setting unit that sets a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the oil jet flow rate in the oil jet mechanism, and sets a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the oil jet flow rate in the oil jet mechanism. The cooling amount change unit is an oil jet flow rate change unit that changes the flow rate of the oil jet by the oil jet mechanism based on the increase timing and the decrease timing set by the oil jet flow rate change timing setting unit and the target oil jet flow rate set by the target oil jet flow rate setting unit. The predetermined time is determined by the step response time of the piston temperature of the internal combustion engine. In-vehicle control device.

3. When the volume of the piston of the internal combustion engine is V (mm3), the diameter of the piston is B (mm), the thickness of the piston is d (mm), and the pi is π, the step response time of the piston temperature is within the range from the time t1 (ms) defined by the following formulas (1), (2), and (3) to the time t2 (ms). t1 = 4.9d2... (1) t2 = 30d2... (2) d = 4V / πB2... (3) The in-vehicle control device according to claim 2.

4. An in-vehicle control device mounted on an automobile having an internal combustion engine having a combustion chamber as a drive source, a cooling mechanism for cooling the combustion chamber; an engine output prediction unit that predicts an engine output that is a future output of the internal combustion engine; a knock intensity prediction unit that predicts a future knock intensity based on the engine output predicted by the engine output prediction unit; a knock occurrence period prediction unit that predicts a future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit; a target cooling amount setting unit that sets a target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit. A cooling timing setting unit that sets the timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the cooling amount of the combustion chamber, and sets the timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the cooling amount of the combustion chamber, A cooling amount changing unit that changes the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set by the cooling timing setting unit and the target cooling amount set by the target cooling amount setting unit, comprising, When the difference between the engine output predicted by the engine output prediction unit and the actual engine output becomes equal to or greater than a predetermined value, the cooling amount changing unit changes the cooling amount of the combustion chamber based on the actual engine output, or the actual ignition retard amount, or the actual knock intensity. In-vehicle control device.

5. An in-vehicle control device mounted on an automobile having an internal combustion engine with a combustion chamber as a drive source, a cooling mechanism for cooling the combustion chamber, an engine output prediction unit that predicts the engine output, which is the future output of the internal combustion engine, a knock intensity prediction unit that predicts the future knock intensity based on the engine output predicted by the engine output prediction unit, a knock occurrence period prediction unit that predicts the future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit, a target cooling amount setting unit that sets the target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit, A cooling timing setting unit that sets the timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the cooling amount of the combustion chamber, and sets the timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the cooling amount of the combustion chamber, A cooling amount changing unit that changes the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set by the cooling timing setting unit and the target cooling amount set by the target cooling amount setting unit, comprising, When the ignition retard amount exceeds a predetermined ignition retard amount, or when the knock intensity exceeds a predetermined intensity, or when at least one of the water temperature, oil temperature, wall temperature of the internal combustion engine, and temperature of the intake air exceeds a predetermined temperature, before the increase timing of the cooling amount set by the cooling timing setting unit, the cooling amount changing unit changes the cooling amount of the combustion chamber based on the actual engine output, the actual ignition timing retard amount, or the actual knock intensity. Vehicle-mounted control device. Claim 6 A vehicle-mounted control device mounted on an automobile having an internal combustion engine with a combustion chamber as a drive source, a cooling mechanism for cooling the combustion chamber; an engine output prediction unit that predicts the engine output, which is the future output of the internal combustion engine; a knock intensity prediction unit that predicts the future knock intensity based on the engine output predicted by the engine output prediction unit; a knock occurrence period prediction unit that predicts the future knock occurrence period based on the knock intensity predicted by the knock intensity prediction unit; a target cooling amount setting unit that sets the target cooling amount of the cooling mechanism based on the knock intensity predicted by the knock intensity prediction unit; a cooling timing setting unit that sets the timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the increase timing of the cooling amount of the combustion chamber, and sets the timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted by the knock occurrence period prediction unit as the decrease timing of the cooling amount of the combustion chamber; a cooling amount changing unit that changes the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set by the cooling timing setting unit and the target cooling amount set by the target cooling amount setting unit; comprising When the ignition retard amount exceeds a predetermined ignition retard amount, or when the knock intensity exceeds a predetermined intensity, or when at least one of the water temperature, oil temperature, wall temperature of the internal combustion engine, and temperature of the intake air exceeds a predetermined temperature, at the decrease timing of the cooling amount set by the cooling timing setting unit, the cooling amount changing unit changes the cooling amount of the combustion chamber based on the actual engine output, the actual ignition timing retard amount, or the actual knock intensity. Vehicle-mounted control device. Claim 7 A control method for an internal combustion engine in a motor vehicle, the method comprising an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber, wherein the cooling mechanism is an oil jet mechanism for cooling a piston of the internal combustion engine by an oil jet, an engine output prediction step of predicting an engine output which is a future output of the internal combustion engine, a knock intensity prediction step of predicting a future knock intensity based on the engine output predicted in the engine output prediction step, a knock occurrence period prediction step of predicting a future knock occurrence period based on the knock intensity predicted in the knock intensity prediction step, a target cooling amount setting step of setting a target cooling amount of the cooling mechanism based on the knock intensity predicted in the knock intensity prediction step, a cooling timing setting step of setting a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted in the knock occurrence period prediction step as an increase timing of the cooling amount of the combustion chamber, and setting a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted in the knock occurrence period prediction step as a decrease timing of the cooling amount of the combustion chamber, and a cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step, wherein the target cooling amount setting step is a target oil jet flow rate setting step of setting a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted in the knock intensity prediction step, and the cooling timing setting step is an oil jet flow rate change timing setting step of setting a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted in the knock occurrence period prediction step as an increase timing of the oil jet flow rate in the oil jet mechanism, and setting a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted in the knock occurrence period prediction step as a decrease timing of the oil jet flow rate in the oil jet mechanism, The cooling amount change step is an oil jet flow rate change step of changing the flow rate of the oil jet by the oil jet mechanism based on the increase timing and the decrease timing set in the oil jet flow rate change timing setting step and the target oil jet flow rate set in the target oil jet flow rate setting step. It further includes a piston temperature prediction step of predicting the piston temperature before the start timing of the knocking occurrence period predicted in the knocking occurrence period prediction step. When the piston temperature predicted in the piston temperature prediction step is lower than a predetermined temperature, the oil jet flow rate change timing setting step delays the increase timing of the oil jet flow rate compared to when the piston temperature predicted in the piston temperature prediction step is higher than the predetermined temperature. A control method for an internal combustion engine.

8. A control method for an internal combustion engine in an automobile including an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber, wherein the cooling mechanism is an oil jet mechanism for cooling the piston of the internal combustion engine by an oil jet, an engine output prediction step of predicting an engine output which is a future output of the internal combustion engine, a knocking intensity prediction step of predicting a future knocking intensity based on the engine output predicted in the engine output prediction step, a knocking occurrence period prediction step of predicting a future knocking occurrence period based on the knocking intensity predicted in the knocking intensity prediction step, a target cooling amount setting step of setting a target cooling amount of the cooling mechanism based on the knocking intensity predicted in the knocking intensity prediction step, a cooling timing setting step of setting a timing that is a predetermined time ahead of the start timing of the knocking occurrence period predicted in the knocking occurrence period prediction step as the increase timing of the cooling amount of the combustion chamber, and setting a timing that is a predetermined time ahead of the end timing of the knocking occurrence period predicted in the knocking occurrence period prediction step as the decrease timing of the cooling amount of the combustion chamber, and a cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step. The target cooling amount setting step is a target oil jet flow rate setting step for setting a target oil jet flow rate of the oil jet mechanism based on the knock intensity predicted in the knock intensity prediction step. The cooling timing setting step is an oil jet flow rate change timing setting step for setting, as the increase timing of the oil jet flow rate in the oil jet mechanism, a timing that is a predetermined time earlier than the start timing of the knock occurrence period predicted in the knock occurrence period prediction step, and for setting, as the decrease timing of the oil jet flow rate in the oil jet mechanism, a timing that is a predetermined time earlier than the end timing of the knock occurrence period predicted in the knock occurrence period prediction step. The cooling amount change step is an oil jet flow rate change step for changing the flow rate of the oil jet by the oil jet mechanism based on the increase timing and the decrease timing set in the oil jet flow rate change timing setting step and the target oil jet flow rate set in the target oil jet flow rate setting step. The predetermined time is determined by the step response time of the piston temperature of the internal combustion engine. A control method for an internal combustion engine.

9. A control method for an internal combustion engine in an automobile, comprising an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber. An engine output prediction step for predicting an engine output that is a future output of the internal combustion engine. A knock intensity prediction step for predicting a future knock intensity based on the engine output predicted in the engine output prediction step. A knock occurrence period prediction step for predicting a future knock occurrence period based on the knock intensity predicted in the knock intensity prediction step. A target cooling amount setting step for setting a target cooling amount of the cooling mechanism based on the knock intensity predicted in the knock intensity prediction step. A cooling timing setting step for setting, as the increase timing of the cooling amount of the combustion chamber, a timing that is a predetermined time earlier than the start timing of the knock occurrence period predicted in the knock occurrence period prediction step, and for setting, as the decrease timing of the cooling amount of the combustion chamber, a timing that is a predetermined time earlier than the end timing of the knock occurrence period predicted in the knock occurrence period prediction step. A cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step, In the cooling amount change step, when the difference between the engine output predicted in the engine output prediction step and the actual engine output becomes equal to or greater than a predetermined value, the cooling amount of the combustion chamber is changed based on the actual engine output, the actual ignition retard amount, or the actual knock intensity. A control method for an internal combustion engine.

10. A control method for an internal combustion engine in an automobile including an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber, An engine output prediction step of predicting an engine output which is a future output of the internal combustion engine, A knock intensity prediction step of predicting a future knock intensity based on the engine output predicted in the engine output prediction step, A knock occurrence period prediction step of predicting a future knock occurrence period based on the knock intensity predicted in the knock intensity prediction step, A target cooling amount setting step of setting a target cooling amount of the cooling mechanism based on the knock intensity predicted in the knock intensity prediction step, A cooling timing setting step of setting a timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted in the knock occurrence period prediction step as the increase timing of the cooling amount of the combustion chamber, and setting a timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted in the knock occurrence period prediction step as the decrease timing of the cooling amount of the combustion chamber, A cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step, In the cooling amount change step, if the ignition retard amount exceeds a predetermined ignition retard amount, or the knock intensity exceeds a predetermined intensity, or at least one of the water temperature, oil temperature, wall temperature of the internal combustion engine, and temperature of the intake air exceeds a predetermined temperature, before the increase timing of the cooling amount set in the cooling timing setting step, the cooling amount of the combustion chamber is changed based on the actual engine output, the actual ignition timing retard amount, or the actual knock intensity. A control method for an internal combustion engine.

11. A control method for an internal combustion engine in an automobile, comprising an internal combustion engine having a combustion chamber and a cooling mechanism for cooling the combustion chamber, an engine output prediction step of predicting an engine output which is a future output of the internal combustion engine, a knock intensity prediction step of predicting a future knock intensity based on the engine output predicted in the engine output prediction step, a knock occurrence period prediction step of predicting a future knock occurrence period based on the knock intensity predicted in the knock intensity prediction step, a target cooling amount setting step of setting a target cooling amount of the cooling mechanism based on the knock intensity predicted in the knock intensity prediction step, a cooling timing setting step of setting the timing that is a predetermined time ahead of the start timing of the knock occurrence period predicted in the knock occurrence period prediction step as the increase timing of the cooling amount of the combustion chamber, and setting the timing that is a predetermined time ahead of the end timing of the knock occurrence period predicted in the knock occurrence period prediction step as the decrease timing of the cooling amount of the combustion chamber, including a cooling amount change step of changing the cooling amount of the combustion chamber by the cooling mechanism based on the increase timing and the decrease timing set in the cooling timing setting step and the target cooling amount set in the target cooling amount setting step, in the cooling amount change step, when the ignition retard amount exceeds a predetermined ignition retard amount, or the knock intensity exceeds a predetermined intensity, or at least one of the water temperature, oil temperature, wall temperature of the internal combustion engine, and temperature of the intake air exceeds a predetermined temperature, at the decrease timing of the cooling amount set in the cooling timing setting step, the cooling amount of the combustion chamber is changed based on the actual engine output, the actual ignition timing retard amount, or the actual knock intensity. A control method for an internal combustion engine.

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