Internal combustion engine control device

Abstract

The internal combustion engine control device of the present invention includes an engine state estimation unit, a wall temperature estimation unit, and an operation amount calculation unit. The engine state estimation unit calculates the energy transfer amount from the gas to the wall based on parameters related to operating conditions, parameters related to chemical conditions of combustion, and parameters related to the operating status. The wall temperature estimation unit estimates the wall temperature based on the energy transfer amount from the gas to the wall. The operation amount calculation unit calculates the operation amount of an actuator provided in the internal combustion engine based on the wall temperature estimated by the wall temperature estimation unit.

Description

Technical Field

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

[0002] Generally, an internal combustion engine mounted on a vehicle operates according to the operation amounts of various actuators that are suitable under specific environmental conditions such as temperature, humidity, and air pressure. For example, when driving on an actual road, the vehicle may travel under conditions that deviate from the environmental conditions or operating conditions of the internal combustion engine that are assumed to be suitable. Various sensors are used to detect the environmental conditions, and the operation amounts are corrected according to the detected conditions.

[0003] Furthermore, when driving on actual roads, the suitable conditions are not only environmental conditions, but also the state of the internal combustion engine itself (e.g., wall temperature, cooling water temperature, and components), which may deviate from the state assumed to be suitable. Therefore, when driving on actual roads, in order to improve various performances of the vehicle (fuel consumption performance, exhaust performance), it is important to estimate and detect the state of the internal combustion engine to grasp the state in operation, and to operate the actuator according to the grasped state of the internal combustion engine.

[0004] As a state related to the performance of the internal combustion engine, there is the temperature of the combustion chamber wall of the internal combustion engine (hereinafter referred to as the wall temperature). The wall temperature is a physical quantity related to the operation amount of the actuator that affects the fuel consumption performance and exhaust performance. For example, under the condition of high wall temperature, abnormal combustion (knock) is likely to occur due to the intensified heating of the gas near the wall. On the other hand, under the condition of low wall temperature, the fuel attached to the wall is likely to remain in a liquid state, which may lead to the generation of unburned hydrocarbons and soot, thereby causing deterioration of exhaust performance. Therefore, in order to operate the various actuators provided in the internal combustion engine, it is required to improve the estimation accuracy of the wall temperature.

[0005] As a technique for estimating the wall temperature and controlling an actuator provided in an internal combustion engine, there is a technique described in Patent Document 1. Patent Document 1 describes a technique for estimating the wall temperature based on a wall temperature map with load state, rotation speed, and cooling water temperature as axes and operating the injection.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-64374 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] However, in the technology described in Patent Document 1, it is confirmed that the estimated error of the wall surface temperature deteriorates when the engine block is cooled, that is, when the temperature of the cooling water for cooling the engine block is reduced. Therefore, in the technology described in Patent Document 1, there is a problem that the operation amounts of various actuators cannot be properly controlled due to the deterioration of the estimated value of the wall surface temperature.

[0011] An object of the present invention is to provide an internal combustion engine control device in view of the above-mentioned problems, which can improve the estimation accuracy of the wall surface temperature.

[0012] Technical means for solving technical problems

[0013] In order to solve the above problems and achieve the purpose, an internal combustion engine control device includes an engine state estimation unit, a wall temperature estimation unit and an operation amount calculation unit. The engine state estimation unit calculates the energy transfer amount from the gas to the wall surface in the internal combustion engine based on parameters related to the operating conditions of the internal combustion engine, parameters related to the chemical conditions of combustion, and parameters related to the operating conditions of the internal combustion engine. The wall temperature estimation unit estimates the wall temperature based on the energy transfer amount from the gas to the wall surface calculated by the engine state estimation unit. The operation amount calculation unit calculates the operation amount of an actuator provided in the internal combustion engine based on the wall temperature estimated by the wall temperature estimation unit.

[0014] Effects of the Invention

[0015] According to the internal combustion engine control device having the above-described structure, it is possible to improve the estimation accuracy of the wall surface temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic configuration diagram showing a system configuration of an internal combustion engine equipped with the internal combustion engine control device according to the first embodiment.

[0017] Figure 2 This is a block diagram showing the configuration of an internal combustion engine control device according to the first embodiment.

[0018] Figure 3 This is a control block diagram showing the outline of control of the internal combustion engine control device according to the first embodiment.

[0019] Figure 4 This is a flowchart showing an example of the operation of the engine state estimating unit of the internal combustion engine control device according to the first embodiment.

[0020] FIG. 5A to FIG. 5C A map of the combustion period with dilution and ignition timing as axes is shown. Figure 5A is a map showing the relationship between dilution and ignition timing, Figure 5B is a map showing the relationship between dilution and combustion period, Figure 5CIt is a map showing the relationship between the ignition timing and the combustion period.

[0021] FIG. 6A to FIG. 6C is a map showing the ratio of energy transfer to the wall, Fig. 6A is a map showing the relationship between the combustion period and ignition timing and the wall temperature. Figure 6B is a map showing the relationship between the ignition timing and the energy transfer ratio to the wall surface. Figure 6C It is a map showing the relationship between the combustion period and the energy transfer ratio to the wall surface.

[0022] Figure 7 This is a flowchart showing an example of the operations of the cooling water energy flow rate estimating unit, the wall surface temperature estimating unit, and the cooling water temperature estimating unit of the internal combustion engine control device according to the first embodiment.

[0023] Figure 8 This is a flowchart showing a modified example of the operation of the engine state estimating unit of the internal combustion engine control device according to the first embodiment.

[0024] Fig. 9 This is a flowchart showing an example of the operation of the operation amount calculation unit of the internal combustion engine control device according to the first embodiment.

[0025] Fig.10 It is shown based on Fig. 9 The operation example of the operation amount calculation unit shown is a timing chart of an operation example of various actuators.

[0026] Fig.11 This is a control block diagram showing an outline of control executed by the internal combustion engine control device according to the second embodiment.

[0027] Fig.12 This is a flowchart showing an example of the operations of the operation amount calculation unit and the knock determination module in the internal combustion engine control device according to the second embodiment.

[0028] Fig.13 It is shown based on Fig.12 The operation example of the operation amount calculation unit shown is a timing chart of an operation example of various actuators.

[0029] Fig.14 This is a flowchart showing another example of the operations of the operation amount calculation unit and the knock determination module in the internal combustion engine control device according to the second embodiment.

[0030] Fig.15 It is shown based on Fig.14 The operation example of the operation amount calculation unit shown is a timing chart of an operation example of various actuators.

[0031] Fig.16 This is a control block diagram showing an outline of control executed by the internal combustion engine control device according to the third embodiment.

[0032] Fig.17 This is a flowchart showing the operation of the operation amount calculation unit of the internal combustion engine control device according to the third embodiment.

[0033] Fig.18 It is shown based on Fig.17 The operation example of the operation amount calculation unit shown is a timing chart of an operation example of various actuators. DETAILED DESCRIPTION

[0034] In the following, reference is made to Figures 1 to 18 An embodiment of the internal combustion engine control device will be described. In the drawings, the same reference numerals are used to denote common components.

[0035] 1. Implementation Example 1

[0036] First, refer to Figures 1 to 10 , an internal combustion engine control device according to implementation example 1 (hereinafter referred to as “this example”) is described. Figure 1 It is a schematic structural diagram showing the system structure of an internal combustion engine.

[0037] 1-1. Example of the structure of an internal combustion engine

[0038] First, a structural example of an internal combustion engine will be described.

[0039] Figure 1 The internal combustion engine 100 shown is an in-cylinder injection type internal combustion engine (direct injection engine) that injects fuel formed of gasoline directly into a cylinder. The internal combustion engine 100 is not limited to the in-cylinder injection type, and a port injection type internal combustion engine that injects fuel into an intake port may be applied.

[0040] The internal combustion engine 100 is a four-stroke engine that repeats four strokes of an intake stroke, a compression stroke, a combustion (expansion) stroke, and an exhaust stroke. In addition, for example, the internal combustion engine 100 is a multi-cylinder engine having four cylinders. In addition, the number of cylinders that the internal combustion engine 100 has is not limited to four, but may have six or eight or more cylinders. In addition, the number of strokes of the internal combustion engine 100 is not limited to four strokes.

[0041] like Figure 1 As shown, the internal combustion engine 100 includes an air flow sensor 1, an electronically controlled throttle valve 2, an intake pressure sensor 3, a compressor 4a, an intercooler 7, and a cylinder 14. The air flow sensor 1, the electronically controlled throttle valve 2, the intake pressure sensor 3, the compressor 4a, and the intercooler 7 are arranged on the intake pipe 6 at a position leading to the cylinder 14.

[0042] In addition, the air flow sensor 1 measures the amount of intake air and the intake air temperature. The electronically controlled throttle valve 2 is driven to be opened and closed by a drive motor (not shown). Then, the opening of the electronically controlled throttle valve 2 is adjusted based on the driver's accelerator operation. As a result, the amount of intake air is adjusted and the pressure of the intake pipe 6 is adjusted. The intake pressure sensor 3 measures the pressure of the intake pipe 6.

[0043] The compressor 4a is a supercharger that supercharges the intake air. The rotational force is transmitted to the compressor 4a via a turbine 4b described later. The intercooler 7 is arranged on the upstream side of the cylinder 14 and cools the intake air.

[0044] In addition, in the internal combustion engine 100, an ignition device is provided in each cylinder 14, and the ignition device includes a fuel injection device 13 for injecting fuel into the cylinder of the cylinder 14, and an ignition coil 16 and a spark plug 17 for providing ignition energy. The ignition coil 16 generates a high voltage under the control of the internal combustion engine control device 20 and applies the high voltage to the spark plug 17. Thereby, a spark is generated at the spark plug 17. Then, the mixed gas in the cylinder is burned and exploded by the spark generated at the spark plug 17.

[0045] A voltage sensor (not shown) is attached to the ignition coil 16. The voltage sensor measures the primary side voltage or the secondary side voltage of the ignition coil 16. Then, the voltage information measured by the voltage sensor is sent to the internal combustion engine control device 20 as an ECU (Engine Control Unit).

[0046] Furthermore, the variable valve 5 is provided on the cylinder head of the cylinder 14. The variable valve 5 adjusts the mixed gas flowing into the cylinder 14 or the exhaust gas discharged from the cylinder. By adjusting the variable valve 5, the intake amount and the internal EGR amount of all the cylinders 14 are adjusted.

[0047] In addition, the piston is slidably arranged in the cylinder 14. The piston compresses the mixed gas of fuel and gas flowing into the cylinder 14. Then, the piston reciprocates in the cylinder 14 by the combustion pressure generated in the cylinder. In addition, a crank angle sensor 19 for detecting the position of the piston is installed.

[0048] The fuel injection device 13 is controlled by an internal combustion engine control unit (ECU) 20 described later, and injects fuel into the cylinder 14. As a result, a mixed gas of air and fuel is generated in the cylinder 14. In addition, a high-pressure fuel pump (not shown) is connected to the fuel injection device 13. The fuel with increased pressure by the high-pressure fuel pump is supplied to the fuel injection device 13. In addition, a fuel pressure sensor for measuring the fuel injection pressure is provided on the fuel pipe connecting the fuel injection device 13 and the high-pressure fuel pump.

[0049] In addition, a temperature sensor 18 is provided on the cylinder 14. The temperature sensor 18 measures the temperature of the cooling water surrounding the cylinder 14. As a cooling water device, there is a water pump (not shown) by which the flow rate of the cooling water surrounding the cylinder 14 is adjusted. The water pump uses a pump driven by the output of the internal combustion engine, an electric water pump (electric water pump), etc. In addition, although not shown, as a device for adjusting the cooling water, in addition to the water pump, sometimes also includes a thermostat for controlling the cooling water flowing into the cylinder, and a valve for switching the direction of flow in each component such as a heat exchanger and a cylinder of the cooling water provided in the internal combustion engine.

[0050] In addition, each cylinder 14 of the internal combustion engine 100 is provided with an oil injection system 110. The oil injection system 110 is connected to an oil pump not shown in the figure, and cooling oil is supplied from the oil pump. Then, the oil injection system 110 injects the cooling oil to the piston and reduces the temperature of the piston. In addition, the output (flow rate, oil pressure) of the oil pump is adjusted by the internal combustion engine control device 20, and the oil injection system 110 sometimes includes a valve for switching between injection and non-injection of oil to the piston. The oil injection system, oil pump, valve, etc. are also referred to as lubricating oil devices hereinafter.

[0051] In addition, an exhaust pipe 15 is connected to the exhaust port of the cylinder 14. The exhaust pipe 15 is provided with a turbine 4b, an electronically controlled waste gate valve 11, a three-way catalyst 10, and an air-fuel ratio sensor 9. The turbine 4b rotates by the exhaust gas passing through the exhaust pipe 15, and transmits the rotational force to the compressor 4a. The electronically controlled waste gate valve 11 adjusts the exhaust gas flow path flowing through the turbine 4b.

[0052] The three-way catalyst 10 purifies harmful substances contained in the exhaust gas by oxidation-reduction reaction. In addition, the air-fuel ratio sensor 9 is arranged on the upstream side of the three-way catalyst 10. Then, the air-fuel ratio sensor 9 detects the air-fuel ratio of the exhaust gas passing through the exhaust pipe 15.

[0053] In addition, signals detected by various sensors such as the air flow sensor 1, the intake pressure sensor 3, and the voltage sensor are sent to the internal combustion engine control device 20. In addition, the amount of depression of the accelerator pedal, that is, the signal detected by the accelerator opening sensor 12 for detecting the accelerator opening, is also sent to the internal combustion engine control device 20.

[0054] The internal combustion engine control device 20 calculates the required torque based on the main signal of the accelerator opening sensor 12. That is, the accelerator opening sensor 12 is used as a required torque detection sensor for detecting the required torque for the internal combustion engine 100. In addition, the internal combustion engine control device 20 calculates the rotation speed of the internal combustion engine 100 based on the output signal of the crank angle sensor (not shown). Then, the internal combustion engine control device 20 optimally calculates the main operation quantities of the internal combustion engine 100, such as the air flow rate, the fuel injection amount, the ignition timing, and the fuel pressure, based on the operating state of the internal combustion engine 100 obtained from the outputs of various sensors.

[0055] The fuel injection amount calculated by the internal combustion engine control device 20 is converted into a valve opening pulse signal and output to the fuel injection device 13. In addition, the ignition timing calculated by the internal combustion engine control device 20 is output as an ignition signal to the spark plug 17. In addition, the throttle valve opening calculated by the internal combustion engine control device 20 is output as a throttle valve drive signal to the electronically controlled throttle valve 2.

[0056] Furthermore, the internal combustion engine 100 may be provided with an EGR (Exhaust Gas Recirculation) pipe (not shown) for connecting the intake pipe 6 and the exhaust pipe 15. A part of the exhaust gas passing through the exhaust pipe 15 can be returned to the intake pipe 6 by the EGR pipe.

[0057] 1-2. Configuration Example of Internal Combustion Engine Control Device 20

[0058] Next, refer to Figure 2 A configuration example of the internal combustion engine control device 20 will be described.

[0059] Figure 2 It is a block diagram showing the structure of the internal combustion engine control device 20.

[0060] like Figure 2 As shown, the internal combustion engine control device 20 as an ECU (Engine Control Unit) includes an input circuit 21, an input / output port 22, a RAM (Random Access Memory) 23c, a ROM (Read Only Memory) 23b, and a CPU (Central Processing Unit) 23a. In addition, the internal combustion engine control device 20 has an ignition control unit 24, a fuel injection control unit 25, and a fuel injection control unit 26.

[0061] The intake flow rate from the air flow sensor 1, the intake pressure from the intake pressure sensor 3, and the primary voltage or secondary voltage of the coil from the voltage sensor are input to the input circuit 21. In addition, the input circuit 21 inputs not only the intake flow rate, intake pressure, primary voltage or secondary voltage, but also information measured by various sensors such as crank angle, throttle valve opening, exhaust air-fuel ratio, etc.

[0062] The input circuit 21 performs signal processing such as noise removal on the input signal and transmits it to the input / output port 22. The value of the input port input to the input / output port 22 is stored in the RAM 23c.

[0063] The ROM 23b stores a control program describing the contents of various calculation processes executed by the CPU 23a, a MAP used for each process, a data table, etc. The RAM 23c is provided with a storage area that stores values ​​input to the input port of the input / output port 22 and values ​​representing the operation amount of each actuator calculated according to the control program. In addition, the values ​​representing the operation amount of each actuator stored in the RAM 23c are sent to the output port of the input / output port 22.

[0064] The ignition signal provided at the output port of the input / output port 22 is sent to the ignition coil 16 via the ignition control unit 24. The ignition control unit 24 controls the energization timing and energization time of the ignition coil 16. The ignition control unit 24 also controls the discharge energy at the spark plug 17.

[0065] The fuel injection control unit 25 controls the fuel injection device 13 as a fuel injection device and a high-pressure fuel pump for supplying fuel to the fuel injection device 13. In other words, the fuel injection control unit 25 controls the valve opening and closing timings of the fuel injection device 13 and the valve for adjusting the pressure of the high-pressure fuel pump.

[0066] The oil injection control portion 26 controls an oil pump that supplies oil to the oil injection system 110. Then, the oil injection control portion 26 controls the oil pump, thereby controlling the amount of oil injected from the oil injection system 110.

[0067] In this example, the example in which the ignition control unit 24, the fuel injection control unit 25, and the fuel injection control unit 26 are provided in the internal combustion engine control device 20 is described, but the present invention is not limited thereto. For example, a part of the ignition control unit 24, the fuel injection control unit 25, and the fuel injection control unit 26, or all of the ignition control unit 24, the fuel injection control unit 25, and the fuel injection control unit 26 may be installed in a control device different from the internal combustion engine control device 20.

[0068] 1-3. Control overview of internal combustion engine control device

[0069] Next, refer to Figure 3 The outline of control performed by the internal combustion engine control device 20 will be described.

[0070] Figure 3 2 is a control block diagram showing an outline of control executed by the internal combustion engine control device 20 .

[0071] like Figure 3 As shown, the internal combustion engine control device 20 includes a wall temperature estimation module 31 and an operation amount calculation unit 36 ​​for calculating the operation amounts of various actuators. The wall temperature estimation module 31 is composed of an engine state estimation unit 32, a cooling water energy flow estimation unit 33, a wall temperature estimation unit 34, and a cooling water temperature estimation unit 35.

[0072] The operating conditions, chemical conditions, and operating status of the internal combustion engine 100 are input to the engine state estimation unit 32. Examples of parameters related to the operating conditions include the intake air flow rate and the rotation speed of the internal combustion engine 100. Intake pressure may be used instead of the intake air flow rate.

[0073] The chemical condition indicates the combustion condition of the fuel in the cylinder 14. Examples of parameters related to the chemical condition include EGR rate, air-fuel ratio, humidity, intake air temperature, etc. The parameters related to the chemical condition are not limited to EGR rate, air-fuel ratio, humidity, intake air temperature, and for example, the type of fuel, etc. may be used.

[0074] The operating state indicates the operation amount of various actuators. Parameters related to the operating state include, for example, the ignition timing, the valve timing indicating the operation amount of the variable valve 5, etc. In addition, as a parameter related to the operating state, the fuel injection timing as the operation amount of the fuel injection device 13 can be used.

[0075] In addition, the wall temperature (estimated value) calculated by the wall temperature estimation unit 34 described later in the previous calculation cycle is input to the engine state estimation unit 32. The engine state estimation unit 32 calculates the energy transfer amount as one of the engine states based on the various information input. The energy transfer amount is the amount of energy transferred from the combustion gas generated in the cylinder 14 to the engine wall surface (hereinafter referred to as "wall surface"). Then, the engine state estimation unit 32 outputs the calculated energy transfer amount from the cylinder gas to the wall surface to the wall temperature estimation unit 34.

[0076] Furthermore, when the engine state estimation unit 32 calculates the energy transfer amount, the estimation accuracy can be improved by using the wall surface temperature (estimated value).

[0077] The cooling water energy flow rate estimation unit 33 is input with the cooling water temperature in the cylinder (estimated value) calculated by the cooling water temperature estimation unit 35 described later in the previous calculation cycle and the wall temperature (estimated value) calculated by the wall temperature estimation unit 34 in the previous calculation cycle. In addition, the flow rate of the cooling water flowing into the engine cylinder (cooling water flow rate) is input to the cooling water energy flow rate estimation unit 33.

[0078] The cooling water energy flow rate estimation unit 33 calculates the energy transfer amount between the cooling water and the wall surface based on the various information inputted. Then, the cooling water energy flow rate estimation unit 33 outputs the calculated energy transfer amount between the cooling water and the wall surface to the wall surface temperature estimation unit 34 and the cooling water temperature estimation unit 35.

[0079] The energy transfer amount from the cylinder gas to the wall surface calculated by the engine state estimation unit 32 and the energy transfer amount between the cooling water and the wall surface calculated by the cooling water energy flow rate estimation unit 33 are input to the wall surface temperature estimation unit 34. In addition, the wall surface temperature (estimated value) calculated by the wall surface temperature estimation unit 34 in the previous calculation cycle is input to the wall surface temperature estimation unit 34.

[0080] Then, the wall surface temperature estimation unit 34 estimates the wall surface temperature based on the various information inputted. The wall surface temperature estimation unit 34 outputs the estimated wall surface temperature to the operation amount calculation unit 36 ​​, the engine state estimation unit 32 , and the cooling water energy flow rate estimation unit 33 .

[0081] The cooling water temperature estimation unit 35 is input with the temperature of the cooling water inlet, that is, the temperature of the cooling water flowing into the engine cylinder (inflow cooling water temperature), the cooling water flow rate, and the energy transfer amount between the cooling water and the wall calculated by the cooling water energy flow rate estimation unit 33. In addition, the cylinder cooling water temperature (estimated value) calculated by the cooling water temperature estimation unit 35 in the previous calculation cycle is input to the cooling water temperature estimation unit 35 as the current cooling water temperature.

[0082] Then, the cooling water temperature estimation unit 35 estimates the temperature of the cooling water in the engine block based on the various information inputted. The cooling water temperature estimation unit 35 outputs the estimated cooling water temperature to the operation amount calculation unit 36 ​​and the cooling water energy flow rate estimation unit 33 .

[0083] The engine state estimating unit 32, the cooling water energy flow rate estimating unit 33, the wall temperature estimating unit 34, and the cooling water temperature estimating unit 35 perform predetermined calculations in a preset calculation cycle. The calculation cycle is appropriately set for each estimating unit.

[0084] The operation amount calculation unit 36 ​​calculates the operation amounts of various actuators such as the oil pump used to supply oil to the spark plug 17, the fuel injection device 13 and the injection system 110 based on the wall temperature estimated by the wall temperature estimation unit 34 and the cooling water temperature estimated by the cooling water temperature estimation unit 35, and outputs the operation amounts.

[0085] 1-4. Example of operation of engine state estimation unit

[0086] Next, refer to Figures 4 to 6C An example of the calculation operation of the energy transfer amount to the wall surface by the above-mentioned engine state estimation unit 32 will be described.

[0087] Figure 4 : is a flowchart showing an operation example of the engine state estimation unit 32 .

[0088] First, if Figure 4As shown, the engine state estimation unit 32 calculates the input energy Efuel input per cylinder in one combustion stroke based on the input operating conditions and chemical conditions (step S11). In the process of step S11, the engine state estimation unit 32 calculates based on the air flow rate Mair (kg / s) according to the following mathematical formula 1. The air flow rate Mair is calculated based on the intake air flow rate and the EGR rate. In addition, the EGR rate Yegr is calculated according to the mathematical formula 2 described later.

[0089]

Mathematical formula 1

[0090] Efuel=Mair / (1+AFR) / (1-Yegr))×(120÷Ne)×Hfuel÷Ncyl

[0091] Here, AFR is an air-fuel ratio, and a target air-fuel ratio or an exhaust air-fuel ratio calculated based on an air-fuel ratio sensor 9 or an O2 sensor provided in the exhaust pipe 15 can be used. Ne is an engine speed (rpm), and is calculated based on the detection value of the crank angle sensor 19. Hfuel is a low calorific value of fuel (J / kg), which is a predetermined value. As a low calorific value (Hfuel), a value of about 44.9×106J / kg is used, for example. In addition, Ncyl is the number of cylinders.

[0092] Next, the engine state estimation unit 32 calculates the combustion period in the cylinder 14 in one combustion stroke based on the chemical conditions and the operating conditions (step S12). When calculating the combustion period, for example, the dilution degree can be selected as the chemical condition, the ignition timing can be selected as the operating condition, and the combustion period can be calculated using a map.

[0093] For example, under lean combustion conditions, the air-fuel ratio (AFR) can be used as the dilution degree. In addition, when the exhaust gas is recirculated using an EGR pipe, the EGR rate can be used for calculation. The EGR rate Yegr is calculated, for example, according to the following mathematical formula 2.

[0094]

Mathematical formula 2

[0095] EGR rate = EGR gas flow rate / (EGR gas flow rate + air flow rate)

[0096] Here, the EGR gas flow rate is estimated based on the opening degree of an EGR valve provided in the EGR pipe that controls the EGR gas flow rate, or is calculated through detection by an EGR gas sensor provided in the EGR pipe.

[0097] FIG. 5A to FIG. 5C A map of the combustion period with dilution and ignition timing as axes is shown. Figure 5A is a map showing the relationship between dilution and ignition timing, Figure 5Ais a map showing the relationship between dilution and ignition timing, Figure 5B is a map showing the relationship between the combustion period and the ignition timing, Figure 5C is a map showing the relationship between combustion period and dilution. FIG. 5A to FIG. 5C The shown map is stored in the engine state estimating unit 32 .

[0098] like Figure 5B As shown in FIG. 1 , if the ignition timing is retarded, the combustion period tends to increase. This is because if the ignition timing is delayed, the flame propagation intensifies during the expansion stroke, and the time required for the flame to expand to the entire engine increases. In addition, Figure 5C As shown in FIG. 1 , if the dilution increases, the combustion speed decreases, so there is a tendency for the combustion period to increase. FIG. 5A to FIG. 5C The engine state estimation unit 32 calculates the combustion period based on the map shown.

[0099] In this example, an example of calculating the combustion period using a map is described, but the present invention is not limited thereto. For example, the combustion period calculated based on the output of the crank angle sensor 19 may be used instead of a value preset for the combustion period representing an example of the combustion state.

[0100] Thus, by using the combustion period calculated based on the detection value, the actual operating conditions can be reflected in the combustion period. As a result, the fuel period can be set in consideration of the deviation of each engine, the change over time, and the deviation of each cylinder. In addition, by setting the combustion period using the detection value, the value of the combustion period that affects the amount of heat transfer to the wall surface can be made close to the actual state, thereby improving the estimation accuracy of the wall surface temperature.

[0101] Next, the engine state estimation unit 32 calculates the amount of energy transferred from the cylinder gas to the wall surface based on the input energy calculated in step S11, the combustion period calculated in step S12, the chemical conditions, the operating conditions, the operating conditions, and the wall surface temperature (estimated value) (step S13). The wall surface temperature (estimated value) is the wall surface temperature calculated by the wall surface temperature estimation unit 34 in the previous calculation cycle. Thus, the operation of the engine state estimation unit 32 is completed.

[0102] In this example, it is assumed that the wall temperature at multiple locations is predicted and the wall is divided into multiple areas for calculation. Examples of areas to be divided are the head, piston, and bushing. Then, the divided areas are represented as wall elements below, and it is assumed that each cylinder is composed of N wall elements. Below, when describing the N wall elements, each element is assigned an integer from 1 to N (N ≥ 1) for description. In addition, the content applicable to all wall elements is described using i as the subscript.

[0103] In this example, the head, the piston, and the bushing are assumed as the wall surface elements, but each component may be divided into a plurality of regions and each of the divided portions may be used as a wall surface element.

[0104] In step S13, the energy transfer amount Qcl_i(j) of the wall surface element i (i=1 to N) is calculated according to the following mathematical formula 3, for example.

[0105]

Mathematical formula 3

[0106] Qcl_i=Efuel×ηwall×Ne÷120×Δt×A_i÷Aall

[0107] Here, i is a subscript (an integer from 1 to N (N ≥ 1)), Qcl_i is the energy transfer to wall element i (j / s), ηwall is the energy transfer ratio to the wall, Δt is the calculation period (s), and A_i is the surface area of ​​wall element i (m 2 ), Aall is the total surface area of ​​the engine (m 2 ). In addition, the total surface area Aall is the sum of the surface areas A_i of the wall element i from i=1 to N.

[0108] The energy transfer ratio ηwall to the wall surface changes according to the wall surface temperature, the combustion period, and the ignition timing. FIG. 6A to FIG. 6C It is a map that represents the ratio of energy transferred to the wall. Fig. 6A is a map showing the relationship between the combustion period and ignition timing and the wall temperature. Figure 6B is a map showing the relationship between the ignition timing and the energy transfer ratio to the wall. Figure 6C It is a map showing the relationship between the combustion period and the energy transfer ratio to the wall surface.

[0109] For example, by using FIG. 6A to FIG. 6C The wall temperature, combustion period, and ignition timing are mapped to calculate the energy transfer ratio μwall to the wall. Figure 6B As shown in Figure 1, the earlier the ignition timing, the higher the energy transfer ratio ηwall to the wall surface. This is because the combustion starts early, the combustion gas is compressed, and the temperature of the combustion gas increases. As a result, the difference between the temperature of the combustion gas and the wall surface temperature increases, and the energy transfer ratio ηwall to the wall surface increases.

[0110] In addition, if Figure 6C As shown in FIG. 1 , the energy transfer ratio ηwall to the wall tends to decrease as the combustion period increases. This is because the increase in the combustion period suppresses the increase in the combustion gas temperature, and the combustion gas temperature and the wall surface temperature become smaller. As a result, the energy transfer ratio ηwall to the wall decreases.

[0111] As described above, in the internal combustion engine control device 20 of this example, when estimating the wall surface temperature, the amount of energy transferred to the wall surface is first calculated by the engine state estimation unit 32. Thus, the amount of energy transferred to the wall surface, which changes according to the parameters related to the operating conditions of the internal combustion engine 100, the parameters related to the chemical conditions of combustion, and the parameters related to the operating conditions of the internal combustion engine 100, can be reflected in the estimation of the wall surface temperature. Thus, since the temporal change of the wall surface temperature can be estimated, the estimation accuracy of the wall surface temperature can be improved in the process in which the wall surface temperature of the internal combustion engine (engine block) 100 changes from a relatively low condition to a relatively high condition.

[0112] 1-5. Operation examples of cooling water energy flow rate estimation unit, wall surface temperature estimation unit, and cooling water temperature estimation unit

[0113] Next, refer to Figure 7 An operation example of the cooling water energy flow rate estimating unit 33 , the wall surface temperature estimating unit 34 , and the cooling water temperature estimating unit 35 described above will be described.

[0114] Figure 7 1 is a flowchart showing an example of the operations of the cooling water energy flow rate estimating unit 33 , the wall surface temperature estimating unit 34 , and the cooling water temperature estimating unit 35 .

[0115] First, if Figure 7 As shown, the cooling water energy flow rate estimation unit 33 calculates the amount of energy transferred to the cooling water based on the cooling water flow rate, the current cooling water temperature, and the wall surface temperature (step S21). The current cooling water temperature is the cooling water temperature (estimated value) calculated by the cooling water temperature estimation unit 35 in the previous calculation cycle. And the wall surface temperature is the wall surface temperature (estimated value) calculated by the wall surface temperature estimation unit 34 in the previous calculation cycle.

[0116] The amount of energy transferred to the cooling water, Qwtc (J), is calculated according to the following mathematical formula 4.

[0117]

Mathematical formula 4

[0118] Qwtc=∑Qwtc_i(i=1~N)

[0119] Here, Qwtc_i is the amount of energy transferred from the wall surface portion of the prediction target to the cooling water. The amount of energy transferred from the wall surface portion of the prediction target to the cooling water Qwtc_i(J) is calculated according to the following mathematical formula 5.

[0120]

Mathematical formula 5

[0121] Qwtc=∑Qwtc_i(i=1~N)

[0122] Awtc_i in equation 5 is the contact area between wall element i and cooling water (m 2), hwtc is the heat transfer rate between cooling water and wall (W / m 2 / K), Tcb is the estimated value of the cooling water temperature in the cylinder (K), Tw_i is the wall temperature of the prediction object (K). And Δt is the calculation period (s). In addition, the estimated value Tcb of the cooling water temperature in the cylinder is the current cooling water temperature.

[0123] Here, the setting of the calculation cycle Δt can be appropriately set according to the operation cycle of the actuator to be operated. For example, in the case where the ignition period and the injection period are changed in each cycle, and the state of the wall temperature is to be reflected for the change, the calculation cycle Δt is set to a time equivalent to one combustion cycle. In addition, in the case of implementing a change in the operation amount corresponding to a specific operation cycle, the calculation cycle Δt is set to the cycle of the operation. For example, in the case where the cycle of the operation is 10Hz, the calculation cycle Δt is set to 0.1 seconds. In this way, by appropriately setting the calculation cycle Δt, it can be executed under an appropriate calculation load according to the phenomenon of the control object and the operation amount.

[0124] In addition, the heat transfer coefficient hwtc between the cooling water and the wall depends on parameters related to the speed of the cooling water flow (e.g., flow rate and Reynolds number) and parameters related to the thermal conductivity of the cooling water temperature (e.g., temperature and Prandtl number). Therefore, the heat transfer coefficient hwtc between the cooling water and the wall can be calculated by the following mathematical formula 6.

[0125]

Mathematical formula 6

[0126] hwtc=Chwtc×F(Tc)×G(Mc_i)

[0127] Chwtc in Mathematical Formula 6 is a model constant, F(Tc) is a function that increases monotonically with respect to the cooling water temperature in the cylinder, and G(Mc_i) is a function that increases monotonically with respect to the cooling water flow rate (kg / s) in the cylinder. In addition, the function F(Tc) is calculated according to the following Mathematical Formula 7, and the function G(Mc_i) is calculated according to the following Mathematical Formula 8. In addition, Af and Bf in Mathematical Formula 7 are model constants, which are identified through experiments and simulations. In addition, Mathematical Formulas 7 and 8 are examples, and they can also be formulated in a form that can express the sensitivity to the cooling water temperature and flow rate.

[0128]

Mathematical formula 7

[0129] F(Tc)=Af×Tc-Bf

[0130]

Mathematical formula 8

[0131] G(Mc_i)=(Mc_i)^1.3

[0132] Next, the wall surface temperature estimation unit 34 calculates the wall surface temperature after the temperature change based on the energy transfer amount to the wall surface calculated by the engine state estimation unit 32, the energy transfer amount to the cooling water calculated by the cooling water energy flow rate estimation unit 33 in the process of step S21, and the current wall surface temperature (step S22). The current wall surface temperature is the wall surface temperature (estimated value) calculated by the wall surface temperature estimation unit 34 in the previous calculation cycle.

[0133] The wall surface temperature Tw_i (K) can be calculated, for example, according to the following mathematical formula 9. The wall surface temperature Tw_i (K) is the wall surface temperature of the wall surface element i.

[0134]

Mathematical formula 9

[0135] Tw_i(n+1)=Tw_i(n)+(Qcl_i-Qwtc_i) / Mw_i / Cwall

[0136] In Mathematical formula 9, Mw_i is the wall mass (kg) of the wall element, i is a subscript and is an integer from 1 to N, Cwall is the specific heat of the wall (J / kg / K), and n represents the current time, and n+1 represents the time after the cycle is calculated from the current time.

[0137] If the wall temperature is calculated, the cooling water temperature estimation unit 35 estimates the cooling water temperature in the cylinder (step S23). That is, the cooling water temperature estimation unit 35 calculates the cooling water temperature after the temperature change based on the inflow cooling water temperature, the cooling water flow rate, the amount of energy transferred to the cooling water, and the current cooling water temperature. The current cooling water temperature is the cooling water temperature (estimated value) calculated by the cooling water temperature estimation unit 35 in the previous calculation cycle.

[0138] The cooling water temperature Tc(n+1)(K) in the cylinder after the temperature change can be calculated from the following mathematical formula (10), for example.

[0139]

Mathematical formula 10

[0140] Tc(n+1)=Tc(n)+(Qwtc×Ncyl+Mc_in×Cc×(Tc_in-Tc(n))×Δt)÷(Mc×Cc)

[0141] In Mathematical formula 10, Cc is the specific heat of cooling water (J / kg / K), and Mc is the mass of cooling water (kg).

[0142] Thus, the operations of the cooling water energy flow rate estimating unit 33, the wall temperature estimating unit 34, and the cooling water temperature estimating unit 35 are completed. In addition, the wall temperature calculation process in step S22 and the cooling water temperature calculation process in step S23 may be performed simultaneously, or the cooling water temperature calculation process in step S23 may be performed first.

[0143] Thus, according to the internal combustion engine control device 20 of this example, when estimating the wall surface temperature, the amount of energy transferred between the engine block and the cooling water is calculated based on the wall surface temperature, the cooling water flow rate, and the cooling water temperature estimated last time by the cooling water energy flow rate estimation unit 33. Thus, the time change of the wall surface temperature can be estimated while taking into account the wall surface transfer efficiency caused by the wall surface temperature, the cooling water flow rate, and the cooling water temperature, and the time change of the cooling water temperature. As a result, the estimation accuracy of the wall surface temperature can be improved under the condition that the wall surface temperature of the internal combustion engine (engine block) 100 is low.

[0144] 1-6. Modification of the Operation Example of the Engine State Estimation Unit 32

[0145] Next, refer to Figure 8 A modification of the operation of calculating the amount of energy transferred to the wall surface by the engine state estimating unit 32 described above will be described.

[0146] Figure 8 : is a flowchart showing a modified example of the operation of the engine state estimating unit 32 .

[0147] In the above Figure 4 In the process of step S13 in FIG. 6A to FIG. 6C The amount of energy transferred to the wall is calculated by using the mapping shown in FIG. However, if the number of various actuators that affect the wall temperature increases, the amount of operation will also increase. As a result, the number of mappings increases in accordance with the increase in actuators, and the effort to create the mapping increases. However, the amount of energy transferred to the wall can be calculated by a mathematical model that represents the combustion in the internal combustion engine 100. Thus, the increase in the number of mappings can be suppressed.

[0148] First, an example of a model formula used as a mathematical model of the internal combustion engine 100 is shown in Mathematical Formula 11, Mathematical Formula 12, and Mathematical Formula 13. Mathematical Formula 11, Mathematical Formula 12, and Mathematical Formula 13 shown below are formulas derived from the energy conservation formula of the combustion gas in the cylinder 14 and the state equation of the ideal gas. In addition, mathematical formulas different from Mathematical Formula 11, Mathematical Formula 12, and Mathematical Formula 13 shown below may also be used.

[0149] If the mathematical model of the internal combustion engine 100 derived from the energy conservation formula and the ideal gas state equation is expressed in a discretized state, there are the following equations 11, 12, and 13.

[0150]

Mathematical formula 11

[0151] E(θ+Δθ)=E(θ)-(γ-1)×E(θ)×In{V(θ+Δθ) / V(θ)}-dQcl(θ)+dQHR(θ)

[0152]

Mathematical formula 12

[0153] T(θ+Δθ)=(γ-1)×E(θ+Δθ) / (M×R)-

[0154]

Mathematical formula 13

[0155] p(θ+Δθ)=(γ-1)×E(θ+Δθ) / V(θ+Δθ)

[0156] Here, θ is the crank angle (radians), Δθ is the time span (time step) from the current moment (radians), E(θ) is the internal energy of the gas in the cylinder 14 (in the cylinder) (J), γ is the specific heat ratio, V(θ) is the volume in the cylinder (m 3 ), dQcl(θ) is the amount of energy transferred to the wall between Δθ (J). In addition, dQHR(θ) is the amount of heat generated by combustion between Δθ (J), T(θ) is the gas temperature (K), p(θ) is the cylinder pressure (Pa), M is the amount of gas in the cylinder (kg), and R is the gas constant (J / kg / K).

[0157] The engine state estimation unit 32 calculates the internal energy E, temperature T, and pressure p at the crank angle θ+Δθ using the above-mentioned equations 11, 12, and 13. The engine state estimation unit 32 calculates the change from the intake valve closing timing to the exhaust valve opening timing by repeating the calculation.

[0158] Here, if the moment of crank angle θ is assumed, various values ​​at crank angle θ are known, while various values ​​at crank angle θ+Δθ are unknown. However, the cylinder volume V can be expressed as a function of crank angle θ by a formula or a mapping. Therefore, the values ​​of the cylinder volume V at crank angle θ and crank angle θ+Δθ are known. The cylinder volume V can be calculated, for example, from the following mathematical formula 14.

[0159]

Mathematical formula 14

[0160] V(θ)=V0+0.25×π×D^2×Rc×{1-cos(θ)+[λ(1-(1-(sin(θ) / λ)^2)^0.5)}

[0161] V0 in equation 14 is the cylinder volume when the piston is at the top dead center (m 3 ), π is the circumference of a circle, D is the bore diameter of the piston (m), and Rc is the crank radius (half the stroke of the piston) (m). In addition, λ is the ratio of the connecting rod length to the crank radius (connecting rod length ÷ crank radius), and is a value determined by the mechanism of the internal combustion engine 100.

[0162] Thus, the engine state estimation unit 32 can obtain the internal energy E at the crank angle θ+Δθ by using the above-mentioned equations 11 to 14, and then obtain the temperature T and pressure p at the crank angle θ+Δθ. In addition, the energy transfer amount dQcl to the wall surface can be calculated by the following equations 15 and 16.

[0163]

Mathematical formula 15

[0164] dQcl(θ)=dQcl_1(θ)+…+dQcl_N(θ)

[0165]

Mathematical formula 16

[0166] dQcl_i(θ)=αA_i×(T-Tw_i)×Δθ×60÷Ne

[0167] Qcl_i shown in Math. 16 can be calculated by adding dQcl_i to one combustion cycle. Specifically, it is calculated from Math. 17.

[0168]

Mathematical formula 17

[0169] Qcl_i=Qci_i+dQcl_i(θ)

[0170] Here, dQcl_i is the heat transfer amount (W) of the wall element i between Δθ, and α is the wall heat transfer coefficient (W / K / m 3 ). The wall heat transfer coefficient α can be calculated by, for example, the Eichelberg equation shown in the following mathematical formula 18.

[0171]

Mathematical formula 18

[0172] α=CEi×(Ne×Rc÷30)^(1 / 3)×p(θ)^0.3×T(θ)^0.3

[0173] Here, CEi is a model constant, and is adjusted so that the experimental result and the calculation result are consistent. CEi is adjusted to a value of about 0.5, for example.

[0174] Thus, when calculating the energy transfer amount to each wall element, the changes in temperature and pressure relative to the crank angle are reflected. Therefore, when the operating conditions, chemical conditions, action conditions, and operating conditions for various actuators change, the changes can be reflected in the energy transfer amount according to these changes.

[0175] The calorific value dQHR generated by combustion can be obtained by using the Wiebe function shown in the following Math. 19, Math. 20, and Math. 21, for example.

[0176]

Mathematical formula 19

[0177] dQHR(θ)=Efuel×(fw(θ+Δθ)--fw(θ))

[0178]

Mathematical formula 20

[0179] fw(θ)=1-exp(-x(θ))

[0180]

Mathematical formula 21

[0181] x(θ)=a{(θ-θADV) / δθcomb]^(b+1)

[0182] Here, Efuel is the input energy obtained by equation 1, 6θcomb is the combustion period (radian), θADV is the ignition timing (radian), and a and b are model constants.

[0183] In addition, the work Weng of the internal combustion engine 100 can be calculated according to the following mathematical formulas 22 and 23.

[0184]

Mathematical formula 22

[0185] dWeng(θ)=-p×{V(θ+Δθ)-V(θ)}

[0186]

Mathematical formula 23

[0187] Weng=Weng+dWeng(θ)

[0188] Next, refer to Figure 8 A modified example of the operation of the engine state estimating unit 32 using the above-mentioned mathematical model will be described. Figure 8 : is a flowchart showing a modified example of the operation of the engine state estimating unit 32 .

[0189] like Figure 8 As shown in FIG. 1 , the engine state estimation unit 32 calculates the input energy (step S31). The processing of step S31 is the same as Figure 4 The processing of step S11 in is the same, so its description is omitted.

[0190] Next, the engine state estimation unit 32 sets the crank angle θ as the closing period of the intake valve and initializes various parameters (step S32). That is, in the process of step S32, the engine state estimation unit 32 sets the values ​​of the internal energy E, temperature T, and pressure p to the values ​​of the closing period of the intake valve. For example, the temperature T is set to the same temperature as the temperature of the intake pipe 6, and the pressure p is set to the same pressure as the pressure of the intake pipe 6. Then, the internal energy E can be calculated by the following mathematical formula 24 obtained by transforming the above mathematical formula 12.

[0191]

Mathematical formula 24

[0192] E(θ)=M×R×T(θ) / (γ-1)

[0193] In addition, in the process of step S32 , the engine state estimation unit 32 sets the energy transmission amount Qcl_i to each wall surface element to zero.

[0194] Next, the engine state estimation unit 32 sets Δθ for calculating the amount of energy transferred to the wall surface element in the compression stroke (step S33). Δθ can be obtained according to the following mathematical formula 25, for example.

[0195]

Mathematical formula 25

[0196] Δθ=(ignition timing - intake valve closing timing) / Ncomp

[0197] Ncomp is a parameter for adjusting how many times the calculation from the intake valve closing period to the ignition period is divided.

[0198] When Δθ in the compression stroke is set, the engine state estimation unit 32 calculates the change in gas in the compression stroke and the amount of energy transferred to the wall surface (step S34). In the process of step S34, the engine state estimation unit 32 uses the above-mentioned mathematical formulas 11 to 18, 22, and 23 for calculation. In addition, in mathematical formula 11, the heat value dQHR generated by combustion is set to 0 for calculation.

[0199] Next, the engine state estimation unit 32 determines whether the crank angle θ is smaller than the ignition timing, that is, whether the crank angle θ is located on the advance angle side of the ignition timing (step S35). In the process of step S35, if it is determined that the crank angle θ is smaller than the ignition timing (the determination in step S35 is "yes"), the engine state estimation unit 32 adds Δθ to the crank angle θ (step S36), and returns to the process of step S34. Here, the added Δθ is the Δθ calculated in step S33.

[0200] On the other hand, when it is determined in the process of step S35 that the crank angle θ is greater than the ignition timing (the determination of step S35 is "No"), the engine state estimation unit 32 sets Δθ for calculating the energy transfer amount to the wall element in the combustion stroke (step S37). Δθ can be obtained, for example, according to the following mathematical formula 26.

[0201]

Mathematical formula 26

[0202] Δθ=Δθcomb / Ncomb

[0203] Ncomb is a parameter for adjusting how many times the combustion period is divided into calculations.

[0204] When Δθ in the combustion stroke is set, the engine state estimation unit 32 calculates the change in the combustion gas in the combustion stroke and the amount of energy transferred to the wall surface (step S38). In the process of step S38, the engine state estimation unit 32 uses the above-mentioned equations 11 to 23 for calculation.

[0205] Next, the engine state estimation unit 32 determines whether the crank angle θ is smaller than the sum of the ignition timing and the combustion period, that is, whether the crank angle θ is located on the advance angle side of the combustion end timing (step S39). In the process of step S39, if it is determined that the crank angle θ is smaller than the sum of the ignition timing and the combustion period (the determination in step S39 is "yes"), the engine state estimation unit 32 adds Δθ to the crank angle θ (step S40), and returns to the process of step S38. Here, the added Δθ is the Δθ calculated in step S37.

[0206] On the other hand, when it is determined in the process of step S39 that the crank angle θ is greater than the sum of the ignition timing and the combustion period (the determination of step S39 is "No"), the engine state estimation unit 32 sets Δθ for calculating the energy transfer amount to the wall element in the expansion stroke (step S41). Δθ can be obtained, for example, according to the following mathematical formula 27.

[0207]

Mathematical formula 27

[0208] Δθ = {exhaust valve opening time - (ignition time + combustion period)} / Nexpa

[0209] Nexpa is a parameter for adjusting how many times the calculation is divided from the end of combustion to the valve opening period.

[0210] If Δθ in the expansion stroke is set, the engine state estimation unit 32 calculates the change in gas in the expansion stroke and the amount of energy transferred to the wall surface (step S42). In the process of step S42, the engine state estimation unit 32 uses the above-mentioned mathematical formulas 11 to 18, 22, and 23 for calculation. In addition, in mathematical formula 11, the heat value dQHR generated by combustion is set to 0 for calculation.

[0211] Next, the engine state estimation unit 32 determines whether the crank angle θ is smaller than the opening timing of the exhaust valve, that is, whether the crank angle θ is on the advanced angle side of the opening timing of the exhaust valve (step S43). In the process of step S43, if it is determined that the crank angle θ is smaller than the opening timing of the exhaust valve (the determination in step S43 is "yes"), the engine state estimation unit 32 adds Δθ to the crank angle θ (step S44), and returns to the process of step S42. Here, the added Δθ is the Δθ calculated in step S41.

[0212] On the other hand, when it is determined in the process of step S43 that the crank angle θ is greater than the opening timing of the exhaust valve (the determination in step S43 is NO), the engine state estimation unit 32 ends the operation.

[0213] Therefore, in Figure 8 In the operation example shown, the combustion state in the cylinder 14 is predicted using the mathematical model of the internal combustion engine 100, and the amount of energy transferred to the wall surface is calculated. As a result, the amount of energy transferred to the wall surface can be calculated in consideration of the combustion state that changes according to various parameters. As a result, the amount of energy transferred to the wall surface can be calculated without having to prepare a map for calculating the amount of energy transferred to the wall surface in advance. In addition, even if the operating conditions or operating conditions of the internal combustion engine 100 deviate from the operating conditions or operating conditions assumed in the map, the estimation accuracy of the wall surface temperature can be improved, and the model fitting time can be shortened.

[0214] In addition, it can be calculated Figure 8 The energy transfer amount Qcl calculated in the illustrated operation example, the work Weng of the internal combustion engine 100, and the energy (exhaust energy) Qex flowing from the input energy Efuel to the exhaust gas. For example, the exhaust energy Qex is calculated according to the following mathematical formula 28.

[0215]

Mathematical formula 28

[0216] Qex=Efuel-Qcl-Weng

[0217] Therefore, the exhaust energy Qex can be calculated in addition to predicting the combustion state in the internal combustion engine 100. As a result, a sensor for detecting the exhaust energy Qex is unnecessary, and the number of parts can be reduced.

[0218] In addition, the temperature of the cooling water has a distribution of the inlet temperature flowing into the engine block and the outlet temperature discharged from the engine block. If the wall temperature of the cylinder 14 serving as a reference among the plurality of cylinders 14 is estimated by the above structure, the calculation load increases in order to estimate the wall temperatures of the plurality of cylinders 14 individually.

[0219] In order to reduce the calculation load, for example, the inlet temperature and outlet temperature of the cooling water may be detected, and the estimated value may be corrected based on such information. For example, it is assumed that the cooling water flows from the first cylinder 14 closest to the cooling water inlet to the fourth cylinder 14 closest to the cooling water outlet among the plurality of cylinders 14. When estimating the water temperature of the third cylinder 14, the wall temperature of each cylinder 14 may be estimated using the following mathematical formula 29.

[0220]

Mathematical formula 29

[0221] Tw_i_j=Tw_j×{1+C×(Tc_out-Tc_in) / 4×(j-3)}

[0222] In the mathematical formula 29, j is the number of the cylinder 14, and in the case of a four-cylinder engine, it is set to, for example, 1, 2, 3, and 4. C is a constant for matching the estimated value of the wall surface temperature of each cylinder 14, and is set to, for example, a value less than 1. Thus, the wall surface temperature of each cylinder 14 can be estimated by estimating the wall surface temperature of one cylinder 14 among the plurality of cylinders 14 without estimating the wall surface temperature of the internal combustion engine 100 of the plurality of cylinders. As a result, the load for calculating the wall surface temperature of the plurality of cylinders 14 can be reduced.

[0223] 1-7. Operation example of the operation amount calculation unit

[0224] Next, an operation example of the operation amount calculation unit 36 ​​will be described.

[0225] The operation amount calculation unit 36 ​​calculates and outputs the operation amounts of various actuators that control the distribution of combustion energy based on the wall surface temperature calculated by the wall surface temperature estimation unit 34 and the cylinder cooling water temperature calculated by the cooling water temperature estimation unit 35 .

[0226] Here, operating the distribution of combustion energy refers to operating the output of the input energy distribution, the amount of heat transfer to the wall, the distribution rate of the amount discharged as exhaust gas, etc. For example, in the case of a gasoline engine, the piston cooling amount is operated by the ignition timing, the fuel injection timing, and the injection, and the distribution rate is operated by the flow rate and temperature of the cooling water. As various actuators for which the operation amount is calculated and output by the operation amount calculation unit 36 ​​in this example, for example, the spark plug 17 and the ignition coil 16 as the ignition device, the fuel injection device 13, the lubricating oil device such as the injection system 110, and the cooling water device such as the water pump can be cited.

[0227] The operation amount of the ignition device is the energization period and energization time of the ignition coil 16. The operation amount of the fuel injection device 13 is the valve opening period and valve closing period of the fuel injection device 13, or the opening and closing operation of the valve for adjusting the pressure provided in the high-pressure fuel pump. In addition, the operation amount of the fuel injection system 110 is the output of the oil pump, and the operation amount of the cooling device is the flow rate of the cooling water and the temperature of the cooling water entering the engine cylinder.

[0228] Furthermore, as described above, the wall surface temperature estimation module 31 estimates the time variation of the wall surface temperature in consideration of the operating conditions, the chemical conditions of combustion, and the operating conditions of the internal combustion engine 100. Thus, the operation amount calculation unit 36 ​​can effectively set the distribution amount of energy input for combustion according to the estimated wall surface temperature.

[0229] Next, refer to Fig. 9 An example of calculation and output operation of the operation amount of various actuators in the operation amount calculation unit 36 ​​will be described.

[0230] Fig. 9 : is a flowchart showing an example of operation of the operation amount calculation unit 36. In the example shown below, as described above, an example of dividing the wall element into a piston, a head, and a bushing is described. In addition, the wall temperature is estimated by the above-mentioned wall temperature estimation module 31, and it can be an average temperature of each element, or a specific location of each element can be assumed. In addition, the wall element is not limited to the piston, the head, and the bushing, and can also include wall elements of various other locations such as valves.

[0231] like Fig. 9 As shown, first, the operation amount calculation unit 36 ​​determines whether the piston temperature is greater than a preset cooling determination reference value (step S51). The cooling determination reference value is a reference value for determining whether the piston is cooled in the injection system 110, and is set in advance through experiments or the like. As the cooling determination reference value, for example, the piston temperature when the internal combustion engine 100 is operated under a specific operating condition and reaches a stable state when the internal combustion engine 100 reaches a warm-up condition is used.

[0232] When it is determined in the process of step S51 that the piston temperature is greater than the cooling determination value (the determination in step S51 is "yes"), the operation amount calculation unit 36 ​​performs oil injection through the oil injection system 110 (step S52). In the process of step S52, the operation amount calculation unit 36 ​​sets not only the operation amount of the oil injection system 110 but also the operation amount of the fuel injection.

[0233] In addition, in the process of step S52, the operation amount calculation unit 36 ​​determines that the piston is in the same state as the warm-up state. Therefore, the operation amount calculation unit 36 ​​uses the setting values ​​of the injection period and the fuel pressure that are suitable as the operation amount of the injection system 110 and the operation amount of the fuel injection in the warm-up condition map. Specifically, in the case where there is a valve for controlling whether or not to inject oil toward the piston, the injection system 110 is operated so that the valve is opened and oil is injected toward the piston. Alternatively, the oil pressure is increased to a specified value, and the amount of oil injected toward the piston reaches a suitable value.

[0234] When the process of step S52 is completed, the operation amount calculation unit 36 ​​proceeds to the process of step S54 to be described later.

[0235] On the other hand, when it is determined in the process of step S51 that the piston temperature is less than the cooling determination reference value (the determination of step S51 is "No"), the operation amount calculation unit 36 ​​determines that the piston is in a cold engine condition and transfers to the process of step S53. In the process of step S53, the operation amount calculation unit 36 ​​stops the injection of fuel through the injection system 110, and changes the injection amount and injection period as the operation amount of fuel injection to the set value of the low wall temperature setting. The set value of the low wall temperature setting is a value different from the value suitable under the warm engine condition.

[0236] Specifically, when there is a valve for controlling whether or not to spray oil toward the piston, the valve is closed to stop spraying oil toward the piston. Alternatively, the oil pressure is set to a pressure lower than the appropriate value for warm-up conditions, thereby reducing the amount of oil sprayed toward the piston. This can reduce the energy flowing from the piston to the oil, thereby suppressing the decrease in piston temperature.

[0237] In addition, the injection period as the operation amount of fuel injection is set to be earlier than the value set in the warm-up condition map. In addition, the injection pressure as the operation amount of fuel injection is set to be larger than the value set in the warm-up condition map. In this way, the fuel adhering to the piston can be suppressed, and the energy flowing from the piston to the fuel can be reduced, thereby suppressing the decrease in the piston temperature.

[0238] When the process of step S53 is completed, the operation amount calculation unit 36 ​​proceeds to the process of step S56 described later.

[0239] In the process of step S54, the operation amount calculation unit 36 ​​determines whether the piston temperature is less than the high temperature judgment reference value 1. The high temperature judgment reference value 1 is a reference value for judging whether the piston temperature is high and whether it has reached a temperature that causes abnormalities of the internal combustion engine 100 such as abnormal combustion. The high temperature judgment reference value 1 is set to a value greater than the cooling judgment reference value. The high temperature judgment reference value 1 is the same as the cooling judgment reference value and is set in advance through experiments or the like. The high temperature judgment reference value 1 is particularly preferably set under the condition that the output of the internal combustion engine 100 is large, such as when abnormal combustion occurs.

[0240] When it is determined in the process of step S54 that the piston temperature is lower than the high temperature determination reference value 1 (“YES” in step S54 ), the operation amount calculation unit 36 ​​proceeds to the process of step S56 described later.

[0241] On the other hand, when it is determined in the process of step S54 that the piston temperature is greater than the high temperature determination reference value 1 (the determination in step S54 is "No"), the operation amount calculation unit 36 ​​determines that the piston temperature is high and abnormal combustion may occur. Then, the operation amount calculation unit 36 ​​performs an operation to increase the amount of injection oil in order to increase the amount of energy transferred from the piston to the oil (step S55).

[0242] Specifically, the oil pressure is set to a value greater than the set value set in the process of step S52 and in accordance with the set value of the warm-up condition map, and the amount of oil injected toward the piston is set to increase. In this way, the energy transfer amount from the piston to the oil can be increased, and the piston temperature can be reduced. When the process of step S55 is completed, the operation amount calculation unit 36 ​​transfers to the process of step S56.

[0243] In the process of step S56, the operation amount calculation unit 36 ​​determines whether the head temperature is less than the high temperature judgment reference value 2. The high temperature judgment reference value 2 is a reference value for judging whether the head temperature is high and whether it has reached a temperature that causes abnormality of the internal combustion engine 100 such as abnormal combustion. The high temperature judgment reference value 2 is set in advance through experiments, etc., similar to the cooling judgment reference value and the high temperature judgment reference value 1. In addition, the high temperature judgment reference value 2 is preferably set under the condition that the output of the internal combustion engine 100 is large, such as when abnormal combustion occurs.

[0244] In the process of step S56, when it is determined that the head temperature is less than the high temperature determination reference value 2 (the determination in step S56 is "Yes"), the operation amount calculation unit 36 ​​transfers to the process of step S58 described later. On the other hand, in the process of step S56, when it is determined that the head temperature is greater than the high temperature determination reference value 2 (the determination in step S56 is "No"), the operation amount calculation unit 36 ​​determines that the head temperature is high and abnormal combustion may occur.

[0245] Then, in order to increase the amount of energy transferred from the head to the cooling water, the operation amount calculation unit 36 ​​increases the cooling water flow rate and decreases the cooling water temperature (step S57). Specifically, the rotation speed of the pump provided for circulating the cooling water is increased, or the cooling water flow rate to the radiator for performing energy exchange between the external air and the cooling water is increased, thereby reducing the cooling water amount at the outlet of the radiator.

[0246] This can increase the amount of energy transferred from the wall surface to the cooling water, and can reduce the temperature of the head.

[0247] When the process of step S57 is completed, the operation of the operation amount calculation unit 36 ​​in one cycle is completed.

[0248] In addition, in the processing of step S58, the operation amount calculation unit 36 ​​determines whether the bushing temperature is less than the warm-up judgment reference value. The warm-up judgment reference value is a reference value for judging whether the bushing temperature has reached the warm-up state. The warm-up judgment reference value is also set in advance through experiments, etc., similar to the cooling judgment reference value, the high temperature judgment reference value 1, and the high temperature judgment reference value 2. The warm-up judgment reference value uses, for example, the bushing temperature when the internal combustion engine 100 is operated under specific operating conditions under the condition that the internal combustion engine 100 reaches the warm-up condition and reaches a stable state.

[0249] When it is determined in the process of step S58 that the bushing temperature is less than the warm-up determination reference value (the determination in step S58 is "yes"), the operation amount calculation unit 36 ​​determines that the bushing temperature is in a cold state. Then, in order to reduce the amount of energy transferred from the engine block to the cooling water, the operation amount calculation unit 36 ​​performs an operation to reduce the flow rate of cooling water flowing to the engine block (step S59). For example, the rotation speed of the pump used to circulate the cooling water is reduced, or the valve used to adjust the cooling water flowing to the engine block is closed. In this way, the flow rate of cooling water flowing to the engine block can be reduced.

[0250] On the other hand, when it is determined in the process of step S58 that the bushing temperature is greater than the warm-up determination reference value (the determination in step S58 is "No"), the operation amount calculation unit 36 ​​determines that the internal combustion engine 100 is warmed up and reaches an appropriate temperature. Therefore, the operation amount calculation unit 36 ​​sets the cooling water flow rate so as to achieve the cooling water flow rate and temperature setting suitable under the warm-up condition (step S60). For example, the cooling water flow rate flowing to the pump or radiator for adjusting the cooling water flow rate is adjusted.

[0251] Thereby, the operation of the operation amount calculation unit 36 ​​in one cycle is completed.

[0252] Fig.10 It is shown that based on the above Fig. 9 The operation example of the operation amount calculation unit 36 ​​shown is a timing chart of an operation example of various actuators.

[0253] Fig.10 In the figure, time t1 indicates the time when the piston temperature reaches the cooling judgment reference value, time t2 indicates the time when the bushing temperature reaches the warming judgment reference value. In addition, time t3 indicates the time when the piston temperature reaches the high temperature judgment reference value 1, and time t4 indicates the time when the head temperature reaches the high temperature judgment reference value 2.

[0254] like Fig.10 As shown, if the piston temperature reaches the cooling determination reference value at time t1, the amount of injection oil becomes a state further reduced than that under the warm-up condition or the amount of injection oil under the warm-up condition. Fig.10 The dotted line in the graph represents the target value, and the solid line represents the actual response. In addition, as the piston temperature rises, the amount of fuel injection increases.

[0255] In addition, the fuel injection timing is changed from the low wall temperature setting to the setting value of the warm-up condition. Under cold conditions, the fuel injection timing may be advanced compared to warm-up conditions from the perspective of ensuring the time for fuel vaporization. This can slowly increase the piston temperature.

[0256] At time t2, when the bushing temperature reaches the warm-up determination reference value, the operation amount calculation unit 36 ​​determines that the bushing temperature has reached a sufficient value. Therefore, the cooling water flow rate increases, and the rise in bushing temperature becomes slow.

[0257] Furthermore, if the piston temperature reaches the high temperature judgment reference value 1 at time t3, the operation amount calculation unit 36 ​​determines that the probability of abnormal combustion is increased. Therefore, in order to reduce the piston temperature, the amount of fuel injection is increased. In addition, in the case where it is effective to absorb heat from the piston by the fuel attached to the piston, the combustion injection period is advanced to increase the amount of fuel attached to the piston. As a result, when the fuel attached to the piston vaporizes, it can take away energy from the piston. As a result, Fig.10 As shown, the piston temperature can be lowered from the high temperature judgment reference value 1.

[0258] Furthermore, at time t4, if the head temperature reaches the high temperature judgment reference value 2, the operation amount calculation unit 36 ​​operates the associated various actuators to increase the cooling water flow rate and reduce the cooling water temperature. With the increase in the cooling water flow rate to the engine block and the decrease in the cooling water temperature, the amount of heat removed from the engine block by the cooling water can be increased. As a result, Fig.10 As shown, the head temperature can be lowered from the high temperature judgment reference value 2.

[0259] Thus, according to the internal combustion engine control device 20 of this example, the wall surface temperature of a plurality of wall surface elements can be estimated in the wall surface temperature estimation module 31, and thus the wall surface temperature of each element in the internal combustion engine 100 can be estimated. Thus, based on the wall surface temperatures of a plurality of wall surface elements, the operation amounts of various actuators can be appropriately calculated and outputted by the operation amount calculation unit 36. As a result, the energy distribution amounts of oil, cooling water, and fuel flowing to the wall surface, the injection system 110 can be operated according to the wall surface temperatures of each wall surface element.

[0260] 2. Implementation Example 2

[0261] Next, refer to Figures 11 to 15 An internal combustion engine control device according to Embodiment 2 will be described.

[0262] Fig.11 This is a control block diagram showing an outline of control executed by the internal combustion engine control device according to the second embodiment.

[0263] like Fig.11 As shown, the internal combustion engine control device of the second embodiment includes a wall temperature estimation module 1001, a knock determination module 1002, and an operation amount calculation unit 1003. Since the wall temperature estimation module 1001 has the same structure as the wall temperature estimation module 31 of the first embodiment, its description is omitted.

[0264] The knock determination module 1002 receives a signal from a knock sensor provided in the internal combustion engine 100. Then, the knock determination module 1002 outputs whether knocking occurs (knock determination result) based on the signal received from the knock sensor. In addition, the knock determination module 1002 outputs the knock determination result to the operation amount calculation unit 1003. The operation amount calculation unit 1003 calculates the operation amounts of various actuators based on the knock determination result input from the knock determination module 1002, the wall temperature input from the wall temperature estimation module 1001, and the cylinder body cooling water temperature.

[0265] Fig.12 This is a flowchart showing an example of the operations of the operation amount calculation unit 1003 and the knock determination module 1002 in the internal combustion engine control device of the second embodiment.

[0266] like Fig.12 As shown, first, operation amount calculation unit 1003 determines whether knocking occurs based on the knock determination result output from knock determination module 1002 (step S71). As a knock determination method, for example, the intensity of the knock sensor signal, the maximum amplitude, etc. are used to determine whether knocking occurs.

[0267] When it is determined in the process of step S71 that knocking does not occur (the determination of step S71 is "No"), the operation amount calculation unit 1003 performs a normal operation (step S73). As the normal operation in step S73, for example, as described above Fig. 9 As shown, the actuator is operated so as to operate the energy transfer amount corresponding to various temperatures.

[0268] If it is determined in the process of step S71 that knocking occurs (the determination in step S71 is "yes"), the operation amount calculation unit 1003 determines the magnitude of the piston temperature and the head temperature (step S72). Specifically, the operation amount calculation unit 1003 compares the piston temperature with the sum of the head temperature and the correction value to determine whether the piston temperature is larger.

[0269] Here, the correction value is a coefficient for correcting the difference in the degree of influence of the piston temperature and the head temperature on abnormal combustion. For example, when the internal combustion engine 100 is in a stable state, the difference between the piston temperature and the head temperature can be used as the correction value.

[0270] When it is determined in the process of step S72 that the piston temperature is greater than the sum of the head temperature and the correction value (the determination in step S72 is "yes"), the operation amount calculation unit 1003 estimates that the piston temperature is a knock factor (step S74). Here, when the piston temperature is a knock factor, it can be considered that the knock occurs because the heat transfer amount from the high-temperature piston to the gas around the piston is large.

[0271] Next, in order to increase the amount of energy transferred from the piston to the oil and the amount of energy transferred from the piston to the fuel, the operation amount calculation unit 1003 performs an operation for increasing the amount of oil injection and an operation for increasing the amount of fuel attached to the piston (step S75). Specifically, in order to increase the amount of oil injection, the output of the oil pump is increased and the oil pressure is increased. In addition, in order to increase the amount of fuel attached, the fuel injection period is advanced and set to the initial value of the intake stroke. As a result, the amount of energy transferred from the piston to the oil and fuel can be increased. As a result, the piston temperature, which is a knock factor, can be reduced, knocking can be suppressed, and the efficiency of the internal combustion engine 100 can be increased.

[0272] When it is determined in the process of step S72 that the piston temperature is less than the sum of the head temperature and the correction value (the determination in step S72 is "No"), the operation amount calculation unit 1003 estimates that the head temperature is a knock factor (step S76). Here, when the piston temperature is a knock factor, it can be considered that the knock occurs because the amount of heat transfer from the high-temperature head to the gas around the head is large.

[0273] Next, in order to increase the amount of energy transferred from the head to the cooling water, the operation amount calculation unit 1003 performs an operation of increasing the cooling water flow rate and further reducing the cooling water temperature (step S77). Specifically, in order to increase the cooling water flow rate, the output of the pump used to circulate the cooling water is increased. In addition, in order to reduce the cooling water temperature, it is set to increase the flow rate of the cooling water flowing through the radiator and increase the amount of energy transferred from the cooling water to the outside air. Therefore, the amount of energy transferred from the head to the cooling water can be increased. As a result, the head temperature, which is a knock factor, can be reduced, knocking can be suppressed, and the efficiency of the internal combustion engine 100 can be increased.

[0274] Fig.13 It is shown that based on the above Fig.12 The operation example of the operation amount calculation unit 1003 shown is a timing chart of an operation example of various actuators.

[0275] Fig.13 The time t1 in represents the time when knocking occurs under the condition that the sum of the head temperature and the correction value is less than the piston temperature, and the time t2 represents the time when knocking occurs under the condition that the sum of the head temperature and the correction value is greater than the piston temperature.

[0276] like Fig.13As shown in FIG. 1 , if knocking is detected at time t1, the operation amount calculation unit 1003 operates the actuator to reduce the piston temperature based on the relationship between the piston temperature and the head temperature. In the second embodiment, in order to increase the cooling amount of the oil on the piston, the amount of oil injection is increased. In addition, in order to increase the amount of energy taken away from the piston by the fuel attached to the piston, the injection period is advanced to increase the amount of fuel attached. By operating these actuators, the piston temperature can be reduced, and the occurrence of knocking caused by the piston temperature can be suppressed.

[0277] If knocking is detected at time t2, the operation amount calculation unit 1003 operates the actuator to reduce the head temperature based on the relationship between the piston temperature and the head temperature. In the second embodiment, an operation is performed to reduce the temperature of the cooling water circulating in the engine. In addition, an operation is performed to increase the flow rate of the cooling water flowing to the engine cylinder. By operating these actuators, the head temperature can be reduced, and the occurrence of knocking caused by the head temperature can be suppressed.

[0278] According to the internal combustion engine control device of this embodiment example 2, the knock factor can be determined based on the result of whether knock occurs and the estimated value of the wall surface temperature of each wall surface element. By operating the injection system 110's oil injection, fuel injection, and cooling water according to the determined knock factor, the occurrence of knock can be suppressed. In addition, by operating the actuator according to the knock factor, the loss caused by the increase in the amount of energy transferred from the gas to the wall surface due to the cooling of the wall surface can be suppressed to a minimum. As a result, the efficiency of the internal combustion engine 100 near the condition where knock occurs can be improved.

[0279] Next, refer to Fig.14 Another example of the operation of the operation amount calculation unit 1003 and the knock determination module 1002 in the internal combustion engine control device according to the second embodiment will be described.

[0280] Fig.14 This is a flowchart showing another example of the operations of the operation amount calculation unit 1003 and the knock determination module 1002 in the internal combustion engine control device of the second embodiment.

[0281] like Fig.14 As shown, first, the operation amount calculation unit 1003 determines whether knocking has occurred based on the knock determination result output from the knock determination module 1002 (step S81). If it is determined that knocking has not occurred in the processing of step S81 (the determination of step S71 is "No"), the operation amount calculation unit 1003 performs a normal operation (step S82). As the normal operation in step S82, for example, as described above Fig. 9 As shown, the actuator is operated so as to operate the energy transfer amount corresponding to various temperatures.

[0282] Furthermore, in the process of step S81, it is determined that knocking has occurred (the determination in step S81 is "yes"), and the operation amount calculation unit 1003 sets the correction amount of the ignition timing according to the wall temperature of each cylinder (cylinder) 14 (step S83). Usually, after knocking occurs, the ignition timing is delayed once compared to when knocking occurs, and then the ignition timing is gradually advanced. Fig.14 In the example shown, the amount of advance of the ignition timing after the occurrence of knocking is set so that the amount of advance of the ignition timing is smaller for the cylinder 14 having a higher wall surface temperature.

[0283] Next, the operation amount calculation unit 1003 determines whether the cylinder (cylinder) 14 in which knocking has occurred is the cylinder (cylinder) with the highest wall surface temperature (step S84). In the process of step S84, if it is determined that the cylinder in which knocking has occurred is not the cylinder with the highest wall surface temperature (the determination in step S84 is "no"), the operation amount calculation unit 1003 ends the process.

[0284] When it is determined in the process of step S84 that the cylinder in which knocking has occurred is the cylinder with the highest wall surface temperature (the determination in step S84 is "yes"), the operation amount calculation unit 1003 determines that the high wall surface temperature is the cause of the knocking. Then, the operation amount calculation unit 1003 determines that it is necessary to cool the wall surface of the cylinder with the highest wall surface temperature, and performs an operation for increasing the flow rate of cooling water flowing through the engine cylinder block and reducing the temperature of the cooling water flowing into the engine cylinder block (step S85). Thus, the process of the operation amount calculation unit 1003 is completed.

[0285] Fig.15 It is shown that based on the above Fig.14 The operation example of the operation amount calculation unit 1003 shown is a timing chart of an operation example of various actuators.

[0286] Fig.15 The time t1 in represents the time when knock is determined to have occurred in the fourth cylinder having the highest wall temperature. If knock is detected in the fourth cylinder at time t1, the operation amount calculation unit 1003 sets the ignition delay angle amount of each cylinder according to the state of the wall temperature of each cylinder. Fig.15 In the example shown, the fourth cylinder is set to have the largest retard amount, and the first and second cylinders are not ignited. Then, the retard amount is set to become smaller in the order of the fourth cylinder and the third cylinder.

[0287] Furthermore, since the wall temperature of the fourth cylinder is the highest and knocking occurs, an operation of lowering the temperature of the cooling water flowing into the engine block and an operation of increasing the flow rate of the cooling water flowing to the engine block are performed. Fig.15The dotted line of the cooling water flow rate and the cooling water temperature in represents the target value, and the solid line represents the actual response. As a result, when the retardation angle of the ignition timing is increased, the wall surface temperature of the fourth cylinder can be reduced.

[0288] Furthermore, by advancing the ignition timing advance angle, the wall temperature of each cylinder can be reduced. Furthermore, when the ignition timing is set to the same setting as when knocking occurs, internal combustion engine 100 can be operated without knocking.

[0289] Thus, based on the estimated values ​​of the wall surface temperature of each cylinder, by manipulating the ignition timing and the cooling water when knock occurs, it is possible to determine that the factor causing knock is the wall surface temperature that differs from cylinder to cylinder, and to perform manipulation. As a result, the loss generated in each cylinder can be reduced, and excessive manipulation of the cooling water temperature and flow rate can be suppressed.

[0290] 3. Implementation Example 3

[0291] Next, refer to Figures 16 to 18 An internal combustion engine control device according to Embodiment 3 will be described.

[0292] Fig.16 This is a control block diagram showing an outline of control executed by the internal combustion engine control device according to the third embodiment.

[0293] like Fig.16 As shown, the internal combustion engine control device of the third embodiment includes a wall temperature estimation module 1201, an energy distribution rate calculation unit 1202, and an operation amount calculation unit 1203. Since the wall temperature estimation module 1201 has the same structure as the wall temperature estimation module 31 of the first embodiment, its description is omitted.

[0294] The energy distribution rate calculation unit 1202 receives the required information of heating energy and the catalyst temperature information from the internal combustion engine 100. Then, the energy distribution rate calculation unit 1202 calculates the distribution rate of energy flowing to the output, cooling water, and exhaust gas based on the received information. In addition, the energy distribution rate calculation unit 1202 calculates the operation amount of various actuators used to achieve the calculated energy distribution rate. Then, the energy distribution rate calculation unit 1202 outputs the calculated operation amount to the operation amount calculation unit 1203, and the operation amount calculation unit 1203 calculates the operation amount of various actuators based on the operation amount output from the energy distribution rate calculation unit, the wall temperature input from the wall temperature estimation module 1001, and the cooling water temperature in the cylinder.

[0295] Fig.17 This is a flowchart showing the operation of the operation amount calculation unit of the internal combustion engine control device according to the third embodiment.

[0296] like Fig.17As shown in FIG. 1 , the operation amount calculation unit 1203 determines whether the ignition timing set by the energy distribution rate calculation unit 1202 is set closer to the advance angle side than the ignition timing suitable for normal heating conditions (step S91). That is, it is determined whether there is a heating energy requirement, and the ignition timing is set to advance the advance angle in order to increase the energy transfer amount flowing to the cooling water.

[0297] In the process of step S91, it is determined that the ignition timing is the same as the ignition timing suitable under the normal warm-up condition, or the ignition timing is set to the retarded angle side (the determination in step S91 is "No"), and the operation amount calculation unit 1203 performs the normal operation (step S100). That is, the operation amount calculation unit 1203 determines that no special energy distribution is required in the energy distribution rate calculation unit 1202. As a normal operation, for example, as described above Fig. 9 As shown, the operation amount calculation unit 1203 operates the actuator so as to operate the energy transfer amount corresponding to each temperature.

[0298] On the other hand, when it is determined in the process of step S91 that the ignition timing is set to the advanced angle side than the ignition timing suitable under the normal warm-up condition (YES in step S91), the operation amount calculation unit 1203 transfers to the process of step S92.

[0299] In the process of step S92, the operation amount calculation unit 1203 determines whether the head temperature is greater than the advance angle permission reference 1. The advance angle permission reference 1 is a reference value for determining whether the ignition can be advanced without causing abnormal combustion (knocking) due to energy transfer from the head to the gas, and is set in advance through experiments, etc. The advance angle permission reference 1 is set to, for example, the head temperature measured under the high output condition of the internal combustion engine 100.

[0300] When it is determined in the process of step S92 that the head temperature is greater than the advance angle permission reference 1 (the determination in step S92 is "yes"), the operation amount calculation unit 1203 determines that the head temperature is high and the energy transfer amount from the head to the gas is large. In addition, the operation amount calculation unit 1203 determines that the energy transfer amount from the head to the gas increases due to the advance angle, so that abnormal combustion occurs.

[0301] Therefore, the operation amount calculation unit 1203 reduces the energy transfer amount from the head to the gas by increasing the energy transfer amount from the head to the cooling water and lowering the head temperature (step S93). That is, in the process of step S93, the operation amount calculation unit 1203 implements an operation for increasing the cooling water flow rate and lowering the cooling water temperature. Specifically, in order to increase the cooling water flow rate, the output of the pump for circulating the cooling water is increased. In addition, in order to lower the cooling water temperature, it is set to increase the flow rate of the cooling water flowing through the radiator and increase the energy transfer amount from the cooling water to the outside air. If the process of step S93 is completed, it is transferred to the process of step S94 described later.

[0302] In addition, when it is determined in the process of step S92 that the head temperature is less than the advance angle allowable reference 1 (the determination in step S92 is "No"), the operation amount calculation unit 1203 determines that the abnormal combustion caused by the increase in the amount of energy transferred from the head to the gas due to the advance angle will not occur. That is, the operation amount calculation unit 1203 performs the normal cooling water operation (step S95). In the process of step S95, the operation amount calculation unit 1203 performs the equivalent Fig. 9 Then, the operation amount calculation unit 1203 proceeds to the processing of step S96 described later.

[0303] In the process of step S94, the operation amount calculation unit 1203 determines whether the piston temperature is greater than the advance angle permission reference 2. The advance angle permission reference 2 is a reference value for determining whether the ignition can be advanced without causing abnormal combustion (knocking) due to energy transfer from the piston to the gas, and is set in advance through experiments, etc. The advance angle permission reference 2 is set to, for example, the piston temperature measured under the high output condition of the internal combustion engine 100.

[0304] In the process of step S96, the operation amount calculation unit 1203 determines whether the piston temperature is greater than the advance angle permission reference 2, similarly to the process of step S94. When it is determined in the process of step S94 that the piston temperature is greater than the advance angle permission reference 2 (the determination in step S94 is "yes"), the operation amount calculation unit 1203 transfers to the process of step S98 described later. When it is determined in the process of step S94 that the piston temperature is less than the advance angle permission reference 2 (the determination in step S94 is "no"), the operation amount calculation unit 1203 transfers to the process of step S97 described later.

[0305] In the process of step S96, the operation amount calculation unit 1203 determines whether the piston temperature is greater than the advance angle permission reference 2, similarly to the process of step S94. When it is determined in the process of step S96 that the piston temperature is greater than the advance angle permission reference 2 (the determination in step S96 is "yes"), the operation amount calculation unit 1203 transfers to the process of step S98 described later. When it is determined in the process of step S96 that the piston temperature is less than the advance angle permission reference 2 (the determination in step S96 is "no"), the operation amount calculation unit 1203 transfers to the process of step S99 described later.

[0306] When the process is transferred to step S97, the operation amount calculation unit 1203 determines that the abnormal combustion caused by the increase in the amount of energy transferred from the piston to the gas due to the advance angle will not occur. Then, the operation amount calculation unit 1203 performs the normal injection operation. In the process of step S97, the operation amount calculation unit 1203 performs the equivalent Fig. 9 The process of step S52 shown in the figure is completed. Thus, the operation of the operation amount calculation unit 1203 is completed.

[0307] In addition, when the process is transferred to step S98, the operation amount calculation unit 1203 determines that the piston temperature is high and the energy transfer amount from the piston to the gas is large. In addition, the operation amount calculation unit 1203 determines that the energy transfer amount from the piston to the gas increases due to the advance angle, causing abnormal combustion. Therefore, the operation amount calculation unit 1203 reduces the energy transfer amount from the piston to the gas by increasing the energy transfer amount from the piston to the oil or fuel and reducing the temperature of the piston.

[0308] That is, in the process of step S98, the operation amount calculation unit 1203 performs an operation for increasing the amount of fuel injection and an operation for increasing the amount of fuel adhering to the piston. Specifically, in order to increase the amount of fuel injection, the output of the oil pump is increased, and the oil pressure is increased. In addition, in order to increase the amount of fuel adhering to the piston, the fuel injection period is set at the beginning of the intake stroke. Thus, the operation of the operation amount calculation unit 1203 is completed.

[0309] When the process is transferred to step S99, the operation amount calculation unit 1203 determines that the abnormal combustion caused by the increase in the amount of energy transferred from the piston to the gas due to the advance angle will not occur, similarly to the process of step S97. Then, the normal fuel injection operation is performed, similarly to the process of step S97. In addition, in the process of step S99, the ignition timing is set to the ignition timing set by the energy distribution rate calculation unit 1202. Thus, the operation of the operation amount calculation unit 1203 is completed.

[0310] Fig.18 It is shown that based on the above Fig.17 The operation example of the operation amount calculation unit 1203 shown is a timing chart of the operation example of various actuators.

[0311] Fig.18 The state at time t1 in FIG. 1 shows a state in which there is an ignition advance angle request from the energy distribution rate calculation unit 1202, the head temperature is greater than the advance angle permission reference 1, and the piston temperature is greater than the advance angle permission reference 2. The state at time t2 shows a state in which there is an ignition advance angle request from the energy distribution rate calculation unit 1202, the head temperature is less than the advance angle permission reference 1, and the piston temperature is greater than the advance angle permission reference 2.

[0312] At time t1, since the head temperature is greater than the advance angle allowable reference 1 and the piston temperature is greater than the advance angle allowable reference 2, the action of reducing the temperature of each wall surface is implemented to meet the ignition advance angle requirement. Specifically, in order to reduce the head temperature, the cooling water temperature is reduced by increasing the cooling water flow rate and increasing the cooling water flow rate flowing through the radiator. In addition, in order to increase the amount of oil cooling the piston, the amount of oil injection is increased. In addition, in order to increase the amount of energy taken away from the piston by the fuel attached to the piston, the injection timing is advanced to increase the amount of fuel attached.

[0313] Thus, after time t1, the head temperature can be made lower than the advance angle permission reference 1, and the piston temperature can be made lower than the advance angle permission reference 2. As a result, the ignition timing can be controlled to satisfy the ignition advance angle request from the energy distribution rate calculation unit 1202.

[0314] Furthermore, at time t2, since the head temperature is less than the advance angle allowable reference 1 and the piston temperature is greater than the advance angle allowable reference 2, the piston temperature is lowered to meet the ignition advance angle requirement. Specifically, as described above, the amount of injected oil is increased to increase the amount of cooling of the piston by the oil. Furthermore, in order to increase the amount of energy taken away from the piston by the fuel adhering to the piston, the injection timing is advanced to increase the amount of fuel adhering.

[0315] Thus, after time t2, the head temperature can be made lower than the advance angle permission reference 1, and the piston temperature can be made lower than the advance angle permission reference 2. As a result, the ignition timing can be controlled to satisfy the ignition advance angle request from the energy distribution rate calculation unit 1202.

[0316] Thus, according to the internal combustion engine control device of the third embodiment, by setting allowable reference values ​​for the piston and the head as wall surface elements and estimating the respective wall surface temperatures, appropriate measures can be taken at an appropriate time.

[0317] In addition, the operation amount of various actuators is set according to the state of the wall surface temperature, thereby realizing the control of the target ignition timing. As a result, the loss caused by the increase of unnecessary injection and cooling water flow rate can be suppressed, and the target ignition timing can be set when the ignition timing is operated according to the heating requirement, etc. As a result, the operation efficiency of the internal combustion engine 100 can be improved.

[0318] In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the gist of the invention described in the claims.

[0319] For example, the structure of the above-mentioned embodiment 2 and the structure of the embodiment 3 may be combined. That is, the internal combustion engine control device is provided with not only the wall surface temperature estimation module and the operation amount calculation unit, but also the knock determination module of the embodiment 2 and the energy distribution rate calculation unit of the embodiment 3. In this way, not only the knock determination can be performed, but also the operation of the ignition timing according to the heating request and the like can be performed at the same time.

[0320] Description of symbols

[0321] 13…fuel injection device, 14…cylinder (air cylinder), 15…exhaust pipe, 16…ignition coil, 19…crank angle sensor, 20…internal combustion engine control device, 31…wall temperature estimation module, 32…engine state estimation unit, 33…cooling water energy flow estimation unit, 34…wall temperature estimation unit, 35…cooling water temperature estimation unit, 36…operation amount calculation unit, 100…internal combustion engine, 110…fuel injection system.

Claims

1. An internal combustion engine control device, characterized in that: include: an engine state estimating unit that calculates the amount of energy transferred from the gas to the wall surface in the internal combustion engine based on a parameter related to an operating condition of the internal combustion engine, a parameter related to a chemical condition of combustion, and a parameter related to an operating state of the internal combustion engine; a wall surface temperature estimating unit that estimates the wall surface temperature based on the amount of energy transferred from the gas to the wall surface calculated by the engine state estimating unit; as well as an operation amount calculation unit that calculates an operation amount of an actuator provided in the internal combustion engine based on the wall surface temperature estimated by the wall surface temperature estimation unit, The engine state estimation unit calculates a combustion period in one combustion stroke of the internal combustion engine based on a parameter related to the chemical condition and a parameter related to the operating state, and calculates the amount of energy transferred from the gas to the wall surface based on the calculated combustion period.

2. The internal combustion engine control device according to claim 1, characterized in that: A cooling water energy flow estimating unit is provided for calculating the amount of energy transferred between the cooling water circulating in the internal combustion engine and the wall surface. The wall surface temperature estimating unit estimates the wall surface temperature based on the amount of energy transferred between the cooling water and the wall surface calculated by the cooling water energy flow rate estimating unit and the amount of energy transferred from the gas to the wall surface calculated by the engine state estimating unit.

3. The internal combustion engine control device according to claim 2, characterized in that: comprising a cooling water temperature estimating unit for estimating the temperature of the cooling water based on the amount of energy transfer between the cooling water and the wall surface calculated by the cooling water energy flow rate estimating unit, The operation amount calculation unit calculates an operation amount of an actuator provided in the internal combustion engine based on the wall surface temperature estimated by the wall surface temperature estimation unit and the temperature of the cooling water estimated by the cooling water temperature estimation unit.

4. The internal combustion engine control device according to claim 3, characterized in that: The operation amount calculation unit controls the output of the internal combustion engine, the energy to the cooling water, and the distribution of exhaust energy exhausted from the internal combustion engine based on the wall surface temperature estimated by the wall surface temperature estimation unit.

5. The internal combustion engine control device according to claim 4, characterized in that: An energy distribution rate calculation unit is included, which calculates the distribution rate of energy flowing to the output, cooling water, and exhaust gas based on the information received from the internal combustion engine, The operation amount calculation unit calculates an operation amount of an actuator provided in the internal combustion engine based on the energy distribution rate calculated by the energy distribution rate and the wall surface temperature estimated by the wall surface temperature estimation unit.

6. The internal combustion engine control device according to claim 1, characterized in that The engine state estimating unit calculates the amount of energy transferred from the gas to the wall surface using a mathematical model representing combustion in the internal combustion engine.

7. The internal combustion engine control device according to claim 1, characterized in that The engine state estimation unit divides the wall surface of the internal combustion engine into a plurality of wall surface elements, and calculates the amount of energy transferred from the gas to the wall surface for each of the divided wall surface elements. The wall surface temperature estimating unit estimates the wall surface temperature for each of the divided wall surface elements.

8. The internal combustion engine control device according to claim 7, characterized in that: The operation amount calculation unit sets the operation amount of the actuator based on the wall surface temperatures of the plurality of wall surface elements estimated by the wall surface temperature estimation unit.

9. The internal combustion engine control device according to claim 7, characterized in that: A knock determination module is included, the knock determination module is used to determine whether knock occurs in the internal combustion engine, The operation amount calculation unit specifies the wall surface element that is a cause of knocking based on the wall surface temperature estimated by the wall surface temperature estimation unit.

10. The internal combustion engine control device according to claim 1, wherein: The wall surface temperature estimating unit estimates the wall surface temperature of each cylinder of the internal combustion engine based on a temperature on an inlet side and a temperature on an outlet side of cooling water flowing into the internal combustion engine.

11. The internal combustion engine control device according to claim 10, characterized in that: The operation amount calculation unit calculates the operation amount of the actuator based on information of a cylinder having the highest temperature among the wall surface temperatures of the cylinders.

12. The internal combustion engine control device according to claim 1, wherein: The actuator is a fuel injection device for supplying fuel into the cylinder, an ignition device for igniting the mixed gas in the cylinder, a cooling device for operating the flow rate and flow direction of circulating cooling water to cool the internal combustion engine, and a lubricating oil device for operating the oil pressure and oil flow rate of the oil lubricating the internal combustion engine.

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