JP2019157785A - Controller and control method for internal combustion engine - Google Patents

Abstract

To provide a controller and control method for internal combustion engine, capable of accurately estimating a body temperature of an internal combustion engine at low cost, without arranging a temperature sensor in the body of the internal combustion engine.SOLUTION: A controller and control method for internal combustion engine are configured to: when an internal combustion engine is started, detect suction pressure, which is the pressure of gas in a suction pipe, at a plurality of preset time points; and based on a first pressure and a second pressure, which are suction pressures respectively detected at the first time point and the second time point set in advance, determine an individual value used for estimating a body temperature of the internal combustion engine at the time of starting.SELECTED DRAWING: Figure 2

Description

  The present application relates to a control device and a control method for an internal combustion engine.

  Conventionally, an electronic control device called an ECU is mounted on a vehicle. The ECU is mainly configured by using a microcomputer, and controls the operation of the vehicle internal combustion engine related to driving. Various parameters are involved in the operation control of such an internal combustion engine. As one of the parameters involved in the control, temperature information of the internal combustion engine is known.

  In the case of feedback control in which an ECU is used to control the internal combustion engine using a measurement result of the dedicated temperature sensor, the delay from the measurement time of the dedicated temperature sensor to the response time of the ECU Therefore, it is difficult to appropriately control the internal combustion engine.

  Therefore, in Patent Document 1, the body temperature of the internal combustion engine at an arbitrary time is determined by using the body temperature of the internal combustion engine at the time of starting the internal combustion engine, the temperature of the intake pipe at an arbitrary time, and a simulation model. A method for estimating the temperature has been proposed. Further, in Patent Document 1, in order to know the main body temperature of the internal combustion engine when the internal combustion engine is started, a dedicated temperature sensor is installed in the casing of the main body of the internal combustion engine to directly detect the main body temperature of the internal combustion engine. The body of the internal combustion engine is directly detected and the temperature of the engine oil or cooling water in the body of the internal combustion engine that is not the case is directly detected, and the temperature is estimated based on the temperature of the engine oil or cooling water. Indirect detection configurations that indirectly detect temperature have been proposed.

  Further, regarding the estimation of the temperature of the intake pipe, in Patent Document 2, it is assumed that the temperature in the intake pipe and the atmospheric temperature coincide with each other when the internal combustion engine is started, and the pressure in the cylinder of the internal combustion engine is A temperature estimation method for estimating the temperature of the intake pipe based on a certain atmospheric temperature has been proposed.

  In Patent Document 3, the temperature converted from the change rate of the coil resistance of the crank angle sensor is set as the initial value of the virtual temperature of the internal combustion engine, and a fuel injection command corresponding to the virtual temperature is issued while sequentially changing the virtual temperature. There has been disclosed a method of starting an internal combustion engine by repeatedly detecting the rotational speed of the internal combustion engine and searching for the actual temperature at the time of starting.

JP 2005-83240 A JP 2006-132526 A JP2015-63918A

  However, when the conventional method for estimating the body temperature of the internal combustion engine is used, it is difficult to control the internal combustion engine with high accuracy at a relatively low cost.

  For example, when the direct detection configuration of Patent Document 1 is used, it is necessary to prepare a heat-resistant temperature sensor that can withstand the temperature rise of the body of the internal combustion engine, and for mounting the heat-resistant temperature sensor on the surface of the body of the internal combustion engine. It is necessary to perform processing such as drilling. Therefore, the increase in wiring and parts may cause an increase in manufacturing cost and work load. Also, in the case of the indirect detection configuration of Patent Document 1, it is necessary to prepare a heat-resistant temperature sensor that can withstand the temperature rise of engine oil or cooling water, and it is necessary to perform the heat-resistant temperature sensor mounting operation. Therefore, the increase in wiring and parts may cause an increase in manufacturing cost and work load. Therefore, there is a risk that the parts and the manufacturing cost may remain high.

  Further, in the temperature estimation method of Patent Document 2, it is assumed that the temperature in the intake pipe coincides with the atmospheric temperature when the internal combustion engine is started. Therefore, if the time interval from when the internal combustion engine is stopped to when the internal combustion engine is started changes, the assumed range varies and the temperature estimation accuracy deteriorates. Therefore, when the temperature estimation based on Patent Document 1 is performed using the temperature of the intake pipe estimated using the temperature estimation method of Patent Document 2, the estimation accuracy of the body temperature of the internal combustion engine may be further deteriorated.

  For example, in the temperature estimation method of Patent Document 3, the actual temperature of the internal combustion engine before start-up often deviates from the virtual temperature, and extra fuel injection is required to search for the actual temperature of the internal combustion engine. There was a problem. In addition, spraying at low temperatures causes the fuel to adhere as a liquid and is vaporized after the temperature rises, resulting in a temporary fuel-rich state, unstable combustion, and generation of unburned gas. There is a risk of affecting the exhaust gas composition.

  The present application has been made in view of the above circumstances, and an object thereof is to provide a control device and a control method for an internal combustion engine that can accurately estimate the body temperature of the internal combustion engine at low cost.

An internal combustion engine control method according to the present application includes an intake pressure detection step of detecting an intake pressure that is a pressure of gas in an intake pipe at a plurality of preset time points when starting the internal combustion engine;
Based on the first pressure and the second pressure, which are the intake pressures detected respectively at the first time point and the second time point set in advance, individual values used for estimating the body temperature of the internal combustion engine at the time of starting And an individual value determination step to be determined.

An internal combustion engine control apparatus according to the present application includes an intake pressure detection unit that detects an intake pressure that is a pressure of a gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started,
Based on the first pressure and the second pressure, which are the intake pressures detected respectively at the first time point and the second time point set in advance, individual values used for estimating the body temperature of the internal combustion engine at the time of starting And an individual value determining unit for determining.

An internal combustion engine control apparatus according to the present application includes an intake pressure detection unit that detects an intake pressure that is a pressure of a gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started,
An outside air temperature detecting unit for detecting outside air temperature that is the temperature of outside air sucked into the intake pipe;
An individual value determining unit that determines an individual value based on the first pressure and the second pressure, which are the intake pressures detected at the first time point and the second time point set in advance, respectively;
A rotational speed detector for detecting the rotational speed of the internal combustion engine;
Based on the rotational speed, the outside air temperature, the third pressure and the fourth pressure, which are the intake pressure detected at the preset third time point and the fourth time point, respectively, and the individual value, A main body temperature estimating unit for estimating a main body temperature of the internal combustion engine;
And an engine control unit that controls the internal combustion engine based on the body temperature at the time of starting.

  Even with internal combustion engines of the same specification, the behavior of the intake pressure at the time of starting varies due to individual differences such as the degree of closing of the throttle valve. Therefore, an estimation error may occur when trying to estimate the body temperature of the internal combustion engine at the time of starting based on the information of the intake pressure. According to the control device and the control method for the internal combustion engine according to the present application, the individual value is determined based on the information of the intake pressure at the time of starting, so that the individual difference of the internal combustion engine can be learned. At this time, since the information on the intake pressure at two time points, the first time point and the second time point, is used, the difference in behavior of the intake pressure caused by the individual difference can be detected with high accuracy, and the determination accuracy of the individual value can be improved. And even if it does not provide a temperature sensor, the main body temperature of an internal combustion engine can be estimated accurately at low cost using the determined individual value. Therefore, according to the control device and the control method according to the present application, it is possible to accurately estimate the main body temperature of the internal combustion engine at a low cost without being affected by individual differences among the internal combustion engines.

1 is a schematic configuration diagram of an internal combustion engine and a control device according to Embodiment 1. FIG. 2 is a block diagram of a control device according to Embodiment 1. FIG. 2 is a hardware configuration diagram of a control device according to Embodiment 1. FIG. 4 is a timing chart showing the behavior of intake pressure at the time of starting according to the first embodiment. 6 is a characteristic diagram showing a correlation between intake pressure and body temperature according to Embodiment 1. FIG. 4 is a timing chart showing a difference in intake pressure behavior due to individual differences according to the first embodiment. FIG. 5 is a characteristic diagram showing a correlation between a pressure difference between intake pressures and an individual value according to Embodiment 1. 6 is a flowchart for explaining individual value determination processing according to the first embodiment; 6 is a flowchart for explaining body temperature estimation processing according to Embodiment 1; 6 is a timing chart showing detection times of the first pressure and the second pressure according to the second embodiment. FIG. 10 is a characteristic diagram showing a correlation between a pressure difference of intake pressure and an individual value according to the second embodiment. 12 is a flowchart for explaining individual value determination processing according to the second embodiment. 10 is a timing chart showing detection times of the first pressure and the second pressure according to the third embodiment. 10 is a timing chart showing detection times of the fifth pressure, the first pressure, and the second pressure according to the fourth embodiment. 15 is a flowchart for explaining individual value determination processing according to the fourth embodiment. 10 is a flowchart for explaining body temperature estimation processing according to the fifth embodiment.

  Hereinafter, embodiments of a control device and a control method disclosed in the present application will be described in detail with reference to the accompanying drawings. The following embodiments are merely examples, and the present application is not limited by these embodiments.

1. Embodiment 1
An internal combustion engine control device 121 (hereinafter simply referred to as control device 121) and an internal combustion engine control method according to Embodiment 1 will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an internal combustion engine 100 and a control device 121 according to the present embodiment. The internal combustion engine 100 and the control device 121 are mounted on a vehicle, and the internal combustion engine 100 serves as a driving force source for the vehicle (wheel).

1-1. Configuration of Internal Combustion Engine The internal combustion engine 100 is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke as one combustion cycle. The internal combustion engine 100 is a gasoline internal combustion engine. The internal combustion engine 100 has a combustion chamber 105 that burns a mixture of air and fuel. The combustion chamber 105 is constituted by a cylinder and a piston 113. The cylinder includes a cylinder block 122 that forms the wall surface of the cylinder, and a cylinder head 123 that forms the top of the cylinder.

  The main body 100a of the internal combustion engine is a part constituting the combustion chamber 105 such as the cylinder block 122, the piston 113, and the cylinder head 123.

  The internal combustion engine 100 includes an intake passage 101 that supplies air to the combustion chamber 105 and an exhaust passage 117 that discharges exhaust gas burned in the combustion chamber 105. In the intake passage 101, an air filter 102, a throttle valve 103, and an intake pressure sensor 104 are provided from the upstream side. The intake pressure sensor 104 outputs a signal corresponding to the pressure of the gas in the intake pipe 101 a that is the intake passage 101 on the downstream side of the throttle valve 103. An output signal of the intake pressure sensor 104 is input to the control device 121. The intake passage 101 includes a bypass passage 106 that bypasses the throttle valve 103 and communicates the upstream side and the downstream side of the throttle valve 103, and an idle speed control valve 107 that adjusts the opening degree of the bypass passage 106. Is provided. One intake pipe 101 a is connected to one combustion chamber 105.

  An injector 110 that injects fuel to the vicinity of the intake port is provided downstream of the intake pressure sensor 104 in the intake pipe 101a. The fuel pumped up by the fuel pump 108 from the fuel tank 109 is supplied to the injector 110. The injector 110 is driven by a signal output from the control device 121.

  A spark plug 112 for igniting a mixture of air and fuel is provided at the top of the combustion chamber 105. The electrode of the spark plug 112 is exposed in the combustion chamber 105. The ignition plug 112 is supplied with ignition energy from the control device 121 via an ignition coil or the like. An intake valve 111 that adjusts the amount of intake air taken into the combustion chamber 105 from the intake passage 101 and the exhaust passage 117 from the combustion chamber 105 are discharged to the top (cylinder head 123) of the combustion chamber 105. An exhaust valve 116 for adjusting the amount of exhaust gas is provided.

  The piston 113 is connected to the crankshaft 115 via a connecting rod 114. As the crankshaft 115 rotates, the piston 113 reciprocates up and down in the cylinder. A crank angle sensor 118 that outputs a signal corresponding to the rotation of the crankshaft 115 is provided near the crankshaft 115 of the combustion chamber 105. The output signal of the crank angle sensor 118 is input to the control device 121. A three-way catalyst 119 is provided on the downstream side of the exhaust passage 117. Further, upstream of the three-way catalyst 119 in the exhaust passage 117, an O2 sensor 120 that outputs a signal corresponding to the oxygen concentration of the exhaust gas is provided. An output signal of the O2 sensor 120 is input to the control device 121.

  The throttle valve 103 is a valve that opens and closes the intake passage 101. By changing the opening of the throttle valve 103, the amount of air supplied to the combustion chamber 105 via the intake pipe 101a is adjusted. The opening degree of the throttle valve 103 changes according to the amount of operation of an accelerator (not shown) by the driver. The idle speed control valve 107 adjusts the flow rate of air flowing through the bypass passage 106 in order to control the rotational speed of the internal combustion engine 100 during idling operation of the internal combustion engine 100.

  The injector 110 injects fuel into the air flowing through the intake pipe 101a before the intake valve 111 to form an air-fuel mixture. The intake valve 111 supplies the formed air-fuel mixture to the combustion chamber 105. A spark plug 112 provided in the combustion chamber 105 ignites the air-fuel mixture supplied to the combustion chamber 105 with a discharge spark and burns the air-fuel mixture. Work is done outside by the combustion of the air-fuel mixture. Specifically, the crankshaft 115 rotates via the piston 113 and the connecting rod 114, and rotational energy is extracted from the combustion of the air-fuel mixture. The exhaust valve 116 discharges the exhaust gas generated by the combustion of the air-fuel mixture to the exhaust passage 117 by an opening operation.

  A plurality of protrusions (not shown) provided at predetermined intervals in the circumferential direction are provided on the outer peripheral portion of the rotor that rotates integrally with the crankshaft 115, and the crank angle sensor 118 is configured such that these protrusions are at the crank angle. When crossing the sensor 118, a rectangular crank signal is output. In the present embodiment, the plurality of protrusions are provided every 30 degrees at the rotation angle of the crankshaft 115. Note that the protrusions are provided with chipped teeth (locations without protrusions) at predetermined positions, and the control device 121 can determine the position of the piston 113 if the crankshaft 115 rotates 360 degrees at the maximum. . As a result, the control device 121 can recognize that the piston 113 is located at the top dead center and the bottom dead center.

  If the engine is a four-cycle engine, the control device 121 determines the four strokes (intake stroke, compression stroke, expansion stroke, exhaust stroke) of the internal combustion engine 100 by matching the information from the intake pressure sensor 104 and the position of the piston 113. And the detailed position of the piston 113 can be recognized. As a result, the control device 121 controls the internal combustion engine 100 such as the fuel injection amount and the air-fuel ratio by issuing a fuel injection command from the control device 121 to the injector 110 according to the position of the piston 113.

1-2. Configuration of Control Device The control device 121 is a control device that controls the internal combustion engine 1. As shown in FIG. 2, the control device 121 includes control units such as an intake pressure detection unit 51, a rotation speed detection unit 52, an outside air temperature detection unit 53, an eigenvalue determination unit 54, a body temperature estimation unit 55, and an engine control unit 56. It has. Each control unit 51 to 56 of the control device 121 is realized by a processing circuit included in the control device 121. Specifically, as illustrated in FIG. 3, the control device 121 includes, as a processing circuit, an arithmetic processing device 90 (computer) such as a CPU (Central Processing Unit), and a storage device 91 that exchanges data with the arithmetic processing device 90. , An input circuit 92 for inputting an external signal to the arithmetic processing unit 90, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, and the like.

  The storage device 91 includes a volatile storage device such as a RAM (Random Access Memory), and a nonvolatile storage device such as an EEPROM (Electrically Erasable Programmable Read Only Memory). The input circuit 92 is connected to various sensors and switches, and includes an A / D converter or the like that inputs output signals of these sensors and switches to the arithmetic processing unit 90. The output circuit 93 is provided with a drive circuit or the like to which electric loads are connected and which outputs a control signal from the arithmetic processing unit 90 to these electric loads.

  And each function of each control part 51-56 etc. with which the control apparatus 121 is provided, the arithmetic processing unit 90 executes the software (program) memorize | stored in memory | storage devices 91, such as ROM, the memory | storage device 91, the input circuit 92 , And other hardware of the control device 121 such as the output circuit 93. It should be noted that setting data such as individual value characteristic data, constants, and judgment pressures used by the control units 51 to 56 are stored in a storage device 91 such as an EEPROM as part of software (program).

  In the present embodiment, the input circuit 92 is connected to an intake pressure sensor 104, a crank angle sensor 118, an O2 sensor 120, an outside air temperature sensor 125, and the like. An injector 110, a spark plug 112, and the like are connected to the output circuit 93.

  The control device 121 detects various operating states of the internal combustion engine 1 based on output signals of various sensors. For example, the control device 121 detects the rotational speed and crank angle of the internal combustion engine based on the output signal from the crank angle sensor 118 and the like. The control device 121 determines four strokes of the internal combustion engine based on an output signal from the intake pressure sensor 104 or the like. The control device 121 calculates the intake air amount filled in the combustion chamber 105 based on the output signal from the O2 sensor 120. As a basic control, the control device 121 calculates a fuel injection amount and the like based on the detected operating state, and controls the injector 110 and the like.

<Intake pressure change after cranking starts>
The change in the intake pressure in the intake pipe 101a after the start of cranking will be described using the schematic diagram of FIG. The horizontal axis indicates the piston crank number indicating the position of the piston, and the vertical axis indicates the intake pressure which is the pressure of the gas in the intake pipe 101a. Here, the piston crank number represents the protrusions provided every 30 degrees detected by the crank angle sensor 118 in order.

  When the power of the crankshaft is stopped and the power supply to the control device 121 is stopped, the input information of the various sensors stored in the RAM is lost. When the power of the control device 121 is turned on, various sensors start to operate, and output signals from the various sensors are input to the control device 121. At this time, since the intake pressure in the intake pipe 101a is equal to the atmospheric pressure, the intake pressure detected by the intake pressure sensor 104 can be handled as atmospheric pressure information.

  Thereafter, in order to start the internal combustion engine 100, the cell motor is energized, and cranking for rotating the crankshaft from the stopped state is started. After the cranking starts, the control device 121 detects the crank angle based on the output signals of the crank angle sensor 118 and the intake pressure sensor 104, and determines which stroke is in four cycles as described above. .

  In the intake stroke, the piston 113 is lowered from the top dead center toward the bottom dead center, the intake valve 111 is opened, and the exhaust valve 116 is closed, so that the gas in the intake pipe 101a is introduced into the combustion chamber 105. Thus, the intake pressure in the intake pipe 101a becomes a negative pressure lower than the atmospheric pressure.

  When passing through the bottom dead center, the intake valve 111 is closed, and then the process proceeds to the compression stroke. In the compression stroke, the piston 113 rises from the bottom dead center toward the top dead center, and the gas introduced into the combustion chamber 105 is compressed in the combustion chamber 105 as the piston 113 rises. While the intake and exhaust valves 116 are closed, an expansion stroke occurs, and the piston 113 is lowered from the top dead center toward the bottom dead center. Thereafter, the exhaust valve 116 is opened near the bottom dead center, and the exhaust stroke is started. The piston 113 rises from the bottom dead center toward the top dead center, and the gas in the combustion chamber 105 is discharged to the exhaust pipe.

  On the other hand, in the compression stroke, the expansion stroke, and the exhaust stroke, the intake valve 111 is closed and the throttle valve 103 is closed. At this time, outside air flows into the intake pipe 101a from the gap between the throttle valve 103 and the idle speed control valve 107, and the intake pressure in the intake pipe 101a increases toward the atmospheric pressure. Until the fuel injection is started, the change in the intake pressure is caused by the vertical movement of the piston 113, the opening / closing of the valve, the clearance of the throttle valve 103, and the like.

<Estimation principle of main body temperature when starting with intake pressure>
The temperature of the main body 100a of the internal combustion engine at the time of starting (hereinafter referred to as the main body temperature at the time of starting) is a very important parameter in controlling the internal combustion engine 100. The main body temperature at the start before combustion starts varies depending on the outside air temperature, the operation state when the internal combustion engine 100 is stopped before that time, and the elapsed time since the stop. If the temperature of the main body at the time of starting is low, the vaporization rate of the injected fuel is low. Therefore, if the fuel injection amount is not increased, the combustion may not start well.

  Therefore, in the internal combustion engine 100, paying attention to the intake pressure before starting fuel injection, a test was performed assuming different elapsed times after the internal combustion engine 100 was completely stopped. Specifically, using two single-cylinder gasoline internal combustion engines of the same specification, set the temperatures of the main bodies of five types of internal combustion engines (25 ° C, 60 ° C, 80 ° C, 100 ° C, 115 ° C), The intake pressure from the start of cranking to the start of fuel injection was examined. At this time, the installation environment of the internal combustion engine was set to three kinds of outside air temperatures (5 ° C., 25 ° C., 40 ° C.) and two kinds of outside air pressures (101 kP, 0.89 kP).

  When the internal combustion engine 100 is turned on, output signals of the intake pressure sensor 104, the crank angle sensor 118, the O2 sensor 120, and the outside air temperature sensor 125 provided in the internal combustion engine 100 are input to the control device 121. At this time, since the intake pressure in the intake pipe 101a indicates the atmospheric pressure, the ambient environment pressure (third pressure P3) of the internal combustion engine can be known. Next, the internal combustion engine 100 starts a starting operation. That is, the cell motor or the like rotates the crankshaft 115 and the piston starts to move. Until then, the pressure in the intake pipe 101a is almost atmospheric pressure.

  In the intake stroke, the gas in the intake pipe 101a is drawn into the combustion chamber 105, so that the intake pressure decreases from atmospheric pressure to about 40 kP. The pressure change in the intake stroke is relatively fast, and in the same internal combustion engine 100, a difference in pressure change cannot be found with respect to the temperature difference of the main body temperature at the time of starting. On the other hand, a correlation was found between the intake pressure (fourth pressure P4) at the time point set in the compression stroke (fourth time point) and the main body temperature at the start. In this example, the fourth time point is set to the second piston crank number after the bottom dead center between the intake stroke and the compression stroke (60 degrees after the bottom dead center). In the present application, each stroke of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke corresponds to a period between the top dead center and the bottom dead center.

Based on these experimental data, we tried to derive the empirical formula. Here, the intake pressure is affected by the external air pressure and the external air temperature. Further, the moving speed of the gas flowing into the intake pipe 101a and flowing into the combustion chamber 105 from the intake pipe 101a depends on the rotational speed of the internal combustion engine. Therefore, an experiment was performed in which the main body temperature, the outside air temperature, and the outside air pressure were changed as parameters, and an empirical formula (1) that considered these parameters was obtained.
Te0 = A × (P4 / P3 -B) C × T0 D × Ne4 E (1)

  Here, Te0 is the body temperature of the internal combustion engine at the time of starting, P3 is atmospheric pressure (third pressure), P4 is representative intake pressure (fourth pressure), and T0 is outside air temperature. Yes, Ne4 is the rotational speed of the internal combustion engine, A is an individual value, and B, C, D, and E are constants. The rotational speed of the internal combustion engine was a value at the timing when the fourth pressure P4 was acquired.

  FIG. 5 shows a schematic diagram showing the correlation between the fourth pressure P4 and the main body temperature Te0 at the time of starting, and this makes it possible to uniquely estimate the main body temperature at the time of starting from the information of the intake pressure. Was confirmed.

<Estimation error due to individual differences>
Next, in order to examine individual differences between internal combustion engines of the same specification, a comparative test of two internal combustion engines (internal combustion engine X and internal combustion engine Y) of the same specification was performed under the same environmental conditions. FIG. 6 shows typical intake pressure behavior. Under any temperature condition, there was a difference in the behavior of the intake pressure of the two internal combustion engines before and after the bottom dead center between the intake stroke and the compression stroke, the compression stroke, the expansion stroke, and the exhaust stroke. Specifically, the smaller the intake pressure at the bottom dead center between the intake stroke and the compression stroke, the slower the pressure recovery in the compression stroke, the expansion stroke, and the exhaust stroke, and the intake pressure at the same piston crank angle number. Was found to be small. That is, even if the specifications are the same, there are individual differences among the internal combustion engines, and it has been found that the estimation method of the above formula (1) causes an estimation error.

  As a result of analyzing this factor, it is considered that the degree of closing of the throttle valve 103 or the opening degree of the idle speed control valve 107 is different depending on the individual, and the resistance of the intake air is different. In other words, even if the internal combustion engine has the same specifications, the intake pressure behavior fluctuates if the degree of opening of the idle speed control valve 107 and the degree of closing of the throttle valve 103 differ slightly due to parts accuracy and assembly accuracy. I found out that

  The internal combustion engine X and the internal combustion engine Y have the same specifications, but when the body temperature is estimated from the equation (1) under the experimental conditions in which the body temperature and the surrounding environment are changed, the difference between the estimated value and the measured value is 40 ° C. or more. Was seen. As described above, it is estimated that the main factor is that the intake resistance around the throttle valve 103 or the idle speed control valve 107 has changed as described above.

<Individual value adjustment>
Therefore, it was considered that the individual value A is not a constant value but fitting for each individual internal combustion engine. By setting the individual value A to a different value for each individual, the estimated value and the measured value of the main body temperature at the start agree well even when the main body temperature and the surrounding environment at the start are changed. I found it.

  Looking at FIG. 6 in detail, there is a difference in the rate of change of the intake pressure with respect to the crank angle number from the bottom dead center between the intake stroke and the compression stroke to the expansion stroke through the compression stroke. This is a state in which a relatively large amount of air flows through the clearance of the throttle valve 103 and the idle speed control valve 107 into the intake pipe where the negative pressure has increased in the compression stroke and the expansion stroke. It is assumed that the individual difference between the gap area 103 and the opening area of the idle speed control valve 107 appears as a difference in the change rate of the intake pressure.

  Therefore, the intake pressure (first pressure P1) at the time point (first time point) set in the first half of the compression stroke is detected. In this example, the first time point is set to the second piston crank number after the bottom dead center between the intake stroke and the compression stroke (60 degrees after the bottom dead center). Further, the intake pressure (second pressure P2) at the time point (second time point) set in the compression stroke after the first time point is detected. In this example, the second time point is set to the second piston crank number (60 degrees before the top dead center) before the top dead center between the compression stroke and the expansion stroke.

  FIG. 7 is a characteristic diagram showing the pressure difference between the first pressure P1 and the second pressure P2 on the horizontal axis and the individual value A on the vertical axis. It was recognized that the individual value A increased as the pressure difference (pressure change amount) between the predetermined crank angles increased. That is, it is suggested that the individual value A has a correlation with the clearance area of the throttle valve 103 and the opening area of the idle speed control valve 107.

  The individual value A is determined under steady conditions in which the temperature of each part of the internal combustion engine 100 is stable, for example, in an inspection stage and an adjustment stage before shipment of the internal combustion engine. Here, the steady condition of the temperature of each part of the internal combustion engine 100 is, for example, a condition in which the temperature of each part and the ambient temperature substantially match while the internal combustion engine is stopped. The individual value A is determined by referring to the individual value characteristic data in which the relationship between the pressure difference (| P2−P1 |) between the first pressure P1 and the second pressure P2 and the individual value A is set in advance. The determined individual value A is stored in a rewritable nonvolatile storage device such as an EEPROM. Thereby, even when there is an individual difference of the internal combustion engine 100, it is possible to accurately estimate the main body temperature at the time of starting.

<Individual value determination process>
Next, a series of processes for determining the individual value A will be described with reference to the flowchart shown in FIG. The control device 121 performs the processing of the flowchart of FIG. 8 when a preset execution condition for individual value determination is satisfied. For example, in order to determine the individual value A at the time of inspection before shipment, at the time of inspection, etc., the control device 121 is switched on when a switch for instructing individual value determination is turned on or by communication from an external maintenance device When execution of individual value determination is instructed, it is determined that the execution condition for individual value determination is satisfied. Alternatively, in order to respond to changes over time in the degree of closing of the throttle valve 103 and the opening degree of the idle speed control valve 107, the control device 121 determines that the outside air temperature and the body temperature of the internal combustion engine match. In this case, for example, when a preset time has elapsed after the internal combustion engine is stopped, it is determined that the execution condition for determining the individual value is satisfied.

  In step S001, when the power source of the internal combustion engine 100 is switched from OFF to ON and power is supplied to the control device 121 and various sensors, the process proceeds to step S002. In step S002, operations of various sensors such as the intake pressure sensor 104, the crank angle sensor 118, and the outside air temperature sensor 125 are started.

  In step S003, the outside air temperature detection unit 53 detects the outside air temperature T0. The outside air temperature detecting unit 53 may detect the outside air temperature T0 based on the output signal of the outside air temperature sensor 125, or indirectly using the information of other sensors other than the outside air temperature sensor 125. May be estimated.

  Next, in step S004, the control device 121 starts energization of the cell motor and starts cranking for rotating the crankshaft from the stopped state. In step S005, the intake pressure detection unit 51 detects the intake pressure at the preset first time point and second time point based on the output signal of the intake pressure sensor 104. The intake pressure detection unit 51 sets the intake pressure detected at the first time point to the first pressure P1, and sets the intake pressure detected at the second time point to the second pressure P2.

  In the present embodiment, the first time point is a time point of a crank angle (60 degrees after the bottom dead center in this example) preset in the first half of the compression stroke in the first four cycles after the crankshaft rotation starts. ing. The second time point is a crank angle preset in a compression stroke after the first time point in the first four cycles after the start of rotation of the crankshaft (in this example, 60 degrees before top dead center (after bottom dead center). 120 degrees)).

  The reason why the first time point is set to 60 degrees after the bottom dead center is that the intake valve does not completely close instantaneously even after passing through the bottom dead center. Therefore, the air once taken into the combustion chamber 105 due to a delay in the closing time This is to eliminate the possibility of reverse flow into the intake pipe. Of course, since the opening / closing timing of the intake valve may be changed depending on the design of the internal combustion engine 100, the first time point is not limited to 60 degrees after the bottom dead center, and there is little disturbance in the first half of the compression stroke. It may be set at the time of the appropriate crank angle. The second time point is set to 60 degrees before the top dead center. However, in the compression stroke after the first time point, at the time point of an appropriate crank angle at which the amount of change in the intake pressure with respect to the change in the crank angle becomes large. It may be set.

  In step S006, the eigenvalue determining unit 54 determines the individual value A used for estimating the body temperature at the time of starting based on the first pressure P1 and the second pressure P2. In the present embodiment, the eigenvalue determining unit 54 determines the individual value A based on the pressure difference between the first pressure P1 and the second pressure P2. Specifically, the eigenvalue determining unit 54 refers to the individual value characteristic data as shown in FIG. 7 in which the relationship between the pressure difference and the individual value A is set in advance, and calculates the first pressure P1 and the second pressure P2 calculated this time. The individual value A corresponding to the pressure difference (| P2-P1 |) is calculated.

  In order to increase the determination accuracy of the individual value A even under different conditions of the outside air temperature T0, the eigenvalue determining unit 54 calculates the individual value A based on the first pressure P1, the second pressure P2, the outside air temperature T0, and the individual value A. Is configured to determine. In this case, in the individual value characteristic data, the relationship between the pressure difference and the individual value A may be set for each of a plurality of different outside air temperatures T0.

  In step S <b> 007, the eigenvalue determining unit 54 stores the determined individual value A in a nonvolatile storage device such as an EEPROM of the control device 121. Thereby, at the time of starting from the next time onward, the body temperature at the time of starting can be estimated using the individual value A stored in the nonvolatile storage device.

  In this embodiment, it is assumed that the main body temperature is the same as the outside air temperature T0, and the individual value A is determined using the outside air temperature T0. However, instead of the outside air temperature T0, the internal temperature of the internal combustion engine is used for inspection. The individual value A may be determined using temperature information from a temperature sensor provided in the main body. In this case, by combining with other inspection processes or the like, effects such as improvement in work efficiency can be obtained.

<Body temperature estimation process at start-up>
Next, a series of processes for estimating the body temperature at the time of starting will be described with reference to the flowchart shown in FIG. In step S101, when the power source of the internal combustion engine 100 is switched from OFF to ON and power is supplied to the control device 121 and various sensors, the process proceeds to step S102. In step S102, operations of various sensors such as the intake pressure sensor 104, the crank angle sensor 118, and the outside air temperature sensor 125 are started.

  In step S103, the intake pressure detection unit 51 sets the intake pressure detected based on the output signal of the intake pressure sensor 104 as the third pressure P3. That is, in the present embodiment, the third time point is set to a time point until the crankshaft starts rotating after the power is turned on.

  In step S104, the outside air temperature detection unit 53 detects the outside air temperature T0. As described above, the outside air temperature detection unit 53 may detect the outside air temperature T0 based on the output signal of the outside air temperature sensor 125, or indirectly using information from other sensors than the outside air temperature sensor 125. Alternatively, the outside air temperature T0 may be estimated.

  Next, in step S105, the control device 121 starts energization of the cell motor and starts cranking for rotating the crankshaft from the stopped state. In step S <b> 106, the intake pressure detection unit 51 detects the intake pressure at a fourth time point that is set in advance after the crankshaft starts rotating, based on the output signal of the intake pressure sensor 104. The intake pressure detection unit 51 sets the intake pressure detected at the fourth time point to the fourth pressure P4. In the present embodiment, the fourth time point is a time point of a crank angle preset in the compression stroke in the first four cycles after the start of rotation of the crankshaft (in this example, 60 degrees after bottom dead center). .

  The fourth time point is not limited to 60 degrees after the bottom dead center, and may be set to a time point of an appropriate crank angle at which disturbance is reduced in the compression stroke or the expansion stroke.

  In step S107, the rotational speed detector 52 detects the rotational speed Ne4 of the internal combustion engine (crankshaft) at the fourth time point. For example, the rotation speed detection unit 52 calculates the rotation speed Ne4 based on the change cycle of the piston crank number and the corresponding crank angle interval before and after the fourth time point.

  In step S108, the main body temperature estimating unit 55 estimates the main body temperature Te0 at the start based on the rotational speed Ne4, the outside air temperature T0, the third pressure P3 and the fourth pressure P4, and the individual value A. In the present embodiment, the main body temperature estimating unit 55 estimates the main body temperature Te0 at the time of starting using the equation (1). At this time, the main body temperature estimation unit 55 reads the individual value A and four preset constants B, C, D, and E from a non-volatile storage device such as an EEPROM, and uses them to calculate the equation (1). . The main body temperature Te0 at the time of start-up is the main body temperature in the period from the start of cranking to the start of combustion after the power is turned on.

  In step S109, the engine control unit 56 controls the internal combustion engine based on the main body temperature Te0 at the time of starting. In the present embodiment, the engine control unit 56 changes the fuel injection amount at the start based on the main body temperature Te0 at the start. The engine control unit 56 starts fuel injection control and ignition control after the estimation of the main body temperature Te0 at the start. For example, the engine control unit 56 performs the first fuel injection in the first exhaust stroke after the estimation of the main body temperature Te0 at the start.

  As the body temperature Te0 at the time of start-up decreases, the vaporization rate of the injected fuel decreases and the fuel used for combustion becomes insufficient. Therefore, the engine control unit 56 increases the fuel injection amount as the main body temperature Te0 at the time of starting decreases. For example, the engine control unit 56 increases the fuel injection amount from the reference injection amount when the main body temperature Te0 at the time of starting is lower than the preset first reference temperature. On the other hand, the engine control unit 56 sets the fuel injection amount to the reference injection amount because the injected fuel is almost vaporized when the main body temperature Te0 at the time of starting is higher than the preset second reference temperature. To do.

  Here, when the main body temperature Te0 at the start is lower than the first reference temperature, in the second and subsequent fuel injections, the fuel adhering to the inside of the intake pipe 101a by the previous fuel injection is supplied to the combustion chamber 105. It is thought that the fuel to be burned increases. Therefore, the engine control unit 56 may reduce the second and subsequent fuel injection amounts in stages from the first fuel injection amount. Alternatively, the main body temperature estimation unit 55 continues to estimate the main body temperature in the second and subsequent four cycles after the start of crankshaft rotation, and the engine control unit 56 determines that the main body temperature exceeds the third reference temperature. In addition, the fuel injection amount may be reduced.

  With the configuration described above, the individual values learned from the individual differences of the internal combustion engine, the intake pressure, and the outside air temperature can be obtained without providing a dedicated sensor, wiring, and thermoelectric converter for detecting the body temperature of the internal combustion engine. Based on the measurement result of the rotation speed, the main body temperature can be accurately estimated. Then, the internal combustion engine can be favorably controlled, for example, by optimizing the fuel injection amount at the start based on the estimated main body temperature.

2. Embodiment 2
Next, an internal combustion engine control device 121 and an internal combustion engine control method according to Embodiment 2 will be described. The description of the same components as those in the first embodiment is omitted. Although the basic configuration of the control device 121 and the control method according to the present embodiment is the same as that of the first embodiment, the settings of the first time point and the second time point are different from those of the first embodiment.

  In the present embodiment, as shown in FIG. 10, the first time point is a time point until the crankshaft starts to rotate. Therefore, the first pressure P1 is atmospheric pressure. The second time point is a time point of a crank angle preset in the latter half of the intake stroke in the first four cycles after the start of rotation of the crankshaft (in this example, 30 degrees before bottom dead center).

  Even in such a setting, as shown in FIG. 11, a correlation was recognized between the pressure difference between the first pressure P1 and the second pressure P2 and the individual value A. Therefore, the individual value A can be determined also in the present embodiment.

  In the present embodiment, since the first pressure P1 and the second pressure P2 can be acquired and the individual value A can be determined before the bottom dead center between the intake stroke and the compression stroke, The determination time of the individual value A can be advanced.

  The second time point is set to 30 degrees before the bottom dead center, but is not limited to this. In the vicinity of the bottom dead center, the intake valve is often in the open / close operation. Therefore, it is preferable that the intake valve be before the timing at which the intake valve is closed, and more preferably before the start of the close operation.

  The first pressure P1 is the atmospheric pressure detected by the intake pressure sensor 104. However, when the atmospheric pressure can be known using other means, this may be used. For example, a method of obtaining atmospheric pressure information from the position information using satellite communication or the like can be considered.

<Individual value determination process>
A series of processes for determining the individual value A will be described with reference to the flowchart shown in FIG. In step S201, when the power source of the internal combustion engine 100 is switched from OFF to ON and power is supplied to the control device 121 and various sensors, the process proceeds to step S202. In step S202, operations of various sensors such as the intake pressure sensor 104, the crank angle sensor 118, and the outside air temperature sensor 125 are started.

  In step S203, the intake pressure detection unit 51 sets the intake pressure detected based on the output signal of the intake pressure sensor 104 as the first pressure P1. That is, in the present embodiment, the first time point is set to a time point after the power is turned on until the crankshaft starts to rotate. In step S204, the outside air temperature detection unit 53 detects the outside air temperature T0.

  Next, in step S205, the control device 121 starts energization of the cell motor and starts cranking. In step S206, the intake pressure detection unit 51 detects the intake pressure (second pressure P2) at a preset second time point based on the output signal of the intake pressure sensor 104.

  In step S207, the eigenvalue determining unit 54 determines the individual value A used for estimating the body temperature at the start based on the first pressure P1, the second pressure P2, and the outside air temperature T0. In step S <b> 208, the eigenvalue determining unit 54 stores the determined individual value A in a nonvolatile storage device such as an EEPROM of the control device 121.

3. Embodiment 3
Next, an internal combustion engine control device 121 and an internal combustion engine control method according to Embodiment 3 will be described. The description of the same components as those in the first embodiment is omitted. Although the basic configuration of the control device 121 and the control method according to the present embodiment is the same as that of the first embodiment, the settings of the first time point and the second time point are different from those of the first embodiment.

  In the present embodiment, as shown in FIG. 13, the first time point is the crank angle preset in the first half of the compression stroke in the first four cycles after the start of rotation of the crankshaft (in this example, after the bottom dead center). 60 degrees). The second time point is a time point of a crank angle (60 degrees after the top dead center in this example) preset in the first half of the expansion stroke after the first time point in the first four cycles.

  In the present embodiment, since the second pressure P2 is obtained in the expansion stroke, the determination time of the individual value A is later than in the first embodiment, but the difference in the inflow air amount due to the individual difference or the like is caused by the expansion stroke. Since it appears prominently in the intake air pressure, the determination accuracy of the individual value A is increased.

  The second time point is set to 60 degrees after the top dead center, but may be set to an appropriate time point at which the amount of change in the intake pressure with respect to the change in the crank angle becomes large in the first half of the expansion stroke.

4). Embodiment 4
Next, an internal combustion engine control device 121 and an internal combustion engine control method according to Embodiment 4 will be described. The description of the same components as those in the first embodiment is omitted. Although the basic configuration of the control device 121 and the control method according to the present embodiment is the same as that of the first embodiment, the settings of the first time point and the second time point are different from those of the first embodiment.

  FIG. 14 shows a case where cranking is started from a state where the piston 113 is stopped in the middle of the intake stroke. In this case, even if the piston 113 moves to the bottom dead center in the first intake stroke, the volume of air sucked into the combustion chamber 105 from the intake pipe 101a is smaller than in the case where the intake is fully performed in the intake stroke. Less, the decrease in intake pressure is reduced, and the subsequent increase in intake pressure is also reduced. Therefore, when the cranking starts in the middle of the intake stroke, the behavior of the intake pressure is different from that in the case of full intake in the intake stroke. Therefore, if the individual value A is determined based on the intake pressure information in this case, a determination error occurs.

  Therefore, in the present embodiment, the eigenvalue determining unit 54 has a crank angle preset in the compression stroke or expansion stroke in the first four cycles after the start of rotation of the crankshaft (in this example, 60 degrees after bottom dead center). If the fifth pressure P5, which is the intake pressure detected at the fifth time, is higher than the preset determination pressure, the first pressure P1 detected at the first time and the second time in the next four cycles. The individual value A is determined based on the second pressure P2. When the fifth pressure P5 is lower than the determination pressure, the eigenvalue determination unit 54 detects at the first time point and the second time point in the first four cycles after the crankshaft rotation starts, as in the first embodiment. The individual value A is determined based on the first pressure P1 and the second pressure P2.

  According to this configuration, when the fifth pressure P5 detected in the first four cycles is higher than the determination pressure, it is determined that cranking has started in the middle of the intake stroke, and the first pressure detected in the first four cycles is determined. Since the individual value A is not determined using the first pressure P1 and the second pressure P2, it is possible to prevent a determination error from occurring. Then, the individual value A can be accurately determined by using the first pressure P1 and the second pressure P2 detected in the next four cycles that are fully inhaled in the intake stroke. On the other hand, if the fifth pressure P5 detected in the first four cycles is lower than the determination pressure, it is determined that the intake is fully performed in the intake stroke, and the first pressure P1 and the second pressure detected in the first four cycles are determined. The individual value A can be accurately determined using the pressure P2. Therefore, the individual value A can be accurately determined regardless of the stop position of the piston 113 at the start of cranking.

  The first time point and the second time point may be set at the same time as in the second or third embodiment. The determination pressure may be changed according to the atmospheric pressure. Since the change in the intake pressure at the bottom dead center due to the change in the atmospheric pressure can be taken into consideration, the determination can be made with higher accuracy. When the fifth pressure P5 is higher than the determination pressure, the engine control unit 56 does not start fuel injection in the first four cycles of exhaust stroke but starts fuel injection in the second and subsequent four cycles of exhaust stroke.

  A series of processes for determining the individual value A will be described with reference to the flowchart shown in FIG. In step S301, when the power source of the internal combustion engine 100 is switched from OFF to ON and power is supplied to the control device 121 and various sensors, the process proceeds to step S302. In step S202, operations of various sensors such as the intake pressure sensor 104, the crank angle sensor 118, and the outside air temperature sensor 125 are started. In step S303, the outside air temperature detection unit 53 detects the outside air temperature T0.

  Next, in step S304, the control device 121 starts energization of the cell motor and starts cranking. In step S305, the intake pressure detection unit 51, based on the output signal of the intake pressure sensor 104, sets the intake pressure (fifth in the present example, 60 degrees after the bottom dead center of the compression stroke) at a preset fifth time point. The pressure P5) is detected.

  In step S306, the eigenvalue determination unit 54 determines whether or not the fifth pressure P5 is higher than the determination pressure. If cranking has started in the middle of the intake stroke and the fifth pressure P5 is higher than the determination pressure, the process returns to step S305. In step S305, the intake pressure detection unit 51 detects the fifth pressure P5 at the fifth time point in the next four cycles, and proceeds to step S306. In the second four cycles, since full intake is normally performed in the intake stroke, it is determined in step S306 that the fifth pressure P5 is not higher than the determination pressure, and the process proceeds to step S307. In step S307, the intake pressure detection unit 51 detects the intake pressure (first pressure P1) at the first time point in the second four cycles based on the output signal of the intake pressure sensor 104, and at the second time point. The intake pressure (second pressure P2) is detected, and the process proceeds to step S308.

  On the other hand, if cranking has not started in the middle of the intake stroke and the fifth pressure P5 is lower than the determination pressure, the process does not return to step S305 but proceeds to step S306. In step S306, the intake pressure detection unit 51 detects the intake pressure (first pressure P1) at the first time point in the first four cycles based on the output signal of the intake pressure sensor 104, and the intake pressure (first pressure P1) at the second time point. The second pressure P2) is detected, and the process proceeds to step S308.

  In step S308, the eigenvalue determining unit 54 determines the individual value A used for estimating the body temperature at the start based on the first pressure P1, the second pressure P2, and the outside air temperature T0. In step S <b> 309, the eigenvalue determining unit 54 stores the determined individual value A in a nonvolatile storage device such as an EEPROM of the control device 121.

5). Embodiment 5
Next, an internal combustion engine control device 121 and an internal combustion engine control method according to Embodiment 5 will be described. The description of the same components as those in the first embodiment is omitted. The basic configuration of the control device 121 and the control method according to the present embodiment is the same as that of the first embodiment, but in the present embodiment, the body temperature is continuously estimated even after the start of combustion. It is different in the configuration.

  By the same method as in the first embodiment, body temperature estimation unit 55 estimates body temperature Te0 at the time of starting. After the start of combustion, the main body temperature estimation unit 55 estimates the main body temperature based on the energy balance, with the main body temperature Te0 at the time of starting as an initial value.

Here, the relational expression of the change amount ΔTe of the body temperature of the internal combustion engine per update interval Δt can be expressed by Expression (2). Furthermore, the sum total of the energy output from the internal combustion engine can be expressed by Expression (3). Note that the second term on the right side of Equation (3) indicates the amount of heat release, and the first term on the right side indicates other output energy.
M × CP × ΔTe / Δt = QIN−QOUT (2)
QOUT = Σ (Qj) + β × (Te−T0) (3)

  Here, M is the weight (kg) of the main body of the internal combustion engine, CP is the specific heat (J / (kg · K)) of the main body of the internal combustion engine, and QIN is input to the main body of the internal combustion engine by combustion. QOUT is the total energy (J / s) output from the main body of the internal combustion engine, and Qj is the output energy of the individual element j from the main body of the internal combustion engine. Where t is the time (s) and β is a preset constant (W / K). QIN is energy corresponding to combustion energy. The update interval Δt is set to, for example, a combustion interval (4 cycle interval).

  By solving the equations (2) and (3), the change amount ΔTe of the main body temperature after the update interval Δt has elapsed can be calculated. Therefore, every time the update interval Δt elapses, the main body temperature Te can be continuously estimated by changing the main body temperature Te0 from the main body temperature Te0 at the time of starting by a change amount ΔTe of the main body temperature.

  Next, a series of processes for estimating the body temperature will be described with reference to the flowchart shown in FIG. In step S401, when the power source of the internal combustion engine 100 is switched from OFF to ON and power is supplied to the control device 121 and various sensors, the process proceeds to step S402. In step S402, control device 121 estimates main body temperature Te0 at the time of starting by a method similar to the flowchart of FIG. 9 of the first embodiment.

  In step S403, the main body temperature estimating unit 55 sets the main body temperature Te0 at the time of starting to the initial value of the main body temperature Te. In step S404, the body temperature estimation unit 55 determines whether or not the body temperature update timing has come. If it is determined that the body timing has reached the update timing, the process proceeds to step S405. To do. The update timing is a timing at which fuel injection is performed and combustion is performed.

  In step S405, the main body temperature estimation unit 55 acquires various pieces of information necessary for calculating the sum QIN of input energy, the sum QOUT of output energy, and the output energy Qj of individual elements. In step S406, the body temperature estimation unit 55 calculates the total energy QIN of the input energy, the total energy QOUT of the output energy, and the output energy Qj of the individual elements using the various information acquired in step S405.

  In step S407, the body temperature estimating unit 55 uses the sum of input energy QIN, the sum of output energy QOUT, the output energy Qj of individual elements, the body weight M, the specific heat CP, and the constant β, and uses Equation (2) and Equation (2). According to (3), the amount of change ΔTe of the body temperature of the internal combustion engine is calculated, and the value obtained by adding the amount of change ΔTe to the body temperature Te calculated previously is updated as a new body temperature Te (Te ← Te + ΔTe).

  In step S408, the engine control unit 56 calculates the fuel injection amount based on the main body temperature Te updated in step S408, and performs fuel injection. And the control apparatus 121 returns to step S404, and updates the main body temperature Te repeatedly.

  In this manner, by sequentially predicting the change in the main body temperature after starting and controlling the fuel injection amount, it is possible to supply the fuel suitable for the change in the main body temperature, and to control the internal combustion engine well.

6). Diversion Example In each of the above embodiments, an example of the operation of the internal combustion engine 100 has been described, but the embodiment is not limited thereto. The opening / closing timing of the exhaust valve 116 or the intake valve 111 may be changed in accordance with the characteristics of the internal combustion engine 100. For example, the intake valve 111 and the exhaust valve 116 may be operated to open simultaneously at the top dead center between the exhaust stroke and the intake stroke. Further, the intake valve 111 or the exhaust valve 116 may be opened and closed before the piston reaches the top dead center or the bottom dead center.

  Further, a variable valve timing mechanism for changing the opening / closing timing of one or both of the intake valve and the exhaust valve is provided, and the engine control unit 56 is configured to change the variable valve based on the body temperature at the start and the body temperature after the start of combustion. The timing mechanism may be controlled to change the opening / closing timing of one or both of the intake valve and the exhaust valve.

  In each of the above-described embodiments, the case where the controller 121 is configured to execute the estimation of the main body temperature and the control of the internal combustion engine based on the estimated main body temperature has been described. However, the embodiment is not limited to this. That is, the control device 121 may estimate the main body temperature, and an electronic control device different from the control device 121 may be configured to control the internal combustion engine based on the estimated main body temperature. Therefore, the control device 121 may be composed of a plurality of electronic control devices.

  In each of the above-described embodiments, the case where the control device 121 is configured to execute the determination of the individual value and the estimation of the main body temperature using the determined individual value has been described. However, the embodiment is not limited to this. That is, an electronic control device different from the control device 121 determines an individual value, the determined individual value is stored in a nonvolatile storage device of the control device 121, and the control device 121 is stored in the individual storage device from the nonvolatile storage device. It may be configured to read the value and estimate the body temperature. Therefore, the control device 121 may be composed of a plurality of electronic control devices.

  In each of the above-described embodiments, the case where the temperature of the main body of the internal combustion engine is estimated has been described. However, an object having the same temperature behavior as the main body of the internal combustion engine, for example, engine oil, internal combustion engine You may be comprised so that temperature, such as cooling water, may be estimated.

  In each of the embodiments described above, the intake pressure detection unit 51 has been described to detect the intake pressure based on the output signal of the intake pressure sensor 104 at a specific time point. However, the embodiment is not limited to this. It is not limited. For example, the intake pressure detection unit 51 continuously detects the intake pressure based on the output signal of the intake pressure sensor 104, and uses the information on the intake pressure after performing noise removal processing such as moving average to specify the intake pressure. The intake pressure at the time may be detected.

  In each of the above embodiments, the physical dimension of temperature is described in ° C., but a numerical value representing temperature may be used. Thus, the physical dimension need not be in degrees Celsius.

  It should be noted that the embodiment can be modified or omitted as appropriate.

Ne4 rotational speed, 51 intake pressure detection unit, 52 rotational speed detection unit, 53 outside air temperature detection unit, 54 eigenvalue determination unit, 55 body temperature estimation unit, 56 engine control unit, 100 internal combustion engine, 100a body of internal combustion engine, 101a intake air Pipe, 121 Internal combustion engine controller, A individual value, T0 outside air temperature, Te0 body temperature at start-up, P1 first pressure, P2 second pressure, P3 third pressure, P4 fourth pressure, P5 fifth pressure

An internal combustion engine control method according to the present application includes an intake pressure detection step of detecting an intake pressure that is a pressure of gas in an intake pipe at a plurality of preset time points when starting the internal combustion engine;
Exhaust stroke, an intake stroke, a compression stroke, and the preset later than the first time point is previously set in the compression stroke, and the first time within the compression stroke of the contained expansion stroke cycle An individual value determining step for determining an individual value used for estimating the body temperature of the internal combustion engine at the time of starting based on the first pressure and the second pressure, which are the intake pressures detected at two time points , respectively. It is something to execute.

An internal combustion engine control apparatus according to the present application includes an intake pressure detection unit that detects an intake pressure that is a pressure of a gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started,
Exhaust stroke, an intake stroke, a compression stroke, and the preset later than the first time point is previously set in the compression stroke, and the first time within the compression stroke of the contained expansion stroke cycle An individual value determination unit for determining an individual value used for estimating the body temperature of the internal combustion engine at the time of starting based on the first pressure and the second pressure, which are the intake pressures detected at two time points , respectively. It is provided.

An internal combustion engine control apparatus according to the present application includes an intake pressure detection unit that detects an intake pressure that is a pressure of a gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started,
An outside air temperature detecting unit for detecting outside air temperature that is the temperature of outside air sucked into the intake pipe;
An individual value determining unit that determines an individual value based on the first pressure and the second pressure, which are the intake pressures detected at the first time point and the second time point set in advance, respectively;
A rotational speed detector for detecting the rotational speed of the internal combustion engine;
Based on the rotational speed, the outside air temperature, the third pressure and the fourth pressure, which are the intake pressure detected at the preset third time point and the fourth time point, respectively, and the individual value, A main body temperature estimating unit for estimating a main body temperature of the internal combustion engine;
An engine control unit that controls the internal combustion engine based on the body temperature at the time of starting ,
The main body temperature estimating unit sets the main body temperature at the start to Te0, the rotation speed to Ne, the outside air temperature to T0, the third pressure to P3, the fourth pressure to P4, The value is A, and the four preset constants are B, C, D, and E, respectively.
Te0 = A × (P4 / P3 -B) C × T0 D × Ne E
The main body temperature at the time of start-up is estimated by the following calculation formula.

Claims (14)

An intake pressure detection step of detecting an intake pressure that is a pressure of a gas in the intake pipe at a plurality of preset time points when starting the internal combustion engine;
Based on the first pressure and the second pressure, which are the intake pressures detected respectively at the first time point and the second time point set in advance, individual values used for estimating the body temperature of the internal combustion engine at the time of starting An individual value determination step for determining, and a control method for an internal combustion engine that executes the individual value determination step. An outside air temperature detecting step for detecting an outside air temperature that is the temperature of the outside air sucked into the intake pipe;
A rotational speed detection step for detecting the rotational speed of the internal combustion engine;
Based on the rotational speed, the outside air temperature, the third pressure and the fourth pressure, which are the intake pressure detected at the preset third time point and the fourth time point, respectively, and the individual value, A body temperature estimating step for estimating the body temperature;
The internal combustion engine control method according to claim 1, further comprising an engine control step of controlling the internal combustion engine based on the main body temperature at the time of starting.   The control method for an internal combustion engine according to claim 1 or 2, wherein, in the individual value determining step, the individual value is determined based on a pressure difference between the first pressure and the second pressure. Further executing an outside air temperature detecting step of detecting an outside air temperature that is the temperature of outside air sucked into the intake pipe,
The method for controlling an internal combustion engine according to any one of claims 1 to 3, wherein, in the individual value determination step, the individual value is determined based on the first pressure, the second pressure, and the outside air temperature. The internal combustion engine is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke,
The first time point is a time point of a crank angle preset in the first half of the compression stroke in the first four cycles after the start of rotation of the crankshaft, and the second time point is the time in the first four cycles. The method for controlling an internal combustion engine according to any one of claims 1 to 4, wherein the internal combustion engine is a time point of a crank angle preset in the compression stroke after the first time point. The internal combustion engine is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke,
The first time point is a time point until the crankshaft starts to rotate, and the second time point is a crank angle set in advance in the second half of the intake stroke in the first four cycles after the start of rotation of the crankshaft. The control method for an internal combustion engine according to any one of claims 1 to 4, wherein The internal combustion engine is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke,
The first time point is a time point of a crank angle preset in the first half of the compression stroke in the first four cycles after the start of rotation of the crankshaft, and the second time point is the time in the first four cycles. 5. The method for controlling an internal combustion engine according to claim 1, wherein the control point is a time point of a crank angle set in advance in the first half of the expansion stroke after the first time point. The internal combustion engine is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke,
In the individual value determination step, a fifth pressure that is the intake pressure detected at the fifth time point of the crank angle preset in the compression stroke or the expansion stroke in the first four cycles after the start of rotation of the crankshaft. Is higher than a preset judgment pressure, the first pressure and the second pressure detected at the first time point and the second time point in the next four cycles, or the next four cycles. The method for controlling an internal combustion engine according to any one of claims 1 to 7, wherein the individual value is determined based on the second pressure detected at the second time point. In the body temperature estimating step, the body temperature at the time of starting is set to Te0, the rotation speed is set to Ne, the outside air temperature is set to T0, the third pressure is set to P3, the fourth pressure is set to P4, The value is A, and the four preset constants are B, C, D, and E, respectively.
Te0 = A × (P3 / P4 -B) C × T0 D × Ne E
The method for controlling an internal combustion engine according to claim 2, wherein the main body temperature at the time of starting is estimated by a calculation formula: The internal combustion engine is a four-cycle engine that performs four cycles of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke,
The third time point is a time point until the crankshaft starts to rotate, and the fourth time point is preset in the compression stroke or the expansion stroke in the first four cycles after the start of rotation of the crankshaft. The method for controlling an internal combustion engine according to claim 2 or 9, wherein the control time is a time of a crank angle.   11. The body temperature estimation step according to claim 2, wherein the body temperature at the time of starting is set as an initial value, and the body temperature is estimated based on an energy balance after the start of combustion. The control method of the internal combustion engine as described.   The internal combustion engine control method according to claim 2, wherein in the engine control step, the fuel injection amount at the start is changed based on the body temperature at the start. An intake pressure detection unit that detects an intake pressure that is a pressure of gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started;
Based on the first pressure and the second pressure, which are the intake pressures detected respectively at the first time point and the second time point set in advance, individual values used for estimating the body temperature of the internal combustion engine at the time of starting A control apparatus for an internal combustion engine, comprising: an individual value determination unit for determining. An intake pressure detection unit that detects an intake pressure that is a pressure of gas in the intake pipe at a plurality of preset time points when the internal combustion engine is started;
An outside air temperature detecting unit for detecting outside air temperature that is the temperature of outside air sucked into the intake pipe;
An individual value determining unit that determines an individual value based on the first pressure and the second pressure, which are the intake pressures detected at the first time point and the second time point set in advance, respectively;
A rotational speed detector for detecting the rotational speed of the internal combustion engine;
Based on the rotational speed, the outside air temperature, the third pressure and the fourth pressure, which are the intake pressure detected at the preset third time point and the fourth time point, respectively, and the individual value, A main body temperature estimating unit for estimating a main body temperature of the internal combustion engine;
An internal combustion engine control device comprising: an engine control unit that controls the internal combustion engine based on the body temperature at the time of starting.

Images