JP6261840B1 - Internal combustion engine temperature prediction apparatus and temperature prediction method - Google Patents

Abstract

An internal combustion engine temperature predicting apparatus and a temperature predicting method include an intake pressure acquired as an outside air pressure at a timing within a period from when an internal combustion engine starts to start from a stopped state to when the internal combustion engine starts to rotate, and an internal combustion engine The initial temperature of the internal combustion engine based on the intake pressure acquired as the intake representative pressure at the timing within the period from the start of rotation to the start of combustion in the combustion chamber and the internal combustion engine speed acquired at the timing And the temperature of the internal combustion engine after the start of combustion is predicted using the predicted initial temperature.

Description

  The present invention relates to a temperature predicting apparatus and a temperature predicting method for predicting the temperature of an internal combustion engine using intake pressure in an intake pipe.

  Conventionally, an electronic control device called an ECU is mounted on a vehicle. The ECU is mainly configured using a microcomputer, and controls the operation of an internal combustion engine for a vehicle 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.

  Here, when a dedicated temperature sensor is arranged in the internal combustion engine main body and the ECU adopts feedback control in which the ECU controls the internal combustion engine using the measurement result of the temperature sensor, the response of the ECU from the measurement time of the temperature sensor Due to the delay in time, it is difficult to control the internal combustion engine appropriately.

  Therefore, a method for predicting the temperature of the internal combustion engine body at an arbitrary time using the temperature of the internal combustion engine body at the start of the internal combustion engine, the temperature of the intake pipe at an arbitrary time, and a simulation model has been proposed. (For example, refer to Patent Document 1). In the prior art described in Patent Document 1, as a configuration for knowing the temperature of the internal combustion engine body when the internal combustion engine is started, a dedicated temperature sensor is arranged in the housing of the internal combustion engine body, and the internal combustion engine body is detected by the temperature sensor. Direct detection configuration that directly detects the temperature of the engine, and directly detects the temperature of the engine oil or cooling water of the internal combustion engine, and indirectly detects the temperature of the internal combustion engine body by predicting the temperature based on the detection result An indirect detection configuration is proposed.

  Also, assuming that the temperature in the intake pipe at the start of the internal combustion engine matches the atmospheric temperature, there is a technique for predicting the temperature of the intake pipe based on the pressure in the cylinder of the internal combustion engine and the atmospheric temperature around the internal combustion engine. It has been proposed (see, for example, Patent Document 2).

JP 2005-83240 A JP 2006-132526 A

  However, in order to know the temperature of the internal combustion engine body, when applying the direct detection configuration described above, it is necessary to prepare a heat-resistant temperature sensor that can withstand the temperature rise of the internal combustion engine body. In addition, it is necessary to perform operations such as drilling for mounting the temperature sensor on the surface of the internal combustion engine main body, mounting the temperature sensor, and the like. In addition, when applying the indirect detection configuration described above in order to know the temperature of the internal combustion engine body, it is necessary to prepare a heat-resistant temperature sensor that can withstand the temperature rise of engine oil or cooling water, as described above. Furthermore, it is necessary to perform the above operations.

  That is, in the prior art described in Patent Document 1, in order to know the temperature of the internal combustion engine main body, even if either the direct detection configuration or the indirect detection configuration is applied, the manufacturing cost and There is a risk of increasing the work load. As a result, there is a risk that parts and manufacturing costs may remain high.

  In the prior art described in Patent Document 2, as described above, it is assumed that the temperature in the intake pipe when the internal combustion engine is started matches the atmospheric temperature. Therefore, based on the time interval between when the internal combustion engine is started and when the internal combustion engine is stopped, the assumed range varies, and the temperature prediction accuracy may deteriorate. Therefore, for example, when the temperature of the internal combustion engine body is predicted using the temperature of the intake pipe predicted by applying the conventional technique described in Patent Document 2 in the prior art described in Patent Document 1, the internal combustion engine body There is a possibility that the prediction accuracy of the temperature will be further deteriorated.

  The present invention has been made in view of the above circumstances, and the temperature of the internal combustion engine that can predict the temperature of the internal combustion engine at a relatively low cost without using a dedicated temperature sensor for high temperatures. An object is to obtain a prediction device and a temperature prediction method.

  An internal combustion engine temperature predicting apparatus according to the present invention performs an intake step of taking outside air from an intake pipe into a combustion chamber, and ignites the injected fuel to the outside air sucked in the intake step, thereby causing combustion in the combustion chamber. In a temperature predicting apparatus for predicting the temperature of an internal combustion engine configured to wake up, the intake pipe in the intake pipe has a timing within a period from when the internal combustion engine starts to start from a stopped state to when the internal combustion engine starts to rotate. An outside air pressure acquisition unit that acquires an atmospheric pressure as an outside air pressure; an intake air representative pressure acquisition unit that acquires an intake air pressure as an intake air representative pressure at a timing within a period from the start of rotation of the internal combustion engine to the start of combustion; A parameter information acquisition unit for acquiring the number of revolutions per unit time of the internal combustion engine, an outside air pressure acquired by the outside air pressure acquisition unit, an intake representative pressure and a parameter acquired by the intake representative pressure acquisition unit. An initial temperature prediction unit that predicts an initial temperature of the internal combustion engine in a period from the start to the start of combustion based on the number of revolutions acquired by the data information acquisition unit, and an initial value predicted by the initial temperature prediction unit And a temperature prediction unit that predicts the temperature of the internal combustion engine after the start of combustion using the temperature.

  An internal combustion engine temperature predicting method according to the present invention performs an intake step of sucking outside air from an intake pipe into a combustion chamber, and ignites the injected fuel to the outside air sucked in the intake step to cause combustion in the combustion chamber. In the temperature prediction method for predicting the temperature of an internal combustion engine configured to occur, the intake pipe in the intake pipe is at a timing within a period from when the internal combustion engine starts to start from a stopped state to when the internal combustion engine starts to rotate. The intake pressure is acquired as the intake representative pressure at the timing from the step of acquiring the atmospheric pressure as the outside air pressure and the period from the start of rotation of the internal combustion engine to the start of combustion, and the number of rotations per unit time of the internal combustion engine On the basis of the acquired outside air pressure, the representative intake air pressure, and the rotational speed, the initial value of the internal combustion engine in the period from the start to the start of combustion. And predicting the temperature by using the initial temperature expected, those having the steps of: predicting a temperature of the internal combustion engine since the start of combustion, the.

  According to the present invention, it is possible to obtain an internal combustion engine temperature predicting apparatus and temperature predicting method capable of predicting the temperature of an internal combustion engine at a relatively low cost without using a dedicated temperature sensor for high temperatures.

It is a block diagram of the internal combustion engine provided with the temperature prediction apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the pressure change of the intake pipe of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the correlation of the intake pressure and main body temperature which concern on Embodiment 1 of this invention. It is a flowchart which shows a series of operation | movement of the temperature prediction apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the pressure change of the intake pipe of the internal combustion engine which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the pressure change of the intake pipe of the internal combustion engine which concerns on Embodiment 3 of this invention. It is a schematic diagram which shows the pressure change of the intake pipe of the internal combustion engine which concerns on Embodiment 4 of this invention. It is a flowchart which shows a series of operation | movement which estimates the initial temperature of the temperature prediction apparatus of the internal combustion engine which concerns on Embodiment 4 of this invention.

  Hereinafter, embodiments of a temperature prediction device and a temperature prediction method for an internal combustion engine disclosed in the present application will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same portions or corresponding portions are denoted by the same reference numerals, and redundant description is omitted.

  The following embodiments are merely examples, and the present invention is not limited to these embodiments. Furthermore, the internal combustion engine to which the present invention is applied is, for example, a vehicle internal combustion engine. In the following embodiments, the case where the present invention is applied to a vehicle internal combustion engine will be exemplified.

Embodiment 1 FIG.
The internal combustion engine temperature predicting apparatus 121 according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a configuration diagram of an internal combustion engine 100 including an internal combustion engine temperature predicting apparatus 121 according to Embodiment 1 of the present invention.

  The internal combustion engine 100 performs an intake process for sucking outside air into the combustion chamber 105 from the intake pipe 101a, and ignites the injected fuel to the outside air sucked in the intake process so as to cause combustion in the combustion chamber 105. It is a prime mover configured as follows. More specifically, the internal combustion engine 100 is a four-cycle gasoline internal combustion engine that is operated with four steps of an intake process, a compression process, an expansion process, and an exhaust process as one combustion cycle.

  The internal combustion engine 100 includes an intake passage 101, an air filter 102, a throttle valve 103, an intake pressure sensor 104, a combustion chamber 105, a bypass passage 106, an idle speed control valve 107, a fuel pump 108, a fuel Tank 109, injector 110, intake valve 111, spark plug 112, piston 113, connecting rod 114, crankshaft 115, exhaust valve 116, exhaust passage 117, crank angle sensor 118, and three-way catalyst 119, the oxygen sensor 120, and the temperature prediction apparatus 121 are comprised.

  The internal combustion engine body 100a is located above the piston 113, the piston 113, the connecting rod 114 and the crankshaft 115 covered with the cylinder, the intake valve 111, the exhaust valve 116 and the spark plug 112 installed on the cylinder head. It includes a piston 113 and a combustion chamber 105 sandwiched between cylinder heads.

  In an intake passage 101 of the internal combustion engine 100, an air filter 102, a throttle valve 103, and an intake pressure sensor 104 are provided in order from the upstream side.

  The intake pressure sensor 104 detects the intake pressure of the gas in the intake pipe 101 a corresponding to the intake passage 101 on the downstream side of the throttle valve 103. The intake pressure sensor 104 is communicably connected to a temperature prediction device 121 described later, and gives the detection result to the temperature prediction device 121 as intake pressure information.

  The intake passage 101 is provided with a bypass passage 106 and an idle speed control valve 107 so that the upstream side and the downstream side with respect to the throttle valve 103 communicate with each other.

  In the intake pipe 101a, an injector 110 that supplies the fuel pumped up from the fuel tank 109 by the fuel pump 108 to the vicinity of the intake port is provided downstream of the intake pressure sensor 104. The injector 110 is communicably connected to a temperature prediction device 121 described later.

  The combustion chamber 105 of the internal combustion engine body 100 a is provided with an intake valve 111 for intake, and the intake passage 101 is connected to the combustion chamber 105 via the intake valve 111. The combustion chamber 105 is provided with an exhaust valve 116 for exhaust, and the combustion chamber 105 is connected to the exhaust passage 117 via the exhaust valve 116.

  At the upper part of the combustion chamber 105, a spark plug 112 with an electrode protruding is provided. The spark plug 112 is communicably connected to a temperature prediction device 121 described later. A piston 113 that reciprocates up and down is provided below the combustion chamber 105. The piston 113 is connected to the crankshaft 115 through a connecting rod 114.

  A crank angle sensor 118 that detects the rotation angle of the crankshaft 115 is provided in the vicinity of the crankshaft 115. The crank angle sensor 118 is communicably connected to a temperature prediction device 121 described later, and gives the detection result to the temperature prediction device 121 as crank angle information.

  A three-way catalyst 119 for purifying NOx, HC and CO of combustion exhaust gas from the combustion chamber 105 is provided on the downstream side of the exhaust passage 117. In the exhaust passage 117, an oxygen sensor 120 that detects the oxygen concentration in the exhaust gas is provided upstream of the three-way catalyst 119. The oxygen sensor 120 is communicably connected to a temperature prediction device 121 described later, and gives the detection result to the temperature prediction device 121 as oxygen information.

  The throttle valve 103 adjusts the opening of the throttle. The air from which dust has been removed by the air filter 102 is supplied to the combustion chamber 105 through the intake passage 101. The throttle valve 103 controls the flow rate of air supplied to the combustion chamber 105 by adjusting the opening of the throttle. From the viewpoint of the driver, the throttle valve 103 controls the throttle opening adjustment in accordance with the amount of operation of an accelerator (not shown) operated by the driver. The idle speed control valve 107 provided in the bypass flow path 106 adjusts the flow rate of air flowing through the bypass flow path 106 in order to control the rotational speed of the internal combustion engine 100 when the internal combustion engine 100 is idling.

  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 through 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 are provided at equal intervals in the circumferential direction on the outer peripheral portion of the rotor that rotates integrally with the crankshaft 115. When these protrusions cross the crank angle sensor 118, the crank angle sensor 118 outputs a rectangular crank signal as crank angle information. In the first embodiment, as a specific example, the plurality of protrusions are provided every 30 degrees with the center of the crankshaft 115 as a reference.

  In addition, the outer peripheral part of the rotor is provided with a missing tooth portion in which a part of the plurality of protrusions provided at equal intervals is missing. With such a configuration, if the crankshaft 115 rotates 360 degrees at the maximum, the temperature prediction device 121 can determine the position of the piston 113 from the detection value of the crank angle sensor 118. Therefore, the temperature prediction device 121 can recognize that the piston 113 has reached the top dead center and the bottom dead center. If the internal combustion engine 100 is a four-cycle internal combustion engine, the temperature predicting device 121 determines the four steps of the internal combustion engine body 100a (ie, the intake air) from the detection value of the crank angle sensor 118 and the detection value of the intake pressure sensor 104. Process, compression process, expansion stroke and exhaust process) and the detailed position of the piston 113 can be recognized.

  The temperature prediction device 121 controls the internal combustion engine 100 such as the fuel injection amount and the air-fuel ratio by outputting a fuel injection command to the injector 110 in accordance with the position of the piston 113.

  As described above, the temperature predicting device 121 is communicably connected to the intake pressure sensor 104, the injector 110, the spark plug 112, the crank angle sensor 118, the oxygen sensor 120, and the like.

  The temperature prediction device 121 includes, for example, a microcomputer that executes arithmetic processing, a ROM (Read Only Memory) that stores data such as program data and fixed value data, and a RAM that can be sequentially rewritten by updating stored data. (Random Access Memory), a power supply, an output processing circuit, an input processing circuit, an A / D conversion circuit, a power device, a communication IC, and the like.

  The temperature prediction device 121 predicts the temperature of the internal combustion engine main body 100a (hereinafter referred to as main body temperature) based on the detection value of the intake pressure sensor 104. Further, the temperature prediction device 121 controls the fuel injection amount from the injector 110 based on the predicted main body temperature.

  Next, starting of the internal combustion engine 100 will be described with reference to FIG. FIG. 2 is a schematic diagram showing a change in pressure in intake pipe 101a of internal combustion engine 100 according to Embodiment 1 of the present invention. In FIG. 2, the horizontal axis indicates the crank number indicating the position of the piston, and the vertical axis indicates the intake pressure Pm that is the internal pressure of the intake pipe 101a.

  In FIG. 2, since the case where the crankshaft 115 rotates twice in one combustion cycle is considered, 2 for each of the plurality of protrusions provided at every 30 ° on the outer periphery of the rotor rotating integrally with the crankshaft 115. The crank number for rotation is attached. As shown in FIG. 2, in one combustion cycle, in the first rotation of the crankshaft 115 (that is, the compression process and the expansion stroke), the numbers 0 to 11 are sequentially assigned to the protrusions, and the second rotation of the crankshaft 115 is performed. (In other words, in the exhaust process and the intake process), the numbers 12 to 23 are sequentially assigned to the protrusions.

  When the internal combustion engine 100 is stopped and the power supply of the internal combustion engine 100 is turned off, the power supply of the temperature prediction device 121 is also turned off, and the power supply to the temperature prediction device 121 is stopped. In this case, each information that the temperature prediction device 121 has acquired from the intake pressure sensor 104, the crank angle sensor 118, and the oxygen sensor 120 so far is lost unless it is stored in the memory.

  Next, when the power of the temperature prediction device 121 is turned on as the power of the internal combustion engine 100 is turned on, power is supplied to the temperature prediction device 121. In this case, the temperature prediction device 121 starts acquiring information from the intake pressure sensor 104, the crank angle sensor 118, and the oxygen sensor 120. The intake pressure information acquired from the intake pressure sensor 104 immediately after the internal combustion engine 100 is turned on can be treated as atmospheric pressure information around the vehicle on which the internal combustion engine 100 is mounted.

  Next, when starting the internal combustion engine body 100a, the cell motor or the like rotates the crankshaft 115 to move the piston 113. In the process of starting the internal combustion engine main body 100a, the temperature predicting device 121 detects that the internal combustion engine main body 100a is in the intake process based on each information acquired from the crank angle sensor 118 and the intake pressure sensor 104.

  In the intake process, the piston 113 is lowered 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 and the gas pressure in the intake pipe 101a is Becomes negative pressure. When the piston 113 passes the bottom dead center, the intake valve 111 is closed, and thereafter, the intake process is shifted to the compression process.

  The compression process is a process in which the gas in the combustion chamber 105 is compressed by the piston 113 that moves in the vertical direction in the cylinder as the crankshaft 115 rotates. The expansion process that shifts from the compression process is a process in which the gas in the combustion chamber 105 is expanded by the piston 113.

  More specifically, in the compression step, the gas mainly composed of air introduced into the combustion chamber 105 is compressed in the combustion chamber 105 as the piston 113 rises. Further, when the piston 113 reaches near the top dead center, the fuel is injected by the injector 110 and the intake valve 111 is opened, so that the fuel is introduced into the combustion chamber 105. When the intake valve 111 is closed and fuel is ignited in the combustion chamber 105 by the spark plug 112, combustion occurs. In the meantime, while both the intake valve 111 and the exhaust valve 116 are closed, the expansion stroke is started, and the piston 113 is lowered toward the bottom dead center. Thereafter, when the piston 113 reaches near the bottom dead center, the exhaust valve 116 is opened, and the combustion gas in the combustion chamber 105 is exhausted by the exhaust passage 117.

  On the other hand, the intake valve 111 is closed and the throttle valve 103 is closed inside the intake pipe 101a in the compression process, the expansion process, and the exhaust process, which has shifted from the intake process before ignition by the spark plug 112. Yes. During this time, outside air flows from the gap of the throttle valve 103 and the like, and the inside of the intake pipe 101a changes to approximately atmospheric pressure. Note that, before the transition from the compression process to the expansion stroke and before fuel injection is started, the inside of the intake pipe 101a is a gas difference due to the pressure difference due to the vertical movement of the piston 113 and the opening and closing of the valve associated therewith. It has been moved.

  Here, the main body temperature predicted by the temperature prediction device 121 is a very important parameter in controlling the internal combustion engine 100. Further, the initial temperature varies depending on the operating condition when the internal combustion engine 100 is stopped before the start of the internal combustion engine 100 and the elapsed time since the stop.

  The initial temperature referred to here is a period from when the power source of the internal combustion engine 100 is switched from OFF to ON and when the internal combustion engine 100 starts starting from a stopped state until combustion starts in the combustion chamber 105. The main body temperature of the internal combustion engine 100 is meant.

  Therefore, in the internal combustion engine 100, focusing on the gas pressure inside the intake pipe 101a before the fuel is injected, a test was performed assuming different elapsed times after the internal combustion engine 100 was completely stopped. Specifically, using a single cylinder gasoline internal combustion engine as the internal combustion engine 100, five types of initial temperatures (specifically, 25 ° C., 60 ° C., 80 ° C., 100 ° C. and 115 ° C.) are set and The behavior of the intake pressure after starting the engine 100 and until the start of combustion was examined.

  When the power supply of the internal combustion engine 100 is switched from OFF to ON, detection signals from the intake pressure sensor 104, the crank angle sensor 118, and the oxygen sensor 120 provided in the internal combustion engine 100 are input to the temperature prediction device 121. At this time, since the pressure in the intake pipe 101a indicates atmospheric pressure, the outside air pressure (ambient environmental pressure) outside the internal combustion engine 100 can be determined from the detection result of the intake pressure sensor 104.

  When the power source of the internal combustion engine 100 is switched from OFF to ON, the internal combustion engine 100 starts from a stopped state. When starting of the internal combustion engine main body 100a is started, a cell motor or the like rotates the crankshaft 115 and the piston 113 starts to move. During the period from when the internal combustion engine 100 is started until the crankshaft 115 rotates, the pressure in the intake pipe 101a is almost atmospheric pressure.

  When the intake process is started along with the rotation of the crankshaft 115, the gas in the intake pipe 101a is drawn into the combustion chamber 105, so that the gas pressure in the intake pipe 101a decreases from atmospheric pressure to about 40 kPa. To do. The pressure change in the intake process was fast, and no difference in pressure change could be found for the five initial temperatures.

  As can be seen from the above, the intake air pressure detected by the intake air pressure sensor 104 between the time when the internal combustion engine 100 is started from the stop state and the rotation of the crankshaft 115 is started can be used as the outside air pressure.

  On the other hand, at the bottom dead center changing from the intake process to the compression process, a correlation was observed between the initial temperature and the intake pressure, and the higher the initial temperature, the higher the intake pressure at the bottom dead center. Therefore, the intake pressure detected by the intake pressure sensor 104 when the piston 113 is located at the bottom dead center where the intake process shifts to the compression process is set as the intake representative pressure.

  The above temperature test was performed in an environment where the internal combustion engine 100 was arranged, that is, in an environment where the outside air temperature and the outside air pressure were 25 ° C. and 1 atmosphere, respectively. Incidentally, the intake pressure is affected by the outside air pressure and the outside air temperature. Further, the moving speed of the gas flowing into the intake pipe 101a and the moving speed of the gas discharged from the intake pipe 101a and moving to the combustion chamber 105 are defined as the number of revolutions per unit time of the internal combustion engine body 100a (hereinafter referred to as the internal combustion engine). Depends on the number of revolutions).

  Therefore, verification tests were performed at different outside air temperatures and different outside air pressures, and empirical equations were obtained that took the above parameters into consideration. The result is shown in Formula (1). FIG. 3 is a schematic diagram showing the correlation between the intake pressure and the body temperature according to Embodiment 1 of the present invention.

T _ENG ⁰ = a (P / P ₀ -b) ^c · T ₀ ^d · N _e ^e (1)

However, in Formula (1),
T _ENG ⁰ is the initial temperature of the internal combustion engine body,
P ₀ is the outside air pressure,
P is the intake representative pressure,
T ₀ is the outside temperature,
N _e is the engine speed,
a, b, c, d and e are constants.

  As can be seen from the above equation (1) and FIG. 3, it has been found that the initial temperature can be uniquely predicted using the intake pressure detected by the intake pressure sensor 104.

  Further, as can be seen from the above, the outside air pressure, the intake air representative pressure, the outside air temperature, and the internal combustion engine speed can be obtained without providing the internal combustion engine body 100a with a dedicated sensor, wiring, thermoelectric converter, and the like for obtaining the initial temperature. If known, the initial temperature corresponding to the operating environment of the internal combustion engine 100 can be predicted according to the equation (1).

  Here, the outside air pressure is an intake pressure (hereinafter referred to as a first pressure) detected by the intake pressure sensor 104 between the time when the internal combustion engine 100 is started from a stopped state and the rotation of the crankshaft 115 is started. To do. The temperature prediction device 121 is configured to acquire the intake air pressure as the outside air pressure at a timing within a period from when the internal combustion engine 100 starts to start from a stopped state to when the internal combustion engine body 100a starts to rotate. Yes. Note that the function of acquiring the outside air pressure is performed by the outside air pressure acquiring unit provided in the temperature prediction device 121.

  The intake representative pressure is an intake pressure (hereinafter referred to as a second pressure) detected by the intake pressure sensor 104 when the piston 113 is located at a bottom dead center where the intake process is changed to the compression process. The temperature prediction device 121 is configured to acquire the intake pressure as the intake representative pressure at a timing within a period from when the internal combustion engine main body 100a starts to rotate until combustion starts in the combustion chamber 105. In the first embodiment, as a specific example of such timing, the timing at which the piston 113 reaches the bottom dead center at which the suction process shifts to the compression process is illustrated. The function of acquiring the intake representative pressure is performed by the intake representative pressure acquisition unit provided in the temperature prediction device 121.

  The outside air temperature is a value obtained by a method of directly detecting using an outside air temperature sensor, a method of indirectly predicting using a detection value of another sensor, or the like. The temperature prediction device 121 is configured to acquire the outside air temperature by such a method. Note that the function of acquiring the outside air temperature is performed by the outside air temperature acquiring unit provided in the temperature prediction device 121.

  The engine speed is calculated based on crank angle information detected by the crank angle sensor 118. In order to calculate the internal combustion engine speed, specifically, in addition to the crank angle sensor 118, a timer for measuring the time taken to detect a certain crank angle is required. The temperature predicting device 121 is configured to acquire the internal combustion engine rotational speed by such a method at a timing within a period from when the internal combustion engine main body 100a starts rotating to when combustion starts in the combustion chamber 105. Has been. Note that the parameter information acquisition unit provided in the temperature prediction device 121 is responsible for acquiring the internal combustion engine speed.

  The temperature prediction device 121 stores the above-described equation (1) and the constants a to e according to the equation (1) in a nonvolatile memory, or stores the mapping table determined from the equation (1) and each constant in a nonvolatile manner. Stored in the memory. As described above, the temperature prediction device 121 acquires the outside air pressure, the intake representative pressure, the outside air temperature, and the internal combustion engine speed. The temperature prediction device 121 uses the acquired parameters and the stored constants a to e to perform prediction by calculating the initial temperature according to the equation (1). Note that the function of predicting the initial temperature is performed by the initial temperature prediction unit provided in the temperature prediction device 121.

  Next, a method of sequentially predicting the body temperature after the start of combustion using the predicted initial temperature as an initial value will be described. The main body temperature in the period from the start of the internal combustion engine 100 to the start of combustion is equivalent to the initial temperature predicted by the above method.

  On the other hand, after the combustion in the combustion chamber 105 is started, the main body temperature is predicted by the following method. That is, it is predicted by calculating the body temperature after time Δt from the energy balance of the internal combustion engine body 100a.

Here, the body temperature at time t is T _ENG (t), and the body temperature at time t + Δt after the lapse of Δt from time t is T _ENG (t + Δt), T _ENG (t + Δt) −T _ENG (t) = ΔT _ENG , ΔT _ENG / Δt can be expressed as shown in Equation (2). Further, the total energy Q _OUT output from the internal combustion engine main body 100a can be expressed as in Expression (3). In Equation (3), the second term on the right side represents the amount of heat release, and the first term on the right side represents other output energy.

M ・ C _P・ ΔT _ENG / Δt = Q _IN −Q _OUT (2)
Q _OUT = Σ (Qj) + β (T _ENG (t) −T ₀ ) (3)

However, in Formula (2) and Formula (3),
M is the weight (kg) of the internal combustion engine body 100a,
C _P is the specific heat of the internal combustion engine body 100a (J / (kg · K)),
Q _IN is the total energy (J / s) of energy input to the internal combustion engine body 100a,
Q _OUT is the total energy (J / s) output from the internal combustion engine body 100a,
Qj is the output energy of the individual element j from the internal combustion engine body 100a,
T ₀ is the outside air temperature (K),
t is time (s),
β represents a constant (W / K).
As for Q _IN , part or all of the energy is fuel flow energy supplied to the internal combustion engine 100.

Temperature predicting apparatus 121 as the above-described formula (2) and (3), the constant M, and C _P according to the equation (2), and stores a constant β according to formula (3) in the non-volatile memory. The temperature predicting device 121 calculates the above Q _IN , Q _OUT and Qj, and further acquires the outside air temperature. The temperature prediction device 121 solves the equations (2) and (3) using the calculated Q _IN , Q _OUT and Qj, the acquired outside air temperature, and the stored M, C _P and β. [Delta] _TENG is calculated by the above, and the body temperature _TENG (t + [Delta] t) is predicted using the [Delta] _TENG .

  In addition, said time (DELTA) t shows the time interval of the timing of the fuel injection of the internal combustion engine 100, for example. In the above calculation, the initial temperature, that is, the outside air temperature is used. The temperature prediction device 121 acquires the outside air temperature by applying a method for directly detecting the outside temperature using an outside temperature sensor, a method for indirectly predicting using a detection value of another sensor, or the like.

  As described above, the temperature predicting device 121 predicts the main body temperature after the start of combustion in the combustion chamber 105 from the energy balance of the internal combustion engine main body 100a using the predicted initial temperature. Note that the function of predicting the main body temperature after the start of combustion is performed by the temperature prediction unit provided in the temperature prediction device 121.

  Next, a series of operations of the temperature prediction apparatus 121 according to the first embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a series of operations of the temperature predicting apparatus 121 for an internal combustion engine according to Embodiment 1 of the present invention.

  In step S101, when the internal combustion engine body 100a is switched from OFF to ON, the process proceeds to step S102.

In step S102, the temperature prediction device 121 acquires various parameters necessary for predicting the initial temperature T _ENG ⁰ , and the process proceeds to step S103. Specifically, the temperature prediction device 121 acquires the first pressure and the second pressure as the outside air pressure and the intake air representative pressure from the intake pressure sensor 104, respectively, and acquires the outside air temperature and the internal combustion engine speed by the above-described method. In addition, the temperature prediction device 121 acquires Expression (1) and constants a to e according to Expression (1) from the nonvolatile memory.

In step S103, the temperature prediction device 121 predicts the initial temperature T _ENG ⁰ according to the equation (1) using the various parameters acquired in step S102 and the constants a to e, and the process proceeds to step S104. .

In step S104, the temperature prediction device 121 sets the initial temperature T _ENG ⁰ predicted in step S103 as the main body temperature T _ENG (t), and the process proceeds to step S105.

In step S105, the temperature prediction apparatus 121 acquires various parameters necessary for calculating Q _IN , Q _OUT and Qj, and the process proceeds to step S106.

In step S106, the temperature prediction device 121 calculates Q _IN , Q _OUT and Qj using the various parameters acquired in step S105, and the process proceeds to step S107.

In step S107, the temperature predicting apparatus 121 uses the Q _IN , Q _OUT and Qj calculated in step S106 and the constants M, C _P and β according to the equations (2) and (3) to determine the body temperature T _ENG (t + Δt) is predicted. Thereafter, the process proceeds to step S108, and returns to step S104 in order to predict the main body temperature after a further time has elapsed.

In step S108, the temperature prediction device 121 controls the fuel injection amount from the injector 110 based on the main body temperature T _ENG (t + Δt) predicted in step S107.

When the process returns from step S107 to step S104, the temperature prediction device 121 sets the main body temperature T _ENG (t + Δt) predicted in step S107 as the main body temperature T _ENG (t), and the processes after step S104 are performed again. Do. As described above, the temperature predicting device 121 repeatedly performs the processing from step S104 onward using the initial temperature T _ENG ⁰ predicted in step S103, so that the main body temperature is sequentially predicted over time, and the fuel injection amount is determined. Control.

  As described above, the temperature prediction device 121 controls fuel injection when fuel is injected based on the predicted main body temperature. Note that the fuel injection control unit provided in the temperature prediction device 121 has a function of controlling the fuel injection.

  As described above, according to the first embodiment, the intake pressure acquired as the outside air pressure at the timing within the period from the start of the internal combustion engine from the stopped state to the start of rotation of the internal combustion engine, and the internal combustion engine The initial temperature of the internal combustion engine body based on the intake pressure acquired as the intake representative pressure at the timing within the period from the start of rotation to the start of combustion in the combustion chamber, and the internal combustion engine speed acquired at the timing The main body temperature of the internal combustion engine body after the start of combustion is predicted using the predicted initial temperature.

  2. Description of the Related Art Conventionally, a temperature sensor is attached to an internal combustion engine body, and a combustion condition (for example, throttle opening adjustment for setting an air flow rate) is controlled according to the temperature state of the internal combustion engine body. On the other hand, in the first embodiment, since it is configured as described above, it is possible to predict the temperature of the internal combustion engine body after the start of combustion without attaching a temperature sensor to the internal combustion engine body. It becomes.

  By configuring as described above, it becomes possible to eliminate the need for a dedicated temperature sensor for the internal combustion engine body corresponding to the high temperature. Is possible. Therefore, the temperature of the internal combustion engine body can be predicted at a relatively low cost.

  Although not mentioned in the first embodiment, the detection value of the oxygen sensor 120 provided in the exhaust passage 117 may be used for air-fuel ratio control of the internal combustion engine 100 or the like, or used as a limit value of the air-fuel ratio. May be.

  In the first embodiment, an example of the operation of the internal combustion engine main body 100a is shown, but nothing is limited to this, and the exhaust valve 116 or the intake valve 111 is adjusted according to the characteristics of the internal combustion engine main body 100a. The opening / closing timing and order of the may be changed.

  For example, the intake valve 111 and the exhaust valve 116 may be operated so as to open at the time of transition from the exhaust process to the intake process. Further, the intake valve 111 or the exhaust valve 116 may be opened and closed before the piston 113 reaches the top dead center or the bottom dead center. Further, the valve opening / closing timing is often determined according to the camshaft in accordance with the rotation of the crankshaft 115. However, for example, the temperature predicting device 121 controls the opening / closing of the valve until the internal combustion engine 100 reaches a preset temperature according to the predicted initial temperature in relation to the control of a so-called variable valve mechanism that changes the opening / closing timing of the valve. The timing may be controlled.

  Note that the internal combustion engine rotational speed referred to in the first embodiment may be a local rotational speed calculated in time between adjacent projections provided on the crankshaft 115.

  In the first embodiment, the configuration in which the temperature prediction device 121 executes the temperature prediction of the internal combustion engine 100 and the operation control based on the temperature prediction has been described, but the configuration is not limited thereto. That is, for example, an ECU may be provided separately from the temperature prediction device 121, and the ECU may perform operation control based on the temperature prediction.

Embodiment 2. FIG.
In the second embodiment of the present invention, a temperature predicting device 121 in which the process of acquiring the intake representative pressure is different from that of the first embodiment will be described. In the second embodiment, description of points that are the same as those of the first embodiment will be omitted, and points different from the first embodiment will be mainly described.

  In the second embodiment, the basic configuration of the internal combustion engine 100 is the same as that of the first embodiment, while the control program incorporated in the temperature prediction device 121, specifically, the temperature prediction device 121 is executed. The intake representative pressure acquisition process is different from that of the first embodiment.

  FIG. 5 is a schematic diagram showing a pressure change in the intake pipe 101a of the internal combustion engine 100 according to Embodiment 2 of the present invention.

  Similar to the first embodiment, the cell motor or the like rotates the crankshaft 115 as the internal combustion engine main body 100a is started. At this time, the temperature prediction device 121 detects a bottom dead center at which the internal combustion engine main body 100a shifts from the intake process to the compression process based on the information from the intake pressure sensor 104 and the crank angle sensor 118. After detecting the bottom dead center, the temperature predicting device 121 acquires the intake pressure from the intake pressure sensor 104 at the timing when the crank angle sensor 118 detects the protrusion whose crank number is, for example, No. 2, and uses the intake pressure as the intake representative. Pressure.

  Here, in the first embodiment, the temperature prediction device 121 acquires the intake pressure from the intake pressure sensor 104 at the timing when the position of the piston 113 reaches the bottom dead center, and uses the intake pressure as the intake representative pressure. It is configured as follows. However, in the actual internal combustion engine main body 100a, the timing at which the position of the piston 113 reaches the bottom dead center is the timing at which the intake process is shifted to the compression process, and thus the intake valve 111 is often being opened and closed. It is done. In this case, since the amount of gas movement between the intake pipe 101a and the combustion chamber 105 is determined from the gap between the combustion chamber 105 and the intake valve 111, the intake pressure varies easily.

  Therefore, in the second embodiment, in the compression process and the expansion stroke from when the position of the piston 113 passes the bottom dead center and the intake valve 111 is closed until the exhaust valve 116 is opened near the top dead center. The intake pressure detected by the intake pressure sensor 104 is used as the representative intake pressure.

  That is, the temperature predicting device 121 is not at the time when the position of the piston 113 reaches the bottom dead center as in the first embodiment, but at the time when the piston 113 reaches the bottom dead center at which the suction process shifts to the compression process. After that, the intake pressure is acquired as the intake representative pressure at a timing within a period until the piston 113 reaches the next bottom dead center through the top dead center where the piston 113 shifts from the compression process to the expansion stroke. In this way, the intake pressure that is a relatively stable value that is not affected by the opening and closing of the valve can be set as the intake representative pressure.

  In the expansion stroke, since the intake pressure gradually approaches the outside air pressure, the difference in intake pressure due to the difference in the body temperature or the outside air temperature is small. Therefore, in consideration of accuracy, it is desirable that the intake pressure detected by the intake pressure sensor 104 at the timing of the compression process after the intake valve 111 is closed be the intake representative pressure.

  As described above, according to the second embodiment, the piston moves from the compression process to the expansion stroke after reaching the bottom dead center where the piston moves from the intake process to the compression process with respect to the configuration of the first embodiment. The intake pressure is acquired as the intake representative pressure at a timing within a period from the top dead center to the next bottom dead center. Even in such a configuration, the same effect as in the first embodiment can be obtained.

  In the second embodiment, the case where one intake pressure detected by the intake pressure sensor 104 at a specific timing is set as the intake representative pressure is described, but the present invention is not limited to this.

  That is, an average value of a plurality of intake pressures detected by the intake pressure sensor 104 at a plurality of successive timings may be used as the intake representative pressure. In this case, even if noise is included in the detection value of the intake pressure sensor 104, there is an effect that the noise can be reduced.

Embodiment 3 FIG.
In the third embodiment of the present invention, a temperature predicting device 121 in which the process of acquiring the intake representative pressure is different from that in the first and second embodiments will be described. In the third embodiment, description of points that are the same as in the first and second embodiments will be omitted, and the description will focus on points that are different from the first and second embodiments.

  In the third embodiment, the basic configuration of the internal combustion engine 100 is the same as that of the first and second embodiments. The intake representative pressure acquisition process is different from those of the first and second embodiments.

  FIG. 6 is a schematic diagram showing a pressure change in the intake pipe 101a of the internal combustion engine 100 according to Embodiment 3 of the present invention.

  Similar to the first embodiment, the cell motor or the like rotates the crankshaft 115 as the internal combustion engine main body 100a is started. At this time, the temperature prediction device 121 detects a bottom dead center at which the internal combustion engine main body 100a shifts from the intake process to the compression process based on the information from the intake pressure sensor 104 and the crank angle sensor 118. After detecting the bottom dead center, the temperature predicting device 121 detects the first intake pressure and the second intake pressure from the intake pressure sensor 104 at the timing when the crank angle sensor 118 detects the protrusions having the crank numbers of No. 2 and No. 5, for example. Each atmospheric pressure is acquired, and a differential pressure between the two intake pressures is set as an intake representative pressure.

  That is, the temperature predicting device 121 reaches the bottom dead center after the piston 113 reaches the bottom dead center at which the suction process shifts from the intake process to the compression process and then passes through the top dead center at which the piston 113 shifts from the compression process to the expansion stroke. The first intake pressure and the second intake pressure are respectively acquired at two different timings within the period until. The temperature prediction device 121 acquires the differential pressure between the first intake pressure and the second intake pressure acquired in this way as the intake representative pressure.

  This differential pressure can be replaced with the flow rate of the outside air flowing into the intake pipe 101a, and is accompanied by a time term. Here, when the time difference between the two times is a short time, the outside air flowing into the intake pipe 101a is not easily affected by the temperature of the main body, and conversely, when it is a long time, the outside air is It is easily affected by the body temperature. Therefore, the effect of heating from the internal combustion engine to the inflowing outside air that depends on the time difference between these timings must be considered in terms of thermohydrodynamics, but there is an advantage that the inflowing outside air can be organized in a dimension with a time term. As a result, the body temperature can be predicted with higher accuracy.

  As described above, according to the third embodiment, the piston moves from the compression process to the expansion stroke after reaching the bottom dead center where the piston moves from the intake process to the compression process, as compared with the configuration of the first embodiment. The first intake pressure and the second intake pressure are acquired at different timings within the period from the top dead center to the next bottom dead center, and the difference between the acquired first intake pressure and second intake pressure The pressure is acquired as the intake representative pressure. Even in such a configuration, the same effect as in the first embodiment can be obtained.

  In the third embodiment, the timing at which the first intake pressure and the second intake pressure are respectively acquired from the intake pressure sensor 104 is set to the crank angle sensor for the protrusions with the crank numbers 2 and 5 after the bottom dead center. Although the timing detected by 118 is used, the present invention is not limited to this.

  That is, the timing for obtaining these two intake pressures may be any timing after the bottom dead center at which the intake process shifts to the compression process and between the compression process and the completion of the expansion stroke and the exhaust process. However, the timing at which the first intake pressure (that is, the first intake pressure) is acquired is the timing at which the influence of the internal combustion engine body 100a is noticeable, that is, the bottom dead center after the transition from the intake process to the compression process. It is desirable that the timing is as close to the bottom dead center as possible.

Embodiment 4 FIG.
In the fourth embodiment of the present invention, a temperature prediction device 121 that predicts the initial temperature by a method different from the first to third embodiments will be described. In the fourth embodiment, description of points that are the same as those in the first to third embodiments will be omitted, and description will be made focusing on differences from the first to third embodiments.

  In the fourth embodiment, the basic configuration of the internal combustion engine 100 is the same as that of the first to third embodiments. On the other hand, the control program incorporated in the temperature prediction device 121, specifically, the temperature prediction device 121 executes it. The operation for predicting the initial temperature to be performed is different from those of the first to third embodiments.

  FIG. 7 is a schematic diagram showing a pressure change in the intake pipe 101a of the internal combustion engine 100 according to Embodiment 4 of the present invention.

  In FIG. 7, it is assumed that the piston 113 is stopped during the intake process when the internal combustion engine 100 is stopped. Similar to the first embodiment, the cell motor or the like rotates the crankshaft 115 as the internal combustion engine main body 100a is started. At this time, the temperature predicting device 121 uses the information from the intake pressure sensor 104 and the crank angle sensor 118 to perform the first first time that the internal combustion engine body 100a shifts from the intake process to the compression process after the internal combustion engine body 100a is started. Detect bottom dead center. After the temperature predicting device 121 detects the first bottom dead center, the internal combustion engine main body 100a moves from the compression process to the expansion stroke through the first top dead center, and from the expansion stroke to the exhaust stroke through the second bottom dead center. The process proceeds to the intake process from the exhaust process through the second top dead center.

  After the internal combustion engine body 100a shifts from the intake process to the compression process after passing through the third bottom dead center, the temperature predicting device 121 performs the suction at the timing when the crank angle sensor 118 detects the protrusion whose crank number is, for example, 2. The intake pressure is acquired from the atmospheric pressure sensor 104, and the intake pressure is set as the intake representative pressure.

  Here, when the internal combustion engine 100 is started from a state where the piston 113 is stopped in the middle of the intake process, even if the piston 113 moves to the bottom dead center after the start, it is compared with a case where the intake is fully performed in the intake process. As a result, the volume decreases and the intake pressure increases.

  Therefore, in the fourth embodiment, the temperature predicting device 121 detects the bottom dead center that shifts from the intake process to the compression process based on the information from the intake pressure sensor 104 and the crank angle sensor 118, and the crank number is, for example, The intake pressure is acquired from the intake pressure sensor 104 at the timing when the crank angle sensor 118 detects the second protrusion. The temperature predicting device 121 controls the crankshaft 115 to continue rotating when the acquired intake pressure is higher than a preset pressure value.

  Subsequently, the temperature prediction device 121 acquires the intake pressure detected by the intake pressure sensor 104 in the second compression step after the third bottom dead center without operating the injector 110 and the spark plug 112, and absorbs the intake pressure. Atmospheric pressure is the representative intake pressure.

  That is, the temperature predicting device 121 reaches the bottom dead center after the piston 113 reaches the bottom dead center at which the suction process shifts from the intake process to the compression process and then passes through the top dead center at which the piston 113 shifts from the compression process to the expansion stroke. If the intake pressure is acquired as the intake representative pressure at a timing within the previous period, and the acquired intake representative pressure is higher than the set pressure value, the intake pressure is regenerated as the intake representative pressure at the timing within the next period. Is configured to get.

  In such a configuration, for example, when the piston 113 is stopped in the middle of the intake process as described above, an accurate detection value cannot be obtained, such as an error in reading the detection value of the intake pressure sensor 104, or the like. It is effective for. As a result, the reliability of the intake representative pressure can be improved.

  Next, a series of operations for predicting the initial temperature of the temperature predicting apparatus 121 according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 8 is a flowchart showing a series of operations for predicting the initial temperature of the temperature predicting apparatus 121 for an internal combustion engine according to the fourth embodiment of the present invention.

  In step S201, when the internal combustion engine 100 is switched from OFF to ON, the process proceeds to step S202.

  In step S202, as the power of the internal combustion engine 100 is turned on in step S201, sensors such as the intake pressure sensor 104 and the crank angle sensor 118 operate, and the process proceeds to step S203.

  In step S203, the temperature prediction device 121 acquires the first pressure detected by the intake pressure sensor 104 as the outside air pressure, and the process proceeds to step S204.

  In step S204, the temperature prediction apparatus 121 acquires the outside air temperature by the method described in the first embodiment, and the process proceeds to step S205.

  In step S205, the temperature prediction device 121 controls the cell motor or the like to rotate the crankshaft 115, and the process proceeds to step S206.

  In step S206, the temperature predicting apparatus 121 acquires the formula (1) necessary for predicting the initial temperature and the constants a to e related to the formula (1) from the nonvolatile memory, and the process proceeds to step S207. .

  In step S207, after detecting the bottom dead center (first bottom dead center) at which the temperature prediction apparatus 121 shifts from the intake process to the compression process, the temperature predicting apparatus 121 acquires the intake pressure from the intake pressure sensor 104 in the compression process. Proceed to step S208.

  In step S208, the temperature prediction device 121 determines whether or not the intake pressure acquired in step S207 is higher than the set pressure value. If the intake pressure acquired in step S207 is higher than the set pressure value, the process returns to step S207.

  When the process returns to step S207, the temperature prediction device 121 detects the bottom dead center (third bottom dead center) from the next intake process to the compression process, and then receives the suction pressure from the intake pressure sensor 104 in the compression process. The atmospheric pressure is acquired again, and the process proceeds to step S208.

  On the other hand, if the intake pressure acquired in step S207 is less than or equal to the set pressure value, the process proceeds to step S209.

  In step S209, the temperature prediction device 121 acquires the internal combustion engine speed by the method described in the first embodiment, and the process proceeds to step S210.

  In step S210, the temperature prediction device 121 sets the intake pressure equal to or lower than the set pressure value acquired in step S207 as the intake representative pressure. Subsequently, the temperature predicting device 121 determines the representative intake pressure, the outside air pressure and the outside air temperature acquired in Step S203 and Step S204, the constants a to e acquired in Step S206, and the internal combustion engine speed acquired in Step S209. Is used to predict the initial temperature according to equation (1). Thereafter, the process proceeds to step S211.

  In step S211, the temperature prediction device 121 can predict the initial temperature in step S210, and therefore controls the injector 110 and the spark plug 112 to operate at a specific timing.

  As described above, the temperature prediction device 121 is configured to control the fuel injection when the fuel is injected for the first time based on the predicted initial temperature. Note that the function of controlling the first fuel injection after the initial temperature prediction is performed by the initial fuel injection control unit provided in the temperature prediction device 121.

  As described above, according to the fourth embodiment, after the piston reaches the bottom dead center at which the intake process proceeds from the compression process to the compression process, the piston moves to the next bottom dead center through the top dead center at which the piston proceeds from the compression process to the expansion stroke. The intake pressure is acquired as the intake representative pressure at the timing within the period until it reaches, and if the acquired intake representative pressure is higher than the set pressure value, the intake pressure is set as the intake representative pressure at the timing within the next period. Is configured to reacquire. Even in such a configuration, the same effect as in the first embodiment can be obtained.

Embodiment 5. FIG.
In the fifth embodiment of the present invention, a temperature predicting apparatus 121 in which the body temperature prediction method after the start of combustion in the combustion chamber 105 is different from that of the first embodiment will be described. In the fifth embodiment, description of points that are the same as in the first to fourth embodiments will be omitted, and the description will focus on the points that are different from the first to fourth embodiments.

  In the fifth embodiment, the basic configuration of the internal combustion engine 100 is the same as that of the first to fourth embodiments. On the other hand, the control program incorporated in the temperature prediction device 121, specifically, executed by the temperature prediction device 121. The operation of predicting the main body temperature after the start of combustion is different from the first to fourth embodiments. Moreover, the temperature prediction apparatus 121 in Embodiment 5 shall estimate initial temperature with the method in any one of previous Embodiment 1-4.

  The operation for predicting the main body temperature after the start of combustion executed by the temperature prediction device 121 is as follows. That is, in the process in which the intake air passes through the throttle valve 103, the intake pipe 101a, the intake valve 111, and the combustion chamber 105, the intake air temperature per unit time is calculated using the mass conservation law, the state equation, the orifice equation, and the like. It is obtained by modeling hydrodynamically. Further, the intake air temperature and the main body temperature have a correlation, and the main body temperature can be predicted using the intake air temperature by replacing it with an empirical formula.

  Therefore, the temperature prediction device 121 acquires the intake air temperature by the above-described method, and predicts the main body temperature by using the above-described correlation using the predicted initial temperature and the acquired intake air temperature.

  As described above, according to the fifth embodiment, the main body temperature of the internal combustion engine is predicted from the correlation between the main body temperature of the internal combustion engine and the intake air temperature using the predicted initial temperature and the acquired intake air temperature. Has been. Even if it is a case where it comprises in this way, the effect similar to previous Embodiment 1-4 is acquired.

  In each of the above-described embodiments, the case where the present invention is applied to predict the temperature of the internal combustion engine body has been described. However, the present invention is not limited to this. The present invention can also be applied to the prediction. For example, in addition to the temperature of the internal combustion engine body, the present invention can be applied to predict the temperature of engine oil of the internal combustion engine, the temperature of cooling water of the internal combustion engine, and the like.

  The outside air pressure acquisition unit, the intake representative pressure acquisition unit, the parameter information acquisition unit, the initial temperature prediction unit, and the temperature prediction unit described above may be realized by software in one control unit such as an ECU, or separately. It may be prepared as hardware.

  In addition, the present invention is not limited to the specific details and representative embodiments described and described above, and modifications and effects that can be easily derived by those skilled in the art are also invented. include. Accordingly, various modifications can be made without departing from the scope of the general invention as defined by the claims and their equivalents.

  DESCRIPTION OF SYMBOLS 100 Internal combustion engine, 100a Internal combustion engine main body, 101 Intake passage, 101a Intake pipe, 102 Air filter, 103 Throttle valve, 104 Intake pressure sensor, 105 Combustion chamber, 106 Bypass flow path, 107 Idle speed control valve, 108 Fuel pump, 109 Fuel tank, 110 injector, 111 intake valve, 112 spark plug, 113 piston, 114 connecting rod, 115 crankshaft, 116 exhaust valve, 117 exhaust passage, 118 crank angle sensor, 119 three-way catalyst, 120 oxygen sensor, 121 temperature prediction device .

Claims (10)

The internal combustion engine configured to perform an intake process of sucking outside air from an intake pipe into a combustion chamber, and ignite fuel injected into the outside air sucked in the intake process to cause combustion in the combustion chamber In the temperature prediction device that predicts the temperature of
An outside air pressure acquisition unit that acquires an intake pressure in the intake pipe as an outside air pressure at a timing within a period from when the internal combustion engine starts to start from a stopped state until the internal combustion engine starts rotating;
An intake representative pressure acquisition unit that acquires the intake pressure as an intake representative pressure at a timing within a period from when the internal combustion engine starts the rotation to when the combustion starts.
A parameter information acquisition unit for acquiring the rotational speed per unit time of the internal combustion engine;
Based on the outside air pressure acquired by the outside air pressure acquisition unit, the intake representative pressure acquired by the intake representative pressure acquisition unit, and the rotation speed acquired by the parameter information acquisition unit, the start is started and then the combustion An initial temperature predicting unit for predicting an initial temperature of the internal combustion engine in a period until starting
Using the initial temperature predicted by the initial temperature prediction unit, a temperature prediction unit that predicts the temperature of the internal combustion engine after the start of the combustion;
An internal combustion engine temperature prediction apparatus comprising: It further includes an outside air temperature acquisition unit for acquiring outside air temperature,
The initial temperature prediction unit includes the outside air pressure acquired by the outside air pressure acquisition unit, the intake representative pressure acquired by the intake representative pressure acquisition unit, the rotation speed acquired by the parameter information acquisition unit, and the outside air temperature acquisition unit. The temperature prediction device for an internal combustion engine according to claim 1, wherein the initial temperature is predicted based on the outside air temperature acquired by the engine. The outside air pressure is P ₀ , the intake representative pressure is P, the rotation speed is N _e , the outside air temperature is T ₀ , the constants are a, b, c, d, and e, and the initial temperature is T _ENG ⁰ . When
The initial temperature prediction unit predicts the initial temperature according to the following equation: T _ENG ⁰ = a (P / P ₀ −b) ^c · T ₀ ^d · N _e ^e
The temperature prediction apparatus for an internal combustion engine according to claim 2. The internal combustion engine is configured to further perform a compression process in which the gas in the combustion chamber is compressed by a piston that moves with the rotation, and an expansion stroke in which the gas in the combustion chamber is expanded by the piston.
The intake representative pressure acquisition unit
Within a period of time from when the piston reaches the bottom dead center at which the intake stroke is transferred to the compression stroke to when the piston reaches the next bottom dead center through the top dead center at which the piston moves from the compression stroke to the expansion stroke. The temperature prediction device for an internal combustion engine according to any one of claims 1 to 3, wherein the intake pressure is acquired as the intake representative pressure at a timing of. The intake representative pressure acquisition unit
The temperature prediction device for an internal combustion engine according to claim 4, wherein the intake pressure is acquired as the intake representative pressure at a timing when the piston reaches the bottom dead center at which the transition from the intake process to the compression process is reached. The internal combustion engine is configured to further perform a compression process in which the gas in the combustion chamber is compressed by a piston that moves with the rotation, and an expansion stroke in which the gas in the combustion chamber is expanded by the piston.
The intake representative pressure acquisition unit
Within a period of time from when the piston reaches the bottom dead center at which the intake stroke is transferred to the compression stroke to when the piston reaches the next bottom dead center through the top dead center at which the piston moves from the compression stroke to the expansion stroke. The first intake pressure and the second intake pressure are respectively acquired at different timings, and a differential pressure between the acquired first intake pressure and the second intake pressure is acquired as the intake representative pressure. The internal combustion engine temperature prediction apparatus according to any one of the preceding claims. The internal combustion engine is configured to further perform a compression process in which the gas in the combustion chamber is compressed by a piston that moves with the rotation, and an expansion stroke in which the gas in the combustion chamber is expanded by the piston.
The intake representative pressure acquisition unit
Within a period of time from when the piston reaches the bottom dead center at which the intake stroke is transferred to the compression stroke to when the piston reaches the next bottom dead center through the top dead center at which the piston moves from the compression stroke to the expansion stroke. The intake pressure is acquired as the intake representative pressure at the timing of, and if the acquired intake representative pressure is higher than the set pressure value, the intake pressure is converted to the intake representative pressure at the timing within the next period. The temperature prediction device for an internal combustion engine according to any one of claims 1 to 3, wherein the temperature prediction device is acquired again. The fuel injection control part which controls the fuel injection at the time of injecting the said fuel based on the temperature of the said internal combustion engine after the start of the said combustion estimated by the said temperature prediction part was further provided in any one of Claim 1 to 7 The temperature prediction device for an internal combustion engine according to claim 1. The first fuel injection control unit that controls fuel injection when the fuel is injected for the first time after the prediction of the initial temperature based on the initial temperature predicted by the initial temperature prediction unit. The temperature prediction apparatus for an internal combustion engine according to any one of the above. An internal combustion engine configured to perform an intake process of sucking outside air from an intake pipe into a combustion chamber and ignite fuel injected into the outside air sucked in the intake process to cause combustion in the combustion chamber. In the temperature prediction method for predicting the temperature,
Acquiring the intake pressure in the intake pipe as an outside air pressure at a timing within a period from when the internal combustion engine starts to start from a stopped state until the internal combustion engine starts rotating;
Obtaining the intake pressure as the intake representative pressure at a timing within a period from the start of the rotation of the internal combustion engine to the start of combustion, and obtaining a rotation speed per unit time of the internal combustion engine; ,
Predicting an initial temperature of the internal combustion engine in a period from the start to the start of combustion based on the acquired outside air pressure, the intake representative pressure, and the rotational speed;
Predicting the temperature of the internal combustion engine after the start of the combustion using the predicted initial temperature;
An internal combustion engine temperature prediction method comprising:

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