JP6881187B2 - Engine temperature estimator - Google Patents

Description

The present invention relates to a temperature estimation device for an engine.

Patent Document 1 discloses a temperature estimation device that estimates the temperature of an intake valve of an engine. The temperature estimation device of Patent Document 1 has a combustion gas heat receiving amount received by the intake valve from the combustion gas in the cylinder, an intake heat receiving amount which is a heat receiving amount from the intake air flowing around the intake valve, and when the intake valve comes into contact with the valve seat. Calculate the amount of heat received from the contact surface. Further, the temperature estimation device of Patent Document 1 calculates the amount of heat of vaporization taken away from the intake valve when the fuel adhering to the intake valve is vaporized. Then, the temperature estimation device of Patent Document 1 estimates the temperature of the intake valve based on the combustion gas heat receiving amount, the flowing gas heat receiving amount, the contact surface heat receiving amount, and the vaporization heat amount.

Japanese Unexamined Patent Publication No. 2007-278906

In the temperature estimation device of Patent Document 1, the amount of heat received by combustion gas is determined based on parameters such as engine load factor, fuel injection amount, engine speed, and combustion gas pressure in a cylinder. Further, in the temperature estimation device of Patent Document 1, the intake heat receiving amount is obtained based on parameters such as the temperature of the intake valve, the intake temperature, the engine speed, and the lift amount of the intake valve. Further, in the temperature estimation device of Patent Document 1, the contact surface heat receiving amount is obtained based on parameters such as engine cooling water temperature, engine speed, and intake pressure. Then, in the temperature estimation device of Patent Document 1, the amount of heat of vaporization is obtained based on parameters such as the temperature of the intake valve, the intake pressure, the fuel temperature, and the engine speed.

In the temperature estimation device of Patent Document 1, when estimating the temperature of the intake valve, a plurality of maps for calculating various heat receiving amounts, vaporization heat amounts, and the like are required. Moreover, each of these maps is a map with multiple parameters as variables. Therefore, in order to realize appropriate intake valve temperature estimation under various engine operating conditions, a huge amount of test data and simulation results are required to create each map, which contributes to the increase in engine cost. ing.

In order to solve the above problems, the present invention is applied to a hybrid vehicle including an engine and an electric motor driven and connected to the crank shaft of the engine, and the temperature of the intake valve or the intake port of the engine is set to the temperature of the intake portion. This is an engine temperature estimation device that estimates the temperature of the intake unit using the engine speed, engine load, and engine cooling water temperature during firing in which fuel is supplied to the cylinder of the engine. However, during motoring in which fuel is not supplied into the cylinder of the engine and the crank shaft is rotated by the electric motor, the engine speed and the engine load of the engine are not used. The temperature of the intake unit is estimated using the intake air temperature and the engine cooling water temperature.

According to the above configuration, since the engine speed and the engine load are not used in estimating the intake air temperature of the engine during motoring, the parameters in the map and the calculation formula for estimating the intake air temperature are excessive. It won't increase. Therefore, it is possible to simplify the time and effort required to create a map for estimating the temperature of the intake unit, a calculation formula, and the like, and it is possible to suppress an increase in engine cost.

Schematic diagram of the engine of a hybrid vehicle and its peripheral configuration. The flowchart which shows the temperature estimation process of an intake valve.

Hereinafter, embodiments of the present invention will be described. First, a schematic configuration of the engine 10 of the hybrid vehicle and its surroundings will be described.
As shown in FIG. 1, the engine 10 includes a cylinder block 11 for partitioning a plurality of cylinders 12. A cylinder head 13 is attached to the upper part of the cylinder block 11. The cylinder head 13 is provided with an intake port 14 and an exhaust port 15 so as to connect the outside of the cylinder head 13 with the cylinder 12 of the cylinder block 11. The cylinder head 13 is provided with an intake valve 16 that opens and closes an opening on the cylinder 12 side of the intake port 14. Further, the cylinder head 13 is provided with an exhaust valve 17 that opens and closes an opening on the cylinder 12 side in the exhaust port 15.

An intake pipe 21 for introducing intake air (outside air) from the outside into the cylinder 12 is connected to the intake port 14 of the cylinder head 13. In the middle of the intake pipe 21, an intake air temperature sensor 22 for measuring the intake air temperature Tin of the intake air flowing through the intake pipe 21 is provided. Further, an air flow meter 23 for detecting the intake air amount Ga, which is the amount of intake air flowing through the intake pipe 21, is attached in the middle of the intake pipe 21. A throttle valve 24 for adjusting the amount of intake air introduced into the cylinder 12 is provided on the downstream side of the intake pipe 21 with respect to the intake air temperature sensor 22 and the air flow meter 23. A throttle sensor 25 for detecting the throttle opening TA, which is the opening degree of the throttle valve 24, is attached to the throttle valve 24. An exhaust pipe 26 for exhausting the exhaust gas in the cylinder 12 to the outside is connected to the exhaust port 15 in the cylinder head 13.

A piston 31 is provided in the cylinder 12 of the cylinder block 11 so as to be movable in the axial direction in the cylinder 12. The piston 31 is connected to the crank pin 33 via a connecting rod 32. The crank pin 33 is connected to the crank shaft 35 via the crank arm 34. The crankshaft 35 rotates as the piston 31 reciprocates in the cylinder 12 in the axial direction. The crankshaft 35 is provided with a crank angle sensor 36 for detecting the crank angle θ of the crankshaft 35.

The crankshaft 35 is driven and connected to a motor generator 42 as an electric motor via a power distribution mechanism 41. The motor generator 42 is a three-phase synchronous motor generator including a rotor in which a permanent magnet is embedded and a stator in which a three-phase coil is wound. That is, the motor generator 42 functions as an electric motor by being supplied with electric power from, for example, a battery (not shown), and rotates the rotating shaft 42a. Further, the motor generator 42 functions as a generator by rotating the rotating shaft 42a, and outputs electric power to, for example, a battery (not shown).

A drive shaft 43 is drive-connected to the power distribution mechanism 41. Further, the drive shaft 43 is drive-connected to the drive wheels 45 of the vehicle via the reduction mechanism 44. The reduction gear mechanism 44 is composed of a plurality of gears having different numbers of teeth, reduces the rotation of the drive shaft 43 at a predetermined reduction ratio (gear ratio), and transmits the rotation as the rotation of the drive wheels 45.

The power distribution mechanism 41 distributes the mutual power of the crankshaft 35, the rotation shaft 42a of the motor generator 42, and the drive shaft 43 according to the driving condition of the vehicle. For example, when the charging power of the battery mounted on the vehicle is low, the power distribution mechanism 41 distributes the driving force of the crankshaft 35 to the drive shaft 43 and the motor generator 42, and causes the motor generator 42 to function as a generator. .. When a large torque is required as the rotational torque of the drive shaft 43 (drive wheel 45), the driving force of the crankshaft 35 and the rotary shaft 42a of the motor generator 42 is transmitted to the drive shaft 43.

The crankshaft 35 may be rotated at a certain number of revolutions without fuel being supplied into the cylinder 12 of the engine 10. Specifically, for example, when the vehicle is driven only by the driving force of the motor generator 42, fuel is not supplied into the cylinder 12 of the engine 10. In addition, the fuel supply to the cylinder 12 of the engine 10 may be stopped while the vehicle is decelerating or stopping. In this way, even when the fuel is not supplied to the cylinder 12 of the engine 10, the crankshaft 35 rotates at a constant rotation speed so that the engine 10 is driven quickly when the fuel supply is restarted, for example. May be done. In such a case, the power distribution mechanism 41 distributes the driving force of the rotating shaft 42a of the motor generator 42 to the crankshaft 35 and the driving shaft 43.

In this embodiment, as described above, the fact that fuel is not supplied into the cylinder 12 of the engine 10 and the crankshaft 35 is rotated by the motor generator 42 is referred to as "motoring". Further, the fact that fuel is supplied into the cylinder 12 of the engine 10 and the crankshaft 35 is rotated by burning the fuel in the cylinder 12 is referred to as "firing". Even if a part of the rotational torque of the drive shaft 43 is supplemented by the motor generator 42, if fuel is supplied to the cylinder 12 of the engine 10, it is “firing”.

The cylinder block 11 and the cylinder head 13 of the engine 10 are provided with a water jacket 51 through which cooling water for cooling the engine 10 flows. A cooling water channel 52 through which cooling water flows is connected to the water jacket 51 outside the cylinder block 11 and the cylinder head 13. The cooling water channel 52, together with the water jacket 51, constitutes a return channel through which the cooling water circulates. The cooling water channel 52 is provided with a cooling water pump 53 for pumping cooling water. When the cooling water pump 53 is the most upstream portion, the radiator 54 is provided on the downstream side of the water jacket 51 in the cooling water channel 52. The radiator 54 functions as a heat exchanger that releases the heat of the warmed cooling water to the outside. A cooling water temperature sensor 55 that detects the temperature of the cooling water at the outlet (downstream port) of the water jacket 51 as the engine cooling water temperature Tw on the downstream side of the water jacket 51 in the cooling water channel 52 and on the upstream side of the radiator 54. Is installed. Note that FIG. 1 shows only the water jacket 51 of the cylinder block 11.

The engine 10, the motor generator 42, and the like configured as described above are controlled by the electronic control unit 60 (ECU). The electronic control unit 60 includes a computing device that executes various programs, a non-volatile ROM in which various programs (software) are stored, a volatile RAM in which data is temporarily stored when the programs are executed, and the like. It is a computer. Detection signals from various sensors indicating the state of the vehicle are input to the electronic control unit 60. The electronic control unit 60 controls the combustion state of the engine 10 and controls whether the motor generator 42 functions as a motor or a generator based on detection signals from various sensors. Further, the electronic control unit 60 controls the power distribution mode in the power distribution mechanism 41 in accordance with these controls.

The electronic control unit 60 also functions as a temperature estimation device that estimates the temperature of the intake valve 16 in the engine 10. The intake air temperature Tin detected by the intake air temperature sensor 22 is input to the electronic control unit 60 as an intake air temperature signal, and the throttle opening TA detected by the throttle sensor 25 is input as a throttle opening signal. Further, the intake air amount Ga detected by the air flow meter 23 is input to the electronic control unit 60 as an intake air amount signal, and the crank angle θ detected by the crank angle sensor 36 is input as a crank angle signal. Further, the engine cooling water temperature Tw detected by the cooling water temperature sensor 55 is input to the electronic control unit 60 as a cooling water temperature signal. In addition, the electronic control unit 60 is input with a depression amount signal indicating the depression amount Acc from the accelerator sensor 62 that detects the depression amount Acc of the accelerator pedal 61 provided in the vehicle. Further, a vehicle speed signal indicating the vehicle speed SP of the vehicle is input to the electronic control unit 60 from the vehicle speed sensor 63 provided in the vehicle. The electronic control unit 60 estimates the temperature of the intake valve 16 based on each of these input signals. In this embodiment, the temperature of the intake valve 16 corresponds to the temperature of the intake portion.

Next, the temperature estimation process of the intake valve 16 by the electronic control unit 60 (temperature estimation device) will be described. The series of temperature estimation processes are repeatedly executed at predetermined control cycles while the vehicle hybrid system is activated.

As shown in FIG. 2, when the temperature estimation process is started, the electronic control unit 60 executes the process of step S11. In step S11, the electronic control unit 60 determines whether or not the engine 10 has been started. Specifically, the electronic control unit 60 calculates the engine speed NE based on the crank angle θ detected by the crank angle sensor 36. The electronic control unit 60 has a predetermined time or more since the power-on switch (ignition switch) of the hybrid system is turned on, and the engine speed NE exceeds the predetermined speed. Is a condition, and it is determined that the engine 10 has been started. The predetermined rotation speed is predetermined to be smaller than the minimum rotation speed (rotation speed during idle operation) that allows the engine 10 to operate stably and independently. In this embodiment, the predetermined rotation speed is It is zero. If it is determined in step S11 that the engine 10 has not started, that is, the engine 10 has stopped (NO in step S11), the processing of the electronic control unit 60 shifts to step S21.

In step S21, the electronic control unit 60 sets the engine cooling water temperature Tw detected by the cooling water temperature sensor 55 as the steady intake valve temperature Tst. The steady intake valve temperature Tst is a temperature at which the temperature of the intake valve 16 converges when a sufficient time elapses without changing the state of the engine 10. When the step S21 is completed, the process of the electronic control unit 60 shifts to the step S14.

On the other hand, if it is determined in step S11 that the engine 10 has been started (YES in step S11), the processing of the electronic control unit 60 shifts to step S12. In step S12, the electronic control unit 60 determines whether or not fuel is not supplied to the cylinder 12 of the engine 10 and the motor generator 42 is rotating the crankshaft 35 during motoring. When not in motoring, that is, in firing in which fuel is being supplied into the cylinder 12 of the engine 10 (NO in step S12), the processing of the electronic control unit 60 shifts to step S22.

In step S22, the electronic control unit 60 estimates the steady intake valve temperature Tst using the engine speed NE, the engine load KL, and the engine cooling water temperature Tw. As described above, the engine speed NE is calculated based on the crank angle θ detected by the crank angle sensor 36. The engine load KL is calculated based on the throttle opening TA detected by the throttle sensor 25. For example, when the throttle opening TA is in the fully open state, the engine load is 100% and the throttle opening TA is It is calculated as 0% engine load when fully closed. The engine cooling water temperature Tw is detected by the cooling water temperature sensor 55. The electronic control unit 60 estimates a higher temperature as the steady intake valve temperature Tst as the engine speed NE is higher, the engine load KL is larger, and the engine cooling water temperature Tw is higher. The relationship between the engine speed NE, the engine load KL, the engine cooling water temperature Tw, and the steady-state intake valve temperature Tst has been mapped and calculated by conducting tests and simulations in advance, and the electronic control unit 60 Estimates the steady-state intake valve temperature Tst with reference to these maps and calculation formulas. After estimating the steady intake valve temperature Tst, the process of the electronic control unit 60 proceeds to step S14.

On the other hand, when it is determined in step S12 that the engine 10 is being motorized (YES in step S12), the processing of the electronic control unit 60 shifts to step S13. In step S13, the electronic control unit 60 estimates the steady intake valve temperature Tst using the engine cooling water temperature Tw detected by the cooling water temperature sensor 55 and the intake air temperature Tin detected by the intake air temperature sensor 22. The electronic control unit 60 estimates a higher temperature as the steady intake valve temperature Tst as the engine cooling water temperature Tw is higher and the intake air temperature Tin is higher. The relationship between the engine cooling water temperature Tw and the engine cooling water temperature Tw and the steady intake valve temperature Tst has been made into a map or a calculation formula by conducting tests or simulations in advance, and the electronic control unit 60 has such a map or a calculation formula. The steady intake valve temperature Tst is estimated with reference to the calculation formula. After estimating the steady intake valve temperature Tst, the process of the electronic control unit 60 proceeds to step S14.

In step S14 after estimating the steady-state intake valve temperature Tst in step S21, step S22, or step S13, the electronic control unit 60 determines the number of times of smoothing M. In this embodiment, the electronic control unit 60 determines the number of times of smoothing M based on the intake air amount Ga detected by the air flow meter 23 and the vehicle speed SP detected by the vehicle speed sensor 63. Specifically, the electronic control unit 60 determines the number of times of smoothing M, which is smaller as the intake air amount Ga increases. Further, the electronic control unit 60 determines whether or not the vehicle is decelerating based on the vehicle speed SP. Then, when the electronic control unit 60 is decelerating, the number of times of smoothing M is determined so that the rate of decrease of the number of times of smoothing M according to the above-mentioned intake air amount Ga becomes small. In other words, the number of times of smoothing M tends to be larger when the vehicle is decelerating than when it is not. After determining the number of times of smoothing M, the processing of the electronic control unit 60 shifts to step S15.

In step S15, the electronic control unit 60 estimates the estimated intake valve temperature Tv based on the previous (one control cycle before) estimated intake valve temperature Tv, the steady intake valve temperature Tst, and the number of times of smoothing M. Specifically, when the estimated intake valve temperature Tv estimated this time is "Tv (N)" and the estimated intake valve temperature Tv of the previous time (one control cycle before) is "Tv (N-1)", the electronic control unit. 60 estimates the estimated intake valve temperature Tv by the following calculation formula.
-Tv (N) = Tv (N-1) + (Tst-Tv (N-1)) / M
That is, the electronic control unit 60 smoothes the difference between the steady intake valve temperature Tst estimated in the current control cycle and the previous estimated intake valve temperature Tv by the number of times of smoothing M according to the intake air amount Ga and the like. The estimated intake valve temperature Tv (N) this time is estimated by adding the value after the anneading to the estimated intake valve temperature Tv (N-1) of the previous time. Therefore, the electronic control unit 60 estimates the temperature closer to the steady intake valve temperature Tst estimated in the current control cycle as the estimated intake valve temperature Tv (N) this time as the number of times of smoothing M is smaller. Further, the electronic control unit 60 estimates a temperature closer to the previous estimated intake valve temperature Tv (N-1) as the current estimated intake valve temperature Tv (N) as the number of times of smoothing M increases. After estimating the estimated intake valve temperature Tv, a series of temperature estimation processes by the electronic control unit 60 are completed, and the processes from step S11 are executed again in the next control cycle.

Next, the effect of the above embodiment will be described.
In the above embodiment, when the engine 10 is in motoring, when estimating the steady intake valve temperature Tst of the intake valve 16, the engine rotation speed NE and the engine load KL are not used, and only the engine cooling water temperature Tw and the intake temperature Tin are used. Is used. In this way, if there are only two variables, the engine cooling water temperature Tw and the intake air temperature Tin, the amount of data is so enormous when creating a map, calculation formula, etc. for obtaining the steady intake valve temperature Tst. I don't need it. Therefore, it is possible to reduce the trouble of creating a map or the like for calculating the estimated intake valve temperature Tv when the engine 10 is in motoring, and it is possible to contribute to the cost reduction of the engine 10.

When the engine 10 is in motoring, no fuel is supplied into the cylinder 12, and the fuel does not burn in the cylinder 12. When the engine 10 is being motorized, the crankshaft 35 is rotated by the motor generator 42, and the influence of the engine speed NE and the engine load KL on the temperature of the intake valve 16 is small.

On the other hand, when the engine 10 is being motorized, it does not receive the combustion heat in the cylinder 12, but from the heat received from the valve seat (cylinder head 13) when the intake valve 16 is closed and the intake air that hits the intake valve 16. The influence of the heat received becomes dominant. Therefore, if the engine cooling water temperature Tw and the intake air temperature Tin are used in estimating the steady intake valve temperature Tst of the intake valve 16, the steady intake is sufficiently accurate without using the engine speed NE or the engine load KL. It is possible to estimate the valve temperature Tst.

Further, in the above embodiment, when the engine 10 is not started, the engine cooling water temperature Tw is set to the steady intake valve temperature Tst. As described above, when the engine 10 is not started, the steady intake valve temperature Tst can be uniquely estimated from the engine cooling water temperature Tw, so that a complicated map or calculation formula is not required. Therefore, it is possible to reduce the trouble of creating a map or the like for calculating the estimated intake valve temperature Tv when the engine 10 is not started, and it is possible to contribute to the cost reduction of the engine 10.

By the way, for example, when the intake air amount Ga is large, heat exchange is constantly performed between the intake air and the intake valve 16, and the frequency of fuel combustion in the cylinder 12 is also high. Therefore, the temperature of the intake valve 16 converges to the steady intake valve temperature Tst relatively quickly.

On the other hand, when the vehicle is decelerating, the engine speed NE and the engine load KL of the engine 10 are lower than those before deceleration, and the temperature of the intake valve 16 in the engine 10 decreases. Probability is high. Although the cylinder block 11 and the cylinder head 13 in the engine 10 are cooled by the cooling water flowing in the water jacket 51, the intake valve 16 is compared with the rising speed when the temperature of the intake valve 16 rises. As the temperature of the cylinder decreases, the rate of decrease decreases. That is, the temperature of the intake valve 16 becomes difficult to converge to the steady intake valve temperature Tst as the temperature decreases.

Focusing on this point, in the above embodiment, the number of times of smoothing M used when calculating the estimated intake valve temperature Tv is set to a variable value according to the intake air amount Ga and whether or not the vehicle is decelerating. Therefore, it is possible to calculate an accurate estimated intake valve temperature Tv for the temperature of the intake valve 16 in consideration of the ease of convergence to the steady intake valve temperature Tst.

The above embodiment can be modified as follows. Further, if necessary, a plurality of modification examples can be combined and adopted.
-In the above embodiment, the power of the crankshaft 35 in the engine 10 can be transmitted to the drive shaft 43, but the present invention is not limited to this. For example, the power of the crankshaft 35 of the engine 10 may be used as the power for power generation in the generator (motor generator), and the drive shaft 43 may be rotated by the drive motor. That is, it may be a so-called series type hybrid vehicle. Further, a motor generator for power generation and a motor generator for driving may be provided, and the power of the crankshaft 35 of the engine 10 may be distributed to the motor generator for power generation and the driving shaft 43 according to the situation. That is, it may be a so-called series parallel type hybrid vehicle. Further, the motor generator 42 does not have to be able to travel the vehicle by itself, and may be used exclusively as an auxiliary drive source for the engine 10. In any case, if the crankshaft 35 of the engine 10 can be rotated at a certain number of revolutions in a situation where fuel is not supplied into the cylinder 12 of the engine 10, that is, if the motoring of the engine 10 is possible. It may be a hybrid vehicle of any type.

-In the above embodiment, the electronic control unit 60 performs temperature estimation of the intake valve 16 and power distribution control in the power distribution mechanism 41, but these processes may be carried out by different units. For example, the electronic control unit 60 may execute the control of the engine 10 including the temperature estimation of the intake valve 16, and the power control unit different from the electronic control unit 60 may execute the power distribution control in the power distribution mechanism 41.

In the temperature estimation process of the intake valve 16, the determination condition for determining whether or not the engine 10 has been started (step S11 in FIG. 2) is not limited to the example of the above embodiment. For example, the condition regarding the elapsed time since the power-on switch (ignition switch) of the hybrid system is turned on may be omitted. Further, for example, the condition may be that the engine cooling water temperature Tw is equal to or higher than a predetermined temperature.

The method of estimating the steady intake valve temperature Tst when the engine 10 is not started is not limited to the example of the above embodiment. For example, the steady intake valve temperature Tst may be estimated using the engine speed NE, the engine load KL, and the engine cooling water temperature Tw as in the case where the engine 10 is fired (step S22 in FIG. 2). .. In this case, the estimation map of the steady intake valve temperature Tst when the engine 10 is firing and the estimation map of the steady intake valve temperature Tst when the engine 10 is not started may be separately provided. You may have one map that integrates the two.

The method of estimating the steady intake valve temperature Tst when the engine 10 is firing (step S22 in FIG. 2) is not limited to the example of the above embodiment. For example, the steady intake valve temperature Tst may be estimated using the intake air temperature Tin in addition to the engine speed NE, the engine load KL, and the engine cooling water temperature Tw. If there are many parameters required to estimate the steady intake valve temperature Tst, a lot of test data or the like is required to create a map for estimating the steady intake valve temperature Tst. Therefore, from the viewpoint of simplifying the time and effort required to create the map, it is preferable that the number of parameters used when estimating the steady intake valve temperature Tst is small.

-Other parameters may be used in estimating the steady intake valve temperature Tst when the engine 10 is motorized (step S13 in FIG. 2). For example, the steady intake valve temperature Tst may be estimated using the intake pressure in addition to the engine cooling water temperature Tw and the intake air temperature Tin. Even in this case, if the engine speed NE and the engine load KL are not used, the time and effort required to create the map can be simplified as compared with the case where the steady intake valve temperature Tst is estimated using these.

The determination of the number of times of smoothing M (step S14 in FIG. 2) and the calculation of the estimated intake valve temperature Tv using the number of times of smoothing M and the like may be omitted. In this case, the steady intake valve temperature Tst is estimated as the estimated intake valve temperature Tv in steps S13, S21, and S22 in FIG.

-The abnormality of various sensors may be determined before the determination of whether or not the engine 10 has been started (step S11). As a sensor that is symmetrical to the abnormality determination, it is necessary for a series of temperature estimation processes such as an intake air temperature sensor 22, an air flow meter 23, a throttle sensor 25, a crank angle sensor 36, a cooling water temperature sensor 55, an accelerator sensor 62, and a vehicle speed sensor 63. It is a sensor that detects the parameters. Whether or not the sensor is abnormal can be determined, for example, that the value indicated by the signal output from the sensor remains constant for a predetermined time or longer, that the signal from the sensor is not input to the electronic control unit 60, and the like. Is judged as a condition. Further, when determining the abnormality of various sensors in this way, when the abnormality of the sensor is determined, the temperature of the intake valve 16 is set to a predetermined predetermined temperature. The valve opening timing, valve opening period, etc. of the intake valve 16 may be changed on the condition that the temperature of the intake valve 16 is below a certain temperature or above a certain temperature. If it is necessary to prevent such changes in valve opening timing and valve opening period from being executed when various sensors have an abnormality, the valve opening timing and valve opening period can be changed as the predetermined temperature. It is preferable to set the temperature outside the range of the execution conditions.

-In the above embodiment, the temperature of the intake valve 16 (estimated intake valve temperature Tv) has been estimated, but the technique for estimating the temperature of the intake valve 16 can also be applied as a technique for estimating the temperature of the intake port 14. it can. In the case of this modification, the temperature of the intake port 14 corresponds to the temperature of the intake portion.

10 ... engine, 11 ... cylinder block, 12 ... cylinder, 13 ... cylinder head, 14 ... intake port, 15 ... exhaust port, 16 ... intake valve, 17 ... exhaust valve, 21 ... intake pipe, 22 ... intake temperature sensor, 23 ... Airflow meter, 24 ... Throttle valve, 25 ... Throttle sensor, 26 ... Exhaust pipe, 31 ... Piston, 32 ... Connecting rod, 33 ... Crank pin, 34 ... Crank arm, 35 ... Crankshaft, 36 ... Crank angle sensor, 41 ... power distribution mechanism, 42 ... motor generator, 42a ... rotary shaft, 43 ... drive shaft, 44 ... reduction mechanism, 45 ... drive wheel, 51 ... water jacket, 52 ... cooling water channel, 53 ... cooling water pump, 54 ... radiator, 55 ... Cooling water temperature sensor, 60 ... Electronic control unit, 61 ... Accelerator pedal, 62 ... Accelerator sensor, 63 ... Vehicle speed sensor, Tin ... Intake temperature, TA ... Throttle opening, Ga ... Intake air amount, θ ... Crank angle, Tw ... Engine cooling water temperature, Acc ... Accelerator pedal depression amount, SP ... Vehicle speed, NE ... Engine speed, Tst ... Steady intake valve temperature, M ... Number of smoothing, Tv ... Estimated intake valve temperature.

Claims (1)

An engine temperature estimation device that is applied to a hybrid vehicle equipped with an engine and an electric motor that is driven and connected to the crankshaft of the engine, and estimates the temperature of the intake valve or intake port of the engine as the intake portion temperature. ,
During the firing in which fuel is supplied into the cylinder of the engine, the temperature of the intake portion is estimated using the engine speed, the engine load, and the engine cooling water temperature.
During motoring in which fuel is not supplied into the cylinder of the engine and the crankshaft is rotated by the electric motor, the intake air temperature of the engine is used without using the engine speed and the engine load. An engine temperature estimation device, which estimates the intake unit temperature using the engine cooling water temperature.

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