JP2014105686A - Cooling water temperature estimating device for engine and engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly estimate a cooling water temperature of an engine.SOLUTION: A cooling water temperature estimating device includes a cooling water temperature estimating means 51 for obtaining an estimated water temperature by estimating a cooling water temperature of an engine 1 based on a detected operation state of the engine 1. An in-operation water temperature estimating means 52 provided in the cooling water temperature estimating means 51 and estimating the cooling water temperature during operation of the engine includes an estimated value calculating part 52a for calculating an estimated value of the cooling water temperature based on the operation state, an upper limit value setting part 52b for setting an upper limit value of the cooling water temperature based on the operation state, and an estimated value correcting part 52c for obtaining the estimated water temperature by regulating the upper limit of the estimated value by the upper limit value.

Description

  The present invention relates to a cooling water temperature estimation device for an engine mounted on an automobile or the like and an engine control device using the same.

  In a water-cooled engine (internal combustion engine) mounted on a vehicle such as a gasoline vehicle, a diesel vehicle, or a PHEV vehicle (plug-in hybrid vehicle), the cooling water is used for control of engine coolant circulation or other engine control. It is necessary to know the water temperature. For this reason, in general, a water temperature sensor for detecting the water temperature of the engine cooling water is provided, but a countermeasure in case the water temperature sensor fails is also developed.

  As a countermeasure, for example, there is a technique of changing water temperature information (control water temperature) used for control to a virtual water temperature (fixed value). In the case of this technology, when the water temperature sensor fails while the engine is completely warmed up, even if the engine is started, stopped, or accelerated / decelerated by setting a water temperature of about 80 ° C. as a fixed value, for example. There is no particular inconvenience, and the required amount of fuel can be supplied and stopped, and the engine can be used without much difference from the case where the water temperature sensor is normal.

  However, if the water temperature sensor fails in a state before the engine is completely warmed up, that is, while the engine is warming up, the actual cooling water temperature may be considerably low. The divergence increases. In this case, the actual water temperature is much lower than the virtual water temperature (fixed value). For example, if the fuel amount to the engine is controlled based on the virtual water temperature, the fuel amount required for starting, stopping, and acceleration / deceleration is supplied. As a result, drivability deteriorates, and in the worst case, it is assumed that the engine cannot be started.

On the other hand, Patent Documents 1 and 2 describe techniques for estimating the coolant temperature of an engine.
In Patent Document 1, cooling is performed during engine operation based on engine speed, engine load, fuel injection amount, and the like, which are engine operation parameters related to the amount of heat generated by the engine (the amount of heat transferred from the engine to the cooling water). Describes technology for calculating the water temperature rise, calculating the cooling water temperature drop based on the temperature difference between the vehicle speed and the estimated value of the cooling water temperature and the outside air temperature, and calculating the estimated cooling water temperature from the rise and fall of these water temperatures. Has been.

  In Patent Document 2, the cooling loss, which is the ratio of the cooling heat that contributes to the increase in the engine block and cooling water temperature of the supply heat that the fuel has and the supply heat that the fuel has, is expressed as the engine operating load and the rotational speed. From this cooling loss and supply heat, the cooling loss heat is obtained, the heat released from the engine block to the outside air is calculated from the product of the heat dissipation coefficient determined by the vehicle speed, and the engine block and A technique for estimating the temperature of the cooling water temperature is described.

Japanese Patent No. 3956663 Japanese Patent No. 3896288

As in the techniques described in Patent Documents 1 and 2, the cooling water temperature of the engine is estimated, and if this estimated water temperature is used as the virtual water temperature, for example, for water temperature information (control water temperature) used for engine control or the like, it is fixed. Since the difference between the virtual water temperature and the actual water temperature is unlikely to increase as in the case of using the value, it is considered that the engine control can be appropriately performed.
However, even when the cooling water temperature is estimated based on the heat absorption amount and the heat radiation amount of the cooling water as in the techniques of Patent Documents 1 and 2, the occurrence of the estimation error cannot be avoided, and the estimation error accumulates. It can be a big error. If the estimated water temperature becomes excessively higher than the actual water temperature due to the accumulation of estimation errors, the influence on the engine control and the like will increase. Therefore, it is desirable to avoid the estimated water temperature from becoming excessively higher than the actual water temperature.

  The present invention was devised in view of such a problem, so that the engine coolant temperature can be appropriately estimated, and the engine control based on the estimated coolant temperature can be appropriately performed. An object of the present invention is to provide an engine coolant temperature estimation device and an engine control device using the same.

  (1) In order to achieve the above object, an engine cooling water temperature estimation device of the present invention is a device for estimating a cooling water temperature, which is a temperature of cooling water of an engine mounted on a vehicle, and operates the engine. Operating state detecting means for detecting a state, and cooling water temperature estimating means for obtaining an estimated water temperature that is an estimated value of the cooling water temperature of the engine based on the operating state detected by the operating state detecting means, and the cooling The water temperature estimating means includes an operating water temperature estimating means for estimating the cooling water temperature during operation of the engine, and the operating water temperature estimating means is based on the operating state detected by the operating state detecting means. An estimated value calculating unit for calculating an estimated value of the water temperature, an upper limit setting unit for setting an upper limit value of the cooling water temperature based on the operating state detected by the operating state detecting means, It is characterized by having an estimation value correcting portion for obtaining the estimated water temperature and the upper limit restricted by the upper limit value set to the estimated value calculated by the upper limit setting unit by estimation value calculation unit.

  (2) The vehicle is equipped with a heat-related device (for example, a heater) that operates by exchanging heat with the cooling water, and the estimated value calculation unit is configured to turn off the heat-related device when the heat-related device is in operation. The estimated value having a magnitude different from the estimated value at the time of operation is calculated, and the upper limit value setting unit is different from the upper limit value at the time of non-operation of the heat related device when the heat related device is operated. It is preferable to set the upper limit value. In this case, the estimated value calculation unit calculates the estimated value by correcting the estimated value when the heat-related device is not operated with a first correction gain when the heat-related device is operated, and the upper limit It is also preferable that the value setting unit sets the upper limit value by correcting the upper limit value of the non-operation of the heat related device with a second correction gain when the heat related device is operated.

  (3) The operation state detection means includes a rotation speed detection means for detecting a rotation speed of the engine, and a load state detection means for detecting a load state of the engine. It is preferable to set the upper limit value based on the rotation speed detected by the rotation speed detection means and the load state detected by the load state detection means.

(4) The driving state detecting means includes an outside air temperature detecting means for detecting an outside air temperature around the engine, and a vehicle speed detecting means for detecting a vehicle speed of the vehicle, and the upper limit value setting unit includes at least the The upper limit value is preferably set based on the outside air temperature detected by the outside air temperature detecting means and the vehicle speed detected by the vehicle speed detecting means.
(5) The operation state detection unit includes a rotation speed detection unit that detects a rotation speed of the engine, and a load state detection unit that detects a load state of the engine. Based on the rotation speed detected by the rotation speed detection means and the load state detected by the load state detection means, a temperature addition gain is calculated, and the temperature addition gain is added to the previous estimated value. It is preferable to calculate the estimated value this time by going.

  (6) The operation state detection unit includes a rotation speed detection unit that detects a rotation speed of the engine and a load state detection unit that detects a load state of the engine, and the estimated value calculation unit includes: Based on at least the rotation speed detected by the rotation speed detection means and the load state detected by the load state detection means, a final reached water temperature when the cooling water is not subjected to heat radiation processing is set at a predetermined cycle. It is preferable that the estimated value is calculated by performing the first and second first-order lag filters on the final water temperature.

(7) In this case, it is preferable that the filter gains of the first and second first-order lag filters are set according to at least one of the rotational speed and the load state.
(8) The cooling water temperature estimation means stops the calculation of the estimated value by the estimated value calculation unit at the time of fuel cut to the engine, and maintains the estimated water temperature that is obtained immediately before the fuel cut. It is preferable to have a means.

  (9) The operating state detection means includes intake air temperature detection means for detecting an intake air temperature of the engine, and the cooling water temperature estimation means includes a stopped water temperature estimation means for estimating the cooling water temperature while the engine is stopped. The stopping water temperature estimating means corresponds to a deviation between the cooling water temperature and the intake air temperature and a water temperature convergence time which is a time required for the cooling water temperature to coincide with the intake air temperature while the engine is stopped. When the engine is stopped when the engine is stopped, the correspondence storage unit storing the relationship and the intake water detected by the intake water temperature detecting means and the estimated water temperature obtained by the operating water temperature estimating means The engine is stopped using the correspondence stored in the correspondence storage unit from the deviation from the temperature and the engine stop time from the engine stop time. It is preferred to have a stop in temperature calculating unit for calculating the estimated water temperature.

  (10) In this case, the during-stop water temperature calculation unit obtains a first water temperature convergence time that is the water temperature convergence time corresponding to the deviation using the correspondence relationship, and the engine stop time is the first water temperature convergence. When the time is shorter than the time, it is preferable to obtain the second water temperature convergence time by subtracting the engine stop time from the first water temperature convergence time, and obtain the estimated water temperature from the deviation corresponding to the second water temperature convergence time.

(11) Further, the correspondence relationship storage unit stores a single correspondence relationship regardless of the intake air temperature, and the during-stop water temperature calculation unit calculates the estimated water temperature using the single correspondence relationship. It is preferable to obtain.
(12) It is preferable that the stopped water temperature estimation means estimates the cooling water temperature when the engine is started.

  (13) The engine control device of the present invention is an engine control device that controls an engine mounted on a vehicle based on a control water temperature corresponding to the temperature of the cooling water, and detects the temperature of the cooling water. When the water temperature detecting means is normal, the engine is controlled based on a detection value detected by the water temperature detecting means, and when the water temperature detecting means is faulty, the engine is controlled. And a control means for controlling the engine based on the estimated water temperature estimated by the cooling water temperature estimation device.

  (1) According to the engine coolant temperature estimation device of the present invention, the coolant temperature estimation means provided in the coolant temperature estimation means is configured to estimate the coolant temperature during operation of the engine based on the engine operating state. The estimated water temperature is calculated and the upper limit value of the cooling water temperature is set based on the operating condition of the engine, and the estimated water temperature is obtained by restricting the estimated value with the upper limit value, so that the estimated water temperature is excessively higher than the actual water temperature. It is avoided that the temperature is increased, and it is possible to appropriately estimate the cooling water temperature when the temperature rises during engine operation.

(2) When the vehicle is equipped with a heat-related device such as a heater that operates by heat exchange with the cooling water, when the heat-related device is activated, the estimated value is different from the estimated value of non-operation. Is calculated, and the cooling water temperature can be appropriately estimated by setting the upper limit value to a magnitude different from the upper limit value for non-operation.
(3) By setting the upper limit based on at least the engine speed and the engine load state, the estimated water temperature can be appropriately suppressed from becoming excessively high, and the cooling water temperature can be estimated appropriately.

  (4) Even if the upper limit value is set based on the outside air temperature and the vehicle speed instead of the engine rotation speed and the engine load state, the estimated water temperature is appropriately suppressed from becoming excessively high, and the engine rotation speed If the upper limit value is set based on the outside air temperature and the vehicle speed in addition to the engine load state, the estimated water temperature can be suppressed more appropriately and the cooling water temperature can be estimated more appropriately. .

(5) It is more appropriate to calculate the current estimated value by calculating the temperature added gain based on at least the engine speed and the engine load condition, and adding the temperature added gain to the previous estimated value. The cooling water temperature can be estimated.
(6) Also, based on at least the rotational speed of the engine and the load state of the engine, the final reached water temperature when the cooling water is not radiated is set, and the first and second primary delay filters with respect to the final reached water temperature When the estimated value is calculated by performing the processes according to (1), the coolant temperature can be estimated easily and appropriately.

(7) In this case, if the filter gains of the first and second first-order lag filters are set according to at least one of the engine speed and the engine load state, the coolant temperature can be estimated more appropriately. Can do.
(8) Further, if the calculation of the estimated value is stopped at the time of fuel cut of the engine and the estimated water temperature obtained immediately before the fuel cut is maintained, the cooling water temperature can be estimated easily and appropriately even at the time of fuel cut.

  (9) The cooling water temperature estimation means that is provided in the cooling water temperature estimation means and estimates the cooling water temperature while the engine is stopped is a deviation between the cooling water temperature and the intake air temperature, and the cooling water temperature matches the intake air temperature while the engine is stopped. The correspondence relationship with the water temperature convergence time, which is the time required until the engine is stopped, and when the engine is stopped, the deviation between the estimated water temperature obtained at this time and the detected intake air temperature, and the engine stop time from the engine stop time Thus, the estimated coolant temperature while the engine is stopped is calculated using the stored correspondence relationship, so that the coolant temperature while the engine is stopped can be appropriately estimated.

(10) At this time, using the correspondence relationship, the first water temperature convergence time, which is the water temperature convergence time corresponding to the deviation, is obtained, and the engine stop time is subtracted from the first water temperature convergence time to obtain the second water temperature convergence time. If the estimated water temperature is obtained from the deviation corresponding to the second water temperature convergence time, the cooling water temperature can be easily estimated.
(11) If a single correspondence is used regardless of the intake air temperature, it is possible to properly estimate the cooling water temperature while suppressing the storage capacity related to the correspondence and simply estimating the cooling water temperature.

(12) Further, the estimation of the cooling water temperature during stoppage is performed at the time of engine start, so that the calculation load can be reduced as compared with the case where calculation is always performed at a predetermined cycle even during stoppage.
(13) Further, according to the engine control apparatus of the present invention, when the water temperature detecting means is normal, the engine is appropriately controlled based on the detected value detected by the water temperature detecting means, and when the water temperature detecting means is faulty, the engine cooling water temperature is estimated. The engine can be appropriately controlled based on the estimated water temperature estimated by the apparatus.

It is a block diagram which shows the structure of the engine concerning the 1st and 2nd embodiment of this invention, its cooling water temperature estimation apparatus, and its control apparatus. Corresponding relationship used for estimation of water temperature during stop in engine coolant temperature estimation device according to first and second embodiments of the present invention (deviation between cooling water temperature and intake air temperature, and cooling water temperature coincides with intake air temperature while engine is stopped) It is a graph explaining the correspondence relationship with the engine stop time required until. It is a figure explaining the map of stop water temperature estimation in the engine cooling water temperature estimation apparatus concerning 1st and 2nd embodiment of this invention, (a) is a graph which shows the correspondence of FIG. 2, (b). Is a graph obtained by converting the graph of (a), and (c) is a graph (map) obtained by converting the graph of (b). The transition of the estimated water temperature (no upper limit) at a plurality of engine rotational speeds obtained by the first operating water temperature estimation means in the engine coolant temperature estimation device according to the first embodiment of the present invention is compared with the transition of the actual water temperature. (A), (b), and (c) show transitions in different engine load states (states of charging efficiency). It is a figure which shows the difference of transition of the actual water temperature explaining the significance of the switching of the water temperature estimation by the operation non-operation of the heater in the engine cooling water temperature estimation apparatus according to the first and second embodiments of the present invention, (a) The case where the heater is not operated is shown, and (b) shows the case where the heater is operated. It is a main flowchart explaining the water temperature estimation by the engine cooling water temperature estimation apparatus concerning 1st and 2nd embodiment of this invention. It is a flowchart of the subroutine explaining the water temperature estimation in a stop by the engine cooling water temperature estimation apparatus concerning 1st and 2nd embodiment of this invention. It is a flowchart of the subroutine explaining the water temperature estimation (the 1) during driving | operation with the cooling water temperature estimation apparatus of the engine concerning 1st Embodiment of this invention. It is a flowchart of the subroutine explaining the setting of the upper limit concerning driving | running water temperature estimation by the engine cooling water temperature estimation apparatus concerning 1st and 2nd embodiment of this invention. It is a time chart explaining the water temperature estimation by the engine cooling water temperature estimation apparatus concerning 1st and 2nd embodiment of this invention. Changes in estimated water temperature (no upper limit) in a plurality of engine load states (charging efficiency states) obtained by the second operating water temperature estimating means in the engine coolant temperature estimating device according to the second embodiment of the present invention. It is a figure shown compared with transition of actual water temperature, (a), (b), (c) shows each transition in a different engine speed. It is a figure which shows the filter gain and final final water temperature which are used with the 2nd water temperature estimation means during operation in the engine cooling water temperature estimating device concerning a 2nd embodiment of the present invention corresponding to the operating state of an engine, and (a). The filter gain of the first primary delay filter is shown, (b) shows the filter gain of the second primary delay filter, and (c) shows the final water temperature. It is a flowchart of the subroutine explaining the water temperature estimation (the 2) in driving | operation by the engine cooling water temperature estimation apparatus concerning 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a device configuration according to the first and second embodiments, FIG. 2, FIG. 3, FIG. 5 and FIG. 6 show water temperature estimation according to the first and second embodiments, and FIG. FIG. 6, FIG. 7 and FIG. 9 show water temperature estimation according to the first and second embodiments, and FIG. 8 shows water temperature estimation according to the first embodiment, respectively. FIG. 10 is a flowchart for explaining water temperature estimation according to the first and second embodiments. 11 and 12 are graphs for explaining water temperature estimation according to the second embodiment, and FIG. 13 is a flowchart for explaining water temperature estimation according to the second embodiment. The present embodiment will be described with reference to these drawings.

[First Embodiment]
[1. Configuration of engine and engine control device]
First, with reference to FIG. 1, the configuration of the engine according to the first embodiment, its cooling water temperature estimation device, and its control device will be described. As shown in FIG. 1, an engine 1 mounted on a vehicle includes a cylinder block 2 and a cylinder head 3. A cylinder 4 is formed in the cylinder block 2, and a water jacket 5 is formed around the cylinder 4. Has been. A piston 6 is slidably mounted in the cylinder 4, and the piston 6 is connected to a crankshaft 8 via a connecting rod 7. A combustion chamber 9 is formed above the piston 6 in the cylinder 4. FIG. 1 is a cross-sectional view focusing on one cylinder 4 of the engine, and a plurality of cylinders 4 are provided side by side.

  The cylinder head 3 is formed with an intake port 11 and an exhaust port 12 that open to the combustion chamber 9. The intake port 11 is provided with an intake valve 13, and the exhaust port 12 is provided with an exhaust valve 14. A spark plug 10 is disposed at the top of the combustion chamber 9 of the cylinder head 3 toward the combustion chamber 9. An intake pipe 15 and an intake manifold 16 are connected upstream of the intake port 11, and an air filter 17, a throttle valve 18, and an injector 20 are installed in the intake passages 15, 16 from the upstream. An exhaust manifold 19 and an exhaust pipe (not shown) are connected downstream of the exhaust port 12.

  An air flow sensor 21 is provided upstream of the intake pipe 15, and a throttle opening sensor 22 is provided on the throttle valve 18. Further, the cylinder block 2 is equipped with a water temperature sensor (water temperature detecting means) 23 for detecting the temperature (actual water temperature) of the cooling water (coolant) flowing through the water jacket 5 in the vicinity of the water jacket 5. A crank angle sensor 24 that detects a crank angle is provided in the vicinity of the crank angle sensor 24, and the crank angle sensor 24 also functions as a rotation speed detection unit that detects the rotation speed of the engine.

The cooling water in the water jacket 5 circulates in a cooling water circulation circuit equipped with a radiator (not shown) and is heated by engine cooling to reach a predetermined temperature range, for example, by a known technique using a thermostat or the like. The heat radiation by the radiator is adjusted and controlled to an appropriate temperature range.
Further, for example, a vehicle speed sensor (vehicle speed detection means) 25 for detecting the vehicle speed from the wheel speed and an outside air temperature sensor 26 for detecting the temperature Tout of the outside air around the vehicle are provided. Since the temperature Tia of the intake air to the engine 1 corresponds to the outside air temperature Tout, the outside air temperature sensor 26 functions as an outside air temperature detecting unit and an intake air temperature detecting unit. Further, an accelerator opening sensor (accelerator opening detecting means) 27 for detecting the depression amount of the accelerator pedal of the vehicle is also provided.

  The engine 1 is controlled by an engine control device (engine ECU) 50 based on information from an operation state detection unit that detects the operation state of the engine 1 including the sensors 21 to 27. The engine ECU 50 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium), thereby allowing the fuel injection amount and fuel from the injector 20 to be changed according to the engine operating state. The injection timing, the ignition timing by the spark plug 10 and the like are controlled.

  The engine ECU 50 uses an engine speed (engine speed) Ne and a charging efficiency Ec corresponding to the engine load for each control of the engine. The filling efficiency Ec is obtained by normalizing the volume of air filled in the cylinder 4 during the intake stroke (one stroke until the piston 16 moves from the top dead center to the bottom dead center) to the gas volume in the standard state. Thereafter, it is divided by the cylinder volume, and can be calculated from, for example, the crank angle detection information by the crank angle sensor 24 and the intake air amount detection information by the air flow sensor 21.

  Further, a fuel injection control unit 60 is provided in the engine ECU 50 in order to perform fuel injection control such as the fuel injection amount in the engine control. The fuel injection control unit 60 controls fuel injection mainly based on the engine speed Ne, the charging efficiency Ec, and the coolant temperature Tw. In addition, the fuel injection control unit 60 is provided with a fuel cut control unit 61 that stops (cuts) fuel injection in accordance with the operating state of the engine 1 while the engine 1 is operating.

That is, the fuel cut control unit 61 performs fuel cut to stop fuel injection when the fuel cut condition is satisfied, and restarts fuel injection when the fuel injection return condition is satisfied at the time of this fuel cut.
The fuel cut condition is, for example, that the engine speed Ne is equal to or higher than a predetermined speed Ne01, and the engine 1 is switched from the off-idle state to the idle state (or the load request to the engine 1 has been eliminated). Is defined as The fuel injection return condition is, for example, that the engine speed Ne is equal to or lower than a predetermined speed Ne02 (Ne02 <Ne01), or that the engine 1 is switched from the idle state to the off-idle state (or to the engine 1). This is specified as the occurrence of a load request.

  Whether the engine is in an off-idle state or an idle state can be determined from the detection value of the throttle opening sensor 22. If the throttle opening detected by the throttle opening sensor 22 is fully closed (0 or the minimum value), the engine is idle. Otherwise, it can be determined as an off-idle state. The load request to the engine 1 can be determined from the detection value of the accelerator opening sensor 27. If the accelerator opening detected by the accelerator opening sensor 27 is fully closed (0 or the minimum value), the load request Otherwise, it can be determined that there is no load request.

[2. Configuration of cooling water temperature estimation device)
Incidentally, the engine coolant temperature (actual water temperature) Twr is detected by the water temperature sensor 23, but the vehicle is equipped with a coolant temperature estimation device in case the water temperature sensor 23 fails (fails). . This cooling water temperature estimation device estimates various coolants (operating state detection means) for detecting the operating state of the engine 1 and the cooling water temperature of the engine 1 based on the operating state of the engine 1 detected by these sensors. A cooling water temperature estimating unit (cooling water temperature estimating means) 51. In the present embodiment, the coolant temperature estimation unit 51 is provided as a functional element of the engine ECU 50.

  The cooling water temperature estimation unit 51 includes an in-operation water temperature estimation unit (in-operation water temperature estimation means) 52 that estimates the cooling water temperature during operation of the engine 1, and an in-stop water temperature estimation unit that estimates the cooling water temperature during engine stop ( (Stopped water temperature estimating means) 53 and an estimated water temperature holding section (estimated water temperature holding means) 54 for stopping the calculation of the estimated value of the cooling water temperature at the time of fuel cut and holding the estimated water temperature obtained immediately before the fuel cut. doing.

[2.1 Estimated water temperature during shutdown]
When the engine 1 is started, first, the cooling water temperature lowered while the engine 1 is stopped is estimated by the stopping water temperature estimation unit 53. The water temperature estimation unit 53 during the stop requires an engine required for the deviation ΔT between the estimated cooling water temperature (estimated water temperature) Twe and the detected intake air temperature Tia and the cooling water temperature Twr to be reduced to coincide with the intake air temperature Tia due to the engine 1 being stopped. Using the correspondence relationship storage unit 53a that stores the correspondence relationship with the water temperature convergence time tcs that is the stop time, and the correspondence relationship stored in the correspondence relationship storage unit 53a, the stop for calculating the estimated water temperature Twe at the time of engine start A medium water temperature calculation unit 53b.

  FIG. 2 is a diagram for explaining the correspondence relationship stored in the correspondence relationship storage unit 53a. In the drawing, the region surrounded by the thin solid curve is the state where the outside air temperature is extremely low to high in a certain engine A. The region where the correspondence data between the deviation ΔT and the water temperature convergence time tcs exists is shown, and the area surrounded by the dashed curve is the difference between the deviation ΔT and the water temperature convergence time tcs when the outside air temperature is medium. The region where the corresponding data exists is shown, and the region surrounded by the bold solid curve shows the region where the corresponding data between the deviation ΔT and the water temperature convergence time tcs when the outside air temperature is extremely high in another engine C. .

  In addition, each corresponding data exists in a region where the deviation ΔT at the time when the engine is stopped is plotted so as to be on the vicinity of the curve L in the figure, and the deviation decreases with the subsequent elapsed time (the elapsed time after the engine stops). This is a region where a plurality of collected plots of ΔT plotted with the horizontal axis (time axis) shifted according to the elapsed time. As shown in the figure, it can be seen that even if the conditions change, the deviation ΔT and the water temperature convergence time tcs are aligned along the vicinity of the curve L in the figure. From this, it is understood that the relationship between the deviation ΔT and the water temperature convergence time tcs can be represented by a common curve L in various engines.

  FIG. 3A shows this curve L. The curve L gradually decreases as the engine stop time elapses, and eventually the deviation ΔT becomes 0 (that is, the cooling water temperature Twr and the intake air temperature Tia coincide). become. That is, there is an elapsed time after the engine stop where the deviation ΔT becomes zero. Therefore, when the curve L is converted with the elapsed time after the engine stop at which the deviation ΔT becomes 0 as the horizontal axis, a curve L1 shown in FIG. 3B is obtained. In the figure, the arrow from the horizontal axis to the curve L1 indicates the engine stop time required until each deviation ΔT becomes 0 (the cooling water temperature Twr and the intake air temperature Tia coincide). When the horizontal axis represents the engine stop time required until each deviation ΔT in FIG. 3B becomes 0, the corresponding deviation ΔT represents the vertical axis, and the curve L1 is converted, the curve L2 shown in FIG. It becomes like this.

Here, the case where the estimated water temperature Twe at the time of starting the engine is calculated using the curve L2 shown in FIG. Assuming that the deviation ΔT at the time of engine stop is ΔT ₀ and the engine 1 is started after the engine 1 is stopped for the time t ₁ , the time at the point on the curve L2 where the deviation ΔT becomes ΔT _{1 is} assumed. , The deviation ΔT ₁ of the point on the curve L2 displaced by time t ₁ can be obtained. There Since the difference [Delta] T ₁ is a deviation between the intake air temperature Tia and the estimated water temperature Twe at the start time of the engine 1, the estimated water temperature Twe is be obtained by correcting (Twe = Tia + [Delta] T ₁₎ by the difference [Delta] T ₁ the intake air temperature Tia it can. That is, this difference ΔT ₁ can be used as an addition correction amount.

Similarly, after stopping only the engine 1 time t _2, when the engine 1 is assumed to have been started, the curve deviation [Delta] T is based on the time of the point on the curve L2 of the [Delta] T _2, displaced by time t ₂ L2 The deviation ΔT ₂ of the upper point can be determined. Since the difference ΔT ₂ is the deviation between the intake air temperature Tia and the estimated water temperature Twe when the engine 1 is started, the estimated water temperature Twe can be obtained by correcting the intake air temperature Tia by the difference ΔT ₂ (Twe = Tia + ΔT ₂ ). it can. In this case, the difference ΔT ₂ can be used as an addition correction amount.

[2-2. Estimating water temperature during operation (part 1)]
When the engine 1 is started, the cooling water temperature that has been lowered while the engine 1 is stopped is estimated by the during-stop water temperature estimation unit 53, and thereafter, the cooling water temperature that increases as the engine 1 is operated is calculated by the during-operation water temperature estimation unit 52. presume.
The operating water temperature estimation unit 52 includes an estimated value calculation unit 52a that calculates an estimated value of the cooling water temperature based on the operating state of the engine, and an upper limit value setting unit 52b that sets an upper limit value of the cooling water temperature based on the operating state of the engine. And an estimated value correcting unit 52c that obtains an estimated water temperature by regulating the upper limit of the estimated value calculated by the estimated value calculating unit 52a with the upper limit value set by the upper limit value setting unit 52b.

In the estimated value calculation unit 52a of the present embodiment, the temperature is added to the previous estimated water temperature value (estimated value) as shown by the white circle, black circle, and white square marks in FIGS. 4 (a) to 4 (c). By adding the gain G, the current estimated water temperature value (estimated value) is calculated.
4A to 4C, the engine speed Ne is low when the charging efficiency Ec is low level Ec1 (Ec low), medium level Ec2 (medium Ec), and high level Ec3 (Ec high). It is a time chart which shows transition of each engine water temperature of level Ne1 (Ne low), middle level Ne2 (Ne middle), and high level Ne3 (Ne high). In each figure, each curve of a solid line, a broken line, and an alternate long and short dash line shows a detected value, and each mark of a white circle, a black circle, and a white square shows an estimated water temperature. The estimated water temperature is obtained by adding a temperature addition gain at every predetermined period, with the estimated water temperature estimated by the stopped water temperature estimating unit 53 as an initial value.

In the example shown in FIG. 4, a constant temperature addition gain G (fixed G) is sequentially added for each engine load state (charging efficiency Ec). However, in the estimated value calculation unit 52a, the temperature addition gain G is The estimated value is calculated based on the operating state (here, the engine speed Ne and the engine load state (charging efficiency Ec)).
However, as can be seen from FIGS. 4 (a) to 4 (c), the detected water temperature, that is, the actual water temperature rises with time. However, if the time corresponding to the operating state elapses, it reaches a constant temperature. On the other hand, the estimated water temperature rises with time even after the actual water temperature reaches its peak. Therefore, a difference between the estimated water temperature value and the actual water temperature value occurs.

Therefore, the estimated value correction unit 52c limits the estimated value calculated by the estimated value calculating unit 52a to the upper limit value Twmax set by the upper limit value setting unit 52b to obtain the estimated water temperature.
The upper limit value setting unit 52b sets the upper limit value Twmax while paying attention to the temperature at which the actual water temperature reaches a peak. In the present embodiment, the upper limit value Twmax is set based on the engine speed Ne, the charging efficiency Ec, the outside air temperature Tout, and the vehicle speed V. As can be seen from FIGS. 4 (a) to 4 (c), the temperature at which the water temperature reaches a peak varies slightly depending on the engine speed Ne and the charging efficiency Ec, but of course the outside air temperature Tout and the vehicle speed V It also changes depending on.

That is, the upper limit value Twmax tends to increase as the engine speed Ne or the charging efficiency Ec increases, and the upper limit value Twmax tends to increase as the outside air temperature Tout increases. Cooling by air is promoted as the vehicle speed V increases. The upper limit value Twmax tends to decrease. Therefore, in the upper limit setting unit 52b, for example, a map in which these parameters Ne, Ec, Tout, V are associated with the upper limit Twmax is prepared in advance, and the parameters Ne, Ec, Tout, V are set using this map. Based on this, the upper limit value Twmax is set. The upper limit value Twmax is usually considered to be about 80 to 90 ° C.
In the operating water temperature estimation unit 52, the estimated value correction unit 52c restricts the estimated value to the upper limit value Twmax and obtains the estimated water temperature Twe. Therefore, the difference between the water temperature estimation Twe value and the actual water temperature Twr value is different. It is to be avoided or suppressed.

[2-3. (Estimated change due to non-operation of heater (heat-related equipment))
By the way, the vehicle is equipped with equipment (heat-related equipment) that operates by heat exchange with cooling water, such as a heater 28 that heats the passenger compartment. When the heat-related equipment such as the heater 28 is operated, the temperature of the cooling water also changes. FIG. 5 is a graph showing changes in the actual water temperature (water temperature detection value) of the cooling water and the estimated water temperature (water temperature estimation value) by the operating water temperature estimation unit 52 when an engine is left in an idle state after starting. FIG. 5 (a) is when the heater 28 is not operated, and FIG. 5 (b) is when the heater 28 is not operated. In addition, all the examples shown in FIG. 4 already described are those when the heater 28 is not operated.

  As shown in FIGS. 5 (a) and 5 (b), when the heater 28 is activated, the rate of increase in the detected water temperature is lower than when the heater 28 is not activated, and the rise in the water temperature reaches a peak. It is confirmed that the maximum value also decreases. Therefore, if the estimated water temperature of the estimated water temperature when the heater is not operated is applied as it is when the heater is operated, the difference between the estimated water temperature and the actual water temperature increases. Therefore, the operating water temperature estimation unit 52 calculates the estimated water temperature value with respect to the engine operating state by using different correspondences between when the heater 28 is activated and when the heater 28 is not activated.

That is, the estimated value calculation unit 52a lowers the filter gains of the first and second first-order lag filters when the heater is activated than when the heater is not activated, and lowers the final water temperature as compared with when the heater is not activated. The upper limit value setting unit 52b also lowers the upper limit value compared to when the heater is not operating.
In addition, in the estimated value calculation unit 52a of the present embodiment, the temperature addition gain G is set based on the operating state of the engine (the engine speed Ne and the charging efficiency Ec), but is different between when the heater is operating and when the heater is not operating. A map (a map in which the temperature addition gain G is smaller when the heater is operating than when the heater is not operating) may be prepared. Alternatively, for example, only a map when the heater is not activated is prepared, and when the heater is activated, each value obtained by the map when the heater is not activated is multiplied by a predetermined gain (<1) to obtain a filter gain, a final reached water temperature, or an upper limit value. May be requested.

  In the case of the heater 28, the heat transfer from the cooling water to the heater is limited. Therefore, when the heat-related device (heater) is operated, the temperature addition gain G, the final reached water temperature, and the upper limit value are set based on the non-operating values. However, in the case of a heat-related device that transfers heat from the heat-related device to the cooling water, each value is raised above the value when the heat-related device is in operation.

[3. Action and effect)
Since the engine coolant temperature estimating apparatus according to the present embodiment is configured as described above, the engine coolant temperature is estimated, for example, as shown in the flowcharts of FIGS. These flowcharts are repeatedly executed at a preset control cycle not only during operation of the engine 1 but also during non-operation. The flag F described in the flowchart is 1 in the previous control cycle if the engine 1 is operating, 0 if the engine 1 is stopped, and 0 is the initial value.

[3-1. (Main flowchart)
As shown in FIG. 6, it is determined whether or not the engine 1 is operating (step A10). If the engine 1 is operating, it is determined whether or not the flag F is 0 (step A20). The operation and stop of the engine 1 can be determined, for example, based on whether or not the engine speed Ne is equal to or greater than the determination reference value Ne0.

  If it is determined in step A20 that the flag F is 0, this corresponds to the case where the engine 1 has been stopped in the previous control cycle and the engine 1 has been started in the current control cycle. The water temperature estimation unit 53 estimates the stopped water temperature Twe (step A30). Then, the flag F is set to 1 (step A40). The process of estimating the stopped water temperature Twe will be described later.

  If it is determined in step A20 that the flag F is 1, it is determined whether or not the fuel is being cut (step A50). If the fuel is not being cut, the operating water temperature estimation unit 52 estimates the operating water temperature Twe (step A60). The estimation process of the operating water temperature Twe will be described later. On the other hand, if the fuel is being cut, the estimated water temperature holding unit 54 holds the previous estimated water temperature Twe (step A70).

  In Step A10, if it is determined that the engine 1 is not operating (stopped), it is determined whether or not the flag F is 1 (Step A80). Here, if the flag F is 1, it corresponds to the case where the engine 1 has been operating in the previous control cycle and the engine 1 has been stopped in the current control cycle. The estimated water temperature Twe and the intake air temperature Tia at this time or the deviation ΔTe (= Twe−Tia) between the estimated water temperature Twe and the intake air temperature Tia is stored as the water temperature estimation data during stoppage (step A90). Then, the flag F is set to 0 (step A100).

  Here, the processing of steps A10 and A80 is performed for each control cycle even when the engine is stopped thereafter, but the processing shown in the flowchart of FIG. 6 is started with the engine starting as a trigger and is ended after the engine stops. You may comprise so that it may do. In this case, step A80 may be omitted, and control may be terminated after step A100.

[3-2. Subroutine flowchart for water temperature estimation during stoppage]
The in-stop water temperature estimation by the in-stop water temperature estimation unit 53 in step A30 is performed as shown in FIG.
That is, first, the deviation ΔTe between the estimated water temperature Tw and the intake air temperature Tia when the engine is stopped before starting the engine and the elapsed time te since the engine is stopped are read. If the deviation ΔTe at the time of engine stop is stored in the stopped water temperature estimation unit 53, the deviation ΔTe is read as it is, and if the estimated water temperature Twe and the intake air temperature Tia at the time of engine stop are stored in the stopped water temperature estimation unit 53, the deviation is read. ΔTe is calculated and read (step A31).

Next, the water temperature convergence time tce corresponding to the read deviation ΔTe is read from the map shown in FIG. 3C (step A32). Next, the current water temperature convergence time tcs is calculated by subtracting the elapsed time te from the water temperature convergence time tce (step A33). When the water temperature convergence time tcs is negative (tcs <0), the water temperature convergence time tcs is set to 0.
Then, the deviation ΔTs corresponding to the current water temperature convergence time tcs is read from the map shown in FIG. 3C (step A34). Further, a deviation ΔTs is added to the current intake air temperature Tia to calculate a current estimated water temperature (estimated water temperature during stoppage) Tws (step A35). The in-stop estimated water temperature Tws is stored as an initial value of the estimated water temperature Twe (step A36).

[3-3. Subroutine flowchart for estimating water temperature during operation]
The in-operation water temperature is estimated by the in-operation water temperature estimation unit 52 in step A60 as shown in FIG.
That is, first, the upper limit value setting unit 52b sets the upper limit value Twmax of the estimated water temperature (step A61).

As shown in FIG. 9, the upper limit value Twmax is set by first reading the engine speed Ne, the charging efficiency Ec, the outside air temperature Tout, and the vehicle speed V (step A611), and the engine speed Ne, the charging efficiency Ec, the outside air. The upper limit value upper limit value Twmax of the estimated water temperature is set according to the temperature Tout and the vehicle speed V, for example, using a map or the like (step A612).
Then, as shown in FIG. 8, in the estimated value calculation unit 52a, the engine speed Ne and the charging efficiency Ec are read (step A62), and the temperature addition gain is obtained by a map or the like according to the engine speed Ne and the charging efficiency Ec, for example. Twg is set (step A63). Further, the current estimated water temperature value Twe (n) is calculated by adding the temperature addition gain Twg to the previous estimated water temperature value Twe (n−1) (step A64).

Further, the estimated temperature Twe (n) is limited by the upper limit value Twmax to obtain the final estimated temperature Twe (n). That is, if the estimated temperature Twe (n) is equal to or lower than the upper limit value Twmax, the estimated temperature Twe (n) is adopted as it is. If the estimated temperature Twe (n) is larger than the upper limit value Twmax, the upper limit value Twemax is used as the estimated temperature Twe ( n) (step A65).
In addition, the estimated temperature Twe (n) is calculated with different correspondences using different maps or the like when the heat-related device such as the heater 28 is operated or not. Therefore, the estimated temperature Twe (n) has a different magnitude between when the heat-related device such as the heater 28 is activated and when it is not activated.

[3-4. Time chart〕
FIG. 10 is a time chart showing an example of estimating the cooling water temperature. In this example, the vehicle is a hybrid electric vehicle, and can run independently on the engine, run on the engine motor, and run on the motor alone. Therefore, when the motor runs alone, the engine stops even if the key switch (including the ignition switch) is on.

  As shown in FIG. 10, when the key switch is turned on and the engine is started (time point t1), an initial value (estimated water temperature during stoppage) of the estimated water temperature at this time is read. In this case, the engine stop time is long, and the intake air temperature is adopted as the initial value. Thereafter, the estimated water temperature during operation is sequentially estimated, but the estimated water temperature during operation is limited by the upper limit value. When the motor shifts to the independent traveling of the motor (time t2), the engine is stopped, and the estimated water temperature Twe during the stop is estimated.

  First, a deviation ΔTe2 (= Twe−Tia) between the estimated water temperature Twe and the intake air temperature Tia at the time of engine stop is stored. Although the water temperature convergence time is determined corresponding to this deviation ΔTe2, the water temperature convergence time becomes shorter as the engine stop time elongates. Thereafter, when the engine is started (time point t3), a correction amount (addition correction amount) that is a deviation ΔTe3 corresponding to the water temperature convergence time at this time is obtained, and the correction amount is added to the intake air temperature Tia at that time to estimate the water temperature Set the initial value (estimated water temperature during stoppage).

  Thereafter, the estimated water temperature during operation is sequentially estimated, but the estimated water temperature during operation is limited by the upper limit value. When the key switch is turned off (time point t4), the engine is stopped, and the estimated water temperature during stoppage is estimated again. That is, the deviation ΔTe4 between the estimated water temperature Twe and the intake air temperature Tia at the time of engine stop is stored, and the water temperature convergence time is obtained corresponding to this deviation ΔTe4. The water temperature convergence time becomes shorter as the engine stop time elongates. When the engine starts (time t5), a correction amount (addition correction amount) that is a deviation ΔTe5 corresponding to the water temperature convergence time at this time is obtained. Is added to the intake air temperature Tia to set an initial value of the estimated water temperature (estimated water temperature during stoppage). Here, the engine stop time is long, the correction amount ΔTe5 is 0, and the intake air temperature is adopted as the initial value.

[3-5. effect〕
In this way, according to the engine coolant temperature estimating apparatus according to the present embodiment, the estimated water temperature Twe (n) is obtained because the estimated temperature Twe (n) is obtained by regulating the upper limit with the upper limit value Twmax during the operation of the engine. Is prevented from becoming excessively higher than the actual water temperature, and the cooling water temperature at the time of temperature rise can be estimated appropriately.

Moreover, the cooling water temperature can be appropriately estimated by calculating the estimated temperature Twe (n) using different maps or the like when the heat-related device such as the heater 28 is in operation or not.
Further, by setting the upper limit value Twmax based on the engine speed Ne, the charging efficiency (engine load state) Ec, the outside air temperature Tout, and the vehicle speed V, it is possible to appropriately suppress the estimated water temperature Twe from becoming excessively high. The cooling water temperature can be estimated appropriately.

Further, the final reached water temperature Twa and the filter gains of the first and second first-order lag filters are set based on the rotational speed Ne of the engine 1 and the charging efficiency (engine load state) Ec. Thus, the estimated value Twe is calculated by performing the processing by the first and second primary delay filters, respectively, so that the coolant temperature can be estimated easily and appropriately.
Further, if the calculation of the estimated value is stopped when the fuel to the engine 1 is cut and the estimated water temperature Twe obtained immediately before the fuel cut is maintained, the cooling water temperature can be estimated easily and appropriately even when the fuel is cut.

  Further, the water temperature estimation 53 during stoppage is performed by estimating the deviation ΔTe between the cooling water temperature Twe and the intake air temperature Tia when estimating the cooling water temperature that is lowered when the engine 1 is stopped after the engine is started, and the cooling water temperature after the engine is stopped. Is stored and the correspondence relationship with the water temperature convergence time tcs, which is the engine stop time required until the intake air temperature Tia coincides with the intake air temperature Tia, is stored, and the estimated water temperature Twe obtained at this time and the detected intake air temperature when the engine is stopped From the deviation ΔTe from Tia and the elapsed time Te from when the engine is stopped to when the engine is started, by using the stored correspondence relationship, the estimated water temperature while the engine is stopped is calculated. Can be estimated appropriately.

At this time, the first water temperature convergence time, which is the water temperature convergence time tcs corresponding to the deviation ΔTe, is obtained using the correspondence relationship between the deviation ΔTe and the time, and the elapsed time from when the engine is stopped to when the engine is started from the first water temperature convergence time. The cooling water temperature can be easily estimated by subtracting the time to obtain the second water temperature convergence time and obtaining the estimated water temperature from the deviation corresponding to the second water temperature convergence time.
By using a single correspondence between the deviation ΔTe and the time regardless of the intake air temperature, it is possible to appropriately estimate the cooling water temperature while suppressing the storage capacity of the correspondence and simply estimating the cooling water temperature. Can do.

  Further, according to the present engine control device, when the water temperature sensor 23 is normal, the engine control such as the fuel injection amount is appropriately performed based on the detection value Twr detected by the water temperature sensor 23. Based on the estimated water temperature Twe estimated by the water temperature estimating unit 51, engine control such as the fuel injection amount can be appropriately performed.

[Second Embodiment]
Next, an engine coolant temperature estimating apparatus according to the second embodiment will be described with reference to FIGS. The cooling water temperature estimation device of the present embodiment is different from that of the first embodiment in the specific calculation method of the estimated value by the estimated value calculation unit 52a of the operating water temperature estimation unit 52, and other configurations are as follows. It is the same as that of the first embodiment. Therefore, only the method of calculating the estimated value by the estimated value calculating unit 52a will be described.

[4. Configuration of cooling water temperature estimation device)
[4-1. Estimating water temperature during operation (part 2)]
In the estimated value calculation unit 52a of the present embodiment, the final reached water temperature Twa when the cooling water is not radiated by the radiator is set based on the engine speed Ne and the charging efficiency Ec, and the final reached water temperature Twa is set with respect to the final reached water temperature Twa. The estimated value Twa2 is calculated by performing processing by the first and second first-order lag filters, respectively. In this case, it is necessary to set the filter gains of the first and second first-order lag filters as appropriate.

In the estimated value calculation unit 52a according to the present embodiment, the filter gains of the first and second first-order lag filters are set based on the engine speed Ne and the charging efficiency Ec.
In the estimated value calculation unit 52a according to the present embodiment, the final reached water temperature is also set based on the engine speed Ne and the charging efficiency Ec.
FIG. 12A shows an example in which the filter gain of the first primary delay filter is set according to the engine speed Ne and the charging efficiency Ec, and FIG. 12B shows the filter gain of the second primary delay filter. FIG. 12C shows an example in which the final reached water temperature is set in accordance with the engine rotational speed Ne and the charging efficiency Ec.

  In the example shown in FIGS. 12 (a) to 12 (c), the engine speed Ne is divided into three levels: a low level Ne1 (Ne low), a medium level Ne2 (Ne medium), and a high level Ne3 (Ne high). The filling efficiency Ec is divided into three, low level Ec1 (Ec low), medium level Ec2 (medium Ec), and high level Ec3 (Ec high), and the filter gain or final reached water temperature is set respectively. Yes.

  In this way, the filter gain and the final reached water temperature Twa of the first and second primary delay filters are set based on the engine speed Ne and the charging efficiency Ec, and the first and second values are set with respect to the final reached water temperature Twa. When the estimated value Twe (= Twa2) of the water temperature is calculated by performing the processing by the first-order lag filter, a thin solid line, a thin broken line, and a fine point are respectively shown in the time charts of FIGS. 11 (a) to 11 (c). Estimates are obtained as indicated by the dashed curves.

  11A to 11C illustrate cases where the engine speed Ne is different, and FIG. 11A shows the water temperature when the engine speed Ne is at a low level Ne1 (Ne low). 11 (b) shows the water temperature value when the engine speed Ne is the middle level Ne2 (Ne), and FIG. 11 (c) shows the water temperature when the engine speed Ne is the high level Ne3 (Ne high). Each value is shown.

  In FIGS. 11A to 11C, the thick solid line indicates the detected water temperature when the charging efficiency Ec is at the low level Ec1 (Ec low), and the thick broken line indicates the charging efficiency Ec at the intermediate level Ec2 (Ec medium). ), The thick dotted line indicates the water temperature detection value when the filling efficiency Ec is the high level Ec3 (Ec high). The thin solid line indicates the estimated water temperature when the filling efficiency Ec is low level Ec1 (Ec low), the thin broken line indicates the estimated water temperature when the filling efficiency Ec is medium level Ec2 (mid Ec), The estimated water temperature when the charging efficiency Ec is the high level Ec3 (Ec high) is shown.

  It can be seen that the estimated water temperature value is very close to the detected water temperature value at each engine speed range and at each level of the charging efficiency Ec. In order to approximate in this way, it is important to set the filter gain and final water temperature of the first and second first-order lag filters described above. The water temperature can be estimated with sufficient accuracy by the above method by the estimated value calculation unit 52a.

In the example shown in FIG. 11A to FIG. 11C, the upper limit value is not restricted, but in this embodiment as well, the estimated water temperature is obtained by restricting the upper limit value as in the first embodiment. ing.
Further, the estimated temperature Twe is calculated with different correspondences using different maps or the like when the heat-related device such as the heater 28 is in operation or not. Therefore, the estimated temperature Twe has a different magnitude between when the heat-related device such as the heater 28 is activated and when it is not activated.

  That is, the estimated value calculation unit 52a lowers the filter gains of the first and second first-order lag filters when the heater is activated than when the heater is not activated, and lowers the final water temperature as compared with when the heater is not activated. The upper limit value setting unit 52b also lowers the upper limit value compared to when the heater is not operating.

[5. Action and effect)
Since the engine coolant temperature estimating apparatus according to the present embodiment is configured as described above, the ascending water temperature is estimated by the ascending water temperature estimating unit 52 in step A60 of FIG. 6 as shown in FIG. .

That is, first, the upper limit value setting unit 52b sets the upper limit value Twmax of the estimated water temperature (step A61). The setting of the upper limit value Twmax is performed as shown in FIG.
Then, the estimated value calculation unit 52a reads the engine speed Ne and the charging efficiency Ec (step A162), and sets the final reached water temperature Twa by a map or the like according to the engine speed Ne and the charging efficiency Ec (step A163). ). Further, the filter gains of the first and second first-order lag filters are set by, for example, a map or the like according to the engine speed Ne and the charging efficiency Ec (step A164).

  Further, the estimated water temperature Twe estimated and stored by the descending water temperature estimation unit 53 is used as an initial value, and the final reached water temperature Twa is filtered by the first primary delay filter (step A165). The water temperature Twa1 is filtered by the second first-order lag filter (step A166), and the water temperature Twa2 after this processing is set as the current estimated temperature Twe (n) (step A167).

Further, the estimated temperature Twe (n) is limited by the upper limit value Twmax to obtain the final estimated temperature Twe (n). That is, if the estimated temperature Twe (n) is lower than the upper limit value Twmax, the estimated temperature Twe (n) is used as it is. If the estimated temperature Twe (n) is larger than the upper limit value Twmax, the upper limit value Twemax is used as the estimated temperature Twemax. (N) (step A168).
Note that the estimated temperature Twe (n) is calculated with different correspondences using different maps or the like when the heat-related device such as the heater 28 is operated or not. Therefore, the estimated temperature Twe (n) has a different magnitude between when the heat-related device such as the heater 28 is activated and when it is not activated.

In this way, the same operational effects as in the first embodiment can be obtained also in this embodiment.
In this embodiment, the filter gain, the final reached water temperature, and the upper limit value of the first and second first-order lag filters are calculated (set) using a map corresponding to the engine operating state. Different maps may be prepared for when the heater is not operating. Alternatively, for example, only a map when the heater is not operating is prepared, and when the heater is operating, each value obtained from the map when the heater is not operating is multiplied by a predetermined gain to obtain the filter gain, the final water temperature, and the upper limit value. May be.

[6. Others]
Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and the above embodiment can be appropriately modified and implemented without departing from the spirit of the present invention.
For example, in the above-described embodiment, the water temperature estimation by the cooling water temperature estimation unit 51 is performed independently of the water temperature sensor 23. However, if the water temperature sensor 23 can be properly detected as normal or abnormal, immediately before the water temperature sensor 23 becomes abnormal. The water temperature may be estimated by the cooling water temperature estimator 51 using a normal detection value of the water temperature sensor 23 as an initial value.

  Further, the present apparatus can be applied not only to various automobiles but also to vehicles other than automobiles.

1 Engine 23 Water temperature sensor (Water temperature detection means)
26 Outside air temperature sensor (intake air temperature detection means)
28 Heater (heat-related equipment)
50 Engine control device (engine ECU)
51 Cooling water temperature estimation unit (cooling water temperature estimation means)
52 Operating water temperature estimation unit (Driving water temperature estimation means)
52a Estimated value calculation unit 52b Upper limit value setting unit 52c Estimated value correction unit 53 Stopping water temperature estimation unit (stopping water temperature estimation means)
53a Correspondence relationship storage unit 53b Water temperature calculation unit during stoppage 54 Estimated water temperature holding unit (estimated water temperature holding means)
60 Fuel Injection Control Unit 61 Fuel Cut Control Unit

Claims (13)

An apparatus for estimating a cooling water temperature that is a temperature of an engine cooling water mounted on a vehicle,
An operating state detecting means for detecting an operating state of the engine;
Cooling water temperature estimating means for obtaining an estimated water temperature that is an estimated value of the cooling water temperature of the engine based on the operating state detected by the operating state detecting means,
The cooling water temperature estimating means includes an operating water temperature estimating means for estimating the cooling water temperature during operation of the engine,
The operating water temperature estimating means includes:
An estimated value calculating unit that calculates an estimated value of the cooling water temperature based on the operating state detected by the operating state detecting means;
An upper limit value setting unit for setting an upper limit value of the cooling water temperature based on the operating state detected by the operating state detecting means;
An estimated value correction unit that obtains the estimated water temperature by restricting the estimated value calculated by the estimated value calculating unit to the upper limit value by the upper limit value set by the upper limit value setting unit. Cooling water temperature estimation device. The vehicle is equipped with heat-related equipment that operates by heat exchange with the cooling water,
The estimated value calculating unit calculates the estimated value having a magnitude different from the estimated value when the heat-related device is not operating when the heat-related device is operating;
2. The engine according to claim 1, wherein the upper limit value setting unit sets the upper limit value to a magnitude different from the upper limit value of the non-operation of the heat-related device when the heat-related device is operated. Cooling water temperature estimation device. The operating state detecting means includes a rotational speed detecting means for detecting a rotational speed of the engine, and a load state detecting means for detecting a load state of the engine,
The upper limit setting unit sets the upper limit based on at least the rotation speed detected by the rotation speed detection means and the load state detected by the load state detection means, The engine coolant temperature estimation device according to claim 1 or 2. The driving state detecting means includes an outside air temperature detecting means for detecting an outside air temperature around the engine, and a vehicle speed detecting means for detecting a vehicle speed of the vehicle,
The upper limit setting unit sets the upper limit based on at least the outside air temperature detected by the outside air temperature detecting means and the vehicle speed detected by the vehicle speed detecting means. The engine coolant temperature estimation device according to any one of 1 to 3. The operating state detecting means includes a rotational speed detecting means for detecting a rotational speed of the engine, and a load state detecting means for detecting a load state of the engine,
The estimated value calculation unit calculates a temperature addition gain based on at least the rotation speed detected by the rotation speed detection unit and the load state detected by the load state detection unit, and the previous estimated value 5. The engine coolant temperature estimation apparatus according to claim 1, wherein the current estimated value is calculated by adding the temperature addition gain to the engine. The operating state detecting means includes a rotational speed detecting means for detecting a rotational speed of the engine, and a load state detecting means for detecting a load state of the engine,
When the estimated value calculation unit does not radiate the cooling water at a predetermined cycle based on at least the rotation speed detected by the rotation speed detection unit and the load state detected by the load state detection unit. The final reached water temperature is set, and the estimated value is calculated by performing the first and second first-order lag filters on the final reached water temperature, respectively. The engine coolant temperature estimation device according to any one of the preceding claims. The engine coolant temperature estimation device according to claim 6, wherein filter gains of the first and second first-order lag filters are set according to at least one of the rotational speed and the load state. . The cooling water temperature estimating means has an estimated water temperature holding means for stopping the calculation of the estimated value by the estimated value calculating unit and holding the estimated water temperature obtained immediately before the fuel cut when fuel is cut to the engine. The engine cooling water temperature estimation device according to any one of claims 1 to 7, wherein The operating state detecting means includes an intake air temperature detecting means for detecting an intake air temperature of the engine,
The cooling water temperature estimation means comprises a stopped water temperature estimation means for estimating the cooling water temperature when the engine is stopped,
The stopping water temperature estimating means includes:
A correspondence storage unit storing a correspondence between a deviation between the cooling water temperature and the intake air temperature, and a water temperature convergence time which is a time required for the cooling water temperature while the engine is stopped to coincide with the intake air temperature; ,
When the engine is stopped, a deviation between the estimated water temperature obtained by the operating water temperature estimating means at the time of stopping the engine and the intake air temperature detected by the intake air temperature detecting means, and The suspension water temperature calculation unit that calculates the estimated water temperature when the engine is stopped from the engine stop time using the correspondence stored in the correspondence storage unit. The engine cooling water temperature estimation apparatus according to any one of 1 to 8. The stopped water temperature calculation unit obtains a first water temperature convergence time that is the water temperature convergence time corresponding to the deviation using the correspondence relationship, and when the engine stop time is shorter than the first water temperature convergence time, 10. The estimated water temperature is obtained from the deviation corresponding to the second water temperature convergence time by subtracting the engine stop time from the first water temperature convergence time to obtain a second water temperature convergence time. Engine coolant temperature estimation device. The correspondence relationship storage unit stores a single correspondence relationship regardless of the intake air temperature,
The engine cooling water temperature estimation device according to claim 9 or 10, wherein the stopped water temperature calculation unit obtains the estimated water temperature using a single correspondence relationship. The engine coolant temperature estimation device according to any one of claims 9 to 11, wherein the stopped water temperature estimation means estimates the coolant temperature when the engine is started. An engine control device that controls an engine mounted on a vehicle based on a control water temperature corresponding to a cooling water temperature,
Water temperature detecting means for detecting the temperature of the cooling water;
The engine coolant temperature estimation device according to any one of claims 1 to 12,
When the water temperature detecting means is normal, the engine is controlled based on the detection value detected by the water temperature detecting means, and when the water temperature detecting means is faulty, the engine is controlled based on the estimated water temperature estimated by the engine cooling water temperature estimating device. An engine control device comprising: control means for controlling the engine.

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