JP2003232238A - Vehicular engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deterioration by overheat of an auxiliary pump driving motor in a vehicle having a motor-driven auxiliary pump for supplying oil pressure to hydraulic equipment such as an automatic transmission at idle stop time of an engine. <P>SOLUTION: When the auxiliary pump driving motor is a temperature not less than a prescribed judging criterion, an idle stop of the engine is prohibited. Thus, the engine is not stopped even when an idle stop vehicle normally becomes an engine stopping condition according to stopping of a vehicle, and the oil pressure is supplied by a hydraulic pump driven by the engine to the hydraulic equipment such as the automatic transmission. Thus, while securing the oil pressure required for the hydraulic equipment, the overheat and the deterioration of the auxiliary pump driving motor can be prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device provided with an auxiliary hydraulic pressure source by an electric pump.

[0002]

2. Description of the Related Art There is known an idle stop vehicle in which the engine is stopped when the engine is in an idle state such as when the vehicle is stopped to improve fuel economy and exhaust emission performance. The engine is equipped with a hydraulic pump to supply lubricating oil and to operate various hydraulic devices such as a hydraulic automatic transmission. Normally, the engine power drives this hydraulic pump to generate hydraulic pressure. . For this reason, when the idle operation is stopped as described above, the hydraulic pump driven by the engine cannot be used as a hydraulic pressure source, and the hydraulic pressure of the hydraulic automatic transmission cannot be secured. There is a risk of coming. Therefore, for example, in Japanese Patent Laid-Open No. 11-159366, an electric pump is provided to secure the hydraulic pressure when the engine is stopped. However, if there are many opportunities to stop the engine, the load on the electric pump increases, the motor overheats, and the deterioration of the motor is accelerated. Further, when the motor overheats, the original performance cannot be exhibited, and the oil pressure cannot be secured sufficiently.

[0003]

A first aspect of the present invention is provided with a hydraulic pump driven by an engine of a vehicle and an auxiliary pump driven by an electric motor as a hydraulic power source for a hydraulic automatic transmission and the like. In an idle stop vehicle that uses the hydraulic pressure generated by the auxiliary pump as a hydraulic power source when the idle operation of the engine is sometimes stopped,
The stop of the idle operation is prohibited when the temperature of the electric motor is equal to or higher than a predetermined determination reference value.

A second invention is the same as the first invention,
The temperature estimation means estimates the temperature of the electric motor from the outside air temperature and the representative temperature of the electric motor.

According to a third aspect of the invention, the temperature estimating means of the second aspect of the invention is configured to detect at least one of the oil temperature of the automatic transmission and the engine cooling water temperature as the representative temperature of the electric motor.

According to a fourth aspect of the present invention, the temperature estimating means of the second aspect of the present invention is provided with an oil temperature signal from an oil temperature sensor for detecting an oil temperature of an automatic transmission and a water temperature from a water temperature sensor for detecting an engine cooling water temperature. Each signal is detected, and the temperature signal from one of the sensors is used as the representative temperature of the electric motor, and when the sensor fails, the temperature signal from the other sensor is used as the representative temperature.

According to a fifth aspect of the invention, the temperature estimating means of the second aspect of the invention is based on the elapsed time from the stop of the apparatus to the start-up, and when the elapsed time is smaller than the first reference value, the electric motor temperature is set to the apparatus. Estimated to be equivalent to the representative temperature stored when stopped,
When the elapsed time is larger than the second reference value, the temperature of the electric motor is estimated to be equivalent to the outside air temperature when the apparatus is started.

According to a sixth aspect of the invention, the temperature estimating means of the fifth aspect of the invention is based on the difference between the representative temperature stored when the apparatus is stopped and the representative temperature when the apparatus is started, and the larger the temperature difference, the more the apparatus stops. It is configured to estimate that the later elapsed time is large.

A seventh aspect of the present invention is the temperature estimating means of the fifth aspect of the invention, wherein when the elapsed time is between the first reference value and the second reference value, the elapsed time and the outside air temperature are calculated. Based on the relationship, the electric motor temperature is estimated by referring to a map that is set in advance so as to give a lower estimated temperature value as the outside air temperature becomes lower and the elapsed time becomes longer.

According to an eighth aspect of the invention, the temperature estimating means of the second aspect of the invention is based on the operating time of the electric motor and the outside air temperature when the apparatus is operating, the longer the operating time is, the higher the outside air temperature is,
The electric motor temperature is estimated by referring to a map preset to give a high estimated temperature value.

According to a ninth aspect of the invention, the temperature estimating means of the second aspect of the invention is based on the stop time of the electric motor and the outside air temperature when the apparatus is in operation, the shorter the stop time is and the higher the outside air temperature is.
The electric motor temperature is estimated by referring to a map preset to give a high estimated temperature value.

According to a tenth aspect of the invention, the temperature estimating means of the second aspect of the invention is configured to correct the estimated temperature based on the vehicle speed so that the estimated temperature becomes smaller as the vehicle speed increases.

In an eleventh aspect of the invention, the hydraulic pump and the auxiliary pump are configured to supply operating hydraulic pressure to an automatic transmission of a vehicle.

[0014]

According to the present invention, the engine stop is prohibited when the electric motor for driving the auxiliary pump has a temperature equal to or higher than a predetermined judgment reference value. As a result, the engine does not stop even when the engine is normally stopped due to the stoppage of the idle stop vehicle, etc., and hydraulic pressure is supplied from the engine-driven hydraulic pump to hydraulic equipment such as the automatic transmission. It Therefore, it is possible to prevent overheating and deterioration of the electric motor while ensuring the hydraulic pressure required for the hydraulic equipment.

The temperature of the electric motor can be estimated from the outside air temperature and a representative temperature such as the automatic transmission oil temperature or the engine cooling water temperature. Therefore, in an engine system equipped with sensors for detecting these temperatures, without adding a sensor for detecting the electric motor temperature,
The electric motor can be protected simply by adding a control program to the controller of the engine or the transmission.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an embodiment of the present invention. In the figure, 1 is an engine, 2 is an automatic transmission, 3 is an auxiliary pump, and 4 is an electric motor for driving the auxiliary pump 3. The auxiliary pump 3 supplies a required operating hydraulic pressure to the automatic transmission 2 by the driving force of the motor 4 during the idle stop, that is, while the control for stopping the idle operation of the engine 1 is performed with the temporary stop of the vehicle.
While the engine 1 is operating, an operating hydraulic pressure is supplied to the automatic transmission 2 by an engine-driven hydraulic pump (not shown).

Reference numeral 5 is an integrated controller of a vehicle having the function of an engine controller, and reference numeral 6 is an AT controller, which determines the operating state by signals from various sensors described later, and determines the idle stop control and the auxiliary pump 3 described above. Drive control. In relation to the present invention, these controllers 5 and 6 function as temperature estimating means. Reference numeral 7 is a motor controller that controls the drive of the auxiliary pump motor 4 in response to a command from the AT controller 6.

Reference numeral 8 is a water temperature sensor for detecting the engine cooling water temperature, 9 is an ATF temperature sensor for detecting the temperature of the AT fluid of the automatic transmission 2, and 10 is the traveling speed of the vehicle from the output shaft rotation of the automatic transmission 2. A vehicle speed sensor 11 is an outside air temperature sensor for detecting the outside air temperature. Outside temperature sensor 1
As 1, the existing auxiliary equipment such as an air conditioner can be applied.

There are various methods for the idle stop control. Generally, when the ignition key switch is on, the warm-up is completed, the vehicle speed is zero, the brake is on, and the accelerator is off, the idle operation is performed. The engine is stopped at. When the brake is turned off or the accelerator is turned on from this idle stop state, the engine is restarted by the starter motor. As described above, as a general rule, while the engine 1 is stopped by the idle stop control, the hydraulic pressure required by the automatic transmission 2 is supplied by the auxiliary pump 3. However, in the present invention, even under the idle stop condition, when the motor 4 driving the auxiliary pump 3 is at a high temperature, the idle stop is prohibited in order to protect the motor 4. Hereinafter, this control will be described in detail with reference to the flowchart shown in FIG.

In FIG. 2 and the following description, the symbol S represents a processing step number. S101 to S108 are initialization processes, which are executed only when the ignition key switch for starting the engine and the system is turned on. S109 to S115 are main routines for determining whether or not the idle stop control is possible, and are periodically executed while the key switch is turned on. S116 is a termination process executed when the key switch is turned off. In the ending process in S116, the cooling water temperature, the ATF temperature, and the motor temperature at that time are stored in the nonvolatile storage device in the controller 6 as backup values to be used in the next process.

In the initialization process, whether or not the ATF temperature sensor 9 is abnormal is first determined when the key switch is turned on. For example, when no output is obtained from the ATF temperature sensor 9, it is determined to be abnormal. If there is no abnormality, S102
The ATF temperature is detected in step S103, and if there is an abnormality, S103
The cooling water temperature from the water temperature sensor 8 is detected by regarding it as the ATF temperature. As a result, even if the ATF temperature sensor 9 fails, control can be performed to enhance the stability or reliability of the device.

Next, in S104, the elapsed time from the previous key-off to the current key-on is calculated from the difference between the detected temperature and the backup value of the ATF temperature stored in S116 as the ending process at the previous key-off. Estimate the length of. Table 1 shows an example of a map that gives the relationship between the temperature difference and the elapsed time for each outside air temperature. The longer the temperature difference, the longer the elapsed time.

[0023]

[Table 1] Basically, the current motor temperature is estimated based on the elapsed time obtained by referring to the map corresponding to Table 1 and the backup value of the motor temperature (S105 to S106). Table 2 shows an example of a map that gives the relationship between the elapsed time, the motor temperature backup value, and the current motor temperature for each outside air temperature. The larger the motor temperature backup value or the shorter the elapsed time, the higher the motor temperature at present.

[0024]

[Table 2] However, when the elapsed time estimated in S104 is very short, for example, the temperature difference is 5 ° C. as a reference value (first reference value).
When the temperature difference is less than 5 ° C., it is considered that the temperature change in a short time is small, and the motor temperature backup value is estimated as the current motor temperature as it is (S10).
7). Further, when the elapsed time estimated in S104 is very long, for example, when the temperature difference is 80 ° C. as the reference value (second reference value), and when the temperature difference is 80 ° C. or more, the current time may be long. It is estimated that the motor temperature has fallen to the outside air temperature (S108).

Based on the current motor temperature thus obtained, whether or not the idle stop control is possible is then determined by the processing of S109 and subsequent steps. First, in S109, it is determined whether or not the idle stop condition as described above is satisfied. If the idle stop condition is satisfied, the current motor temperature and the reference value (for example, 10
0 ° C.), and if the current motor temperature is equal to or lower than the reference value, idle stop is permitted in S111. Along with this, the idle operation of the engine is stopped by the integrated controller 5, the AT controller 6 outputs a drive command for the auxiliary pump motor 4, and the motor controller 7 drives the auxiliary pump 3.

Next, in S113, the current motor temperature is updated. This is estimated from the outside air temperature, the operating time of the motor 3, and the temperature at the start of the operation. The operating time is the motor 3
Is timed each time is driven. Table 3 shows an example of a map that gives the relationship between the motor operating time and the motor temperature at the start of operation and the current motor temperature for each outside air temperature. The longer the operating time is, or the higher the motor temperature at the start of operation is, the higher the current motor temperature at the time of updating is.

[0027]

[Table 3] Next, in S115, key-off determination is performed. If the key switch is on, the operation is continuing, so the process returns to S109 and the process is repeated using the updated motor temperature.
When the key switch is turned off, the backup process described above is performed in S116 to prepare for the subsequent restart.

On the other hand, when it is determined in S110 that the current motor temperature is higher than the reference value, the idle stop is prohibited in S112. At this time, the integrated controller 5 does not perform the idle stop of the engine even under the idle stop condition, and the AT controller 7 does not drive the auxiliary pump motor 4, so that the motor 4 deteriorates or fails at a high temperature. It is possible to avoid the trouble.

Next, in S114, the process of updating the stopped motor temperature is performed. This is estimated from the outside air temperature, the leaving time of the motor 3, and the temperature at the start of leaving. The leaving time is measured each time the motor 3 is stopped. Table 4 shows an example of a map that gives the relationship between the current time and the motor temperature at the time of disclosure of the neglected time and the present motor temperature for each outside air temperature. The longer the leaving time is, or the lower the motor temperature at the start of leaving is, the lower the current motor temperature at the time of updating is.

[0030]

[Table 4] In this control, when estimating the motor temperature in S114, the outside air temperature is corrected according to the vehicle speed. This corresponds to an increase in heat radiation due to the running wind when the vehicle is running. Table 5 shows an example of a map that gives a correction value for the outside air temperature from the outside air temperature and the vehicle speed. The higher the vehicle speed, the lower the outside air temperature is corrected. The processing after S115 is as described above.

[0031]

[Table 5] The contents of the illustrated Tables 1 to 5 or the maps corresponding thereto are specifically determined experimentally, and generally the characteristics differ depending on the engine and the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing the control contents of the embodiment of the present invention.

[Explanation of symbols]

1 engine 2 automatic transmission 3 auxiliary pumps 4 motor 5 integrated controller 6 AT controller 7 Motor controller 8 Water temperature sensor 9 ATF temperature sensor (oil temperature sensor) 10 vehicle speed sensor 11 Outside air temperature sensor

Continued front page    F term (reference) 3G084 DA02 DA19 DA30 EA07 EA11                       EB08 FA02 FA05 FA06 FA10                       FA20                 3G092 AC03 CA02 DG08 EA09 EA14                       EA17 EC09 FA30 FA38 FB02                       FB05 GA10 GB10 HA04Z                       HE08Y HE08Z HF10Z HF11Y                       HF11Z HF21Z                 3G093 AA05 BA17 BA21 BA22 CA12                       CB14 DA05 DA06 DB05 DB09                       DB15 DB23 FA10 FB05

Claims (11)

[Claims] 1. A hydraulic pump comprising a hydraulic pump driven by an engine of a vehicle and an auxiliary pump driven by an electric motor as hydraulic pressure sources, which are generated by the auxiliary pump when the idle operation of the engine is stopped when the vehicle is stopped. In an idle stop vehicle that uses hydraulic pressure as a hydraulic power source, an engine control device for a vehicle that prohibits stop of the idle operation when the temperature of the electric motor is equal to or higher than a predetermined determination reference value. 2. The engine control device for a vehicle according to claim 1, further comprising temperature estimation means for estimating a temperature of the electric motor from an outside air temperature and a representative temperature of the electric motor. 3. The engine control device for a vehicle according to claim 2, wherein the temperature estimating means detects at least one of an oil temperature of an automatic transmission and an engine cooling water temperature as a representative temperature of the electric motor. 4. The temperature estimating means detects an oil temperature signal from an oil temperature sensor for detecting an oil temperature of an automatic transmission and a water temperature signal from a water temperature sensor for detecting an engine cooling water temperature, respectively. The engine control device for a vehicle according to claim 2, wherein the temperature signal from the sensor is used as a representative temperature of the electric motor, and the temperature signal from the other sensor is used as a representative temperature when the sensor fails. 5. The temperature estimating means estimates the electric motor temperature as a representative temperature stored when the apparatus is stopped, based on the elapsed time from the apparatus stop to the start, when the elapsed time is smaller than a first reference value. 3. The vehicle engine control device according to claim 2, wherein when the elapsed time is greater than a second reference value, the temperature of the electric motor is estimated to be equivalent to the outside air temperature when the device is started. 6. The temperature estimating means, based on the difference between the representative temperature stored when the apparatus is stopped and the representative temperature when the apparatus is started, the larger the temperature difference, the longer the elapsed time after the apparatus is stopped. The vehicle engine control device according to claim 5, which estimates. 7. The temperature estimating means is configured to set the first elapsed time to the first elapsed time.
When it is between the reference value and the second reference value of, the lower the outside air temperature, the lower the outside air temperature, based on the relationship between the elapsed time and the outside air temperature.
The engine control device for a vehicle according to claim 5, wherein the electric motor temperature is estimated with reference to a map preset so as to give a lower estimated temperature value as the elapsed time increases. 8. The temperature estimating means is preset so as to give a higher estimated temperature value as the operating time is longer and the outside air temperature is higher, based on the operating time of the electric motor and the outside air temperature during operation of the device. The engine control device for a vehicle according to claim 2, wherein the electric motor temperature is estimated with reference to the created map. 9. The temperature estimating means is preset so as to give a higher estimated temperature value as the stop time is shorter and the outside air temperature is higher, based on the stopping time of the electric motor and the outside air temperature during the operation of the device. The engine control device for a vehicle according to claim 2, wherein the electric motor temperature is estimated with reference to the created map. 10. The vehicle engine control device according to claim 2, wherein the temperature estimating means corrects the estimated temperature based on the vehicle speed such that the estimated temperature becomes smaller as the vehicle speed increases. 11. The vehicle engine control device according to claim 1, wherein the hydraulic pump and the auxiliary pump are for supplying operating hydraulic pressure to an automatic transmission of the vehicle.