JPH0216338A - Engine control device for vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To prevent an excess increase in oil pressure within a torque inverter by providing a control means for setting the gain of output characteristics of an engine output increasing/decreasing means to the accelerator manipulating variable small when the oil temperature within the torque converter of an automatic transmission reaches a determined value or more. CONSTITUTION:A throttle valve 2 within an inlet passage 1 is driven and opened/closed by a step motor 7, and the step motor 7 is controlled by a control unit 9 according to the driving state. Namely, it is feedback controlled so that the throttle opening detected by a throttle opening sensor 8 follows a desired opening degree set based on the output of an accelerator opening sensor 12. In this case, an oil temperature sensor 19 for detecting the oil temperature within the torque converter of an automatic transmission T is provided. When the detected oil temperature reaches a determined value or more, the gain of output characteristics of the step motor 7 to the accelerator manipulated variable is set small.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized in that an engine output increase/decrease means such as a throttle valve is electrically driven based on an accelerator operation pawl detected by an accelerator operation amount detection means. This paper relates to an engine control device for a vehicle with an automatic transmission.

[Prior Art] Accelerator operation amount detection means for detecting accelerator operation 1;
An electric step motor (engine output increase/decrease means) that opens and closes a throttle valve (engine output increase/decrease means) is provided,
The so-called drive-by-wire throttle valve opening/closing mechanism controls the throttle opening (engine output) by driving the step motor with predetermined characteristics based on the accelerator operation amount detected by the accelerator operation pawl detection means. A throttle valve opening/closing mechanism that is generally known and that changes the gain of the throttle opening in response to the accelerator operation 1 according to the engine operating state has been proposed (for example, Japanese Patent Laid-Open No. 61-200345 reference).

On the other hand, in vehicles equipped with automatic transmissions, the impeller and turbine of the torque converter rotate at different speeds, causing so-called slip, and the frictional heat generated due to this slip causes the oil in the torque converter to leak. heated. If the oil temperature inside the torque converter rises too high (e.g. 150°C), there is a risk that the oil inside the torque converter will deteriorate, which may reduce the reliability of the torque converter. The same problem occurs in a vehicle equipped with an automatic transmission equipped with the drive-by-wire throttle valve opening/closing mechanism described above.

Therefore, in a predetermined operating range, in vehicles equipped with an automatic transmission equipped with a so-called lock-up mechanism, which is a mechanism that mechanically connects the impeller and the turbine to rotate the impeller and turbine as one unit without slipping, lock-up is required. A vehicle that expands the operating range (lock-up range) in which the mechanism operates, reduces the chance of torque converter slippage, suppresses the generation of frictional heat due to slippage, and prevents the oil temperature in the torque converter from rising excessively. is proposed.

[Problems to be Solved by the Invention] Incidentally, since the torque converter transmits engine torque to the driving wheels via liquid (oil), even if the engine torque or the driving wheel torque changes, In other words, even during gear shifting, torque changes are buffered by oil and the occurrence of torque shock is suppressed, but by expanding the lock-up area, excessive rise in oil temperature in the torque converter is suppressed. However, in the above-mentioned conventional automatic transmission vehicles, the chances of driving in a lock-up state where the torque converter does not work increase, so there is a problem that the torque noyoc during gear shifting becomes large. There was a problem that sometimes the A11 temperature reduction effect could not be obtained. Furthermore, there is a problem in that such a method of reducing oil temperature cannot be used in vehicles that are not equipped with a lock-up mechanism.

The present invention has been made in view of the above-mentioned conventional problems, and is effective in preventing oil deterioration in vehicles with automatic transmissions by always preventing excessive rise in oil temperature in the torque converter regardless of driving conditions. An object of the present invention is to provide an engine control device for a vehicle equipped with an automatic transmission, which can prevent such problems and improve the reliability of a torque converter.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes an accelerator operation amount detection means for detecting an accelerator operation amount, an engine output increase/decrease means for increasing/decreasing engine output, and the above-mentioned accelerator operation amount detection means. In a vehicle with an automatic transmission equipped with an engine output control means that controls the output of the engine output increase/decrease means with preset characteristics based on the detected accelerator operation amount, the oil temperature in the torque converter of the automatic transmission When the oil temperature detected by the oil temperature detection means exceeds a predetermined value, the gain of the output characteristic of the engine output increase/decrease means with respect to the accelerator operation amount is set to a small value to control the torque converter. Provided is an engine control device for a vehicle equipped with an automatic transmission, characterized in that it is provided with an engine output characteristic control means for controlling so as to reduce slip.

[Operations and Effects of the Invention] According to the present invention, when the oil temperature in the torque converter is determined by the oil temperature detection means to be equal to or higher than a predetermined value (limit temperature) at which oil deterioration may occur, the accelerator operation is stopped. Throttle opening relative to amount (engine output)
Since the characteristic gain is set small, the throttle opening (engine output) relative to the accelerator operation amount is small (and the amount of engine torque generated is small).When the engine torque is small, the rotation of the torque converter impeller and turbine is The difference is small (and the slip is small, so the amount of frictional heat generated by slip is reduced,
The oil temperature inside the torque converter is maintained below the limit temperature,
Oil deterioration is effectively prevented, and reliability of the torque converter can be improved. Furthermore, in a vehicle with an automatic transmission equipped with a lock-up mechanism, it is possible to prevent an excessive rise in oil temperature in the torque converter without expanding the lock-up region, thereby reducing the occurrence of torque shock during gear shifting.

[Example] Examples of the present invention will be specifically described below.

As shown in FIG. 1, the power plant PS of a vehicle with an automatic transmission has an intake air (air mixture) supplied from an intake passage I according to the opening degree of a throttle valve 2 (engine output increase/decrease means).
The torque of the crankshaft 3 is automatically shifted and transmitted to the output shaft 6 by an engine E that converts thermal energy obtained by burning the engine into rotational energy of the crankshaft 3, a torque converter 4, and a gear train 5. The automatic transmission T is substantially comprised of an automatic transmission T.

In the engine E, a step motor 7 drives the throttle valve 2 to open and close it;
A throttle opening sensor 8 is provided to detect the opening of the throttle opening, and the step motor 7 is feedback-controlled so that the throttle opening follows a target opening set by the control unit 9. Note that the step motor 7 is an ordinary motor driven electrically.

The opening target value of the throttle valve 2 is as explained in detail later.
It is set by the control unit 9 based on the accelerator opening detected by an accelerator opening sensor 12 provided for the accelerator pedal 11. Furthermore, when the ignition switch 13 is turned on, a high-voltage secondary current induced by the ignition coil 15 in response to the primary current supplied from the battery 14 flows through the igniter 16. The air-fuel mixture is supplied to a spark plug (not shown) at a predetermined timing via the air-fuel mixture, and the air-fuel mixture is ignited. Incidentally, the ignition timing and the secondary voltage are controlled in a conventional manner by an ignition controller 17 that receives a signal from the control unit 9.

On the other hand, the torque converter 4 of the automatic transmission T automatically transfers the torque (engine torque) of the crankshaft 3 from an impeller (not shown) directly connected to the crankshaft 3 to a turbine (not shown) via oil. In addition, the gear train 5 is a conventional gear train that essentially consists of a planetary gear system. The impeller and the turbine rotate at different rotational speeds and slip, which generates frictional heat, which heats the oil in the torque converter 4. The higher the engine torque, the greater the slippage, the more frictional heat is generated, and the higher the oil temperature becomes. However, if the oil temperature rises above the oil temperature limit (usually 150°C), there is a risk of thermal deterioration of the oil. There is.

Therefore, an oil temperature sensor 19 is provided to detect the oil temperature in the torque converter 4. When the oil temperature exceeds the limit temperature (150°C), the control unit 9 controls the throttle valve 2 via the step motor 7. The throttle opening target value when performing feedback control of the opening, that is, the gain (opening ratio) of the throttle opening characteristic with respect to the accelerator opening AC, is set smaller than normal, and the throttle opening TVθ with respect to the accelerator opening AC is set smaller than normal. , the amount of torque generated by engine E is reduced, and torque converter 4
This suppresses slippage of the torque converter 4, suppresses generation of frictional heat, and maintains the oil temperature within the torque converter 4 below the limit temperature.

The control unit 9 is constituted by a microcomputer equipped with a CPU 21, a memory 22, an I10 boat 23, a bus 24, etc., and includes an engine output control means and an engine output characteristic control means described in the claims of the present application. It is a comprehensive control device that controls the accelerator opening Ac, the throttle opening TVθ, and the oil fAT in the torque converter 4.
, predetermined control is performed using the mode switch signal detected by the mode switch 25 as control information, but below, according to the flowchart shown in FIG. 2, only the throttle valve opening/closing control related to the present invention will be controlled. Explain how.

When control is started, the accelerator opening sensor! The accelerator opening degree Ac detected by 2 is manually input.

In step S2, the throttle opening TvO detected by the throttle opening sensor 8 is input.

In step S3, the oil temperature T inside the torque converter 4 detected by the oil temperature sensor 19 is input.

In step S4, a mote switch signal detected by the mote switch 25 is input.

” The mode switch 25 selects an opening characteristic value (
Is the throttle characteristic value (hereinafter simply referred to as throttle characteristic value) set to the normal mode for normal driving in which the throttle opening TVθ increases almost linearly with the accelerator opening Ac, or is the It is designed to detect whether the throttle opening degree TVθ is set to a power mode for high output operation in which the throttle opening degree TVθ is wider than that in the normal mode.

In step S5, it is compared whether the oil temperature 'r is 150° C. or higher. As a result of the comparison, if T≧150℃ (
If YES), the oil in the torque converter 4 has risen above the limit temperature and there is a risk that the oil will be thermally degraded, so in order to prevent this, the control proceeds to step S7.

In step S7, the throttle characteristic value, which is the throttle opening target value when the opening degree of the throttle valve 2 is feedback-controlled via the step motor 7, is set to a characteristic for high oil temperature. At this time, for example, as shown by the curve G in FIG. 3, the gain of the throttle opening 'rvθ with respect to the accelerator opening Ac is the throttle characteristic value in the normal mode when the oil temperature is normal, as shown by the straight line G. It is set smaller than the gain. For this reason, the accelerator opening degree A
The throttle opening degree TVθ with respect to c becomes smaller, so the intake air filling amount decreases and the engine torque decreases. In general, in vehicles with automatic transmissions, the higher the engine torque, the greater the slip of the torque converter, which increases the amount of frictional heat generated. When the PS is operated, the slip of the torque converter 4 is reduced, and the amount of frictional heat generated is reduced.

Therefore, the oil temperature 'r in the torque converter 4 is lowered and maintained at a predetermined appropriate value.

In this embodiment, since the control unit 9 or the microcomputer is used, several throttle characteristic values corresponding to the operating conditions are stored as a map in the memory 22 in the control unit 9.
When the control unit is configured with an analog circuit, the control constant of the output calculation section of the step motor 7 is set to the oil temperature T.
You can use the old-fashioned method to switch depending on the situation.

In step SIO, steps are taken so that the throttle opening TVθ follows the throttle opening target value, using the high oil temperature throttle characteristic value (curve G3 in FIG. 3) set in step S7 as the target value. The motor 7 is driven, and the throttle opening T■0 is feedback-controlled. After this, the control goes to step S! will return and continue.

By the way, as a result of the comparison in step S5, T is 150°C.
If so (No), the oil temperature T in the torque converter 4 is normal, and the control proceeds to step S6 to perform operation with the normal throttle characteristic value as the target value.

In step S6, it is compared whether the mote switch signal detected by the mode switch 25 is in the power mode. In this embodiment, when high output is required such as during acceleration, the gain of the throttle opening TVθ relative to the accelerator opening Ac is set to be larger than during normal driving, as shown by curve G1 in Fig. 3. Thus, the output when the accelerator pedal 11 is depressed is increased to improve responsiveness.

As a result of the comparison in step S6, if the mote switch signal is not in the power mode (No), that is, in the normal mode or economy mode, the control is performed in step S8.
The normal mode throttle characteristic value is set such that the throttle opening TVθ increases almost in proportion to the accelerator opening Ac, as shown by the straight line G in FIG.

Subsequently, in step SIO, the throttle opening TVθ is feedback-controlled via the step motor 7 using the normal mode throttle characteristic value (straight line G2 in FIG. 3) set in step S8 as a target value. After this, control returns to step S1 and continues.

On the other hand, as a result of the comparison in step S6, if the mote switch signal is in the power mode (YES), the control proceeds to step S9, and in the normal mode (from the straight line cJ) as shown by the curve G in FIG. A power mode throttle characteristic (direct is set) in which the gain of the throttle opening TVθ with respect to the accelerator opening Ac is large.

Next, in step SIO, the power mode throttle characteristic value set in step S9 is set as a target value,
The throttle opening TVθ is feedback-controlled via the step motor 7. At this time, the accelerator pedal 11
Since the throttle valve 2 is opened wide in response to the depression of the pedal, the engine output is increased and high-output operation is performed. For example, during acceleration, acceleration response is improved.

After this, control returns to step S+ and continues.

Note that the present invention is applicable not only to vehicles that use a throttle valve as a means to increase or decrease engine output, but also to vehicles that are equipped with a means to increase or decrease engine output in accordance with other accelerator operations, such as a diesel engine that uses a fuel injection valve as a means to increase or decrease engine output. Needless to say, it can also be applied to vehicles equipped with the same.

As described above, according to the present invention, it is possible to prevent an excessive rise in the oil pressure in the torque converter 4 and effectively prevent oil deterioration.

[Brief explanation of the drawing]

FIG. 1 shows an engine equipped with an engine control device according to the present invention.
FIG. 1 is a diagram illustrating the system configuration of a power plant for a vehicle with an automatic transmission. FIG. 2 is a flowchart showing a control method for controlling opening and closing of the throttle valve by the control unit. FIG. 3 is a diagram showing throttle opening characteristics with respect to accelerator opening in power mode, normal mode, and when oil temperature rises excessively. PS...power plant, E...engine, T...
・Automatic transmission, 1... Intake passage, 2... Throttle valve, 3... Crankshaft, 4... Torque converter, 7...
・Step motor, ・・Throttle opening sensor, 9・
・Control unit, 11... accelerator pedal,
12...Accelerator opening sensor, 19...Oil temperature sensor, 25...Mode switch. Figure 2 Figure 3

Claims (1)

[Claims] (1) An accelerator operation amount detection means for detecting the accelerator operation amount, an engine output increase/decrease means for increasing/decreasing the engine output, and a characteristic set in advance based on the accelerator operation amount detected by the accelerator operation amount detection means. In a vehicle with an automatic transmission equipped with an engine output control means for controlling the output of an engine output increase/decrease means, an oil temperature detection means for detecting an oil temperature in a torque converter of the automatic transmission, and an oil temperature detected by the oil temperature detection means. and engine output characteristic control means for controlling the output characteristic gain of the engine output increasing/decreasing means to a small value with respect to the accelerator operation amount when the oil temperature exceeds a predetermined value to reduce the slip of the torque converter. An engine control device for a vehicle equipped with an automatic transmission, characterized by: