JPH04350336A - Engine output control device - Google Patents

Abstract

PURPOSE:To improve responsiveness at the torque down time by performing torque down control larger by the specified quantity than the target torque down quantity set by a target torque down quantity setting means, in the torque down starting initial period after the materialization of a torque down condition. CONSTITUTION:A first throttle valve 20 turned by a stepping motor 24, and a second throttle valve 21 interlocked with an accelerator pedal 22 are provided in an intake passage. The first throttle valve 20 is used for traction control or the like at the specified torque down condition satisfied time, that is, the opening of the first throttle valve 20 is controlled by an engine control unit 23 on the basis of the road surface mu and a slip factor based on the detection value difference between a front wheel side and a rear wheel side sensors 35, 36, the shift position of a transmission, and the like. At the time of performing this opening control, the torque down control larger by the specified quantity than the target torque down quantity set according to the torque down condition is performed in the torque down starting initial period after the materialization of the torque down condition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine output control device having a torque reduction function.

0002

2. Description of the Related Art For example, as shown in Japanese Patent Application Laid-open No. 2-221658, a recent automobile engine intake air amount control system employs a stepping motor as an electric actuator for driving a throttle valve. There are an increasing number of electric type motors in which the opening of the throttle valve can be arbitrarily varied by arbitrarily controlling the amount of rotation of the motor using a pulse control signal from an engine control unit (microcomputer).

[0003] When the electric throttle valve control system is adopted, as shown in the above-mentioned prior art publication, the engine torque can be appropriately reduced and controlled in response to wheel slip conditions during acceleration, for example. So-called traction control, which improves the running stability of a vehicle, can be easily realized.

0004

By the way, from the viewpoint of ensuring running safety of the vehicle, it is desirable that the traction control has high responsiveness especially during the torque down.

However, in the above-mentioned conventional traction control system, a required target torque down amount is set in advance according to a predetermined torque down condition such as a wheel slip rate, and the system is set in advance to correspond to the target torque down amount. Since a configuration is adopted in which the throttle valve, which is the intake air amount control means, is controlled to close by a predetermined amount, a predetermined response delay inevitably occurs due to the intake characteristics until the target low torque value is reached. There is a problem in that it takes time for the actual torque to decrease to the target torque value due to the decrease in the intake air filling amount of the engine.

[0006]

[Means for Solving the Problems] The inventions recited in each of claims 1 to 5 of the present application have been made for the purpose of solving the above-mentioned conventional problems, and are each constructed as follows. There is.

(1) Configuration of the invention as claimed in claim 1 The engine output control device of the invention comprises a torque down control means for reducing the output torque of the engine when a predetermined torque down condition is satisfied, and a torque down control means for reducing the output torque of the engine when a predetermined torque down condition is satisfied. and target torque down amount setting means for setting a target torque down amount to be torque down in advance according to conditions, and set by the target torque down amount setting means at the initial stage of starting the torque down after the torque down condition is satisfied. The present invention is characterized in that the torque reduction control is performed by a predetermined amount larger than the target torque reduction amount.

(2) Configuration of the invention according to claim 2 The engine output control device of the invention includes an intake air amount control valve that controls the intake air amount of the engine, and an opening/closing state of the intake air amount control valve. A control valve opening/closing control means is provided, and when a predetermined torque down condition for reducing the engine torque is established, the intake air amount control valve is temporarily closed to a fully closed state to promptly reduce the intake air filling amount of the engine. At the same time, when the intake air amount of the engine decreases to the target intake air filling amount after torque reduction due to the fully closed control of the intake air amount control valve, the opening degree of the intake air amount control valve is changed to the target intake air amount. It is characterized in that it is configured to return to the opening degree corresponding to the filling amount.

(3) Configuration of the invention according to claim 3 The engine output control device of the invention has the basic configuration of the engine output control device of the invention according to claim 2, and the intake air amount in the same configuration is It is characterized in that the control valve is a throttle valve.

(4) Configuration of the invention according to claim 4 The engine output control device of the invention has the basic configuration of the engine output control device of the invention according to claim 2, and in the same configuration, the engine output control device according to the invention has the following configuration: The present invention is characterized in that, when the amount of torque reduction to be performed is less than a predetermined value, full closing control of the intake air amount control valve at the initial stage of the start of torque reduction is prohibited.

(5) Structure of the invention according to claim 5 The engine output control device according to the invention has the following features:
, 4 The configuration of the engine output control device of the invention described in each item is the basic configuration, and the torque down control in each configuration is as follows:
The present invention is characterized in that it is performed for the purpose of traction control to reduce the slip ratio when the slip ratio of the vehicle is equal to or higher than a predetermined value.

0012

[Operations] As a result of each of the inventions recited in claims 1 to 5 of the present application being constructed as described above, each of the inventions exhibits the following functions corresponding to each of the configurations.

(1) Effect of the invention according to claim 1 In the engine output control device according to the invention according to claim 1, as described above, torque down control is performed to reduce the output torque of the engine when a predetermined torque down condition is satisfied. and target torque down amount setting means for setting a target torque down amount in advance according to the torque down condition at that time, and the torque down amount setting means is provided for setting a target torque down amount in advance according to the torque down condition at that time. At the beginning of the control, the torque is quickly reduced by executing torque down control that is larger by a predetermined amount than the original target torque down amount set by the target torque down amount setting means.

As a result, the responsiveness of the torque down operation during torque down control is greatly improved.

(2) Effect of the invention according to claim 2 The engine output control device according to the invention according to claim 2 includes an intake air amount control valve that controls the intake air amount of the engine; A control valve opening/closing control means for arbitrarily controlling the opening/closing state is provided, and the intake air amount control valve is once fully closed at the beginning of the torque down control when a predetermined torque down condition for reducing the engine torque is satisfied. In addition to greatly controlling the closed position to quickly reduce the intake air filling amount of the engine and reduce the torque with good response,
When the intake air amount control valve fully closed control reduces the intake air filling amount of the engine to the target intake air filling amount corresponding to the target torque after torque reduction, the opening degree of the intake air amount control valve is changed to correspond to the target intake air filling amount. The opening angle is returned to the desired opening degree, allowing the vehicle to run at the target torque.

(3) Effect of the invention according to claim 3 The engine output control device according to the invention according to claim 3 has the same effect as the invention according to claim 2 due to its basic components, and in particular, the Since the intake air amount control valve in this case is a throttle valve which is the main output control means of the engine, torque down control can be executed with good responsiveness.

(4) Effect of the invention set forth in claim 4 In the engine output control device of the invention set forth in claim 4, the basic component thereof provides a highly responsive torque down action similar to that of the invention set forth in claim 2. In addition, when the target torque down amount is less than a predetermined value, the fully closed control of the intake air amount control valve at the initial stage of the start of the torque down control is prohibited, so sufficient responsiveness can be ensured. Unnecessary overtorque down when the target torque down amount is small can be prevented, and stable vehicle running can be made possible.

(5) Effect of the invention set forth in claim 5 The engine output control device according to the invention set forth in claim 5 has the following advantages: Each of the configurations operates when the slip ratio of the vehicle exceeds a predetermined value and functions as a traction control device that controls the slip ratio in a direction to reduce it. It will be possible to realize effective traction control action by taking advantage of its characteristics.

[0019]

[Effects of the Invention] Therefore, according to the engine output control device of the present invention, it is possible to effectively improve control responsiveness during engine torque down control without causing deterioration of vehicle behavior due to overtorque down. Become.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 2 to 6 show the structure and operation of an engine output control device according to an embodiment of the present invention, which is configured as a traction control device.

In FIG. 2, reference numeral 11 denotes an engine body, and air taken into the engine body 11 is supplied through an air cleaner 12, a throttle chamber 14, and a surge tank 15 into a cylinder 16 of the engine. Further, fuel is supplied from a fuel tank 18 to the engine body 11 side by a fuel pump 17 and is injected by a fuel injector 19. The amount of air taken into the cylinder 16 during running is controlled by first and second throttle valves 20 and 21 provided in the throttle chamber 14. First, the downstream second throttle valve 21 is operated mechanically in conjunction with the accelerator pedal 22, and is maintained at the minimum opening state in the idling state. In the minimum opening state,
Idle switch ID/SW turns ON.

On the other hand, the first throttle valve 20 is mainly used in a predetermined engine operating range to control traction and to control the amount of intake air to improve the driving feeling, and is used to control the amount of air intake to improve the driving feeling and the detected values of the front and rear wheel speed sensors 35 and 36. The slip rate and road surface μ based on the difference between
The stepping motor 24, whose rotation amount is controlled by an engine control unit 23 (to be described later) via a stepping motor drive circuit 25, uses parameters such as speed, third speed, fourth speed, etc. to open and close as desired. The movement position of the first throttle valve 20 is mechanically regulated by a stopper installed corresponding to its fully closed or fully open position. 1st above,
Each throttle opening degree of the second throttle valves 20 and 21 is
Detected by first and second throttle opening sensors 31 and 32, respectively.

[0023] The engine control unit 23 includes, for example, a microcomputer (CPU) that is an arithmetic unit.
It is mainly composed of a control circuit for intake air amount, ignition timing, etc., memory (ROM and RAM), an interface (I/O) circuit, etc. The interface circuit of the engine control unit 23 receives, for example, an engine start signal (ECU trigger) from the starter switch 28, an engine speed detection signal Ne from the engine speed sensor 29, and an engine speed detected by the water temperature thermistor 30. Cooling water temperature detection signal Tw, throttle opening detection signals TVOE and TVO detected by the first and second throttle opening sensors 31 and 32, intake air amount detection signal Q detected by the air flow meter 13, and accelerator opening. The accelerator opening degree θ detected by the degree sensor 33, the detected value V1 of the front and rear wheel speed sensors 35, 36,
Various detection signals necessary for engine control, such as V2 and the detected value V of the vehicle speed sensor 34, are inputted.

Next, the traction control operation of the vehicle using the first throttle valve 20 by the engine control unit 23 will be explained in detail with reference to the flowchart shown in FIG.

That is, first, in step S1, the road surface μ is estimated, and in step S2, the wheel spin level (
slip rate). The road surface μ can be estimated from the detected value of the humidity sensor and the type of road surface (normal road, rainy road, frozen road, etc.). Also, the wheel spin level is the difference in rotation speed (wheel speed) between the front driving wheel and the rear driven wheel (V1-V2).
Detected from.

As a result, when the road surface μ is low and wheel spin is occurring at a predetermined level or higher, torque down control is performed to maintain a stable running condition.

Therefore, first, in step S3, the target intake air filling efficiency C corresponding to the torque down value after the torque down is determined.
Calculate ea. The target intake air filling efficiency Cea is determined by the first speed (GE) of the transmission gear as shown in the map f1 of FIG.
It is determined by the vehicle speed V and the road surface μ for each gear stage from AR=1) to fourth gear (GEAR=4) (i.e.,
Cea=f1(μ・GEAR・V)).

Next, the process proceeds to step S4, where the first throttle valve 2 is operated to realize the target intake air filling efficiency Cea.
A target throttle opening TVOEA of 0 is calculated. The calculation of the target throttle opening TVOEA is determined from the engine rotation speed Ne and the target intake air filling efficiency Cea calculated in step S3, using the map f2 in FIG.・Ne).

When the above calculation operation is completed, the process proceeds to step S5, where the fully closed throttle opening TVOEC of the first throttle valve 20 and the target throttle of the first throttle valve 20 calculated in step S5 are calculated. Opening TV
It is determined whether the deviation from OEA, TVOE-TVOEC=ΔTVOE, is less than or equal to a predetermined set value ΔTVO1.

As a result, the amount of decrease to the target throttle opening TVOEA determined as YES is large, that is, the road surface μ
If the target torque down amount is low, the slip ratio is large, and the target torque down amount is (close to fully closed), the process continues at step S6.
6, the throttle opening degree TVOE of the first throttle valve 20 is determined once as shown by the broken line in FIG.
By controlling OE to 0 (fully closed), the intake air filling efficiency Ce is quickly reduced as shown by the broken line in FIG. 6(b). As a result,
As shown by the broken line in FIG. 6(c), the torque also quickly decreases to the target torque. Thereafter, the process further advances to step S7 and the actual intake air filling efficiency Ce is read into the CPU.

Then, in the next step S8, the actual intake air filling efficiency Ce is compared with the target intake air filling efficiency Cea.

As a result, by fully closing the first throttle valve 20, the actual intake air filling efficiency Ce has decreased to the target intake air filling efficiency Cea after torque down.Ce≦Cea(
If YES), the process proceeds to the final step S8, and the opening control of the first throttle valve 20 is performed in the return direction so that the opening degree TVOE becomes the original target throttle opening degree TVOEA. As a result, stable running with the original target torque becomes possible.

On the other hand, when the actual intake air filling efficiency Ce is still larger than the target intake air filling efficiency Cea (NO), the operations of steps S6 to S8 are repeated to reduce the intake air filling efficiency to below the target intake air filling efficiency. Only then does the process proceed to step S9.

On the other hand, if NO in the deviation determination in step S5 above,
When the determined target torque down amount itself is small, all the operations in steps S6 to S8 described above are jumped, and control in step S9 according to the target throttle opening TVOEA is executed from the beginning.

In other words, although torque reduction is necessary in view of the current road surface μ and slip ratio, the required torque reduction amount is not as large as in the above case, and therefore normal control can respond with good response. , as mentioned above, once the first
If fully closing the throttle valve 20 would actually result in overtorque reduction, stable control is performed using only normal target throttle opening control. Therefore, deterioration of vehicle behavior and torque shock due to overtorque reduction do not occur (see a in FIG. 6).

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a control system connection diagram of an engine output control device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing the control operation of the device.

FIG. 4 is a control map diagram for calculating the target intake air filling efficiency used in the control of the device shown in FIG. 3;

FIG. 5 is a control map diagram for calculating a target throttle opening degree used in the control of the device shown in FIG. 3;

FIG. 6 is a time chart showing the traction control characteristics of the device.

[Explanation of symbols]

11 is an engine body, 16 is a cylinder, 19 is a fuel injector, 20 is a first throttle valve, 21 is a second throttle valve, 23 is an engine control unit, 24 is a stepping motor, 25 is a stepping motor drive circuit, 31 is a first throttle opening sensor, 3
2 is a second throttle opening sensor.

Claims (5)

[Claims] 1. Torque down control means that reduces the output torque of the engine when a predetermined torque down condition is met, and a target that sets a target torque down amount in advance according to the torque down condition at that time. Torque down amount setting means is provided, and at an initial stage of starting the torque down after the torque down condition is satisfied, torque down control is performed which is larger by a predetermined amount than the target torque down amount set by the target torque down amount setting means. An engine output control device characterized by: 2. An intake air amount control valve that controls the intake air amount of the engine, and a control valve opening/closing control means that controls the opening/closing state of the intake air amount control valve. When the torque down condition is satisfied, the intake air amount control valve is temporarily closed to the fully closed state to quickly reduce the intake air filling amount of the engine to reduce the torque, and the intake air amount control valve is fully closed. An engine characterized in that when the intake air filling amount of the engine decreases to the target intake air filling amount after torque reduction, the opening degree of the intake air amount control valve is returned to the opening degree corresponding to the target intake air filling amount. output control device. 3. The engine output control device according to claim 2, wherein the intake air amount control valve is a throttle valve. 4. The engine according to claim 2, wherein when the target torque reduction amount is less than a predetermined value, fully closing control of the intake air amount control valve at an initial stage of starting the torque reduction is prohibited. Output control device. 5. Claim 1, wherein the torque down control is performed for the purpose of traction control to reduce the slip ratio of the vehicle when the slip ratio is equal to or higher than a predetermined value. ,2,
3. The engine output control device described in 3 and 4.