JPH0417737A - Driving force controller for vehicle - Google Patents

Abstract

PURPOSE:To rapidly decrease driving force before a slipping rate becomes a specified set value at the time of generation of slipping of a vehicle and to effectively prevent the slipping from occurring by detecting driving torque of the vehicle generated by an engine by a torque detection means, and performing judgment whether it is under the driving control or not based on a signal from the torque detection means. CONSTITUTION:Driving torque of a vehicle generated by an engine is detected by a torque detection means 20. Output or driving force of the engine is decreasingly controlled by a brake controller 24 based on a signal from the torque detection means 20, that is of a variation rate of the driving torque and the like at the time of generation of slipping of the vehicle, so as to prevent slipping from occurring.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is suitable for use in a vehicle drive system for reducing slip occurring between the wheels of a vehicle and the road surface, and smoothly accelerating the vehicle. Relating to a force control device.

[Conventional technology]

In general, a vehicle driving force control device that calculates a vehicle slip rate based on the vehicle body speed and wheel speed and controls the engine output based on this slip rate is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-178742. It is known from etc.

In this type of driving force control device, as shown in FIG. 4, based on the vehicle body speed V and the wheel speed ■1, the slip rate S of the vehicle that occurs between the wheels of the vehicle and the road surface is expressed as: When this slip ratio S exceeds a set value S0 of, for example, S = 0.3 at time t and after, the throttle actuator etc. are operated to limit the intake air amount of the engine, and the rotational output is The slip ratio S is controlled to be small by reducing the driving force.

Here, in the middle of the intake passage of the engine, there is a throttle valve whose valve opening degree θ is controlled by the accelerator pedal as shown in characteristic line 1 in FIG. An intake valve consisting of a valve is provided, and the valve opening θ of this intake valve is a fourth valve.
As shown in the characteristic line 2 shown by the dashed line in the figure (when the throttle actuator operates, the opening degree θ of the throttle valve is controlled (controlled), thereby limiting the intake air amount of the engine. When the value becomes smaller than the set value S, the sub-throttle valve is opened by the throttle actuator, and the valve opening θ as an intake valve is controlled in accordance with the valve opening θ of the throttle valve.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional technology, the vehicle body speed (8) and the wheel speed (1) are detected, and based on these, the slip rate S of the vehicle is calculated by the above formula (1). Since the engine output is controlled depending on whether or not the slip rate S exceeds a predetermined set value S0, there is a time lag between when slip actually occurs and when the control is performed, so that the engine output is controlled quickly and appropriately depending on the road surface condition. There is a problem that it is difficult to perform proper control.

On the other hand, if we pay attention to the behavior of the driving torque T of the vehicle when the vehicle is running, we can see the characteristics of the driving torque shown in Fig. 4!
As shown in I3, when slip occurs in the vehicle after time t1 and the slip ratio S begins to increase, the driving torque T suddenly decreases, and the behavior of this driving torque T becomes sensitive to the slip of the vehicle. react.

The present invention has been made in view of the problems of the prior art described above. 1. The present invention detects the driving torque of the vehicle so that the driving force can be quickly controlled when the vehicle slips, and the slip of the vehicle can be effectively reduced. The purpose of the present invention is to provide a vehicle driving force control device with the following features.

[Means for Solving the Problems] The feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that the driving torque of the vehicle by the engine is detected by a torque detection means, and based on the signal from the torque detection means. The structure is such that it is determined whether or not to enter the driving force control.

Further, a torque detecting means for detecting the driving torque of the vehicle by the engine, a fluctuation rate calculating means for calculating a fluctuation rate of the driving torque based on a signal from the torque detecting means, and a fluctuation of the driving torque by the fluctuation rate calculating means. a fluctuation rate determination means for determining whether or not the fluctuation rate is larger than a predetermined fluctuation rate; and when the fluctuation rate determination means determines that the fluctuation rate of the drive torque is larger than the predetermined fluctuation rate,
It is preferable to include a driving force control means for reducing the force.

[For Use] With the above configuration, when the vehicle slips, the engine output or driving force can be controlled based on the fluctuation rate of the driving torque, etc., and faster control than based on the calculated value of the slip ratio is possible.

[Example] Hereinafter, examples of the present invention will be described based on FIGS. 1 to 3.
A driving force control device applied to a rear wheel drive vehicle equipped with an automatic transmission will be explained as an example.

In the figure, 11 is an engine mounted at the front of the vehicle;
Reference numeral 12 indicates an automatic transmission connected to the output shaft of the engine 11. The output shaft of the automatic transmission 12 is connected to a propeller shaft 13, and the tip side of the propeller shaft 13 is driven via a differential gear 14 or the like. It is connected to the rear wheel 15.15. Reference numeral 16.16 indicates a front wheel that is a driven wheel, 17.18 indicates a front wheel speed sensor that detects the rotational speed of each front wheel 16, and the front wheel speed sensors 17 and 18 detect the left and right front wheel speeds V, , Vt. By detecting each of them and outputting them to the control unit 25, which will be described later, the vehicle speed v11 is determined as follows: Vm = Vr"■1 . . .
(2) is detected.

Reference numeral 19 indicates a rear wheel speed sensor that detects the rotational speed of the propeller shaft 130 as the rotational speed of each rear wheel 15, and the rear wheel speed sensor 9 outputs the rotational speed of each rear wheel 15 to the control unit 25 as a wheel speed ■. It is supposed to be done. Reference numeral 20 indicates a torque sensor as a torque detection means provided between the automatic transmission 12 and the propeller shaft 13, etc. 13 and the like is detected as a vehicle drive torque T by the engine 11, and outputted to the control unit 25.

Next, in FIG. 2, reference numeral 21 indicates a throttle sensor that detects the valve opening degree θ of a throttle valve (not shown). When the throttle valve is opened or closed by operating an accelerator pedal (not shown), the valve opening degree θ is detected and a detection signal is output to the control unit 25.

The throttle valve controls the intake air amount of the engine 11 according to the valve opening θ, and increases or decreases the output of the engine 11 in accordance with the intake air amount. Further, a sub-throttle valve (not shown) is provided in the intake passage of the engine 11 in series with the throttle valve.

Reference numeral 22 designates a throttle actuator that opens and closes this sub-throttle valve.The throttle actuator 22 closes the sub-throttle valve to limit the intake air amount when the vehicle slips, and normally keeps the sub-throttle valve fully open. The intake air amount is controlled in accordance with the valve opening θ of the throttle valve. The throttle actuator 22 is constituted by an electric motor or the like that opens and closes a sub-throttle valve based on a control signal from a control unit 25. Reference numeral 23 denotes an ignition device that outputs an ignition signal to the engine 11. Based on the control signal from the control unit 25, the ignition device 23 changes the ignition timing of the engine 11 when the vehicle slips, etc., and changes the output of the engine 11. It is designed to be lowered together with the throttle actuator 22.

Reference numeral 24 indicates a brake control device that controls the braking force of the vehicle, and the brake control device 24 has brake cylinders (not shown) provided on each rear wheel 15 and each front wheel 16, respectively.
For example, when a vehicle slips, it supplies brake fluid pressure,
By applying braking force to each rear wheel 15 and each front wheel 16, the driving force of the vehicle by the engine 11 is forcibly reduced.

Furthermore, 25 indicates a control unit constituted by a microcomputer or the like, and front wheel speed sensors 17, 18, rear wheel speed sensor 19, torque sensor 20, throttle sensor 21, etc. are connected to the input side of control unit 25. A throttle actuator 221, ignition device 23, brake control device 24, etc. are connected to the output side. And the control unit 25
The program stored in the memory circuit shown in FIG. 3 is used to control the driving force of the vehicle by the engine 11. The memory circuit of the control unit 25 also has a slip rate S in its memory area 25A.
Setting value S. , a predetermined set value Δθ for the rate of change of the valve opening θ of the throttle valve. A set value ΔTo as a predetermined fluctuation rate with respect to the fluctuation rate of the drive torque T, etc. are stored in advance.

The vehicle driving force control device according to this embodiment has the above-mentioned configuration.Next, the output control process of the engine 11 by the control unit 25 will be explained with reference to FIG.

First, when the processing operation starts, in step 1, the vehicle speed ■ and the wheel speed VW are read from the front wheel speed sensors 17, 18i3 and the rear wheel speed sensor 19, and in step 2, the slip rate S is calculated using the equation (1) above. . Then, the process moves to step 3, where it is determined whether or not the slip ratio S exceeds the set value S0. The output is output to at least one of the ignition device 23 and the brake control device 24, and when the sub-throttle valve is closed by the throttle actuator 22, for example, this limits the intake air amount of the engine 11 and performs so-called traction control. conduct.

In addition, when it is determined that rNOJ is determined in step 3, the slip ratio S is less than the set value 80, and for example, there is no slip between the tires of each rear wheel 15 and the road surface, or this slip is extremely small. Therefore, in step 6, the throttle sensor 21 reads the valve opening θ of the throttle valve, and in step 7, the rate of change Δθ of this valve opening θ is calculated as d θ △θ=□ (3 ) t, and the process moves to step 8 where this rate of change △θ is set as the set value △θ. When the determination is "NO", the valve opening θ of the throttle valve changes rapidly, indicating that the driver is trying to increase or decrease the output of the engine 11 by operating the accelerator pedal. Therefore, the process moves to step 12 and continues outputting the release signal, for example, the throttle actuator 22 holds the sub-throttle valve in the fully open state and controls the intake air amount of the engine 11 according to the valve opening θ of the throttle valve. , and return in step 5.

On the other hand, when it is determined that rYESJ is determined in step 8, the process moves to step 9 and reads the driving torque T of the vehicle by the engine 11 from the torque sensor 20. In step 10, the fluctuation rate ΔT of the driving torque T is calculated as . Then, it is determined whether or not this variation rate T is larger than the set value ΔT0. When rYESJ is determined in step 11, the driving torque T suddenly decreases at time tI, for example, as shown in characteristic line 3 in FIG. 4, even though the throttle valve opening θ has not changed much. Therefore, it is possible to immediately determine when the vehicle slips, and the process moves to step 4, where a control signal is output, and the throttle actuator 22 etc. closes the sub-throttle valve to output the engine 11. This reduces the slippage of each rear wheel 15 at an early stage.

Further, when it is determined in step 11 that rNOJ is achieved, the slip ratio S is small and the variation in the driving torque T is also small, so the process moves to step 12 to cancel the control by the throttle actuator 22, etc., and returns to step 5. By repeating steps 1 to 12, traction control is performed so that the vehicle can be smoothly accelerated by the output of the engine 11 while avoiding slippage of the vehicle as quickly as possible.

Therefore, according to this embodiment, based on the drive torque T of the engine 11 output from the torque sensor 20, the fluctuation rate ΔT of the drive torque T is the set value ΔT.

Since the output of the engine 11 is controlled by, for example, the throttle actuator 22, depending on whether the output is greater than or not, the behavior of the drive torque T is controlled before the slip rate S reaches the set value S0 when the vehicle slips. Based on this, the driving force can be reduced, the slip of the vehicle can be effectively avoided, the acceleration performance can be improved, and safety can be ensured during starting and running.

In the above embodiment, in the program shown in FIG. 3, step 1o is a specific example of the fluctuation rate calculating means which is a component of the present invention, step 11 is a specific example of the fluctuation rate determining means, and step 4 is a specific example of the driving force control means.

Furthermore, in the above embodiment, when controlling the driving force based on the behavior of the driving torque T, the process of steps 6 to 8 eliminates the case where the valve opening θ of the throttle valve changes and the output torque T fluctuates. For example, step 8
．． 9 may be added to determine the shift timing of the automatic transmission 12. In this case, it is possible to eliminate the case where the drive torque T fluctuates at the shift timing of the automatic transmission 12, and to improve the driving force control. Reliability can be further improved.

Furthermore, in the embodiment described above, the output of the engine 11 is reduced by, for example, the throttle actuator 22, but instead of this, the output may be reduced by, for example, limiting the amount of fuel injected from the injection valve when slip occurs. You can do it like this.

Furthermore, in the above embodiments, a rear wheel drive vehicle equipped with an automatic transmission was used as an example of the vehicle. It can also be used as a vehicle driving force control device.

〔Effect of the invention〕

As described in detail above, according to the present invention, the driving torque of the vehicle by the engine is detected and the engine output is controlled based on the behavior of this driving torque, so that when a slip occurs, the slip rate is maintained at a predetermined level. It is possible to quickly reduce the driving force before reaching the set value, effectively avoiding vehicle slippage, and improving acceleration performance, increasing safety when starting and driving the vehicle. This provides various effects such as the ability to reliably improve the responsiveness of driving force control.

[Brief explanation of drawings]

Figures 1 to 3 show embodiments of the present invention, where Figure 1 is a configuration diagram of a rear-wheel drive vehicle equipped with an automatic transmission, Figure 2 is a control block diagram, and Figure 3 shows driving force control processing. Flow chart shown, No. 4
The figure is a characteristic diagram of vehicle speed, wheel speed, valve opening, drive torque, etc., showing the prior art. 11...Engine, 12...Automatic transmission, 13...
- Propeller shaft, 15... Rear wheel, 16... Front wheel, 17.18... Front wheel speed sensor, 19... Rear wheel speed sensor, 20... Torque sensor, 22... Throttle actuator, 25...Control unit,■
,... Vehicle speed, ■1... Wheel speed, S... Slip rate, T... Driving torque, △T... Fluctuation rate of driving torque. Figure 3

Claims (2)

[Claims] (1) In a vehicle driving force control device that calculates a slip rate of a vehicle based on a vehicle body speed and a wheel speed, and controls an engine output based on this slip rate, the driving torque of the vehicle by the engine is 1. A vehicle driving force control device, characterized in that the vehicle driving force control device is configured to detect the torque by a torque detection means, and to determine whether or not to enter driving force control based on a signal from the torque detection means. (2) Torque detection means for detecting the driving torque of the vehicle by the engine; fluctuation rate calculation means for calculating the fluctuation rate of the driving torque based on the signal from the torque detection means; a fluctuation rate determining means for determining whether the fluctuation rate is larger than a predetermined fluctuation rate; and when the fluctuation rate determining means determines that the fluctuation rate of the drive torque is larger than the predetermined fluctuation rate, The vehicle driving force control device according to claim 1, further comprising a driving force control means for reducing the output of the vehicle.