JP2500156Y2 - Driving force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a driving force control device for preventing acceleration slip of driving wheels of a vehicle.

(Prior Art) When the vehicle is suddenly accelerated, the drive wheels spin idle, and the driving force of the engine is not properly transmitted to the road surface.

(Problems to be Solved by the Invention) It is desired to prevent idling of the drive wheels when the vehicle is suddenly accelerated in this way to improve the acceleration characteristics and running stability of the vehicle.

The present invention has been made in view of the above points, and an object thereof is to provide a driving force control device that prevents acceleration slip of driving wheels of a vehicle.

[Configuration of Device] (Means and Actions for Solving Problems) In an acceleration slip prevention device that prevents acceleration slip by detecting the acceleration slip of the drive wheel and reducing the output of the engine, the wheel speed of the drive wheel is reduced. A vehicle speed sensor that detects the vehicle speed, a vehicle speed sensor that detects the vehicle speed, an output reduction unit that reduces the output of the engine, and the detection values of both sensors to detect the state in which an acceleration slip has occurred on the driving wheels. A control unit is provided which sets a ratio of the engine output after the reduction to the engine output before the reduction and controls the operation of the output reduction unit based on the reduction ratio, and when the control unit detects that an acceleration slip has occurred. The first step of reducing the output of the engine based on the first reduction rate until the slip amount becomes less than or equal to a predetermined value, and the acceleration slip again after the completion of the first step. A second step of reducing the output of the engine based on a second reduction rate that corresponds to the slip amount during the first step execution and is larger than the first reduction rate until the occurrence of the vehicle speed is detected; Is a set value or less, the driving force control device is configured to set the second reduction rate in the second step to a larger value.

(Embodiment) Hereinafter, a driving force control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a traction control device for preventing idling during acceleration in a front-wheel drive vehicle. In FIG. 1, 11 is a drive wheel,
That is, the drive wheel wheel speed sensor that detects the wheel speed Vfl of the left front wheel, 12 is the drive wheel, that is, the drive wheel wheel speed sensor that detects the wheel speed Vfr of the right front wheel, and 13 is the driven wheel, that is, the wheel speed Vrl of the left rear wheel. The driven wheel speed sensor 14 detects the driven wheel speed, and 14 is a driven wheel speed sensor that detects the wheel speed Vrr of the driven wheel, that is, the right rear wheel. The wheel speeds Vfl and Vfr on the drive wheel side are averaged in the average circuit 15 to calculate the wheel speed VW on the drive wheel side. Also, the wheel speed on the driven wheel side
Vrl and Vrr are averaged in the average circuit 16 to calculate the vehicle speed VB. Wheel speed VW and vehicle speed
The VBs are output to the traction control ECU (electronic control unit) 17, respectively, and an output reduction rate command A or B for reducing the output of the engine required for the control for preventing the slip of the driving wheels during acceleration is created. The output reduction rate command A (B) is a command for reducing the output of the engine and is output to the engine ECU 18. E for this engine
The CU18 controls the engine as a whole,
Fuel injection pulses that determine the fuel injection amount are output to the injectors I1 to I4. Further, based on the signal from the ECU 18 for the engine, the advance angle of the ignition timing of the engine is calculated by the ignition advance device 19. Further, 20 is an engine speed sensor for detecting the engine speed, 21 is an intake air amount sensor for detecting the intake air amount, and the intake air amount detected by the intake air amount sensor 21 is for the engine. EC
Output to U18. This engine ECU 18 is an output reduction rate command A output from the traction control ECU 17.
Based on (B), the engine output is controlled by reducing the fuel injection amount from the injectors I1 to I4 and delaying the ignition timing. Then, the intake air amount A / N per stroke is calculated in the engine ECU 18 based on the engine speed and the intake air amount.

Next, the operation of the embodiment of the present invention configured as described above will be described. First, the wheel speeds Vfl and Vfr on the drive wheel side are averaged by the average circuit 15 to calculate the wheel speed VW on the drive wheel side. Also, the wheel speed on the driven wheel side
Vrl and Vrr are averaged in the average circuit 16 to calculate the vehicle speed VB. Wheel speed VW and vehicle speed
Each VB is output to the traction control ECU (electronic control unit) 17. Then, in the ECU 17, the reference speed (VB + Vt based on the drive wheel speed Vw and the vehicle speed is calculated.
h), that is, slip amount DV = VW− (VB + Vth),
Is calculated and the differential value D of the slip amount DV is calculated.

Hereinafter, the driving force control device in the traction control ECU 17 will be described with reference to the flowchart of FIG. First, it is determined whether the slip amount DV> 0 and its differential value D> 0. That is, FIG. 4 (A)
At time t1, the difference between the drive wheel speed VW and the vehicle body speed VB starts to open. This is because the drive wheels start to slip due to sudden acceleration. Then, after the time t2, the drive wheel speed VW exceeds the reference speed (VB + Vth), so the slip amount D
V> 0. Further, since the differential value D> 0 at time t2, it is determined to be “YES” in step S1, and the process of reducing the output of the engine and preventing the occurrence of slip is started as described later. First, as S0, the initial value is "0"
Is set (step S2). And the intake air amount A / N
Based on the above, the first output reduction rate K0 as the command A is determined by referring to the map of FIG. 7 (step S3). Here, the output reduction rate K ₀ indicates the ratio of the engine output after reduction to the engine output before reduction. Also, the seventh
As shown in the figure, the first output reduction rate K0 is changed so as to be inversely proportional to the intake air amount A / N. This is because, as shown in FIG. 5, when the intake air amount A / N is constant, the output torque of the engine has little variation with respect to changes in the engine speed Ne. Therefore, by setting the output reduction rate K0 as shown in FIG. 7 in accordance with the intake air amount A / N, the output reduction rate K0 substantially corresponds to the engine output torque. That is, since the engine output torque is large when the intake air amount A / N is large, the engine output torque is reduced by reducing the output reduction rate. Then, the routine proceeds to step S4, where engine output reduction control based on the output reduction rate K0 is executed (command A in FIG. 3 (first step)). That is, with respect to the engine output before reduction, the output reduction rate K ₀
The fuel injection amounts of the injectors I1 to I4 are reduced and the ignition timing is delayed so that the output is multiplied by. As a result, the engine output is reduced by the amount shown in the A command portion of FIG. This output reduction control of the engine is continued until time t4 in FIG. 3, and its determination is based on the processing in step S5. That is, it is determined in step S5 whether the differential value D <0 and the slip amount DV <γ (for example, 5 Km / h). That is, A started at time t2
At time t3 due to the reduction of the engine output torque by the command,
Drive wheel speed VW peaks, after that drive wheel speed VW
Is reduced toward the vehicle speed VB. And the time
At t4, the condition of step S5 is satisfied and the A command is ended.

Then, after the A command (first step) is completed, the process proceeds to the processing of the B command (second step) after step S6. First, the integrated value S0 of the slip amount DV is calculated. That is, this integrated value S0 is as shown in FIG. 4 (B).
It is calculated as S0 = S1-S2 (step 6). And
ECU18 for engine to ECU17 for traction control
The intake air amount A / N is input to (step S7). Then, the output reduction rate K1 is calculated based on the integrated value S0 calculated in step S6 and the intake air amount A / N in step S7.

That is, output reduction rate K1 = K0 + c / {S0 ・ a ・ (A / N +
b)} is calculated (step S8). In addition, a, b, and c are constants. The control by the output reduction rate K1 is performed as the command B as shown in FIG. Here, the output reduction rate K1 is set to be larger than the output reduction rate K0.
Further, the determination of the output reduction rate K1 in step S8 is determined after the determination of the output reduction rate K0 within a predetermined time (for example, 1 second) (step SA). That is, it is determined whether it is within the set time from the start of the A command. Here, when it is determined that it is within the set time, the vehicle body speed VB is
It is determined whether the speed is 10 Km / h or less (step SB). If the determination in step SB is "YES", the vehicle speed VB is reduced to 1 second after the A command is started.
Is decreased to a small value of 10 Km / h, it is determined to be overcontrol, and a process of increasing the output reduction rate K1 of the B command is performed in step SC. Then step S9
Proceed to the subsequent processing.

On the other hand, in the determination of the above step SA, if the output reduction rate K0 has been determined for more than a predetermined time (step SA) or the vehicle body speed VB is greater than 10 Km / h, it is determined that the driving force control is not over-controlled Therefore, the B command increasing process of step SC is not performed, and the process proceeds to step S9 described later.

Next, it is determined whether the output reduction rate K1 calculated in step S8 is larger than "1" (step S9), and if it is larger, K1 is set to "1" (step S10). When K1 is "1", the engine output is not reduced. On the other hand, when the output reduction rate K1 is "1" or less, the output control of the engine is performed by the value (step S1
1). Then, the engine output reduction control based on the B command is performed until the slip amount DV becomes equal to or less than the threshold value Vth (step S12). On the other hand, when the slip amount DV is larger than the threshold value Vth, the B command is issued until it is determined to be "YES" in step S13. That is, with respect to the engine output before reduction, the output is obtained by multiplying the output reduction rate K1 by
The fuel injection amount of the injectors I1 to I4 is reduced and the ignition timing is delayed. As a result, the engine output is reduced by an amount as shown in the B command portion (after t4) in FIG. That is, during execution of the B command, the above steps
Since the integrated value S0 calculated in S6 gradually decreases, the output reduction rate K1 increases, and the output torque reduction amount is the third value.
As shown in the figure, the output torque gradually decreases, and the output torque gradually recovers during the B command.

In step S12 above, it is determined to be "YES", and the step is repeated
The determination of S1 is made. When the acceleration slip occurs again and the slip amount DV> 0 and the differential value DV> thereof, it is determined to be “YES” in step S1, and the processing of the A command in the first step described above is performed.

Now, the relationship between the road surface torque (= μWR) and the road surface μ during the A command and the B command will be described. Road torque during A command and B command follows the change of μ (W,
Since R is constant, the road surface torque corresponds to the μ-slip ratio curve shown in FIG. In other words, the road surface torque is "1"
~ It changes as shown in "6", but in that case "1" ~
The position of "6" on the μ-slop rate curve is shown in FIG. As described above, the B command is a command for utilizing the high μ portion of the stable region shown in FIG.

Here, the output reduction rate K1 calculated in step S8 is calculated. Generally, the relationship between the driving torque T1 and the road surface torque Tr is T1 = Tr + I ·.

In the equation, I is the moment of inertia of the wheel, and ω is the angular velocity of the wheel.

Here, as a result of the engine output being reduced by the control signal A as shown in FIG. 4, the drive wheel speed Vw is at the peak point P.
The integrated value S0 of the amount slipped until it decreases from (angular velocity ω0) to a predetermined value Vth + 5 (angular velocity ω1) is S0 = ∬dt ² = I · (ω0 ² −ω1 ² ) / 2 · (Tr-T1) = c / (Tr-T1) (c is a constant) (1) Here, the driving torque T0 when traction control is not performed is T0 = ρ · Te = a · (A / N + b) (2) a is a constant, ρ is the total gear ratio, Te is the engine output torque, and the output reduction rate at the time of command A is K0, and T1 = K0.
Since it is T0, the road surface torque Tr is Tr = K0 · a · (A / N + b) + c / S0 from the equations (1) and (2).

 Therefore, the output reduction rate K1 is K1 = Tr / T0 = K0 + c / {S0.a. (A / N + b)}.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 8, the processing of steps S1 to S8 is the same as that of the above-described first embodiment (FIG. 2), and therefore the description of its operation is omitted. Then, after the output reduction rate K1 of the B command is calculated in step S8, it is determined whether the vehicle body speed VB is smaller than 10 Km / h (step S21). That is, it is determined whether or not the vehicle body speed VB has been reduced by the execution of the A command in step S4 described above and has become less than 10 km / h. If the determination in step S21 is "NO", the output control based on the output reduction rate K1 is performed (step S2
2). The engine output reduction control based on the B command is performed until the slip amount DV becomes equal to or less than the vehicle body threshold value Vth (step S23). On the other hand, when the slip amount DV is larger than the vehicle body threshold value Vth, B is determined until “YES” is determined in step S24.
A command is given. That is, during execution of the B command, the integrated value S0 calculated in step S6 gradually decreases, so the output reduction rate K1 increases, and the output torque reduction amount gradually increases as shown in FIG. Decrease, output torque is B
It is gradually recovered during the order.

By the way, when it is determined to be "YES" in step S21, it is determined whether the flag set in step S29 described later is "1" (step S25). This flag is "1" when the differential value D> 0 of the slip amount DV
Is set to When the result of the determination in step S25 is "NO", the output reduction rate K1 = (K1 + 1) / 2 is set, and then the output reduction processing by the B command is performed based on the output reduction rate K1. (Step S27). After this output reduction processing, it is determined whether or not the differential value D> 0 of the slip amount DV (step S28), and if "YES", the flag is set to "1". And the steps above
The process proceeds to the process of S24, and the process from step S6 is repeated to execute the B command until it is determined to be "YES".

[Advantage of the Invention] As described above in detail, according to the present invention, when the A command causes overcontrol, the output reduction rate of the B command is increased to recover the output torque. It is possible to provide a driving force control device that can prevent overcontrol when performing driving force control.

[Brief description of drawings]

FIG. 1 is a block diagram showing a driving force control device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the same embodiment, and FIG. 3 is a change in wheel speed, output reduction amount, and output torque with time. Fig. 4 is a diagram showing changes in wheel speed over time,
FIG. 5 shows the relationship between the engine torque Te-engine speed Ne and the intake air amount A / N, FIG. 6 shows the relationship between the slip ratio and the road surface μ, and FIG. 7 shows the intake air amount. FIG. 8 is a diagram showing the relationship between the A / N and the output reduction rate K0, and FIG. 8 is a flowchart showing the operation according to another embodiment of the present invention. 11,12 …… Drive wheel wheel speed sensor, 13,14 …… Driven wheel wheel speed, 15,16 …… Average circuit, 17 …… Traction control ECU, 18 …… Engine ECU.

Front page continuation (72) Creator Kiichi Yamada 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) Reference JP-A-62-23831 (JP, A)

Claims (1)

(57) [Scope of utility model registration request] 1. An acceleration slip prevention device for a vehicle in which a torque converter is mounted in a drive system, which detects acceleration slip of a drive wheel to reduce the output of an engine to prevent acceleration slip. A wheel speed sensor that detects the wheel speed, a vehicle speed sensor that detects the vehicle speed, an output reduction means that reduces the output of the engine, and the detected values of both sensors detect the state in which an acceleration slip has occurred on the drive wheels. Then, a control means for setting a ratio of the engine output after the reduction to the engine output before the reduction and controlling the operation of the output reducing means based on the reduction rate is provided, and the control means is such that an acceleration slip has occurred. Is detected, the first step of reducing the output of the engine based on the first reduction rate until the slip amount becomes equal to or less than a predetermined value, and after the first step ends Performing a second step of reducing the output of the engine based on a second reduction rate that corresponds to the slip amount during the first step execution and is larger than the first reduction rate until the occurrence of acceleration slip is detected. However, when the vehicle speed is equal to or lower than the set vehicle speed, the driving force control device is configured to further increase the second reduction rate in the second step.