JP2802382B2 - Engine control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine control device that calculates a target vehicle speed based on an accelerator operation amount and controls an engine output in accordance with the target vehicle speed. Things. (Prior Art) Conventionally, as an engine control device, instead of directly controlling the engine output by operating an accelerator, a throttle valve or the like is controlled based on a control amount obtained in accordance with a throttle operation amount or the like. A technique for increasing the degree of freedom in output control is known, for example, as disclosed in JP-A-57-65835. Normally, when the engine output such as throttle opening is electrically controlled with respect to the accelerator operation amount, a method in which the control amount such as the throttle opening is directly set with respect to the accelerator operation amount is used. There is a method of setting the required output by the driver or a method of setting the target vehicle speed with respect to the accelerator operation amount, but the one that can be set most in response to the request of the driver of the vehicle is In this method, the target vehicle speed is set. When setting the target vehicle speed with respect to the accelerator operation amount as described above, conventionally, the accelerator operation amount and the target vehicle speed are set based on a linear relationship. (Problems to be Solved by the Invention) However, if the target vehicle speed is uniquely set based on the absolute operation position with respect to the accelerator operation amount, the request does not conform to the request accompanying the driver's accelerator operation. The vehicle speed may deviate from the target vehicle speed, causing a feeling of operation dissatisfaction. In other words, when performing acceleration or deceleration, the driver performs an accelerator operation at a speed corresponding to the degree of acceleration or deceleration, but the setting of the target vehicle speed based on this operation is independent of the operation speed, The same target vehicle speed corresponding to the accelerator position is attained, and only the transition speed between them is increased. However, in the actual accelerator operation, the fact that the operation speed is high means that the target vehicle speed requested by the driver is also high, and this may not meet the request if the operation only corresponds to the accelerator operation amount. Become. In view of the above circumstances, the present invention considers, for example, that the request for the vehicle speed of the accelerator operation after shifting to the steady running after starting is a relative operation amount, that is, how much is operated in which direction than the absolute operation amount of the accelerator operation. It is an object of the present invention to provide an engine control device capable of performing more accurate engine output control based on the fact that the setting corresponding to the requirement meets the driver's request. (Means for Solving the Problems) An engine control device according to the present invention includes an accelerator operation amount detecting means for detecting an accelerator operation amount, an output of the accelerator operation amount detecting means, and a target based on the accelerator operation amount. A target vehicle speed setting means for setting a vehicle speed; and an output control means for controlling an engine output in accordance with the target vehicle speed by the target vehicle speed setting means, and a rate of change of an accelerator operation amount from an output of the accelerator operation amount detecting means. Receiving the signals from the change rate calculating means, and when the change rate is less than a predetermined value and near 0, the vehicle speed correction value for the change rate is set to 0, and when the change rate is equal to or more than the predetermined value, Is provided with a correction value setting means for setting a larger vehicle speed correction value as the rate of change is larger. In a steady-state operating state at or below a predetermined change rate at which the vehicle speed is determined to be other than acceleration / deceleration, the target vehicle speed is set by adding the vehicle speed correction value to the previous target vehicle speed. FIG. 1 is an overall configuration diagram for clearly showing the configuration of an engine control device according to the present invention. The engine 1 is provided with output control means 2 for controlling the engine output by controlling, for example, the throttle opening or the operation amount of the control lever of the fuel injection pump. The output control means 2 outputs a control signal from a control amount setting means 3 for setting the control amount, and controls the engine to a predetermined output state. Further, the target vehicle speed signal set by the target vehicle speed setting unit 4 is output to the control amount setting unit 3, and the control amount is set according to the target vehicle speed. The target vehicle speed setting means 4 outputs a signal from an accelerator operation amount detecting means 6 for detecting an accelerator operation amount from an operation amount of an accelerator pedal 5, and sets a target vehicle speed based on the accelerator operation amount. . Further, a change rate calculating means 7 for obtaining a change rate of the accelerator operation amount from an output of the accelerator operation amount detecting means 6 is provided, and a signal of the change rate calculating means 7 is received, and a vehicle speed correction value is calculated according to the change rate. The correction value setting means 8 to be obtained is provided. The signal of the correction value setting means 8 is output to the target vehicle speed setting means 4, and the target vehicle speed setting means 4 determines that the target vehicle speed setting means 4 has not changed at least in a steady operation state in which the change rate of the accelerator operation amount is equal to or less than a predetermined change rate. The target vehicle speed is set by adding the vehicle speed correction value from the correction value setting means 8 to the vehicle speed. When the change rate of the accelerator operation amount is less than a predetermined value and is close to 0, the vehicle speed correction value is set to 0 for the change rate, and the target vehicle speed is maintained constant, When the rate of change is equal to or greater than the predetermined value, the larger the change rate, the larger the vehicle speed correction value is set, and the final target vehicle speed is set to a large value, which matches the driver's required vehicle speed. (Operation) In the control device as described above, the target vehicle speed is set in accordance with the accelerator operation amount, the control amount is set based on the target vehicle speed, and the engine output is controlled. The target vehicle speed is set to a different value corresponding to the rate of change even if the accelerator operation amount is the same. In other words, at least in the steady operation state in which the change rate of the accelerator operation amount is equal to or less than the predetermined change rate and the acceleration / deceleration state is not determined, the target vehicle speed is set by adding the vehicle speed correction value to the previous target vehicle speed. When the rate of change is near 0, the vehicle speed correction value for this rate of change is set to 0 to maintain the target vehicle speed constant to obtain stability, while when the rate of change is greater than or equal to a predetermined value, the rate of change is large. By setting the target vehicle speed to a higher value by setting the vehicle speed correction value to a higher value, the target vehicle speed conforms to the target vehicle speed required by the driver. Performance is assured. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Second
The figure is a schematic configuration diagram of a specific example of an engine control device.
In the engine of this example, the engine output is controlled by adjusting the opening of the throttle valve. The engine 1 is provided with an intake passage 15 for supplying intake air and an exhaust passage 16 for discharging exhaust gas.
Is provided with a throttle valve 17 for adjusting the amount of intake air. The throttle valve 17 is opened and closed by a throttle actuator 18 such as a stepping motor. The output of the engine 1 is transmitted from the transmission 19 to the drive wheels 23 via the propeller shaft 20, the differential gear 21, and the axle 22. The control of the engine output by the operation of the throttle actuator 18 is controlled by a control signal (pulse signal) from the control unit 25. The control unit 25 includes an accelerator signal from an accelerator sensor 26 that detects an accelerator operation amount based on a displacement amount of the accelerator pedal 5 in order to set a control amount of the throttle valve 17.
A vehicle speed signal from a vehicle speed sensor 27 provided in 19 and a throttle signal from a throttle sensor 28 for detecting the opening of the throttle valve 17 are input. The control unit 25 basically converts an accelerator signal from the accelerator sensor 26 into a target vehicle speed, and controls the throttle opening so that the actual vehicle speed converges to the target vehicle speed. Also, when starting, the target vehicle speed is set in accordance with the accelerator operation amount and the vehicle speed, and in a steady state, a vehicle speed correction value is obtained according to the change rate of the accelerator and added to the previous target vehicle speed to set the target vehicle speed. During acceleration, a target vehicle speed is set by correcting a target vehicle speed by obtaining a correction coefficient corresponding to the rate of change of the accelerator. The processing of the control unit 25 will be described with reference to the flowcharts of FIGS. FIG. 3 shows a main routine. After the start, initialization is performed in step S1. This initialization involves setting each I / O port, assigning an initial value to each register, and initializing various timers. Next, in step S2, the accelerator signal is A / D converted and the accelerator operation amount Ac is input, and in step S3 the actual vehicle speed Vs
Enter r. The actual vehicle speed Vsr is calculated by an interrupt routine each time a vehicle speed pulse is output from the vehicle speed sensor 27.First, the cycle is calculated from the vehicle speed pulse, and a moving average process of this cycle is performed. The speed Vsr is calculated. Step S4 is a running state determination routine, details of which are shown in the subroutine of FIG. In this subroutine, step S5 determines whether or not the actual vehicle speed Vsr is 0. If the determination is YES and the vehicle speed Vsr is 0, the mode label Fmode is set to the vehicle stop mode STOP in step S6. If the determination in step S5 is NO,
In S7, it is determined whether or not the mode label Fmode is set to the vehicle stop mode STOP. When the determination is YES and the speed is increased from the stop state, the mode label Fmode is determined in step S8.
Is set to the start mode START. Also, in step S7
If the determination is NO, it is determined in step S9 whether or not the actual vehicle speed Vsr has reached the predetermined value 40 km / h, and if this determination is NO and the predetermined value is 40 km / h or less, the process proceeds to step S8. Start mode ST
Keep ART settings. On the other hand, the determination in step S9 is Y
If the actual vehicle speed Vsr exceeds the predetermined value 40 km / h in ES, it is determined in step S10 whether or not the accelerator change rate per unit time ΔAcc is equal to or higher than a steady-state determination level K ₁ (for example, 1 ゜ / sec). If this determination is NO, the mode label Fmo
Set de to steady mode CRUSE. Also, the above step S
If the determination in Step 10 is YES, it is determined in Step S12 whether or not the accelerator change rate ΔAcc per unit time is positive. When the determination is YES and the accelerator operation amount is increased, the accelerator change rate ΔAcc is set to the acceleration determination level K ₂ (for example, 18) in step S13.
(゜ / sec) or more, and if this determination is YES, the mode label Fmode is set to the acceleration mode ACC in step S14. Then, in step S15 of the main routine, the mode label Fmode indicates the vehicle stop mode STOP or the start mode S
Determine whether or not TART is set, and this determination is YES
In the case of, the target vehicle speed Vso ₁ at the start is set in step S16. The target vehicle speed Vso ₁ is set according to the accelerator operation amount Ac.
As the actual vehicle speed Vsr increases, the target vehicle speed Vso
Set in ₁ increases property, sets the target vehicle speed Vso ₁ to the final target vehicle speed Vso at step S17. When the determination in step S15 is NO, step S15 is executed.
18 Mode Label Fmode it is determined whether it is set to the steady mode CRUSE, when the determination is YES it to set the target vehicle speed Vso ₂ during steady at step S19. The setting of the target vehicle speed Vso ₂ is based on the change rate ΔAcc of the accelerator operation amount Ac.
(Differential amount) is obtained from the difference from the previous memory value Acm, and a vehicle speed correction value ΔVso corresponding to the change rate ΔAcc is obtained based on the characteristics shown in FIG. 6, and this vehicle speed correction value ΔVso is obtained from the previous target vehicle speed. It was added to Vso ₂ sets the target vehicle speed Vso ₂ in the steady state by. Then, in step S20, the memory value A of the accelerator operation amount
cm and update the target vehicle speed Vso in step S21.
₂ is set as the final target vehicle speed Vso. As shown in FIG. 6, when the change rate ΔAcc is close to 0 and the throttle operation amount Ac is constant, the vehicle speed correction value ΔVso is also 0.
The throttle valve 17 is operated in the opening direction and the rate of change Δ
When Acc increases in the positive direction, the vehicle speed correction value ΔVso also increases in the positive direction. Conversely, when the throttle valve 17 is operated in the closing direction and the change rate ΔAcc increases in the negative direction, the vehicle speed correction value ΔVso also increases in the negative direction. Are set respectively. Furthermore, the setting of target vehicle speed Vso ₃ during acceleration in step S22 when the determination of step S18 is NO. The target vehicle speed Vso ₃ is set by calculating a vehicle speed correction coefficient Kc corresponding to the accelerator change rate ΔAcc (differential amount).
Separately sets a target vehicle speed Vso ₃ during acceleration over the calculated basic target vehicle speed Vso, sets the target vehicle speed Vso ₃ to the final target vehicle speed Vso at step S23. After setting the target vehicle speed Vso as described above, step S24
The target opening TVo of the throttle valve 17 is set in the target throttle opening calculation subroutine (detailed in FIG. 5).
Then, the actual opening TVr of the throttle valve 17 is feedback-controlled to the target opening TVo in the throttle drive interrupt routine (started every 1 ms) in steps S25 to S28. That is, in step S25, it is determined whether or not the actual opening TVr is equal to the target opening TVo, and when the NO is different, it is determined whether or not the actual opening TVr is larger than the target opening TVo (S26). In step S27, a drive signal for reducing the number of steps of the stepping motor of the throttle actuator 18 by one step is output in step S27 to close the throttle valve 17. On the other hand, actual opening
When TVr is smaller than the target opening TVo, NO, a drive signal for increasing the step number of the stepping motor of the throttle actuator 18 by one step is output in step S28 to open the throttle valve 17. The target throttle opening calculation subroutine of step S24 in the main routine includes the target vehicle speed Vso and the actual vehicle speed V.
The feedback control of the vehicle speed is performed so that sr coincides. As shown in FIG. 5, first, in step S30, the basic required driving force TRob is obtained from the target vehicle speed Vso by table interpolation. The basic required driving force TRob is obtained according to a steady state on a flat road. And step
In S31, it is determined whether or not the target vehicle speed Vso is equal to or less than the actual vehicle speed Vsr. If the determination is YES and the target vehicle speed Vso is smaller, the absolute value of the vehicle speed difference D between the target vehicle speed Vso and the actual vehicle speed Vsr is determined in step S32. The value is calculated, and the basic required driving force TRob is corrected in step S33. This correction is performed by a proportional control component that is corrected by a proportional element proportional to the vehicle speed difference D (constant KPd), and an integral control component that is corrected by an integral element that subtracts an integral constant KId and gives weight in time. , And calculates the correction request driving force TRoc. On the other hand, if the determination in step S31 is NO and the target vehicle speed Vso is greater, the target vehicle speed Vso and the actual vehicle speed are determined in step S34.
The vehicle speed difference D from Vsr is calculated, and the basic required driving force TRob is corrected in step S35. This correction is made by a proportional control component that is corrected by a proportional element proportional to the vehicle speed difference D (constant KPu) and an integral control component that is corrected by an integral element that is added by the integral constant KIu and weighted with time. , Correction required driving force TRoc
Is calculated. Correction required driving force TR obtained as described above
Based on oc, a final target driving force TRo is set in step S36, and the final target driving force TRo and the actual vehicle speed Vsr are set in step S37.
The target opening degree TVo of the throttle valve 17 is obtained by map interpolation based on the map determined by the above. According to the above-described control, a vehicle speed correction value is obtained according to a change rate (differential amount) of the accelerator operation amount during a steady operation according to the traveling state set by the mode label Fmode, and this is set as the current (previous) target vehicle speed. Even if the actual target vehicle speed is set by addition and the change to the same accelerator operation state is performed, the target vehicle speed is set according to the change speed and output control corresponding to the required vehicle speed is performed. Also, at the time of starting, the target vehicle speed is set directly from the accelerator operation amount and matched with the required vehicle speed, rather than the control based on the change rate as described above. Furthermore, during acceleration, the target vehicle speed is set higher to ensure acceleration performance. In the above embodiment, the example of the engine output control by adjusting the opening degree of the throttle valve 17 is described. However, the present invention is also applied to a diesel engine that controls the engine output by adjusting the control lever of the fuel injection pump. It is possible. (Effects of the Invention) According to the present invention as described above, the target vehicle speed is set by adding the vehicle speed correction value to the previous target vehicle speed at least in a steady operation state in setting the target vehicle speed in accordance with the accelerator operation amount. However, when the rate of change of the accelerator operation amount is close to 0, the vehicle speed correction value for this rate of change is set to 0 to maintain the target vehicle speed constant, thereby obtaining steady running stability. Even when the rate of change is equal to or greater than a predetermined value, a larger vehicle speed correction value is set as the rate of change is larger, and the target vehicle speed is set to a larger value. The vehicle speed can be obtained, and the engine output control appropriately corresponding to the accelerator operation can be obtained so that good driving performance can be secured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram for clearly showing the configuration of an engine control device according to the present invention, FIG. 2 is a schematic configuration diagram of a specific example, and FIGS. FIG. 6 is a flow chart for explaining the process, and FIG. 6 is a characteristic diagram showing a setting characteristic of a correction value of the target vehicle speed. DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Output control means, 3 ... Control amount setting means, 4 ... Target vehicle speed setting means, 5 ... Accelerator pedal, 6 ... Accelerator operation amount detecting means, 7 ... Change rate calculating means , 8 ... correction value setting means, 17 ... throttle valve, 18
... throttle actuator, 25 ... control unit, 26 ... accelerator sensor, 27 ... vehicle speed sensor.

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Claims (1)

(57) [Claims] Accelerator operation amount detection means for detecting an accelerator operation amount, target vehicle speed setting means for receiving an output of the accelerator operation amount detection means and setting a target vehicle speed based on the accelerator operation amount, and a target vehicle speed by the target vehicle speed setting means. An engine control device having an output control means for controlling the engine output in response to the change in the accelerator operation amount from the output of the accelerator operation amount detection means; Receiving the signal, and according to the rate of change,
When the rate of change is less than the predetermined value and is near 0, the vehicle speed correction value for the rate of change is set to 0, and when the rate of change is greater than or equal to the predetermined value, the correction value setting means sets a larger vehicle speed correction value as the rate of change increases. The target vehicle speed setting means receives the signal of the correction value setting means, and at least in a steady operation state in which the change rate of the accelerator operation amount is not more than a predetermined change rate determined to be other than the acceleration / deceleration, the previous target vehicle speed setting means An engine control device for setting a target vehicle speed by adding the vehicle speed correction value to the target vehicle speed.