JP2955994B2 - Vehicle constant speed traveling device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant-speed traveling device for a vehicle, and more particularly, to a constant-speed traveling device that reduces an overshoot of a vehicle speed when the vehicle shifts from an uphill to a flat road.

(Conventional technology) In order to maintain a constant traveling speed of a vehicle that continuously travels on a flat road or a sloping road, a driver must adjust the depression amount of an accelerator pedal according to the road surface condition, which is troublesome. It was fortunate. For this reason, in recent years, a constant-speed traveling device capable of causing a vehicle to travel at a constant speed without requiring a driver's accelerator work has been developed.

As a proposal of such a constant speed traveling device, for example,
There is one disclosed in -145430. The constant-speed traveling device disclosed in this publication is configured to perform auxiliary braking by an exhaust brake as means for reducing overshoot of a vehicle, which is a problem particularly in a large vehicle having a large inertial weight.

(Problems to be Solved by the Invention) By the way, as shown in FIG. 7 (a), this kind of constant-speed traveling device climbs up an ascending road while a large vehicle having a large inertial weight is traveling, and as shown in FIG. Figure 7 (b)
As shown in (1), the actual vehicle speed of the vehicle is much higher than the set vehicle speed, and so-called overshoot occurs. When the overshoot amount is large, not only does the driver and the occupant feel uncomfortable, but also the vehicle is caused to pitch, causing load collapse and the like.

The occurrence of such overshoot has a particularly remarkable tendency in a vehicle equipped with a diesel engine having an all-speed governor mounted on a fuel injection pump as a fuel supply device.

In an engine-equipped vehicle equipped with an all-speed governor, the overshoot amount is particularly large during traveling at a constant speed, as shown in FIG. 7 (c). This is because the opening is opened to the full speed position, and the time lag increases when the control lever returns to the opening A corresponding to the set vehicle speed when shifting to a flat road. The governor control lever opening is proportionally based on the difference between the set vehicle speed and the actual vehicle speed.
This is because in the integral control (PI control), the integral term (I) component of the PI control increases, and the time lag increases to return to the opening A. That is, as shown in FIG. 8, when the vehicle travels on an uphill road, the control lever opening to maintain the engine speed Nb at which the engine generated torque Tb is obtained is required to open the uphill road. B (of course, when traveling on an uphill road, the gear position of the transmission is in a lower gear stage than when traveling on a flat road with the lever opening A). The shaded portion in () indicates useless movement of the control lever in the conventional constant-speed traveling device.

However, the proposal disclosed in the above publication does not eliminate useless movement of the control lever,
The problem of overshoot caused by the opening of the control lever going up to the full speed position,
This is intended to solve the problem by performing auxiliary braking by the exhaust brake, and this causes problems such as waste of fuel consumption and complication of the mechanism.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a constant-speed traveling device for a vehicle that attempts to reduce overshoot in vehicle speed during constant-speed traveling and to improve fuel efficiency. It is in.

(Means for Solving the Problems) According to the present invention, a constant speed of a vehicle that controls a fuel supply device of an engine of the vehicle based on a speed difference between a set vehicle speed for causing the vehicle to travel at a constant speed and a measured traveling speed of the vehicle. In the traveling device, a means for setting a vehicle speed for driving at a constant speed, a means for calculating a target engine speed based on the set vehicle speed and a gear position of a running transmission, and a means for calculating a running resistance of the vehicle. Means for calculating an upper limit value of a fuel supply amount necessary to maintain the target engine speed by overcoming the running resistance;
Control means for controlling a fuel supply amount according to the speed difference, wherein the control means calculates a fuel supply amount according to the speed difference, and a proportional-integral control means; When the fuel supply amount calculated by the means is equal to or more than the upper limit value, the proportional-integral.
Means for stopping the integration operation of the control means.

(Operation) The constant speed traveling operation of the vehicle according to the present invention calculates the target engine speed based on the set vehicle speed and the gear position of the transmission,
The upper limit value of the fuel supply amount required to maintain the target engine speed is obtained, and the fuel supply amount is controlled based on the difference between the set vehicle speed and the traveling speed of the vehicle below the upper limit value, and the fuel supply amount is reduced. When the value exceeds the upper limit, the integral operation of the proportional integral control means is stopped, and the fuel supply amount is controlled to be equal to or less than the upper limit.

(Examples) Hereinafter, the present invention will be described in detail based on illustrated examples.

FIG. 1 is a block diagram showing a schematic configuration of a constant-speed traveling device for a vehicle according to the present invention.

In FIG. 1, 1 is the engine, 2 is the engine 1
Pump 3 as a fuel supply device for supplying fuel to the vehicle, 3 is a governor (all speed governor) for controlling the fuel injection pump 2, 4 is a control lever for controlling the governor 3, and the opening of the control lever 4 is a step motor. 5 enables driving from a zero speed position indicated by a solid line to a full speed position indicated by a dotted line. Reference numeral 6 denotes an accelerator pedal, and the degree of opening of the control lever 4 is controlled by the stepping motor 5 in accordance with the amount of depression of the accelerator pedal 6. Reference numeral 7 denotes a selector lever, and reference numeral 8 denotes an electronic control device including a microcomputer. The electronic control unit 8 includes a normal transmission control program for calculating the optimal gear position of the transmission from the vehicle speed and the accelerator pedal depression amount, and a clutch control program for executing the transmission control. It has a memory that stores a program for a constant-speed traveling device and other programs necessary for traveling of a vehicle, a control device for executing these programs, and an input / output circuit. 9
Is a friction clutch, 10 is a clutch actuator for engaging and disengaging the friction clutch 9, 11 is a constant mesh transmission, 12 is an output shaft of the transmission 11, and 13 is a shift operation and a select operation of the transmission 11. Transmission actuator to perform. 1a is an engine rotation sensor that detects the number of revolutions of the engine 1, 4a is a lever opening sensor that detects the opening of the control lever 4, 6a is a depression amount detection sensor that detects the depression amount of the accelerator pedal 6, and 7a is A select position detecting sensor 11a for detecting a select position of the selector lever 7;
Is a gear position detection sensor for detecting the gear position of the transmission 11, 11b
Is a vehicle speed sensor for detecting the vehicle speed from the number of revolutions of the output shaft 12 of the transmission 11, and 14 is a set switch for setting a desired traveling speed in the constant speed traveling mode. Output signals from these sensors and the set switch 14 are input to the electronic control unit 8, and the output signals from the electronic control unit 8 cause the step motor 5, the clutch actuator 10, and the transmission actuator 13 to adjust to the traveling conditions of the vehicle. It is automatically controlled accordingly. The electronic control unit 8 stores a total displacement of the engine, a final ratio, a vehicle weight (set by an empty vehicle and a loaded vehicle), a tire radius, a transmission gear ratio, and the like.

2 and 3 show an embodiment of the present invention. FIG. 2 is a block diagram of a constant-speed traveling device, and FIG. 3 is a flowchart showing the operation thereof.

In the flowchart of FIG.
Set loading vehicle speeds V ₁ to set (step P1),
Calculated from the gear ratio of the target engine speed N ₁ at the current gear stage of the transmission 11 set vehicle speeds V _{1 to} perform (step P2). Next, the running resistance of the vehicle is calculated (step P3).

The running resistance can be obtained, for example, from the following equation based on the rate of change in engine rotation.

(Running resistance) = (engine output) − (force used for acceleration / deceleration) Expressing the above equation using the average shaft effective pressure of the engine,
It becomes like the following formula.

Here, Pmer: average axial effective pressure of the engine corresponding to running resistance Pme: average axial effective pressure of the engine (engine output) K: constant Vs: total engine displacement W: vehicle weight r: tire radius μf: final ratio μti : transmission gear ratio? Ne / Delta] t: target engine speed N ₁ as shown in Figure 6 the variation of the engine speed between time Delta] t, the occurrence of torque T1 can exhibit a driving force to overcome the running resistance R of the vehicle The optimum target engine speed (for example, Na to Ne) is calculated for each gear position of the transmission.

In step P4, the upper control lever opening Leve capable of maintaining the target engine rotation N ₁
Find r (Mex). In the example of FIG. 7, if the current running resistance of the vehicle is R, the control lever opening degrees a to
which can maintain the target engine speed N ₁ of the e is the control lever is opening c, d and e, these lower opening c limit control lever opening Lever (Max)
From the map 20 shown in FIG. Next step
The magnitude of the P5, the difference between the actual vehicle speed Vr and the set vehicle speed V _1, the control lever opening calculated by the PI control, and the control lever opening degree determined by the calculation, the upper limit control lever opening Lever (Max) (Step P
6). As a result of the comparison judgment, when the calculated control lever opening is larger than Lever (Max) (YES), the integration operation in PI control is stopped (step P
7) The control lever is controlled based on the PI control signal in a state where the integration operation is stopped, and the vehicle travels. That is,
As shown in FIG. 3, a comparison circuit 21 compares the control lever opening calculated by PI control with the upper limit control lever opening Lever (Max) obtained from the map 20,
Control lever opening Lever (M
If the value is larger than ax), the operation of the integration circuit 22 in the PI control I control is stopped, and the control lever opening is controlled based on the PI control signal in the stopped state. Thus, the control lever opening is controlled while limiting the integral term component in PI control.

In step P5, when the control lever opening calculated by the PI control is smaller than the Lever (Max) calculated from the map (NO), the vehicle runs at the calculated control lever opening. (Step P
8).

4 and 5 show another embodiment of the present invention. FIG. 4 is a block diagram of a constant-speed traveling device, and FIG. 5 is a flowchart showing the operation thereof.

In the flowchart of FIG. 5, steps Q1, Q2, Q
3, Q4, Q5, and Q6 are the same as those in the embodiment shown in FIGS. 2 and 3, and a detailed description thereof will be omitted.

In this embodiment, as shown in FIG. 4, a control lever opening degree calculated by the PI control based on the difference between the set vehicle speed V ₁ and the actual vehicle speed Vr, corresponding to the target engine speed calculated from the map 20 Upper limit control lever opening Lever (Max)
And the control circuit 23 controls the control lever opening with the smaller value, and compares the control opening calculated by PI control with the upper limit control lever opening Lever (Max). When the control lever opening calculated by the comparison circuit 21 is larger than the upper limit control lever opening, the operation of the integration circuit 22 in PI control is mainly performed.

That is, in step Q6 of the flowchart shown in FIG. 6, when the control lever opening calculated by the PI control is larger than the upper limit control lever opening Lever (Max), the upper limit control lever opening Lever (Max)
(Step Q7), and the operation of the integrating circuit in the PI control is stopped (Step Q8).

If the control lever opening calculated by the PI control is smaller than the upper limit control lever opening (NO) in step Q5, the vehicle travels at the calculated control lever opening (step Q9).

Although the present invention has been described with the above embodiment, various modifications and applications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

(Effect of the Invention) In the constant speed traveling device for a vehicle according to the present invention, the control lever opening of the governor of the fuel injection pump as the fuel supply device to the engine is limited to a certain upper limit opening or less according to the traveling conditions. Because the integral term component in PI control is configured to be limited in accordance with the driving conditions, the transition from an uphill road to a flat road is more difficult than a conventional constant-speed traveling device that opens to a full-speed position. The return time (time lag) of the control lever can be shortened, so that the effect of reducing the overshoot of the vehicle speed at the time of shifting to a flat road is obtained, and the effect that the fuel consumption is improved because the control lever is not opened more than necessary.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a constant speed traveling device for a vehicle according to the present invention, and FIGS. 2 and 3 show an embodiment of the present invention. FIG. 2 is a constant speed traveling device. FIG. 3 is a flowchart showing the operation thereof, and FIGS. 4 and 5 show another embodiment of the present invention. FIG. 4 is a block diagram of a constant speed traveling device, and FIG. Fig. 6 is a flowchart showing the operation, Fig. 6 is an explanatory diagram for obtaining the state of the upper limit control lever, and Figs. 7 (a), (b) and (c).
FIG. 8 is an explanatory diagram for explaining a problem of the conventional constant speed traveling device, and FIG. 8 is a diagram showing a relationship between an engine speed and a torque. DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Fuel injection pump, 3 ... Governor, 4 ... Control lever, 8 ... Electronic control device,
11: transmission, 11a: gear position detection sensor, 11b: vehicle speed sensor, 14: set switch.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-148723 (JP, A) JP-A-57-168038 (JP, A) JP-A-61-92935 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B60K 31/00

Claims (1)

(57) [Claims] An apparatus for controlling a fuel supply device of a vehicle engine based on a speed difference between a set vehicle speed at which a vehicle runs at a constant speed and a measured running speed of the vehicle.
Means for setting a vehicle speed for driving at a constant speed, means for calculating the target engine speed based on the set vehicle speed and the gear position of the running transmission, means for calculating the running resistance of the vehicle, and the running resistance A means for calculating an upper limit value of a fuel supply amount necessary to maintain the target engine speed by overcoming the above-mentioned problem, and control means for controlling a fuel supply amount in accordance with the speed difference, wherein the control means Proportional-integral control means for calculating the fuel supply amount in accordance with the difference, and the proportional-integral control means when the fuel supply amount calculated by the proportional-integral control means is equal to or more than the upper limit. Means for stopping the integration operation of the means.