JPH0788147B2 - Vehicle speed controller - Google Patents

Description

Description: (a) Field of Industrial Application This invention relates to a vehicle speed control device that realizes a predetermined vehicle speed by controlling the number of revolutions of an engine, and particularly relates to a change in gear ratio and load in a transmission. The present invention relates to a vehicle speed control device that can realize stable vehicle speed control even when the state changes.

(B) Conventional Technology In a work vehicle such as a tractor that performs work while moving, vehicle speed control is performed to maintain a constant vehicle speed in order to maintain a uniform processing state. In addition, the optimum vehicle speed for work varies depending on the work content and load condition. Therefore, in the conventional work vehicle, the rotation of the engine is supplied to the axle via a transmission having a plurality of gear stages,
The vehicle speed control device is provided which detects the vehicle speed by detecting the rotational speed of the axle and the like, and increases or decreases the rotational speed of the engine so that the detection result matches the optimal vehicle speed for the work. When the gear ratio in the transmission is constant, the vehicle speed also increases / decreases due to the increase / decrease in the engine speed, and the vehicle speed can be made to match the target value by feedback control based on the vehicle speed detection data.

(C) Problem to be Solved by the Invention However, in the above-described conventional vehicle speed control device, the vehicle speed is detected, the feedback is directly used by using this result, and the fuel supply amount to the engine is increased or decreased by a predetermined amount. Since the engine speed is changed, the engine speed is changed based on the vehicle speed, which is the result of transmitting the engine rotation through the transmission, thereby making the vehicle speed equal to the control value. Since the control is performed, the vehicle speed control cannot be performed in consideration of the relationship between the engine speed and the vehicle speed, which varies depending on the gear ratio and the load state.
Therefore, for example, when the gear ratio or the load largely changes before and after the vehicle speed control, when the gear ratio is changed to the high speed side or when the load is reduced, the vehicle speed is changed by a slight change in the rotational speed. There is a problem that the vehicle speed changes drastically, and stable vehicle speed control cannot be performed.When the gear ratio on the low speed side is selected or when the load is large, there is a problem that the vehicle speed change becomes slow and quick vehicle speed control cannot be performed. It was

An object of the present invention is to obtain an engine rotation speed corresponding to a control vehicle speed from the relationship between the current vehicle speed and the engine rotation speed, and perform control so as to realize this rotation speed, so that the engine rotation speed matches the control value. It is possible to realize the controlled vehicle speed by simply controlling by changing the engine speed so that
It is an object of the present invention to provide a vehicle speed control device capable of performing vehicle speed control quickly and stably in consideration of a gear ratio and a load state.

(D) Means for Solving the Problems A vehicle speed control device of the present invention includes a transmission having a plurality of shift stages for transmitting the rotation of an engine to an axle, and controls the vehicle speed by changing the rotation speed of the engine. In the control device, vehicle speed detection means and rotation speed detection means for detecting vehicle speed and engine rotation speed, and rotation for calculating engine rotation speed corresponding to control vehicle speed from vehicle speed and rotation speed detected by vehicle speed detection means and rotation speed detection means It is characterized in that a number calculation means and a setting means for setting a calculation result of the rotation speed calculation means as a control rotation speed are provided.

That is, as shown in the functional block diagram of FIG. 1, fuel is supplied to the engine from the fuel supply device, and the number of revolutions of the engine increases or decreases depending on the supply amount. The rotation of the engine is transmitted to the axle via the transmission. The rotation speed detecting means detects the rotation of the engine input to the transmission, and the vehicle speed detecting means detects the rotation of the rotating axle according to the output from the transmission. The detection results of the rotation speed detection means and the vehicle speed detection means are input to the rotation speed calculation means, and the rotation speed calculation means calculates the rotation speed corresponding to the control vehicle speed using the detection results of the rotation speed detection means and the vehicle speed detection means. The calculation result is set as control data by the setting means, and the fuel supply device changes the fuel supply amount to the engine so as to realize the set value.

(E) Operation In the present invention, as shown in FIG. 2, when the vehicle speed detecting means and the rotation speed detecting means detect the vehicle speed V and the rotation speed A, the inclination of the straight line shown by the solid line in the figure is obtained, and on this straight line The engine speed Na at the control vehicle speed Va is set as the control speed. Further, when the engine speed is the speed B at the vehicle speed V, a straight line having a slope shown by a two-dot chain line in the figure is obtained, and the rotation speed Nb at the point of the control vehicle speed Va on this straight line is obtained.
Is the control speed. Therefore, the relationship between the vehicle speed including the gear ratio and the load operating state in the transmission and the engine speed is calculated, and the rotation speed that realizes the controlled vehicle speed is calculated based on this relationship.

(F) Embodiment FIG. 3 is a diagram showing the configuration of a vehicle speed control device according to an embodiment of the present invention.

The rotation of the engine E is transmitted to the axle 3 via the clutch 1 and the transmission 2. Inside the transmission 2, the work gear stages 21a to 24a and the traveling gear stage 25a are fixed to the input shaft 7. Further, an output shaft 8 provided in parallel with the input shaft 7
The sliding gears 9 and 10 are slidably mounted on the output shaft 8 so as to be rotatable integrally with the output shaft 8. The sliding gear 9 has gears 21b, 23b, 24b meshing with the work gears 21a, 23a, 24a, respectively.
Are integrated. In addition, the slip gear 10 has a work gear
Gear 22 that meshes with each of the gear 22a and the traveling gear 25a
b and 25b are integrated. The displacement of the speed change lever 4 is transmitted to the sliding gears 9 and 10 via a link 5, and
Reference numerals 9 and 10 slide on the output shaft 8 so that one of the gears 21b to 25b meshes with the gear. The gear ratios of the work gear stages 21a to 24a and the traveling gear stage 25a are represented by the inclinations shown in FIG.
The gear ratio of the traveling gear 25a is set sufficiently higher than that of the work gears 21a to 24a.

The rotation of the engine E is detected by the rotation speed sensor S1 which is the rotation speed detecting means of the present invention, and the detection result is binarized by the A / D converter 16 to be transmitted from the I / O interface 14 to the CPU 11
Entered in. The rotation of the axle 3 is detected by the vehicle speed sensor S2 which is the vehicle speed detecting means of the present invention, and the detection result is binarized by the A / D converter 15 and the I / O interface is used.
Input from 14 to CPU 11. The CPU 11 outputs control data to the fuel supply device 6 according to a program previously written in the ROM 12. The fuel supply device 6 supplies fuel to the engine E. The rotation speed of the engine changes as the fuel supply amount from the fuel supply device 6 increases or decreases.

FIG. 5 is a flowchart showing a processing procedure of the control unit of the vehicle speed control device.

When the vehicle speed control mode is selected (n1), the detection results of the rotation speed sensor S1 and the vehicle speed sensor S2 are read (n2).
Then, the detection result of the rotation speed sensor S1 is removed from the detection result of the vehicle speed sensor S2, and a value obtained by multiplying this value by the control vehicle speed Va is used as the control rotation speed Na (n3). After this control speed
It is determined whether or not Na is less than or equal to the allowable rotation speed Ne of the engine E (n4), and if the control rotation speed Na is less than or equal to the allowable rotation speed Ne, the control rotation speed Na is stored in the memory area MA1 of the RAM 13. If the control speed Na exceeds the permissible speed Ne (n5), the permissible speed Ne is stored in the memory area MA1 (n6).
In the vehicle speed control process (n7) executed thereafter, the fuel supply amount from the fuel supply device 6 is increased or decreased so that the rotation speed of the engine E matches the value stored in the memory area MA1. In the above processing, n3 corresponds to the rotation speed calculation means of the present invention, and n4 and n5 also correspond to the setting means.

As described above, according to this embodiment, regardless of which gear stage is selected in the transmission 2, the rotation speed sensor S1
And the vehicle speed sensor S2 detect the current engine speed and vehicle speed to obtain the gear ratio.
By multiplying by Va, it is possible to know the number of revolutions of the engine E required to realize the limited vehicle speed Va in that state. As a result, when the traveling gear stage 25a is selected, it is possible to easily obtain the number of revolutions N required to obtain the vehicle speed that is substantially close to the speed limit Va that is the control vehicle speed.
In addition, when any one of the work gear stages 21a to 14a is selected, if the control vehicle speed Va is attempted to be achieved, the required engine speed or the allowable speed Ne is exceeded, but in this case, the allowable speed is exceeded. The vehicle speed control process is executed with the number Ne as the target value. Therefore, the rotation of the engine E does not exceed the allowable rotation speed Ne during the work.

(G) Effect of the Invention According to the present invention, the relationship between the current engine speed and the vehicle speed is obtained, the engine speed required to realize the controlled vehicle speed is calculated from this relationship, and this is used as the control value. Can be controlled to change the engine speed. As a result, control can be performed according to the current gear ratio and load condition, and vehicle speed control can be performed safely, quickly and accurately.

[Brief description of drawings]

FIG. 1 is a functional block diagram of the vehicle speed control device of the invention, and FIG. 2 is a diagram showing the relationship between the vehicle speed and the engine speed, which shows the operation of the vehicle speed control device. FIG. 3 is a diagram showing a configuration of a vehicle speed control device according to an embodiment of the present invention, FIG. 4 is a diagram showing a relationship between a vehicle speed and an engine speed in the vehicle speed control device, and FIG. It is a flowchart which shows a part of processing procedure of a control part. 2 ... Transmission, 21a to 24a ... Work gear, 25a ... Travel gear, E ... Engine, S1 ... Rotation speed sensor (rotation speed detection means), S2 ... Vehicle speed sensor (vehicle speed detection) means).

Claims (1)

[Claims] 1. A vehicle speed control device, comprising: a transmission having a plurality of gears for transmitting the rotation of an engine to an axle, and controlling the vehicle speed by changing the number of rotations of the engine; A detection means and a rotation speed detection means; a rotation speed calculation means for calculating an engine rotation speed corresponding to a control vehicle speed from the vehicle speed and the rotation speed detected by the vehicle speed detection means and the rotation speed detection means; and a calculation result of the rotation speed calculation means. A vehicle speed control device comprising: a setting unit that sets the control rotation speed.