JPH0520573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to a governor device used in a diesel engine-equipped agricultural vehicle such as an agricultural tractor or combine harvester.

[Prior Art] Governor devices that control diesel engine fuel injection pumps can be classified into characteristic patterns: all-speed governors, which can control speed in all rotation ranges from idling to maximum rotation;
In order to achieve smooth idling and to prevent the maximum rotation speed from being exceeded, a minimum/maximum speed system that exerts a regulating function only in the low and high speed rotation ranges and does not perform the regulating function in the medium speed rotation range. There is a governor.

The former all-speed governor is used in the above-mentioned agricultural work vehicles, which require stable constant-speed running and constant-speed drive of working equipment regardless of load fluctuations. The latter minimum/maximum speed governor is suitable for cars that require deceleration performance.

[Problem to be solved by the invention]

By the way, in recent years, there has been a strong trend towards faster speeds for the above-mentioned agricultural vehicles due to improvements in work efficiency and mobility, and they are suitable not only for work in the field but also for high-speed movement on the road and high-speed transportation work. We are starting to be able to cope with this.

However, as mentioned above, the governor installed on the engine of an agricultural work vehicle is an all-speed governor that is suitable for its main work in the field, so the feeling of acceleration and deceleration when driving on the road ( Drivability was poor.

This invention solves the above problem by employing a so-called electronically controlled governor that electrically controls the operation of both injection adjustment mechanisms, thereby making it possible to utilize two types of governor characteristics suitable for work driving and road driving. In addition, the configuration of the accelerator setting means, particularly in the work driving mode, is simplified, and its operation is also simplified.

[Means to solve the problem]

In the present invention, the fuel injection amount adjustment mechanism of the installed diesel engine is configured to be operated by an actuator that is linked via a control circuit to an accelerator adjustment tool that is manually operated. The control circuit can be set to a road driving mode in which the fuel is controlled using the governor characteristics set to a small torque curve, and a work driving mode in which the fuel is controlled using the governor characteristics set to the torque curve with a large torque fluctuation rate with respect to engine speed fluctuations. Both modes are configured to be selectable by a mode switching means, and when the mode switching means switches from the road driving mode to the work driving mode, the detected engine rotation speed at the time of switching is set to the target engine rotation speed. It is distinctive in that it is configured to do so.

[Effect]

According to the above configuration, in the road driving mode, by appropriately operating the accelerator adjustment tool, acceleration and deceleration can be performed in accordance with the degree of operation.

Furthermore, when switching during work driving, when the desired engine speed is obtained in the road driving mode, the mode switching means is operated to set the engine speed at the time of the mode change to the target engine speed. , switched to work driving mode. Thereafter, the predetermined engine speed is maintained regardless of load fluctuations.

In other words, the mode switching means of the present invention has both the original mode switching function and the setting function for setting the target rotation speed.

〔Effect of the invention〕

Therefore, according to the present invention, governor control with characteristics suitable for road driving and work driving can be arbitrarily selected, and in the road driving mode, the acceleration/deceleration operation using the accelerator adjuster feels good.

Then, by adjusting the rotation speed and checking the rotation speed in the road driving mode where it is easy to make subtle rotation speed adjustments, you can switch to the work driving mode and set the target for the work driving mode. Since the rotation speed setting operation is easily done at once,
Operability during mode switching can be improved.

〔Example〕

Hereinafter, a case where the present invention is applied to an agricultural tractor will be described.

The output of the diesel engine 2 mounted on the tractor body 1 is transmitted to the transmission case 4 via the main clutch housing 3, where the gear is changed as appropriate and transmitted to the rear wheels 5 or the front and rear wheels 6, 5, as well as the driving transmission. Live PTO independent of system
Working power is branched and transmitted to the rear PTO shaft 7 via a transmission system, and a rotary tiller 10, which is an example of a working device, is connected to the rear of the vehicle body by a hydraulic lift arm 8 and a three-point link mechanism 9 so as to be able to move up and down. rear end
It is designed to be driven by the output from the PTO shaft 7.

A control rack 12, which is a fuel injection amount adjustment mechanism for a fuel injection pump 11 installed in the diesel engine 2, is controlled by an electronic governor.

That is, the control rack 12 is connected to the solenoid 13 which is displaced with a stroke proportional to the excitation current, and the position of the control rack 12 is connected to the stroke sensor 1 using a differential transformer.
4 is detected continuously. The engine rotation speed is detected by a coil sensor 17 facing a gear 16 fixed to a camshaft 15 for driving the pump, and the engine rotation speed is determined by information from the stroke sensor 14 and coil sensor 17 and a separate artificial setting. Control rack 1 based on accelerator setting value
The device is configured to control the position of 2.

This electronic governor is controlled via a control circuit 18 using a microcomputer, and a block diagram thereof is shown in FIG.

In this electronic governor, as an example of the accelerator adjustment device 19 that is manually operated, a foot accelerator pedal is used which can be depressed arbitrarily in the entire range from the idling position to the highest position, and which automatically returns to the idling side. , which is equipped with a rotary potentiometer 20 that outputs the accelerator adjustment position as an analog signal.

Further, in this electronic governor, two types of governor characteristics are set in advance by the control circuit 18.

One of them, as shown in FIG. 3, is a torque curve that has a small torque fluctuation rate with respect to fluctuations in engine speed, and is mainly used for road driving. The other type is set to a torque curve that has a large torque fluctuation rate with respect to changes in engine speed, as shown in Figure 4A, and is mainly used for work driving, and the characteristics of both governors will be discussed later. The following control is performed for each mode.

In the mode using the governor characteristics for road driving, map control is performed. In other words, the torque curve shown in Figure 3 shows the relationship between engine speed and control rack position (torque) for each accelerator setting value.
The relationship between the two is stored in advance as map data, and the target rack position for the detected engine speed is determined based on the map data corresponding to the accelerator setting value obtained from the rotation potentiometer 20.
_P1 is determined by the map control system 21, and the solenoid 13 (corresponding to an actuator) is controlled by PID so that the detected rack position moves toward the target rack position _P1 .

In addition, in a mode that uses the governor characteristics for work travel, PID rotation speed control is performed.

That is, a memory system 23 operated by a mode switching means 22 consisting of a restorative push button switch.
The detected engine speed can be stored in the memory, and the engine speed at that time is stored and set by the memory setting operation of the mode switching means 22, and this is input to the PID speed control system 24 as the target engine speed. The PID rotation speed control system 24 determines a target rack position _P2 so that there is no difference between the target rotation speed and the detected rotation speed, and the solenoid 1 is operated so that the detected rack position approaches the target rack position _P2 .
3 is controlled by PID.

Next, the control mode switching operation will be explained.

To switch between road driving mode and work driving mode,
This is performed by selecting whichever is larger of the target rack positions P ₁ or P ₂ from the map control system 21 and the PID rotation speed control system 24 using the discrimination selection system 25, and this selection control is performed as follows. It is done like this.

The control circuit 18 is initially set so that the memory system 23 is in a memory-released state when the main switch is turned on, and when the engine is started, a road driving mode that can only be set by the accelerator adjuster 19 is brought about.

Therefore, when the vehicle is to be driven on the road immediately after starting the engine, the easy position control can be performed with governor characteristics suitable for road driving by simply operating and adjusting the accelerator adjuster 19.

When moving from road driving to work driving, operate the accelerator adjuster 19, confirm with the travel speedometer or the engine speed that the desired engine speed has been reached, and then operate the mode switching means 22. Then, in the memory system 23, the engine rotation speed at the time of operation of the mode switching means 22 is set and fixed as the target engine rotation speed, and from the PID rotation speed control system 24,
A target rack position _P2 corresponding to this is given.
Here, when the accelerator adjuster 19 is returned to the idling position, the target rack position _P1 from the map control system 21 becomes smaller than the target rack position _P2 from the PID rotation speed control system 24, and the discrimination selection system 2
In step 5, the larger target rack position _P2 is selected, and the work travel mode is maintained thereafter.

To return from the work driving mode to the road driving mode, it is sufficient to operate the mode switching means 22 to clear the memory in the memory system 23, and by this operation, the target engine speed setting is canceled and the PID speed control is performed. There is no output from system 24. Therefore, from then on, control is performed based on the target rack position _P1 from the map control system 21, that is, control in the road driving mode.

In addition, minimum rack position control and maximum rack position control are also carried out to prevent engine stop and overspeed. That is, the discrimination and selection system 25 compares the target rack positions P ₁ and P ₂ with the lowest rack position P ₃ set based on the detected engine speed, and selects the largest rack position P 4 as the target rack position P ₄ . be done. Further, as mentioned above, the target rack position _P4 selected by the discrimination selection system 25 and the maximum rack position _P5 set based on the detected engine speed are compared in the second discrimination system 26, and the smaller of the two is compared. is selected as the final target rack position P ₀ and given to the PID rack position control system 27, and in this way the rack position becomes the lowest rack position.
It is designed to prevent the engine from being operated below P ₃ and above the maximum easy position P ₅ , thereby preventing the engine from stopping or over-speeding.

[Another Example] The ease position control form in the road driving mode and the work driving mode is not limited to the above, but the working form in the road driving mode can be map-controlled, and the control form in the working driving mode can be controlled according to the load. It is also possible to perform map control with additional correction (see FIG. 4B). Further, it is also possible to use PID control or PI control in both modes.

A DC electric motor (with a speed reducer) replaces the solenoid 13 that drives the control rack 12.
You may also use

On/off 2 as the mode switching means 22
It is also possible to use a toggle switch that can be switched and held in a certain position, for example, by turning on the memory system 23 to set the memory system 23, and by turning it off to cancel the memory.

It is convenient to selectively light up a mode display lamp or the like in response to switching of control modes.

[Brief explanation of the drawing]

The drawings show an embodiment of the governor device for a working vehicle according to the present invention, and FIG. 1 is a control block diagram, FIG. 2 is a configuration diagram of the governor device, FIG. 3 is a governor characteristic diagram in road driving mode, and FIG. Figures A and B are governor characteristic diagrams in the working driving mode, and Figure 5 is an overall side view of the agricultural tractor. 2... Diesel engine, 12... Fuel injection amount adjustment mechanism, 13... Actuator, 18...
Control circuit, 19...accelerator adjustment tool, 22...mode switching means.

Claims (1)

[Claims] 1 The fuel injection amount adjustment mechanism 12 of the mounted diesel engine 2 is controlled by an accelerator adjustment tool 19 that is manually operated.
It is configured to be operated by an actuator 13 linked via a control circuit 18, and there is a road driving mode in which fuel is controlled by a governor characteristic set to a torque curve with a small torque fluctuation rate with respect to engine speed fluctuations, and The control circuit 18 sets a work driving mode in which the fuel is controlled using the governor characteristics set to a torque curve with a large torque fluctuation rate, and the mode switching means 2 switches between both modes.
2, and as the mode switching means 22 switches from the road driving mode to the work driving mode, the detected engine rotation speed at the time of switching is set and fixed at the target engine rotation speed. A governor device for a work vehicle.