JPH0569978B2 - - 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.

[Conventional technology]

Governor devices that control diesel engine fuel injection pumps can be classified by characteristic pattern: all-speed governors, which can control speed in all rotation ranges from idling circuit to maximum rotation;
In order to achieve smooth idling and to prevent the maximum rotation speed from being exceeded, a minimum/maxim speed system that exerts a regulating effect only in the low and high speed rotation ranges, and does not perform the regulating effect in the middle 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/maxim speed governor is suitable for cars that require deceleration performance.

[Problem that the invention seeks to solve]

Incidentally, 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 now fully capable of handling not only work in the field but also high-speed transportation work on the road. It is becoming.

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 in which the injection amount adjustment mechanism is controlled by an electric actuator, 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 especially in the working driving mode is simplified, the operation thereof is made easy, and safety after an emergency stop while driving in the working driving mode is improved. This is what I did.

[Means for solving problems]

In the present invention, the fuel injection amount adjustment mechanism of the installed diesel engine is configured to operate an electric actuator that is electrically linked to the manually operated accelerator adjustment tool via a control circuit, and the Controls a road driving mode in which fuel is controlled using a governor characteristic set to a torque curve with a small torque fluctuation rate, and a work driving mode in which fuel is controlled using a governor characteristic set to a torque curve with a large torque fluctuation rate in response to engine speed fluctuations. The circuit is configured so that both modes can be selected by a switch, and a foot accelerator pedal that automatically returns to the low speed side is provided as the accelerator adjustment device, and the mode changeover switch switches from the road driving mode to the work driving mode. Along with switching to the mode, the detected engine rotation speed at the time of switching is set and fixed at the target engine rotation speed, and when it is sensed that the vehicle body has been stopped in the work driving mode, the target engine rotation speed is changed to the target engine rotation speed. The feature is that it is configured to automatically switch to on-road driving mode by releasing the fixed number.

[Effect]

According to the above configuration, in the road driving mode, by appropriately operating the foot accelerator pedal, acceleration/deceleration can be performed according to the degree of depression.In addition, when driving for work, the desired engine speed can be achieved by depressing the accelerator pedal in the road driving mode. When the mode changeover switch is operated when the mode changeover switch is obtained, the accelerator is set to set the rotational speed at the time of the mode change to the target rotational speed, and thereafter the predetermined engine rotational speed is maintained even if the foot accelerator pedal is released. Also, if you operate the brake or main clutch to stop the vehicle while in work driving mode, it will automatically switch to road driving mode, so the accelerator will be in the accelerator state according to the foot accelerator pedal depression.
If you take your foot off the foot accelerator pedal, the vehicle will be idling.

〔Effect of the invention〕

Therefore, according to the present invention, governor control with characteristics suitable for on-road driving and work driving can be arbitrarily selected, and there is no need for a dedicated accelerator adjustment tool especially for setting the accelerator in the work driving mode. After checking the engine speed by adjusting the engine speed using the foot accelerator, it is now possible to easily and quickly set the target engine speed by operating a simple switch. Also, after stopping the vehicle in an emergency while in work driving mode with high output set,
When restarting, unless you consciously press the foot accelerator, the vehicle will start idling, allowing you to start safely.

〔Example〕

The case where the present invention is applied to an agricultural tractor will be described below.

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. It is designed to be driven by the output from the PTO shaft 7.

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

In other words, the control rack 12 has a solenoid 1 which is displaced with a stroke proportional to the excitation current.
3 and control rack 1.
2 is continuously detected by a stroke sensor 14 using a differential transformer, and the engine rotation speed is detected by a coil sensor 17 facing a gear 16 fixed to a pump drive camshaft 15.
The position of the control rack 12 is controlled based on information from these sensors 14 and 17 and an accelerator setting value that is separately set manually.

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

Furthermore, in this electronic governor, two types of governor characteristics are set in advance by the control circuit. 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, as shown in Figure 4, is set to a torque curve that has a large torque fluctuation rate with respect to fluctuations in engine speed, and is mainly used for work driving, and these two governor characteristics are the same as those described later. The following control is performed for each mode.

In the mode using the on-road governor characteristics, map control is performed. In other words, the torque curve shown in FIG. 3 has the relationship between the engine speed and the control rack position (torque) stored in advance as map data for each accelerator setting value, and The map control system 21 determines a target rack position _P1 for the detected engine rotational speed based on the map data corresponding to the value, and PID controls the solenoid 13 so that the detected rack position moves toward the target rack position _P1 .

Further, in the mode using the governor characteristics for work traveling, PID rotation speed control is performed. In other words,
The detected engine speed can be stored and set in a memory system 23 operated by a mode changeover switch 22 consisting of a restoration type push button switch, and the current engine speed can be stored by operating the switch 22 to set the memory. This is input to the PID rotation speed control system 24 as the target engine rotation speed, and the target rack position P ₂ is determined by the PID rotation speed control system 24 so that there is no difference between this target rotation speed and the detected rotation speed. , solenoid 13 is activated so as to bring the detected rack position closer to this target rack position _P1 .
is controlled by PID.

Next, the control mode switching operation will be explained.

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

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 in which only the foot accelerator can be set 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 adjusting the degree of depression of the foot accelerator pedal.

When moving from road driving to work driving, the foot accelerator pedal 19 is depressed, and the switch 22 is pressed after confirming that the desired engine speed has been reached using the travel speedometer or engine tachometer. Then,
In the memory system 23, the engine speed at the time of the switch operation is set and fixed as the target engine speed.
The PID rotation speed control system 24 provides a corresponding target rack position _P2 . Here, when the foot is removed from the accelerator pedal 19 to return it to the idling position, the target rack position P ₁ from the map control system 21 becomes smaller than the target rack position P ₂ from the PID rotation speed control system 24, and the determination selection is made. In system 25, a 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 press the switch 22 to clear the memory in the memory system 23. By this operation, the setting of the target engine speed is canceled and the PID speed control system 24 is reset.
There is no output from. Therefore, from now on, the control based on the target rack position _P1 from the map control system 21,
In other words, control is performed in the road driving mode.

Further, the present invention is further configured so that switching from the work driving mode to the road driving mode is performed by the following two types A and B.

(A): When the comparison system 26 determines that the target rack position P ₁ from the map control system 21 is larger than the target rack position P ₂ from the PID rotation speed control system 24, the memory is released from the storage system 23. A command is issued, and the output from the PID rotation speed control system 24 disappears. Therefore, if the foot accelerator pedal 19 is depressed greatly during work driving to perform an accelerator up operation exceeding the target engine speed, the map control system 21 will subsequently change the target rack position _P1 .
Governor control will be performed in the road driving mode based on the following.

(B): As shown in FIG. 6, the output from the engine 2 is transmitted to the gear transmission mechanism 31 via the main clutch 30.
After being input into the differential mechanism 32 and changing the speed appropriately,
from the left and right differential shafts 33a, 33b to the rear wheels 5, 5.
The transmission is transmitted to the differential shafts 33a, 33b with internally expanding or disc brakes 34a, 34.
b is provided. Switches 37, 38a, and 38b are provided to detect depression of the main clutch pedal 35 and brake pedals 36a, 36b, which are mechanically connected to the main clutch 30 and each brake 34a, 34b. Switches 37, 38a, 38b
A memory release command is given to the memory system 23 when the circuit is closed. Therefore, when the main clutch 30 is disengaged and both brakes 34a and 34b are activated to stop the vehicle during the working mode, the mode is automatically switched to the road mode.

However, even in the work driving mode, mode switching is not performed when the main clutch 30 is disengaged to change the gear, or when one of the brakes 34a or 36b is activated to make a sharp turn.

In addition, minimum rack position control and maximum rack position control are also carried out to prevent engine stop and overspeed. In other words, the discrimination selection system 25
Then, the lowest rack position P ₃ is set based on the target rack positions P ₁ and P ₂ and the detected engine speed.
are compared and the largest one is selected as the target rack position _P4 . In addition, the target rack position selected by the discrimination selection system 25 as described above
_P4 and the maximum rack position _P5 set based on the detected engine speed are compared in the second discrimination system 27, and the smaller one of them is selected as the final target rack position _P0 , and the PID rack position control system 28, and thus the rack position is below the minimum rack position P ₃ and the maximum rack position
It is designed to prevent the engine from being activated beyond _P5 , thereby preventing the engine from stopping or over-revving.

[Another Example] The ease position control form in the road driving mode and the work driving mode is not limited to the above. It is also possible to perform map control with additional corrections. 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

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

In order to detect the vehicle body stop operation state, only the brake operation may be detected.

In the case of a work vehicle such as a combine harvester, in which the main clutch and main brake are operated in series with one operating tool, only a single switch is required to detect the vehicle body stop operation.

[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. 5 is a general side view of the agricultural tractor, and FIG. 6 is a schematic diagram of the transmission system. 2... Engine, 12... Fuel injection amount adjustment mechanism, 13... Actuator, 18... Control circuit, 19... Foot accelerator pedal, 22... Mode changeover switch.

Claims (1)

[Scope of Claims] 1. The fuel injection amount adjustment mechanism 12 of the mounted diesel engine 2 is configured to operate an electric actuator 13 that is electrically linked via a control circuit 18 to an accelerator adjustment tool that is manually operated. , a road driving mode where fuel is controlled using a governor characteristic set to a torque curve with a small rate of torque fluctuation relative to engine speed fluctuations, and a fuel control mode where fuel is controlled using a governor characteristic set to a torque curve with a large torque fluctuation rate relative to engine speed fluctuations. A driving mode is set by a control circuit 18, and both modes are selectable by a switch 22, and a foot accelerator pedal 19 that automatically returns to a low speed side is provided as the accelerator adjustment device, In conjunction with the changeover from the road driving mode to the work driving mode by the changeover switch 22, the detected engine speed at the time of switching is set and fixed at the target engine speed, and the vehicle body is stopped in the work driving mode. A governor device for a work vehicle is configured to sense this, release the set fixation of the engine speed, and automatically switch a governor control mode to a road driving mode. 2. The governor device for a work vehicle according to claim 1, which is configured to sense a brake operation as a vehicle body stop operation. 3. A governor device for a work vehicle according to claim 1, which is configured to sense that a brake operation and a main clutch disengagement operation are performed as a vehicle body stop operation.