JPS61149543A - Governor for working vehicle - Google Patents

Abstract

PURPOSE:To improve operation performance, by a method wherein, when the number of revolutions of an engine is increased to a desired value by stepping on an accel pedal during operation by means of an on-road running mode, a mode changing-over switch is actuated, and in which case, operation is controllable based on the current number of revolutions serving as the desired number of revolutions. CONSTITUTION:A control rack 12 of a fuel injection pump 11 is moved forward and backward through energization control of a solenoid 13 by means of a control circuit 18 according to a step-on amount of an accel pedal 19 to control a fuel injection amount. A titled device so constituted is so adapted that fuel control can be performed according to an on-road running mode or a work running mode selected by a mode changing-over switch 22. Further, along with changeover of the on-road running mode to the work running mode, the number of revolutions of an engine prevailing during changeover can be set and locked to the desired number of revolutions. When it is detected that car body stop control is ions. When it is detected that car body stop control is effected during the work running mode, the above number of revolutions is released from set locking, and a mode can be automatically changed over to the on-road running mode.

Description

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

[Conventional technology]

The governor devices that control the fuel injection pumps of diesel engines are categorized by characteristic patterns: all-speed governors, which can control the speed in all rotation ranges from idling to maximum speed, and In order to prevent the rotation speed from exceeding the speed range, there is a minimum/maximum speed governor that exerts a regulating action only in the low-speed rotation range and high-speed rotation range, but does not perform the regulating action in the medium rotation range.

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 that the invention seeks to solve]

Incidentally, in recent years, there has been a strong trend toward faster speeds for the agricultural vehicles mentioned above due to improvements in work efficiency and mobility.
It is becoming possible to fully handle not only work in the field but also high-speed transportation work on the road.

However, as mentioned above, the governor device installed on the engine of agricultural work vehicles was an all-speed governor that was suitable for the main work in the field.
The sense of acceleration and deceleration (drivability) when driving on the road was poor.

This invention solves the above problem by employing a so-called electronically controlled governor that controls the operation of the injection amount adjustment mechanism using an electric actuator, thereby making it possible to utilize two types of governor characteristics suitable for work driving and road driving. In addition, the structure of the accelerator set 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 be operated by an electric actuator that is electrically linked to a manually operated accelerator adjustment tool via a control circuit, and the mechanism is configured to be operated by an electric actuator that is electrically linked to an accelerator adjustment tool that is manually operated. 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. Both modes are configured to be set by a circuit and 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. With the switching, the detected engine speed at the time of switching is set and fixed at the target engine speed, and when the vehicle body stop operation is detected in the work driving mode, the target engine speed is changed. It is unique in that it is configured to automatically switch to road driving mode when the set is released.

[For production]

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.

In addition, if you operate the brake or main clutch to stop the vehicle during 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 let go of your foot, it will be in an idling state.

〔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 there is no need for a special accelerator adjustment tool for setting the accelerator especially 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 with a simple switch operation. Furthermore, when restarting the vehicle after an emergency stop during the working drive mode with high output set, the vehicle will start at rear idling unless the foot accelerator is intentionally depressed, and the vehicle can start safely.

〔Example〕

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

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), Live PTO independent of transmission system
A rotary rotary is an example of a working device in which working power is branched and transmitted to the rear PTO shaft (7) via a transmission system, and is connected to the rear of the vehicle body by a hydraulic lift arm (8) and a three-point link mechanism (9) so that it can be raised and lowered. The tilling device (10) is the PTO
It is designed to be driven by the output from the shaft (7).

A control rack (12), which is a fuel injection adjustment mechanism for a fuel injection pump (1)) installed in the engine (2), is controlled by an electronic governor.

That is, the control rack (12) is connected to a solenoid (13) that is displaced with a stroke proportional to the excitation current, and the position of the control rack (12) is continuously controlled by a stroke sensor (14) using a differential transformer. a coil sensor (17) that is detected by
The engine speed is detected by these sensors (1
4) The position of the control rank (12) is controlled based on the information from (17) and a separately artificially set accelerator setting value.

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 (1) is used as a manually operated accelerator adjustment device that can be depressed at will in the entire range from the idling position to the highest position, and that automatically returns to the idling position.
9), which is equipped with a rotary potentiometer (20) which 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, in the torque curve shown in FIG. 3, the relationship between the engine speed and the control rank position (torque) is stored in advance as map data for each accelerator setting value, and the potentiometer (
The map control system (21) determines the target rank position (P+) for the detected engine speed based on the map data corresponding to the accelerator setting value obtained from step 20), and the detected rank position moves toward this target rack position (PI). The solenoid (13) is controlled by the PI port.

Further, in the mode using the governor characteristics for work travel, PIG rotation speed control is performed. In other words, the detected engine rotation speed can be stored and set in the memory system (23) operated by the mode changeover switch (22) consisting of a restoration type push button switch, and the engine speed at that time can be set by operating the switch (22). The engine speed is memorized and inputted to the PID engine speed control system (24) as a target engine speed, and the PID engine speed control system (24) sets the target engine speed so that there is no difference between the target engine speed and the detected engine speed. The rack position (P2) is determined, and the solenoid (13) is PID-controlled so that the detected rank position approaches the target rack position (P2).

Next, the control mode switching operation will be explained.

Switching between the road driving mode and the work driving mode is performed using the DiJ 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, ) or (P2) 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 is set is brought about. Therefore, if the vehicle is to be driven on the road immediately after starting the engine, the rack position control will 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, depress the foot accelerator pedal (19), confirm with the travel speedometer or engine tachometer that the desired engine speed has been reached, and then press the switch (22).

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.
A corresponding target rack position (P2) is given from the PID rotation speed control system (24).

At this point, if you take your foot off the accelerator pedal (19) and return it to the idling position, the target rack position (P+) from the map control system (21) will change to the PID rotation speed control system (2
4) is smaller than the target rank position (P2) from
In the discrimination selection system (25), the basic target position (P2
) is selected and the work driving mode is maintained thereafter.

To return from the work driving mode to the road driving mode, simply press the switch (22) to clear the memory system (23), and by this operation the target engine speed setting is canceled and the PID speed control system ( 24) will no longer output. Therefore, from then on, control is performed based on the target rack position (Pl) from the map control system (21), that is, control in the road driving mode.

In addition, in the present invention, the following two types of forms (A) are further provided.
, (B) is also configured to switch from the work driving mode to the road driving mode.

(A): When the comparison system (26) determines that the target rack position (PI) from the map control system (21) is larger than the target rack position (P2) from the PID rotation speed control system (24). , a memory release command is issued to the memory system (23), and the output from the PID rotation speed control system (24) disappears. Therefore, during work driving, the foot accelerator pedal (19)
When the accelerator is stepped up to exceed the target engine speed, the MAP control system (21)
Governor control will be performed in the road driving mode based on the target rack position (PI) from .

(B): As shown in Figure 6, the output from the engine (2) is transmitted to the gear transmission mechanism (31) via the main clutch (30).
After the input is input to the left and right differential wheels (33a) and (33b) of the differential mechanism (32) and the gears are changed appropriately, the rear wheel (5) is
, (5), and each differential shaft (33a), (
33b) is equipped with an internal expansion type or disc type brake (33b).
4a).

(34b) is provided. A switch detects depression of the main clutch pedal (35) and brake pedals (36a), (36b) mechanically linked to the main clutch (30) and each brake (34a), (34b). (37) and (38a),
(38b) is deployed, all switches (37),
(38a).

(38b) is operated to close the memory system (23).
A memory cancellation command can be given to the user. Therefore, when the main clutch (30) is disengaged and both brakes (34a) and (34b) are activated to stop the vehicle during the work drive mode, the mode is automatically switched to the road drive mode.

However, even in the work drive mode, the main clutch (31
)), gear change, and one brake (3)
4a) or (34b) is activated to make a sharp turn, mode switching is not performed.

In addition, minimum rack position control and maximum rack position control are also performed to prevent engine stop and overspeed. In other words, in the discrimination selection system (25), the target rank position (P
+), (pz) and the lowest rack position (P3) set based on the detected engine speed, and the largest one of them is selected as the target rack position (P4). In addition, the maximum rack position (P,) set based on the target rank position (P4) selected by the discrimination selection system (25) and the detected engine rotation speed as described above is determined by the second discrimination system (25).
7), and the smaller one of them is selected as the final target rack position (Po) and given to the PI rack position control system (28), and in this way the rack position is changed to the lowest rack position (P,). Below and maximum rack position (P,
) is prevented from being operated beyond this point, thereby preventing the engine from stalling and over-revving.

[Another example]

■ The rank position control form in the road driving mode and the work driving mode is not limited to the above, but the control form in the road driving mode can be map control, and the control form in the working driving mode can be corrected according to the load. It is also possible to use map control. Also, both modes are PID control or PI
Control is also possible.

(2) A DC electric motor (with a speed reducer) may be used instead of the solenoid (13) that drives the control rack (12).

■ It would be convenient to selectively light up mode indicator lamps, etc. in response to switching of control modes.

■ It is very clever because it only detects brake operation when the vehicle is stopped.

■ For work vehicles, such as combine harvesters, where 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 the actual details of the governor device for a working vehicle according to the present invention, FIG. figure,
FIG. 4 is a characteristic diagram of the governor in the working driving mode, FIG. 5 is an overall 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 controlled by an electric actuator ( 13), and a road driving mode in which fuel is controlled using governor characteristics set to a torque curve with a small torque fluctuation rate with respect to engine speed fluctuations, and a torque curve with a large torque fluctuation rate with engine speed fluctuations. A control circuit (18) is configured to set a work driving mode in which the fuel is controlled according to the governor characteristics set in the control circuit (18), and both modes are selectable by a switch (22). A foot accelerator pedal (19) is provided to be reset, and when the mode changeover switch (22) switches from the road driving mode to the work driving mode, the detected engine speed at the time of switching is set and fixed at the target engine speed. In addition, the vehicle is configured to sense that a vehicle body stop operation is performed in the work drive mode, release the set fixation of the engine speed, and automatically switch the governor control mode to the road drive mode. Governor device for work vehicles. [2] The governor device for a work vehicle according to claim (1), which is configured to sense a brake operation as an operation to stop the vehicle body. [3] The 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.