JPH0353128B2 - - 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 categorized by 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 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 agricultural work vehicles mentioned above, which require stable low-speed running and constant-speed drive of working equipment regardless of load fluctuations, and also provides smooth acceleration and deceleration in response to accelerator adjustment. The latter minimum/maximum speed governor is suitable for cars that require 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 actuator, and by making it possible to utilize two types of governor characteristics suitable for work driving and road driving. In addition, this mode switching can be performed automatically.

[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 actuator linked to a manually operated accelerator adjustment tool via a control circuit, and the torque fluctuation rate with respect to engine speed fluctuation is small. A road driving mode in which fuel is controlled by the governor characteristics set in the torque curve, and a work driving mode in which fuel is controlled by the governor characteristics set in the torque curve with a large torque fluctuation rate with respect to engine speed fluctuations are set in the control circuit. configured to be switchable, and
A working device is attached to the vehicle body so that the position or posture can be freely changed between a working state and a non-working state, and a means for detecting the position or posture of the working device is provided,
When a non-working state is detected, it switches to road driving mode, and
The device is characterized in that it is configured to automatically switch the governor control mode to the work travel mode when the work state is detected.

[Effect]

According to the above configuration, when the position or posture of the work device is set to the working state, the governor is automatically controlled in the work traveling mode, and when the work device is set to the non-working state, the governor is automatically switched to control in the road traveling mode.

〔Effect of the invention〕

Therefore, it is now possible to appropriately perform governor control in a control mode suitable for work driving and road driving without having to perform a special operation to switch the governor control mode.

〔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 single unit so as to be able to rise and lower by a hydraulic lift arm 8 and a three-point link mechanism 9. Said
It is designed to be driven by the output from the PTO shaft 7.

A control rack 12, which is a fuel injection amount adjusting 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 (an example of an actuator), the position of the control rack 12 is continuously detected by a stroke sensor 14 using a differential transformer, and is opposed to a gear 16 fixed to a camshaft 15 for driving the pump. The engine rotation speed is detected by the coil sensor 17, and these sensors 14, 1
Based on the information from 7 and the separately artificially set accelerator setting value, the control rack 1
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.

This electronic governor uses a hand accelerator lever 1 as a manually operated accelerator adjustment device that can be frictionally held at any operating position over the entire range from the idling position to the maximum speed position.
9 and a foot accelerator pedal 20 that automatically returns to the idling side, each of which is equipped with rotary potentiometers 21 and 22 that output 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 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 mode is automatically selected, and the following controls are 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 A map control system 23 determines a target rack position _P1 for the detected engine rotational speed based on map data corresponding to the value, and PID control is performed on 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, in this case, the accelerator set value given by the potentiometer 21 means the target rotation speed, and the PID rotation speed control system 24 sets the target speed so that there is no difference between the target rotation speed and the detected rotation speed. The solenoid 13 determines the position _P2 and moves the detection rack position closer to the target rack position _P2 .
is controlled by PID.

In this case, switching between the road driving mode and the work driving mode is achieved by selecting either of the target rack positions P ₁ or P ₂ from the map control system 23 and the PID rotation speed control system 24 using the selection system 25. This selection control is performed as follows.

In other words, the rotary tilling device (working device) 1
A rotary potentiometer 26 is installed at the fulcrum of the hydraulic lift arm 8 that raises and lowers the hydraulic lift arm ₈ to continuously detect the arm elevation angle. Standard value
It is compared with e ₀ in comparison system 28. This standard value e ₀ is
If the tilling device 10 is set to a value corresponding to an appropriate height (for example, near the upper limit) that is sufficiently higher than the normal tilling work level, and the tilling device 10 is in a range lower than this reference height, the tilling device 10 is in the working state. If the height is above the reference height, the comparison system 28 determines that it is in a non-working state, and based on the determination result, the selection system 25 selects the two-day mark rack position P ₁ or P ₂ .
In other words, in the working state, the target rack position _P2 is
If the rack is in a non-working state, the target rack position _P1 is selected and applied to the PID rack position control system 29.

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 lowest rack position P ₄ is set based on the target rack position P ₃ [P ₁ or P ₂ ] selected by the selection system 25 and the detected engine speed.
are compared in the discriminating system 30, and the largest one is selected as the target rack position _P5 to prevent the engine from stopping. Further, as mentioned above, the target rack position _P5 selected by the discrimination system 30 and the maximum rack position _P6 set based on the detected engine speed are compared in the second discrimination system 31, and the smaller one of them is The final target rack position _P0 is selected to prevent engine overrun.

The potentiometer 26 of the hydraulic lift arm 8 is used not only for switching the governor control mode but also for electrical position control of the lift arm 8.

That is, as shown in FIG. 6, the single-acting hydraulic cylinder 32 that drives the lift arm 8 includes a lifting solenoid valve 33a, a lifting pilot valve 33b,
Lowering solenoid valve 33c and lowering pilot valve 33
It is connected to a control valve 33 consisting of a solenoid valve 33a and 33c, and can be switched to three states: upward, downward, and neutral by controlling the energization of both electromagnetic valves 33a and 33c. The signal e ₂ from the rotary potentiometer 35 that detects the operating angle of the lift adjustment lever 34 provided at the operating part and the signal e ₁ from the lift arm angle detection potentiometer 26 are then compared to a comparison system 36 . The control valve 33 is operated and controlled so that the deviation between the two signals e ₁ and e ₂ is within a set range (dead zone).

That is, the tilling device 10 is controlled to rise and fall to the position set by the lift adjustment lever 34, and is held at that position.

Further, the comparison system 36 uses a detection signal _e3 from a traction load detection sensor (consisting of a differential transformer or the like) 37 provided at the base end of the three-point linkage mechanism 9 and a load setting device 38 which is arbitrarily adjusted manually. The control valve 33 is configured to compare the set signal e ₄ from the 3-point linkage mechanism 9 with a control command so that the deviation of both signals e ₃ and e ₄ is within the set range, and It is now possible to control the raising and lowering of the work equipment (draft control) so as to maintain the traction load within a set range when traveling with a tow type work equipment attached. However, this draft control is possible only in a range higher than the working device height set by position control.

[Another example]

Note that the rack position control form in the road driving mode and 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 perform additional map control (see Fig. 4B). Also, both modes are PID control or PI
Control is also possible.

Also, instead of the solenoid 13 that drives the control rack 12, a DC electric motor (with a speed reducer) is used.
may also be used, and these are collectively referred to as actuators.

Acceleration adjustment may be performed with a single adjustment device.

Further, in the case where electric position control is not performed, a limit switch acting on the lift arm 8 may be used to detect whether or not the working device 10 is within the working height range.

Furthermore, when the present invention is applied to a compine,
The working device 10 has a reaping section that can be raised and lowered, and in this case as well, the governor control mode is switched based on the detection of the height of the reaping section.

In addition, when applied to a transport vehicle equipped with a spraying device such as a boom sprayer, the position of the nozzle boom extended to the side of the vehicle body can be detected and the working status can be determined by detecting whether the nozzle boom is moving in or out of the vehicle body. Detects storage posture and determines non-working state.

[Brief explanation of drawings]

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 1 and 2 are governor characteristics diagrams in the work travel mode, Figure 5 is a side view of the entire agricultural tractor, and Figure 6 is a configuration diagram of the position control and draft control systems. 2...Engine, 10...Working device, 12...
fuel injection amount adjustment mechanism, 13...actuator,
18...Control circuit.

Claims (1)

[Scope of Claims] 1. An actuator 13 that links the fuel injection amount adjustment mechanism 12 of the mounted diesel engine 2 to a manually operated accelerator adjustment tool via a control circuit 18.
In addition, there is a road driving mode in which the fuel is controlled using the governor characteristics, which is set to a torque curve with a small rate of torque fluctuation relative to engine speed fluctuations, and a governor set to a torque curve with a large torque fluctuation rate relative to engine speed fluctuations. Control circuit 18 for work driving mode that controls fuel according to characteristics.
The working device 10 is configured such that it can be set to switch between both modes, and the working device 10 is attached to the vehicle body so that its position or posture can be freely changed between a working state and a non-working state, and the position or posture of this working device 10 is detected. A governor device for a working vehicle, comprising means for automatically switching a governor control mode to a road driving mode when a non-working state is detected, and to a working driving mode when a working state is detected. 2. The working device 10 is a ground-based working device connected to the vehicle body so as to be able to rise and fall freely, and the means for detecting the working/non-working state of the working device 10 detects the lifting position of the working device 10 with respect to the vehicle body, When the working device 10 is in a non-working state at a predetermined level or higher,
The governor device for a working vehicle according to claim 1, wherein the working state is determined when the working device 10 descends from a predetermined level.