JPH0551056B2 - - 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 working 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 adopted for 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 automobiles that require acceleration and deceleration performance.

[Problem that the invention seeks to solve]

Incidentally, in recent years, there has been a strong trend toward faster speeds for the above-mentioned agricultural work vehicles due to improvements in work efficiency and mobility, and they are fully capable of handling not only work in fields but also high-speed transportation work on roads. It's starting to look like this.

However, as mentioned above, the governor installed on the engine of agricultural work vehicles is an all-speed governor that is suitable for the main work in the field, so the sense of acceleration and deceleration when driving on the road is poor. (Drivability) was not good.

This invention solves the above problem by adopting a so-called electronically controlled governor in which the injection amount adjustment mechanism is controlled by an electric actuator, and by making it possible to utilize two types of governor characteristics suitable for work driving and road driving. At the same time, 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. The control circuit can be set to a road driving mode in which the fuel is controlled using the governor characteristics set in the torque curve, and a work driving mode in which the fuel is controlled using the governor characteristics set in the torque curve where the torque fluctuation rate is large with respect to engine speed fluctuations. It is configured to be able to switch between both modes, and is equipped with means for detecting vehicle running speed, so that when the vehicle is in a set high speed range, the governor is controlled in road running mode, and when it is not in the high speed range, the governor is automatically switched to work running mode. The configuration is such that the control mode can be switched.

[Effect]

Generally speaking, a mobile work vehicle travels at a low speed at a work site, and when traveling on the road, it often travels sufficiently faster than the work speed. Therefore,
It is possible to determine whether the vehicle is in a working state or on the road based on the speed of the vehicle during steady operation. In the present invention, the governor control mode is automatically switched based on this determination.

〔Effect of the invention〕

Therefore, simply by changing the speed of the vehicle, a control mode suitable for work driving and a control mode suitable for road driving are automatically provided, and a governor suitable for driving conditions can be created without any special mode switching operation. It became possible to drive with its characteristics.

In particular, since quick and smooth acceleration and deceleration in response to accelerator operation is required when driving on the road at high speeds, switching control modes based on travel speed can be said to be extremely rational.

〔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 3, where the main and sub gear transmission mechanism 26
a, 26b and the super reduction mechanism 26c, and then transmitted to the rear wheels 5, 5 via the differential mechanism 27, and the shifting power branched at the upper end of the differential mechanism 27 is transmitted to the rear wheels 5, 5 via the clutch 28. The signal is transmitted to the differential mechanism 29 of the forward wheels 6, 6. Further, a PTO-based gear change mechanism 30 is provided independently of the travel transmission system, and the output from this is taken out to the rear PTO shaft 7 as working power.

At the rear of the vehicle body, a rotary tiller 10, which is an example of a working device, is connected by a hydraulic lift arm 8 and a three-point link mechanism 9 so as to be movable up and down, and is 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 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, 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.

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 fluctuations in engine speed, as shown in Figure 4A, and is mainly used for work driving, and the characteristics of these two 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 travel, PID rotation speed control is performed so as to obtain the torque curve shown in FIG. 4A. 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. Determine position P ₂ and set the detection rack position to this target rack position.
The solenoid 13 is controlled by PID so that it approaches _P2 . In this case, switching between the road driving mode and the work driving mode is performed by the map control system 23 and
Each target rack position P ₁ from the PID rotation speed control system 24
or P ₂ by selecting with the selection system 25, and this selection control is performed as follows.

The main gear transmission mechanism 26a has three forward speeds _F1 to _F3.
The auxiliary gear transmission mechanism 26b is capable of shifting to 1 reverse gear R, and the auxiliary gear transmission mechanism 26b is capable of shifting to 2 high and low gears (HL), each of which is selected by the main gear shift lever 31 and the auxiliary gear shift lever 32. . In addition, super deceleration mechanism 2
6c is normally switched to "high speed" and is switched to "low speed" only when working at very low speed, such as when digging a deep trench.

The limit switch 33 is configured to detect that the sub-shift lever 32 is at the high speed H, and when the limit switch 33 detects the high speed H, the selection system 25 selects the map control system 2.
The target rack position _P1 from 3 is selected and applied to the PID rack position control system 34.
When 8 does not detect high speed H, selection system 25
The target rack position P ₂ from the PID rotation speed control system 24 is
is configured to select. In this case, the sub-shift lever 32 is generally switched to low speed L when the vehicle is traveling for work, and is switched to high speed H when traveling on the road at high speed. Therefore, when the sub-shift lever 32 is set to high speed H, the governor control is performed in the road driving mode, and at low speed L, the governor control is performed in the work driving mode.

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 35, 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 35 and the maximum rack position _P6 set based on the detected engine speed are compared in the second discrimination system 36, and the smaller one of them is The final target rack position _P0 is selected to prevent engine overrun.

[Another Embodiment] As shown in FIG. 8, limit switches 33a and 33b are provided to detect the high speed H of the auxiliary shift lever 32 and the third speed _F3 of the main shift lever 31, and both switches 33a and 33b operate the lever. The target rack position _P1 from the map control system 23 may be selected and switched to the road driving mode only when the vehicle is detected, that is, when the forward speed is the highest.

The sub-shift is high speed H and the main shift is 2nd speed F ₂ or 3
It may be possible to switch to road driving mode only when the vehicle is in one of the _F3 speeds.

If a continuously variable transmission (hydraulic or mechanical) is used as a travel transmission and the gear lever is operated in a straight line, a sliding contact type is used to indicate that the gear lever is in a high speed range above a specified level. It is preferable to detect it with a switch or a rotary potentiometer and switch to the road driving mode.

The rotating shaft of the wheel transmission system after the gear transmission mechanism is equipped with a rotational speed detection sensor to detect the actual traveling speed, and is configured to switch to road driving mode only when the actual traveling speed is in a high speed range above a predetermined speed. Good too.

The easy 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 is map control, and the control form in the work driving mode is corrected according to the load. It is also possible to use map control to obtain the torque curve shown in 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.
may also be used, and these are collectively referred to as actuators.

Acceleration adjustment can also be performed with a single adjustment device.

[Brief explanation of the drawing]

The drawings show an embodiment of the governor device for a traveling work vehicle according to the present invention, and FIG. 1 is a control block diagram, and FIG. 2 is a control block diagram.
Figure 3 is a configuration diagram of the governor device, Figure 3 is a governor characteristics diagram in road driving mode, Figure 4 A and B are governor characteristics diagrams in work driving mode, Figure 5 is an overall side view of the agricultural tractor, and Figure 6 is a diagram of governor characteristics in road driving mode. A transmission system diagram, FIG. 7 is a schematic plan view of the traveling speed change operation section, and FIG. 8 is a schematic plan view showing another embodiment of the travel speed change operation section. 2... Engine, 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 to setting the torque curve to have a small rate of torque fluctuation relative to engine speed fluctuations, there is also a road driving mode where fuel is controlled using governor characteristics, and a torque curve that has a large torque fluctuation rate relative to engine speed fluctuations. The control circuit 18 is configured to set a work driving mode and a work driving mode in which the fuel is controlled using the governor characteristics to switch between the two modes, and is equipped with means for detecting vehicle running speed, so that when the vehicle is in a set high speed range, the road driving mode is set. 1. A governor device for a traveling work vehicle, which is configured to control a governor at a high speed and automatically switch a governor control mode to a work drive mode when the vehicle is not in the high speed range. 2 The means for detecting the vehicle running speed is the gear shift operation tool 3
2. The governor device for a traveling work vehicle according to claim 1, which detects the operating position of the vehicle. 3. The governor device for a traveling working vehicle according to claim 1, wherein the means for detecting the vehicle running speed directly detects the rotational speed of the traveling transmission shaft.