JP2858878B2 - Governor control device for work vehicles - Google Patents

Description

The present invention relates to a rotational speed detecting means for detecting an engine rotational speed of an onboard diesel engine, an injection amount adjusting means for adjusting a fuel injection amount, and the fuel injection amount. Limit setting means for setting an adjustment limit for increasing the engine speed in association with the engine speed, braking detection means for detecting that the traveling braking means has been operated to a braking operation state, and information on the rotation speed detection means. And control means for adjusting the injection amount adjusting means within the adjustment limit set by the adjustment limit setting means, based on the control of the vehicle. The present invention relates to a governor control device for a work vehicle configured to adjust the adjustment limit setting means to a decrease side when the state is detected as compared with the non-braking operation state.

[Conventional technology]

In the governor control device for a work vehicle, when the load of the diesel engine increases, the control means adjusts the injection amount adjusting means to the increasing side within the adjustment limit set by the adjustment limit setting means to increase the torque, It is possible to prevent the number of revolutions from greatly decreasing due to an increase in load.

However, when the traveling braking means is operated in the braking operation state during traveling, if the injection amount adjusting means is adjusted to the increasing side as the load of the diesel engine increases beyond the braking force, the braking force is increased by an amount corresponding to the increase in the torque. Will be offset.

Therefore, the present applicant proposes that, when the braking detection means for detecting that the traveling braking means has been operated to the braking action state detects the braking action state, the control means sets the adjustment limit setting means to a higher value than in the non-braking action state. Also, a configuration was proposed in which the torque was adjusted to the decreasing side to suppress the increase in torque.

[Problems to be solved by the invention]

By the way, in addition to working while the work vehicle is traveling, there are also cases where stationary work is performed after moving to the destination.
That is, the stationary work is performed by transmitting the power of the diesel engine only to the working device without transmitting it to the traveling system.

In the stationary work described above, even if the traveling braking means is erroneously operated to the braking operation state, the load on the diesel engine is not affected at all. Nevertheless, if the braking detection means detects the operation erroneously, the control means adjusts the adjustment limit setting means to a lower side than in the non-braking operation state. As a result, the adjustment limit for increasing the fuel injection amount is unnecessarily reduced, and in a case where the load on the diesel engine suddenly increases, a sudden decrease in engine speed or engine stall is caused. There was a fear.

The present invention has been made in view of such a situation, and an object of the present invention is to prevent a trouble such as a sudden decrease in engine speed or engine stall even if the traveling braking means is erroneously operated during stationary work. Is to do so.

[Means for solving the problem]

The feature configuration of the governor control device for a work vehicle according to the present invention is as follows.
Stop detection means for detecting a traveling stop state is provided, and the control means is configured not to execute adjustment to the decreasing side of the adjustment limit setting means when the stop detection means detects the traveling stop state. There is in the point.

(Operation)

The control means reduces the traveling speed when the braking detection means detects an operation of the traveling braking means to the braking operation state in a state where the stop detection means detects that the traveling is not stopped. Consider the correct operation of. Then, the adjustment limit setting means performs the adjustment toward the decreasing side to suppress an increase in torque in response to an increase in load due to braking. If the stop detecting means detects that the traveling stop state is detected and the brake detecting means detects the operation of the traveling brake means to the braking operation state, it is regarded as an erroneous operation. Then, the adjustment limit setting means does not execute the adjustment to the decreasing side.

〔The invention's effect〕

Even if the travel braking means is erroneously operated to the braking operation state in the stationary work, the adjustment limit setting means is not adjusted to the decreasing side, so even if the load of the diesel engine suddenly increases, the engine speed is not increased. The occurrence of troubles such as a sudden decrease or engine stall can be prevented as much as possible.

〔Example〕

Hereinafter, the present invention will be described with reference to the drawings, taking as an example a case where the present invention is implemented in a tractor which is an example of a work vehicle.

As shown in FIG. 1, by changing and adjusting the position of a control rack (2) (corresponding to a fuel injection amount adjusting means) for adjusting the fuel injection amount of the fuel injection pump (1), a diesel engine (E) is obtained. A tractor governor control device for changing and adjusting the rotation speed of the tractor is constituted.

The control rack (2) is connected to a solenoid (3) whose position is displaced with a stroke proportional to the exciting current, and further urged by a return spring (4) to push it back in the fuel-free direction. A detecting means (3A) for detecting the rack position is provided so as to detect the rack position from an AC voltage induced in a secondary coil of an operation transformer incorporated in the solenoid (3).

A ring gear (6) for a cell starter is fixedly mounted on a crankshaft (5) of the diesel engine (E), and is a magnetic type as an engine speed detecting means for detecting a tooth portion of the ring gear (6). A rotation speed sensor (7) is provided. From the rotation speed sensor (7), a pulse train proportional to the engine rotation speed is output using an electromagnetic pickup.

The information on the rack position and the engine speed is converted into a voltage output together with information on a speed setting device (9) (specifically, a hand accelerator lever corresponds to this) and input to the control device (8). . The control device (8) executes a calculation for obtaining a deviation between the set rotation speed and the actual rotation speed from the information of the rotation speed sensor (7), further performs necessary amplification and the like, and outputs it as a solenoid drive signal. And solenoid (3)
The drive current is increased or decreased in accordance with the drive signal output from the control device (8), and the control rack (2) is moved accordingly to change the fuel injection amount, thereby correcting the rotational deviation.

The control device (8) includes an adjustment limit setting unit (10) that sets an adjustment limit for increasing the fuel injection amount on the basis of the target rotation speed set by the rotation speed setting unit (9). ing. As shown in FIG. 2, the adjustment limit setting section (10) always sets the adjustment limit to a constant value if the engine speed is the target speed set by the speed setting device (9). Between this target engine speed and the engine speed lower than the set value, the engine speed is gradually increased as the engine speed becomes lower, and at the engine speed even lower than the lower engine speed, the maximum adjustment value is reached. Acts to set the pattern to keep.

As shown in FIG. 3, a pair of left and right brake pedals (11L) and (11R) for operating a pair of left and right traveling braking devices (not shown) of the tractor is provided. When the left and right brake pedals (11L) and (11R) are connected by the connection fitting (12), both of them can be depressed simultaneously by depressing one of them. Left and right brake pedals (11L),
The arm (13) is pivotally supported on the middle support shaft portion (15) of the (11R) while being urged to swing toward the stepping side. The arm (13) has a left and right side portion on its free end side so that it wraps over the upper portions of the left and right brake pedals (11L) and (11R).
It is formed in the shape of a letter. Above the arm (13), a switch (SW) (corresponding to braking detection means) for detecting depression is provided in a state of contacting the free end.

When the left and right brake pedals (11L) and (11R) are simultaneously depressed to operate the pair of left and right traveling braking devices in a braking operation state, the arm (13) also swings to the depressed side and the switch (SW) is switched. The contact state is eliminated. Switch (SW)
Is communicated to the control device (8), and when the contact with the arm (13) is released, the brake operation signal is transmitted to the control device (8).
Output to

Further, a vehicle speed sensor (14) (stop detecting means) for detecting the rotational speed of the driving force transmitted to the traveling system of the tractor is provided. The vehicle speed sensor (14) is connected to a control device (8), and information on the detected rotation speed is converted into a voltage output and output to the control device (8).

When the brake operation signal is input in a state where the vehicle speed is not 0, that is, in a state where the work vehicle is traveling, the control device (8) changes the maximum adjustment value of the fuel injection amount to the non-braking state. A solenoid drive signal is output so that the rack is moved within the range of the maximum adjustment value in the operating state. In this way, by preventing the fuel injection amount from increasing and the shaft torque from increasing, the braking force by the traveling braking device is prevented from being offset.

Explaining this with the graph of FIG. 2, when the engine speed decreases due to an increase in load independent of the braking force,
The maximum adjustment value of the fuel injection amount follows a path of a → b → c, but when the engine speed decreases due to an increase in the load due to the braking force, the maximum adjustment value of the fuel injection amount is a
→ The path d will be followed.

Next, when the stationary operation is performed by stopping the tractor, the traveling wheels (not shown) are supplied from the diesel engine (E).
After the power transmission to the working unit is stopped by controlling the movement of the control rack (2) so as to maintain the engine speed at the target speed in the same manner as described above, (Not shown).

In such stationary work, since the transmission from the diesel engine (E) to the traveling wheels is cut off, the braking force by the traveling braking device does not affect the load on the diesel engine (E). It is not necessary to limit the maximum adjustment value of the fuel injection amount to a low value as described above. In addition, limiting the maximum adjustment value of the fuel injection amount to a low value is not preferable because, when the load on the working device is rapidly increased, the torque is insufficiently increased, and the rotation speed may be reduced or engine stall may occur. .

Therefore, when detecting the state where the vehicle speed is 0, that is, the state where the tractor is performing stationary work, the control device (8)
Even if a brake operation signal is input, the maximum adjustment value of the fuel injection amount is not restricted so as to prevent the maximum torque from decreasing.

(Another embodiment)

The stop detecting means may detect a neutral position of the shift lever, a disengagement operation of the traveling clutch, or may detect a stop of a transmission shaft or a gear of the traveling transmission.

The present invention can be applied to various work vehicles other than the tractor.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of the drawings]

Drawings show an embodiment of a governor control device for a work vehicle according to the present invention, FIG. 1 is a diagram showing an overall configuration of a governor control device, and FIG. 2 is a graph showing a relationship between an engine speed and a fuel injection amount. . FIG. 3 is a perspective view of the brake pedal. (E) ... diesel engine, (SW) ... braking detection means, (2) ... injection amount adjustment means, (7) ... rotation speed detection means, (8) ... control means, (9) ... Rotation speed setting means, (10) adjustment limit setting means, (14) stop detection means.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-264746 (JP, A) JP-A-63-150446 (JP, A) JP-A-61-142339 (JP, A) JP-A-62 63149 (JP, A) Japanese Utility Model 2-40946 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F02D 41/00-41/40 F02D 29/02 321

Claims (1)

(57) [Claims] 1. A rotational speed detecting means (7) for detecting an engine rotational speed of an onboard diesel engine (E), an injection amount adjusting means (2) for adjusting a fuel injection amount, and a fuel injection amount increasing side. Adjustment limit setting means (10) for setting the adjustment limit of the engine in relation to the engine speed, braking detection means (SW) for detecting that the travel braking means has been operated to a braking operation state, and rotation speed detection means Control means (8) for adjusting the injection amount adjusting means (2) within the adjustment limit set by the adjustment limit setting means (10) based on the information of (7), and the control thereof; Means (8)
The work is configured such that, when the braking detection means (SW) detects the braking operation state of the traveling braking means, the adjustment limit setting means (10) is adjusted to a lower side than in the non-braking operation state. A governor control device for a vehicle, comprising: stop detection means (14) for detecting a traveling stop state, wherein the control means (8) controls a state in which the stop detection means (14) detects a traveling stop state. Thus, there is provided a governor control device for a working vehicle which is configured not to execute the adjustment to the decreasing side of the adjustment limit setting means (10).