JP3043356B2 - Governor control device for work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotational speed detecting means for detecting an engine rotational speed of an on-board diesel engine, a rotational speed setting means for setting a target engine rotational speed, and the diesel engine. Injection amount adjusting means for adjusting the fuel injection amount, an actuator for adjusting and operating the injection amount adjusting means, and a target set by the engine speed setting means based on the information of the engine speed detecting means. And control means for controlling the operation of the actuator to maintain the engine speed.

[Conventional technology]

The governor control device for a working vehicle having the above configuration is used for a working vehicle such as an agricultural tractor. In this type of work vehicle, the engine speed detected by the rotation speed detecting means is set by the accelerator setting by the rotation speed setting means while the accelerator setting value for changing and setting the engine output is fixed at a constant value. The fuel injection amount of the diesel engine is adjusted by controlling the operation of the actuator so that the target engine speed set in accordance with the value is obtained.

In such a work vehicle, when the traveling braking device is operated in the braking operation state, a new load is applied to the diesel engine, which causes a decrease in the engine speed. Here, in the conventional governor control device, the control means increases the torque by adjusting the injection amount adjusting means to increase the fuel injection amount, and maintains the engine speed at the rotation speed set by the rotation speed setting means. try to.

[Problems to be solved by the invention]

Normally, the purpose of putting the travel braking device in the braking operation state is to reduce or stop the speed of the work vehicle. However, if the fuel injection amount is increased to maintain the engine speed, the fuel is wasted as a result. Another disadvantage is that the braking force of the traveling braking device is offset.

An object of the present invention is to suppress wasteful consumption of fuel in a braking operation state of a traveling braking device.

[Means for solving the problem]

In the governor device for a work vehicle according to the present invention, braking detection means for detecting whether the traveling braking device is in a braking operation state or a non-braking operation state is provided, and the control unit includes a control unit that controls the braking detection unit to perform the braking operation. The first characteristic configuration is such that when the operation state is detected, a reduction control for reducing the engine speed of the diesel engine is performed.

The control means sets, as the reduction control, a maximum adjustment value of the fuel injection amount, which is set according to the engine speed detected by the speed detection means, when the braking operation state is the non-braking operation. The second characteristic configuration is that the configuration is changed so as to be lower than the state.

A third point is that the control means is configured to set a maximum adjustment value of the fuel injection amount in the braking state based on a fuel injection amount immediately before being operated to a braking operation state.
It has a feature configuration.

A fourth characteristic configuration is that the control means is configured to gradually increase the maximum adjustment value of the fuel injection amount as the operation is performed from the braking operation state to the non-braking operation state. I have.

[Action]

In the first characteristic configuration, when the braking detection unit detects the braking operation state, the control unit performs a reduction control for reducing the engine rotation speed of the diesel engine, and the engine rotation speed becomes the braking operation state. It will be reduced accordingly.

In the second feature configuration, as the reduction control in the first feature configuration, the maximum adjustment value of the fuel injection amount, which is set in accordance with the engine speed detected by the rotation speed detection means, is smaller in the braking operation state. Change so as to be lower than the braking operation state. That is, when the travel braking device is operated in the braking operation state, the fuel injection amount cannot be increased by limiting the maximum fuel injection amount to a low value, and as a result, the engine speed is reduced. is there.

In the third characteristic configuration, the way of setting the maximum adjustment value of the fuel injection amount in the braking operation state in the second characteristic configuration is set. When the travel braking device is operated in the braking operation state, the maximum adjustment value of the fuel injection amount is set based on the immediately preceding fuel injection amount.

According to a fourth feature configuration, in the second or third feature configuration, when the traveling braking device is operated from the braking operation state to the non-braking operation state, that is, when the braking force serving as a load is not applied, the fuel is accordingly increased. The maximum adjustment value of the injection amount will gradually increase.

〔The invention's effect〕

According to the first characteristic configuration, when the braking operation state of the travel braking device is detected, the engine speed is reduced. Therefore, compared to the conventional configuration in which the engine speed is maintained at the current speed, the fuel consumption is reduced. Useless consumption can be suppressed.

According to the second characteristic configuration, in addition to the effect of the first characteristic configuration, the fuel injection amount, that is, the torque is reliably suppressed from increasing more than necessary, and the braking force is improved, so that the deceleration and the stop are performed quickly. Will be able to do it.

According to the third feature configuration, in addition to the effect of the second feature configuration, even if the fuel injection amount is adjusted by the injection amount adjusting means immediately before the travel braking device enters the braking operation state, the adjustment value is obtained. , The maximum adjustment value of the fuel injection amount is set to an appropriate value, so that the vehicle can be quickly decelerated or stopped at any engine speed.

According to the fourth feature configuration, in addition to the effect of the second or third feature configuration, it is possible to prevent the engine speed from increasing rapidly when the engine speed returns to the set speed.

〔Example〕

Hereinafter, a case where the present invention is applied to control of a diesel engine mounted on a tractor will be described as an example.

As shown in FIG. 1, the diesel engine (E)
By changing and adjusting the position of a control rack (2) (corresponding to fuel injection amount adjusting means) for adjusting the fuel injection amount of the fuel injection pump (1), the output rotation speed is changed and adjusted. I have.

The control rack (2) is connected to a solenoid (3) as an actuator whose position is displaced by a stroke proportional to the exciting current, and further urged by a return spring (4) to push back in the fuel injection decreasing direction. . This rack position is detected from the AC voltage induced in the secondary coil of the operation transformer (3A) built 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 of the rack position and the engine speed is converted into a voltage output together with the information of the speed setting device (9) and input to the control device (8). The control device (8) executes a calculation for correcting the 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 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 rack position is moved accordingly to change the fuel injection amount, thereby correcting the rotational deviation.

Although not described in detail, the rack position information is used for improving the responsiveness and safety of the solenoid (3).

As shown in FIG. 2, 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 are provided, and these left and right brake pedals (11L) and (11R) are provided. 11R) ON by each step
A pair of left and right switches (SWL) and (SWR) to be operated (both correspond to braking detection means) are provided. still,
When the left and right brake pedals (11L) and (11R) are connected by the connection fitting (12), by pressing one of them, both can be simultaneously depressed.

As shown in FIG. 3, the switches (SWL), (SWR)
Is connected in series with the control device (8) together with the brake lamp (13). Left and right brake pedals (11L), (11
When R) is simultaneously depressed to operate the pair of traveling braking devices in the braking operation state, the brake lamp (13) is turned on and a brake operation signal is output to the control device (8). The state of the braking action causes a load increase and a decrease in the engine speed. However, when the brake operation signal is input to the control device (8), the control device (8) is detected. The rack position is stored, and a solenoid drive signal is output within a range where the rack position does not move to the fuel injection increase side from that position. In other words, the fuel injection amount in the braking operation state is controlled so that it does not exceed the fuel injection amount immediately before the operation in the braking operation state even if it increases to the maximum level, for example.

When any of the left and right brake pedals (11L) and (11R) is depressed and the travel braking device is operated in the non-braking operation state, the brake operation signal is not output to the control device (8). Although the non-braking operation state causes a reduction in load and an increase in engine speed, the control device (8) gradually increases the maximum adjustment value of the fuel injection amount.

The difference between the governor control device of the present invention and the conventional governor control device is that the governor control device according to the fourth embodiment shows the relationship between the engine speed and the fuel injection amount.
It becomes clear in the figure.

Now, it is assumed that the engine speed is maintained at the set speed with the fuel injection amount of the adjustment value smaller than the maximum adjustment value. In the governor control device of the related art, when the pair of left and right traveling braking devices are operated in the braking operation state, the fuel injection amount sharply increases in an attempt to maintain the engine speed at the set speed. After reaching the maximum adjustment value set according to the engine speed detected by the rotation speed sensor (7) as shown by the solid line in FIG. 4, the fuel injection amount is limited to the maximum adjustment value or less. Therefore, until the operation is performed in the non-braking operation state, the engine speed is reduced by limiting the fuel injection amount to the maximum adjustment value or less. Then, when operated in the non-braking operation state, the engine speed is increased while limiting the fuel injection amount to the maximum adjustment value or less, and when the set speed is reached, the fuel injection amount is returned to the original fuel injection amount. That is,
When the engine speed decreases due to the generation of the braking force or the engine speed increases due to the disappearance of the braking force,
The torque is kept below the maximum torque as specified. By the way, the fuel injection amount on the graph of FIG.
Point → point b → point a.

However, in the governor device of the present embodiment, the control device 8
When the pair of left and right traveling braking devices are brought into a braking operation state, a reduction control for reducing the engine speed is performed. That is, the reduction control is configured to change the maximum adjustment value of the fuel injection amount so that the braking operation state is lower than the non-braking operation state.

Specifically, after limiting the maximum adjustment value of the fuel injection amount in the braking operation state to the fuel injection amount immediately before being operated in the braking operation state, the fuel injection amount is set to the maximum adjustment value or less. The engine speed is reduced while maintaining it.

Explaining with reference to the graph of FIG. 4, the maximum adjustment value of the fuel injection amount in the non-braking operation state set according to the engine speed is a characteristic indicated by a solid line in FIG. The state immediately before the braking operation is point "a" in the figure, and when the state becomes the braking operation state, the amount of fuel injection at the point "a" is limited as the maximum adjustment value, so that the state becomes the braking operation state. Until the vehicle is operated to the non-braking operation state, the engine speed will eventually decrease while following the line a → d in FIG.

When operated in the non-braking operation state, the limited maximum adjustment value is gradually increased, and the engine speed is accordingly increased. When the engine speed reaches the set speed, the limitation of the maximum adjustment value is released. In other words, when the engine speed increases due to the disappearance of the braking force, initially the fuel injection amount immediately before the operation to the braking operation state becomes the maximum, but the maximum adjustment value gradually increases with time, so the fuel The adjustment value of the injection amount will gradually increase.

(Another embodiment)

In the above embodiment, when the travel braking device is operated in the braking operation state, the fuel injection amount immediately before the operation is set to the maximum adjustment value. However, as shown in the graph of FIG. It may be limited as the maximum adjustment value,
As shown in the graph of the figure, a fuel injection amount smaller than immediately before the operation may be limited as the maximum adjustment value. In these cases,
On the graph, all the points follow point a → point b → point c → point b → point a. Furthermore, the limited maximum adjustment value may be reduced as the engine speed decreases.

Further, a predetermined value may be set as the maximum adjustment value in the braking state.

An operation circuit as shown in FIG. 7 may be configured by adding _two relays (L ₁ ) and (L ₂ ) to the operation circuit of the switches (SWL) and (SWR). In this circuit, the switch (SWL),
The brake operation signal when (SWR) is turned on is sent to the control device (8) separately for left and right, and when turned on simultaneously, the brake lamp (13) is lit. Note that the present invention can of course be applied to a work vehicle provided with one traveling brake device operated by one pedal.

The specific configuration of each part such as the type of the engine (E) to be controlled and the actuator for changing the rotation speed can be variously changed. Further, the control means may be configured using a microcomputer.

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]

The drawings show an embodiment of a governor control device for a working vehicle according to the present invention. FIG. 1 is a diagram showing the entire configuration of a governor device, FIG. 2 is a perspective view of a brake pedal, and FIG. FIG. 4 is a graph showing the relationship between the engine speed and the fuel injection amount. FIGS. 5 and 6 are graphs showing the relationship between the engine speed and the fuel injection amount in another embodiment, and FIG. 7 is a circuit diagram of a switch in another embodiment. (E) …… Diesel engine, (SWL), (SWR) ……
Braking detection means (2) ... injection amount adjustment means (3) ...
Actuator, (7) ... rotation speed detecting means, (8) ...
... control means, (9) ... rotation speed setting means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 1/08 F02D 41/38 F02D 1/02 F02D 29/02

Claims (4)

(57) [Claims] A speed detecting means for detecting an engine speed of the on-board diesel engine; a speed setting means for setting a target engine speed; Injection amount adjusting means (2) for adjusting the fuel injection amount, an actuator (3) for adjusting and operating the injection amount adjusting means (2), and the engine speed based on information from the speed detecting means (7). Control means (8) for controlling the operation of the actuator (2) so as to maintain the target engine speed set by the speed setting means (9). Brake detecting means (SWL) and (SWR) for detecting whether the traveling braking device is in a braking operation state or a non-braking operation state are provided. The control means (8) includes the braking detection means (SWL), (S
A working vehicle governor control device configured to perform a reduction control to reduce an engine speed of the diesel engine (WR) when the WR) detects the braking operation state. 2. The work vehicle governor control device according to claim 1, wherein said control means controls said engine speed detected by said speed detection means as said reduction control. A governor control device for a work vehicle configured to change a maximum adjustment value of the fuel injection amount, which is set accordingly, so that the braking operation state is lower than the non-braking operation state. 3. The governor control device for a working vehicle according to claim 2, wherein said control means (8) operates the maximum adjustment value of said fuel injection amount in said braking operation state to a braking operation state. A governor control device for a working vehicle configured to set based on a fuel injection amount immediately before the operation. 4. The governor control device for a working vehicle according to claim 2, wherein the control means (8) is operated from the braking operation state to the non-braking operation state. A governor control device for a work vehicle configured to gradually increase a maximum adjustment value of a fuel injection amount.