JPH03260338A - Governor controller of service car - Google Patents

Abstract

PURPOSE:To improve a braking force while reducing wasteful consumption of fuel by automatically altering the maximum adjusting value of fuel injection amount lower in braking than that in non-braking under the travel braking condition. CONSTITUTION:The rotational speed of an engine is detected by a sensor 7 opposed to a ring gear 6 secured fixedly to the crankshaft 5 of a Diesel engine E and it is set by a setter 9. On the other hand, the fuel injection amount of a fuel injection pump 1 is adjusted by a control rack 2 which is driven by a solenoid 3 against a return spring 4. The solenoid 3 is driven in control by a controller 8 in such a way that the detected value of the rotational speed of the engine becomes a set value. Thus, the travel braking condition is detected by respective switches SWL, SWR. The maximum adjusting amount of the fuel injection amount by the control rack 2 is automatically altered to be lower in the braking than that in the non-braking.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a rotation speed detection means for detecting the engine rotation speed of an installed diesel engine, a rotation speed setting means for setting the engine rotation speed, and a rotation speed detection means for detecting the engine rotation speed of an installed diesel engine. an injection amount adjusting means for adjusting the fuel injection amount of the engine; and adjusting the injection withstand amount adjusting means to maintain the engine speed at the rotation speed set by the rotation speed setting means based on information from the rotation speed detection means. The present invention relates to a governor control device for a work vehicle, including a control means for controlling the work vehicle.

[Conventional technology]

When the travel braking device is operated to a braking state, a new load is added to the diesel engine, which causes the engine speed to decrease. 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 rotation speed at the rotation speed set by the rotation speed setting means. try to.

[Problem to be solved by the invention]

Normally, the traveling brake system is put into the braking state to slow down or stop the work vehicle. However, if the fuel injection amount is increased to maintain the engine speed, the result is that the braking force of the travel braking device is offset and fuel is wasted.

An object of the present invention is to increase the braking force in the braking state of the travel braking device and at the same time to suppress wasteful consumption of fuel.

[Means to solve the problem]

In the governor control device for a work vehicle according to the present invention, a brake detection means is provided for detecting that the traveling brake device is operated to a braking state, and the control means is configured to detect the The first characteristic configuration is that the maximum adjustment value of the fuel injection amount is automatically changed so that it is lower in the braking state than in the non-braking state.

A second feature is that the control means is configured to set the maximum adjustment value of the fuel injection amount in the braking state based on the fuel injection amount immediately before the braking state is operated. It is configured.

A third characteristic configuration is that the control means is configured to gradually increase the maximum adjustment value of the fuel injection amount as the braking state is operated from the braking state to the non-braking state. There is.

[For production]

In the first characteristic configuration, when the braking detection means detects that the traveling brake system is operated to the braking state, the control means is configured to adjust the maximum adjustment value of the fuel injection amount in the braking state to the non-braking state. The injection amount of the injection amount adjusting means is limited so that it is lower than the maximum adjustment value of the fuel injection amount. In other words,
When the travel braking device is operated to a braking state, the maximum fuel injection amount is limited to a low value to suppress an unnecessary increase in maximum torque.

The second characteristic configuration specifies how to set the maximum adjustment value of the fuel injection amount in the braking operation state in the first characteristic configuration. When the travel brake system is operated to the braking state, the maximum adjustment value of the fuel injection amount is set based on the immediately previous fuel injection amount.

In the third characteristic configuration, in the first and second characteristic configurations,
When the travel braking device is operated from a braking state to a non-braking state, that is, when no braking force is applied as a load,
Accordingly, the maximum adjustment value of the fuel injection amount and the maximum torque will gradually increase.

〔Effect of the invention〕

With the first characteristic configuration, the maximum torque does not increase more than necessary when the travel brake system is in the braking state, so braking force is improved and deceleration and stopping can be performed quickly, while fuel is not wasted. It will be possible to suppress the

With the second characteristic configuration, no matter what fuel injection amount is adjusted by the injection amount adjustment means immediately before the travel braking device enters the braking state, the maximum adjustment value of the fuel injection amount is determined based on the adjustment value. Since the value is set to an appropriate value, the vehicle can be quickly decelerated or stopped no matter what engine speed the vehicle is running at.

With the third characteristic configuration, it is possible to prevent the engine speed from increasing rapidly when the engine speed returns to the set speed.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to the control of a diesel engine mounted on a tractor will be described below.

As shown in FIG. 1, the diesel engine (E) is equipped with a control rack (2) (corresponding to a fuel injection amount adjusting means) that adjusts the fuel injection amount of the fuel injection pump (1). It is configured to change and adjust its output rotational speed.

The control rack (2) is connected to a solenoid (3) whose position is displaced with a stroke proportional to the excitation current, and is further urged by a return spring (4) to push it back in the direction of decreasing fuel injection. This rack position is detected from the AC voltage induced in the secondary coil of the actuating transformer (3A) built into the solenoid (3).

A ring gear (6) for a cell starter is fixedly attached to the crankshaft (5) of the diesel engine (E), and a magnetic type engine speed detecting means acts on the teeth of the ring gear (6). A rotation speed sensor (7) is provided. This rotational speed sensor (7) uses an electromagnetic pickup to output a pulse train proportional to the engine rotational speed.

The information on the rack position and the engine speed is converted into a voltage output together with the information on the speed setting device (9) and input into the control device (8). The control device (8) executes a calculation to correct the deviation between the set rotation speed and the actual rotation speed based on the information from the rotation speed sensor (7), performs necessary amplification, and outputs the signal as a solenoid drive signal. The solenoid (3) increases or decreases the drive current according to the drive signal output from the control device (8), and accordingly moves the rack position to change the fuel injection amount and correct rotational deviation. There is.

Although not described in detail, the information on the rack position is used to improve the response of the solenoid (3) and safety.

As shown in Fig. 2, a pair of left and right brake pedals (
A pair of left and right switches (SW
L) and (SWR) (both correspond to braking detection means) are installed. In addition, the left and right brake pedals (II
When L) and (IIR) are connected by a connecting fitting (12), by depressing one, it becomes possible to depress both at the same time.

As shown in FIG. 3, the switch (SWL).

(SWR) is the control device (
8) is connected in series. Left and right brake pedals (
When the brake pedals IIL) and (IIR) are depressed at the same time and the pair of traveling brake devices are operated to a braking state, the brake lamp (13) lights up and a brake operation signal is output to the control device (8). Being in the braking state increases the load and causes the engine speed to decrease, but the control device (8) detects that the brake operation signal is input to the control device (8). The rack position is memorized and a solenoid drive signal is output within a range that does not move toward the fuel injection increasing side from that position.

In other words, the fuel injection amount in the braking state is controlled so as not to exceed the fuel injection amount immediately before the braking state is operated, even if it increases to the maximum level.

When either the left or right brake pedals (IIL) or (IIR) are no longer depressed and the travel braking device is operated to a non-braking state, the brake operation signal is sent to the control device (8).
) will no longer be output. Although the non-braking state causes the load to be reduced and the engine speed to increase, 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 becomes clear in FIG. 4, which shows the relationship between engine speed and fuel injection amount.

It is now assumed that the engine speed is maintained at the set rotation speed with a fuel injection amount that is an adjustment value that is smaller than the maximum adjustment value. In a conventional governor control device, when the pair of left and right travel brakes is operated to a braking state, the fuel injection amount rapidly increases and reaches the maximum adjustment value, and then the fuel injection amount increases until it is operated to a non-braking state. During this period, the engine speed is reduced while limiting the fuel injection amount to below the maximum adjustment value. When the engine is operated to a non-braking state, the engine speed is increased while limiting the fuel injection amount to below the maximum adjustment value, and when the set rotation speed is reached, the original fuel injection amount is restored. In other words, when the engine speed decreases due to the generation of braking force or increases due to the disappearance of the braking force, the torque is suppressed to below the maximum torque specified by the specification. By the way, the fourth
The fuel injection amount on the graph in the figure is point a → point b → point C → b
The path will be traced from point → point a.

However, in the governor control device of this embodiment, when the pair of left and right travel brake devices is operated to the braking state, the fuel injection amount immediately before the operation is limited to the maximum adjustment value, and then the fuel injection amount is adjusted to the maximum adjustment value. The engine speed is reduced while maintaining it below the adjustment value. When the brake is operated to a non-braking state, the limited maximum adjustment value is gradually increased, and the engine speed is increased accordingly.

When the engine speed reaches the set speed, the limit on the maximum adjustment value is lifted. That is, when the engine speed decreases due to the generation of braking force, the torque immediately before the non-braking state is operated becomes the maximum torque. When the engine speed increases due to the disappearance of the braking force, the torque immediately before the braking operation is performed becomes the maximum torque at first, but the maximum torque gradually increases as time passes. Incidentally, the fuel injection amount on the graph of FIG. 4 traces from point a to point b until the brake is operated to the non-braking state.

[Another example]

In the above embodiment, when the travel brake system is operated to the braking state, the fuel injection amount immediately before the operation is set as the maximum adjustment value, but as shown in the graph of FIG. It may be limited as the maximum adjustment value, or as shown in the graph of FIG. 6, the fuel injection amount may be limited as the maximum adjustment value, which is smaller than that immediately before the operation. In these cases, the graph traces point a → point b → point C → point d → point a. Furthermore, it may be provided that the maximum adjustment value that is limited decreases as the engine speed decreases.

Furthermore, a predetermined value may be used as the maximum adjustment value in the braking state.

2 in the operation circuit of the switches (SWL) and (SWR).
An operating circuit as shown in FIG. 7 may be constructed by adding relays (Ll) and (Ll). In this circuit, when the switches (SWL) and (SWR) are turned on, the brake operation signals are sent to the left and right control devices (8) separately.
If they are turned on at the same time, the brake lamp (13) lights up. It goes without saying that the present invention can also be applied to a work vehicle equipped with one travel braking device operated by one pedal.

The specific configuration of each part, such as the type of engine (B) to be controlled and the actuator for changing the rotation speed, can be changed in various ways.

Further, the control means may be configured using a microcomputer.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings by the reference numerals.

[Brief explanation of drawings]

The drawings show an embodiment of the governor control device for a working vehicle according to the present invention, FIG. 1 is a diagram showing the overall configuration of the governor device, FIG. 2 is a perspective view of the brake pedal, and FIG. The circuit diagram of the operating switch, FIG. 4, is a graph showing the relationship between engine speed and fuel injection amount. 5 and 6 are graphs showing the relationship between engine speed and 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 adjusting means, (7) ... Rotation speed detection means, (8) ... Control means, (9) ...
...Rotation speed setting means.

Claims (1)

[Claims] 1. A rotation speed detection means (7) for detecting the engine rotation speed of the installed diesel engine (E), a rotation speed setting means (9) for setting the engine rotation speed, and a rotation speed detection means (9) for setting the engine rotation speed; E) injection amount adjusting means (
2), and adjusting the injection amount adjusting means (2) to maintain the engine speed at the rotation speed set by the rotation speed setting means (9) based on information from the rotation speed detection means (7). A governor control device for a working vehicle is provided with a control means (8) for controlling the vehicle, and is provided with brake detection means (SWL) and (SWR) for detecting that the traveling brake device is operated to a braking state. The control means (8) includes the braking detection means (
A governor of a work vehicle configured to automatically change the maximum adjustment value of the fuel injection amount so that the maximum adjustment value of the fuel injection amount is lower in the braking state than in the non-braking state, based on information of SWL) and (SWR). Control device. 2. A governor control device for a working vehicle according to claim 1,
The control means (8) is configured to set the maximum adjustment value of the fuel injection amount in the braking state based on the fuel injection amount immediately before the braking state is operated. 3. The governor control device for a work vehicle according to claim 1 or 2, wherein the control means (8) adjusts the amount of fuel injection as the braking state is operated to the non-braking state. The maximum adjustment value is configured to increase gradually.