JPH03264746A - Governor controller for work vehicle - Google Patents

Abstract

PURPOSE:To prevent waste consumption of fuel while increasing braking force by setting the maximum adjusting value of a fuel injection amount being based on a predetermined expression and adjusting the fuel injection amount so that it is prevented from not exceeding this maximum adjusting value, when braking operation of a running control device is detected. CONSTITUTION:A governor controller for a work vehicle adjusts a fuel injection amount by controlling a control rack 2, which is an injection amount adjusting means, through a control unit 8 in accordance with a deviation between output signals of a rotational speed detecting means 7 and a rotational speed setter 9. Here a maximum adjusting value Amex of the fuel injection amount in a braking condition is set being based on an expression Amax=Ao+alpha(Bo-Bn) in a manner wherein the maximum adjusting value of the fuel injection amount a braking time is decreased smaller than at non-braking time, by the control unit 8, when braking operation of a running control device is detected by a braking detecting switch SW. In the expression, symbols Ao, Bo and Bn are respectively a fuel injection amount operation enging speed just before the braking and a present engine speed.

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 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. 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;
The engine speed is maintained at the speed set by the speed setting means.

[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 and torque are increased to maintain the engine speed, the result is that the braking force of the travel braking system is canceled out 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 prevent fuel from being wasted.

[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 control fuel injection based on information from the brake detection means. In order to make the maximum adjustment value of the amount lower in the braking action state than in the non-braking action state,
The maximum adjustment value (A) of the fuel injection amount in the braking operation state
max) is set based on the following formula, which is the first characteristic configuration.

Amax = AD + α (Bn Bn) A0: Fuel injection amount immediately before being operated to the braking operation state Bn 2 Engine rotation speed immediately before being operated to the braking operation state B9: Current engine rotation speed α: Setting value (However, from 0 Furthermore, 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. 2
It has a characteristic configuration of.

[For production]

In the first characteristic configuration, when the braking detection means detects that the travel braking device is operated to the braking state, the control means adjusts the maximum adjustment value of the fuel injection amount by the injection amount adjustment means based on the above formula. The fuel injection amount is adjusted so as not to exceed this maximum adjustment value. In other words, when the travel brake system is operated to the braking state and the engine speed drops from the set speed, the maximum adjustment value corresponding to the reduced speed is calculated from the above formula, and the maximum adjustment value is not exceeded. This suppresses the increase in maximum torque. Note that since α is greater than 0, the lower the engine speed, the greater the maximum adjustment value and the greater the maximum torque.

In the second characteristic configuration, when the travel braking device is operated from the braking state to the non-braking state in the first characteristic configuration, that is, when the braking force as a load is no longer applied, the maximum fuel injection amount is adjusted accordingly. The adjustment value will gradually increase.

The engine speed will also increase toward the set speed.

〔Effect of the invention〕

With the first characteristic configuration, the maximum torque is limited to the necessary level when the travel brake system is in the braking state, so braking power is improved and deceleration and stopping can be performed quickly, while fuel is wasted. You will be able to prevent this from happening. Furthermore, since the maximum adjustment value increases in inverse proportion to the decrease in engine speed, this has the effect of suppressing the occurrence of an extreme drop in engine speed and engine stalling due to load.

The second characteristic configuration makes it possible to prevent the maximum torque from increasing rapidly when the engine speed returns to the set rotation 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 operated by changing the position of the control rack (2) (which is connected to the 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 no-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 fixed to the crankshaft (5) of the diesel engine (E), and a magnetic type as an engine rotation speed detection means acts on the teeth of the ring gear (6). A rotation speed sensor (7) is provided.The rotation speed sensor (7) outputs a pulse train proportional to the engine rotation speed using an electromagnetic pickup.

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 calculations 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 it as a solenoid drive signal. (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 accordingly moved to change the fuel injection amount and correct rotational deviation.

Although not described in detail, the rack position information is processed as fuel injection amount information and is used to improve the response and safety of the solenoid (3).

As shown in Figure 2, a pair of left and right brake pedals (
IIL) and (IIR) are provided. The left and right brake pedals (IIL) and (IIR) are connected to the connecting metal fittings (
12), when they are connected, by depressing one, you can depress both at the same time. The shaft part between the left and right brake pedals (IIL) and (IIR) (
12), an arm (13>) is pivotally supported in a state in which it is oscillated toward the depression side.The left and right sides of this arm (13) on the roadside side are connected to the left and right brake pedals (IIL).
, (IIR) is formed in a T-shape so as to wrap over the top of the (IIR). A switch (SW) for detecting depression (corresponding to braking detection means) is provided above the arm (13) so as to be in contact with the free end.

When the left and right brake pedals (IIL) and (IIR) are simultaneously depressed in order to operate the pair of left and right traveling brake devices into a braking state, the arm (13) also swings toward the depression side and engages with the switch (SW). The contact state is canceled. The switch (SW) is connected to the control device (8), and when the contact with the arm (13) is released, a brake operation signal is output to the control device (8).

The control device (8) is configured such that the brake operation signal is transmitted to the control device (8).
8), the maximum adjustment value of the fuel injection amount is limited to be lower than the maximum adjustment value in the non-braking operation state,
By outputting a solenoid drive signal to move the rack position within that range, the fuel injection amount and torque are prevented from increasing rapidly. In other words, the maximum adjustment value (Amax) of the fuel injection amount is calculated based on the following formula from the rack position information, the information of the rotation speed setting device (9), and the rotation speed sensor (7), and the fuel injection amount is determined. The solenoid drive signal is output within a range that does not exceed this maximum adjustment value.

Am a x ”” A o + α (BO-B, “) Ao
: Fuel injection amount immediately before being operated to the braking state Bn 2 Engine speed (set speed) just before being operated to the braking state B, , : Current engine speed α : Setting value (actual number from O Large) As can be seen from the above formula, the maximum adjustment value of the fuel injection amount (A□
X) increases linearly in proportion to the decrease in engine speed.

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. When the brake operation signal is no longer input, 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 from the graph of FIG. 3 showing 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 specified maximum adjustment value. When the non-braking state is operated, the engine speed increases while limiting the fuel injection amount to below the maximum adjustment value for the non-braking state, and when the set speed is reached, the original fuel injection amount is restored. decrease to. Incidentally, the fuel injection amount on the graph of FIG. 3 traces from point a to point b to point C.

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 is limited to below the maximum adjustment value calculated as described above in response to a decrease in the engine speed. do. When the brake is operated to the non-braking state, the limited maximum adjustment value is gradually increased. The restriction on the maximum adjustment value is lifted when the engine speed reaches the set speed or after a certain period of time has elapsed.

In other words, when the engine speed decreases due to the generation of braking force, the torque immediately before being operated to the non-braking state is set as the maximum torque, and as the engine speed decreases, the maximum torque increases linearly. When the engine speed increases due to the disappearance of the braking force, the torque initially becomes the maximum torque immediately before the braking operation is performed, but the maximum torque gradually increases as time passes. Incidentally, the fuel injection amount on the graph of FIG. 3 traces from point a to point d until the brake is operated to the non-braking state.

[Another example]

The set value α is not limited to a constant, but may be a functional expression that changes as the engine speed decreases. For example, the fourth
As shown in the figure, it may be increased or decreased as the engine speed decreases. In the figure, the solid line indicates the case where α is constant, the - dotted chain line indicates the case where α increases, and the two-dot chain line indicates the case where α decreases.

Furthermore, it goes without saying that the present invention can also be applied to a work vehicle with one travel braking device operated by one brake pedal.

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 work 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. 3 is a diagram showing the engine speed and fuel. It is a graph showing the relationship between injection amounts. FIG. 4 is a graph showing the relationship between engine speed and fuel injection amount in another embodiment. (E)・・・Diesel engine, (Si'l)
...braking detection means, (2) ... injection amount adjustment 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). This is a governor control device for a working vehicle, comprising a control means (8) for controlling the vehicle, and a brake detection means (SW) for detecting that the traveling brake device is operated to a braking state, and the control means (8) ) is configured to adjust the maximum adjustment value of the fuel injection amount in the braking state to be lower in the braking state than in the non-braking state based on the information of the braking detecting means (SW). The maximum adjustment value of the fuel injection amount (A_
m_a_x) is set based on the following formula. A_m_a_x=A_0+α(B_0-B_n)A_0
: Fuel injection amount B_0 immediately before being operated to the braking state: Engine speed B_n immediately before being operated to the braking state B_n: Current engine speed α: Set value (but greater than 0) 2. Claims 1. The governor control device for a work vehicle according to 1,
The control means (8) is configured to gradually increase the maximum adjustment value of the fuel injection amount as the brake is operated from the braking state to the non-braking state.