JP2815662B2 - 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 the engine rotational speed, and the diesel engine. An injection amount adjusting means for adjusting the fuel injection amount of the engine, and adjusting the injection amount adjusting means based on information from the rotation speed detecting means so as to maintain the engine speed at the rotation speed set by the rotation speed setting means. The present invention relates to a governor control device for a working vehicle, comprising:

[Conventional technology]

When the travel 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. In the conventional governor control device, the control means adjusts the injection amount adjusting means to increase the fuel injection amount to increase the torque, and tries to maintain the engine speed at the rotation speed set by the rotation speed setting means. I do.

[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 and the torque are increased so as to maintain the engine speed, the braking force of the traveling braking device is offset and the fuel is wasted. .

SUMMARY OF THE INVENTION It is an object of the present invention to increase a braking force in a braking operation state of a traveling braking device and to prevent fuel from being wasted.

[Means for solving the problem]

In the governor control device for a work vehicle according to the present invention, brake detection means for detecting that the travel braking device has been operated to a braking operation state is provided, and the control means performs 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 operation state than in the non-braking operation state, the maximum adjustment value (A _max ) of the fuel injection amount in the braking operation state is _calculated based on the following equation. The point configured as described is the first characteristic configuration.

A _max = A ₀ + α (B ₀ −B _n ) A ₀ : Fuel injection amount immediately before being operated in the braking operation state B ₀ : Engine speed immediately before being operated in the braking operation state B _n : Current engine rotation Number α: Set value (however, it is larger than 0) Further, the control means gradually increases the maximum adjustment value of the fuel injection amount as it is operated from the braking operation state to the non-braking operation state. The above configuration is a second characteristic configuration.

(Operation)

In the first characteristic configuration, when the braking detection unit detects that the travel braking device has been operated to the braking operation state, the control unit determines the maximum adjustment value of the fuel injection amount by the injection amount adjustment unit based on the above equation. The fuel injection amount is adjusted so as not to exceed the maximum adjustment value. That is, when the travel braking device is operated in the braking operation state and the engine speed decreases from the set speed, the maximum adjustment value corresponding to the reduced speed is obtained from the above equation, and the maximum adjustment value is not exceeded. This suppresses an increase in the maximum torque.
Since α is larger than 0, the maximum adjustment value increases and the maximum torque increases as the engine speed decreases.

In the second characteristic configuration, when the travel braking device is operated from the braking operation state to the non-braking operation state in the first characteristic configuration, that is, when the braking force acting as a load is not applied, the maximum fuel injection amount is accordingly increased. The adjustment value is gradually increased. The engine speed will also increase toward the set speed.

〔The invention's effect〕

According to the first characteristic configuration, the maximum torque is limited to a required level in the braking operation state of the traveling braking device, so that the braking force is improved, so that deceleration and stop can be performed quickly, and fuel is wastefully consumed. Can be suppressed. In addition, since the maximum adjustment value increases in inverse proportion to the decrease in the engine speed, there is also an effect of suppressing an extreme decrease in the engine speed and the occurrence of engine stall due to the load.

According to the second characteristic configuration, it is possible to prevent a sudden increase in the maximum torque 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) whose position is displaced with a stroke proportional to the exciting current, and further urged by a return spring (4) to push back in the fuel-less 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, information on the rack position is processed as information on the fuel injection amount, and 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. 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),
An arm (13) is pivotally supported on the middle support shaft portion (12) of (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 When the brake operation signal is input to the control device (8), the control device (8) limits the maximum adjustment value of the fuel injection amount 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 the range, it is possible to prevent the fuel injection amount and the torque from suddenly increasing. That is, the maximum adjustment value (A _max ) of the fuel injection amount is calculated from the information of the rack position and the information of the rotation number setting device (9) and the rotation number sensor (7) based on the following equation, and the fuel injection amount is calculated. Outputs the solenoid drive signal within a range not exceeding the maximum adjustment value.

A _max = A ₀ + α (B ₀ −B _n ) A ₀ : Amount of fuel injection immediately before being operated in the braking operation state B ₀ : Engine speed (set speed) immediately before being operated in the braking operation state B _n : Current engine speed α: Set value (real number greater than 0) As can be seen from the above equation, the maximum adjustment value (A
_max ) increases linearly as the engine speed decreases.

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). When the brake operation signal is not 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 is that the governor control device according to the present invention has a third relationship between the engine speed and the fuel injection amount.
It becomes clear on the graph of 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 conventional governor control device, when the pair of left and right traveling braking devices are operated in the braking operation state, the fuel injection amount rapidly increases and reaches the maximum adjustment value, and thereafter, the fuel injection amount increases until the non-braking operation state is operated. During this time, the engine speed is reduced while the fuel injection amount is limited to a specified maximum adjustment value or less. When the engine is operated in the non-braking operation state, the engine rotation speed is increased while limiting the fuel injection amount to the maximum adjustment value of the non-braking operation state, and when the set rotation speed is reached, the original fuel injection amount is increased. To lower. Incidentally, the fuel injection amount on the graph of FIG. 3 follows point a → point b → point c.

However, in the governor control device of this embodiment, when the pair of left and right traveling braking devices are operated in the braking operation state, the fuel injection amount is limited to the maximum adjustment value calculated as described above according to the decrease in the engine speed. I do. When operated in the non-braking operation state, the limited maximum adjustment value is gradually increased. When the engine speed reaches the set speed or a certain time has elapsed, the restriction on the maximum adjustment value is released. In other words, when the engine speed decreases due to the generation of the braking force, the torque immediately before being operated in the non-braking operation state is set to the maximum torque, and the maximum torque is increased linearly with the decrease in the engine speed. When the engine speed increases due to the disappearance of the braking force, the torque initially becomes the maximum torque immediately before being operated to the braking operation state, but gradually increases with the passage of time. Incidentally, the fuel injection amount on the graph of FIG. 3 follows the point a → the point d until it is operated to the non-braking operation state.

(Another embodiment)

The set value α is not limited to a constant, but may be a function formula that changes as the engine speed decreases. For example, as shown in FIG. 4, it may be increased or decreased as the engine speed decreases. In the drawing, the solid line shows the case where α is constant, the one-dot chain line shows the case where α increases, and the two-dot chain line shows the case where α decreases.

In addition, the present invention is applied to one brake pedal operated by one brake pedal.
It goes without saying that two traveling braking devices can be applied to the work vehicle.

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]

BRIEF DESCRIPTION OF THE DRAWINGS The 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 entire configuration of a governor device, FIG. 2 is a perspective view of a brake pedal, and FIG. It is a graph which shows the relationship of an injection amount. FIG. 4 is a graph showing the relationship between the engine speed and the fuel injection amount in another embodiment. (E) ... diesel engine, (SW) ... braking detection means, (2) ... injection amount adjustment means, (7) ... rotation speed detection means, (8) ... control means, (9) ... Speed setting means.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-98624 (JP, A) JP-A-2-70950 (JP, A) JP-A-61-112745 (JP, A) JP-A-Hei 3- 260338 (JP, A) JP-A 2-28540 (JP, U) JP-A 56-136138 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F02D 41/40 F02D 41 / 38 F02D 1/02 F02D 29/02

Claims (2)

(57) [Claims] 1. A rotational speed detecting means (7) for detecting an engine rotational speed of an on-board diesel engine (E); a rotational speed setting means (9) for setting the engine rotational speed; An injection amount adjusting means for adjusting a fuel injection amount; and an engine speed setting means for setting the engine speed based on information from the engine speed detecting means.
And a control means (8) for adjusting the injection amount adjusting means (2) so as to maintain the rotation speed set in (1), wherein the traveling braking device is operated in a braking operation state. Braking means (SW) for detecting that the fuel injection amount has reached the maximum adjustment value of the fuel injection amount based on the information of the braking detection means (SW). Is configured to set the maximum adjustment value (A _max ) of the fuel injection amount in the braking operation state based on the following equation so as to make it lower than the non-braking operation state. A _max = A ₀ + α (B ₀ −B _n ) A ₀ : Fuel injection amount immediately before being operated in the braking operation state B ₀ : Engine speed immediately before being operated in the braking operation state B _n : Current engine rotation Number α: Set value (however, it is larger than 0) 2. The governor control device for a work vehicle according to claim 1, wherein said control means (8) is adapted to operate from said braking operation state to said non-braking operation state, and to increase said fuel injection amount. Is gradually increased.