JPH0629579B2 - Fuel injection amount control device for diesel engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel injection amount control device for a diesel engine.

(Prior Art) Due to the nature of the engine, an instantaneous speed change is inevitable during one cycle, and in order to mitigate this speed change, a governor that automatically adjusts the fuel supply amount according to the load change is used. With such a governor, speed control can be performed at the idling speed and the maximum rotation speed when the engine speed is low. As this governor, a system is provided in which a stepping motor is connected to a control lever for adjusting the fuel injection amount.

This corresponds to the depression amount of the accelerator pedal,
It acts to obtain the control lever opening characteristic as shown by the curve A in the figure. Further, in such a system, not only the engine speed control but also the clutch control are performed by depressing the accelerator pedal. That is, regarding the accelerator opening-control lever opening characteristic, the control lever opening is reduced in a half-clutch state in a range where the accelerator opening is small so as to prevent the engine from rising when the vehicle starts. The straight line B in FIG. 1 represents the control lever opening characteristic when the movement of the accelerator is transmitted to the control lever by a mechanical link or rod without using a stepping motor.

(Problems of the prior art) However, when the vehicle is normally started after the start of the clutch and the vehicle normally travels, when the accelerator opening is small,
Even if the accelerator opening is increased, the control lever opening changes only slightly.Therefore, the fuel injection amount only slightly increases, sufficient acceleration cannot be obtained, and the drive feeling due to accelerator operation is bad. there were.

(Object of the Invention) In order to smoothly control the clutch operation at the time of starting the vehicle, the present invention makes the response of the control lever opening to the accelerator opening gentle, and controls the clutch when the clutch is discontinued and the vehicle runs steadily. An object of the present invention is to provide a fuel injection amount control device for a diesel engine, which can improve the drive feeling by increasing the responsiveness of the lever opening.

(Summary of the Invention) The present invention relates to a fuel injection amount control device for a diesel engine that detects the amount of depression of the accelerator pedal and operates the fuel injection control lever by an amount corresponding to the detected amount. The first characteristic that the relationship of the fuel injection control lever opening amount with respect to the accelerator pedal depression amount up to the amount is a linear proportional relationship, and the fuel injection with respect to the accelerator pedal depression amount at least in the initial stage of the accelerator pedal depression A second portion having a region where the opening degree of the control lever is smaller than the first characteristic
The engine speed detection means for detecting the engine speed at the initial depression of the accelerator pedal, and the first characteristic of the map when the engine speed is a predetermined value at the initial depression of the accelerator pedal. Is selected, and when the engine speed detected by the engine speed detecting means is smaller than a predetermined value, the selecting means for selecting the second characteristic of the map and the characteristic selected by the selecting means are used. Provided is a fuel injection amount control device for a diesel engine, which is characterized by adjusting the opening of a fuel injection control lever in response to a change in the amount of depression of the accelerator pedal. Has a region where the opening of the fuel injection control lever with respect to the accelerator pedal depression amount is larger than the first characteristic When the engine speed is higher than a predetermined value at the initial depression of the accelerator pedal, the third characteristic of the above map is selected so that the engine speed at the initial depression of the accelerator pedal is 3 The first characteristic of the map is selected when the engine speed is at a predetermined value, and the second characteristic of the map is selected when the engine speed detected by the engine speed detecting means is smaller than the predetermined value. A fuel injection amount control device for a diesel engine is provided.

(Embodiment) FIG. 2 is a block circuit diagram used for implementing the apparatus of the present invention. In the figure, 1 is a processing device, to which a rotation sensor 2 for detecting the engine speed and an accelerator sensor 3 for outputting a signal according to the accelerator opening are connected.

Reference numeral 4 denotes a memory (ROM) connected to the processing device 1, which stores a data map of the optimum control lever opening with respect to the accelerator opening with the engine speed as a parameter. Therefore, the processing device retrieves the target load, that is, the control lever opening signal corresponding to the outputs of the rotation sensor 2 and the accelerator sensor 3 from the data map and outputs it.

Reference numeral 5 denotes a comparator, which compares the target load with the current load detected by the load sensor 6. Load sensor 6
Is linked to a stepping motor 7 for adjusting the control lever opening via a link or the like, and controls the stepping motor 7 to rotate in either the positive or negative direction based on the error output of the comparator 5 to control the fuel injection amount. Make adjustments automatically.

Next, the operation of the block circuit diagram will be described with reference to the control lever opening characteristic diagram of FIG. 3 and the flowchart of FIG.

The reason why the engine speed rises gently with respect to the accelerator operation is to prevent the engine from rising during half-clutch control.However, when the clutch is completely engaged, the engine speed and vehicle running speed Better responsiveness is better. Therefore, the responsiveness can be switched on the condition that the clutch is completely engaged, but in the present invention, the control lever opening is controlled by a simpler method,
The engine output is determined.

In other words, the optimum control lever opening with respect to the accelerator opening is determined by an engine test performed in advance using the engine speed as a parameter, and the control lever opening is controlled using this as a reference data map.

That is, in FIG. 3, when the accelerator pedal is depressed, if the engine speed is a slow rotation up to 880 rpm, the processing device 1 determines that the vehicle starts to move, and the data map 4 (0 .About.880 rpm). Therefore, at the initial depression of the accelerator pedal, the inclination of the opening of the control lever is gentle with respect to the depression amount of the accelerator pedal, so that the engine does not blow up.

The engine speed is 1 when the accelerator pedal is depressed.
If the rotation speed is around 500 rpm, the processing device 1 determines that the vehicle is in the initial stage of running start or during warm running, and selects the characteristic (1500 rpm) in FIG. 3 from the data map 4.
Therefore, since the opening angle of the control lever is moderate with respect to the depression amount of the accelerator pedal at the initial depression of the accelerator pedal, the engine speed increase rate is appropriate for the depression of the accelerator pedal. On the other hand, dissatisfaction with acceleration does not occur.

When the accelerator pedal is depressed, the engine speed is 2
If the rotation speed is 000 rpm or more, the processing device 1 determines that the vehicle is traveling at high speed, and based on the data map 4 shown in FIG.
00 rpm) characteristic is selected. For this reason, the opening angle of the control lever is steep with respect to the depression amount of the accelerator pedal at the initial depression of the accelerator pedal, and the increase rate of the engine speed increases with respect to the depression of the accelerator pedal. There is no dissatisfaction with acceleration.

Next, the governor control system will be described with reference to the flowchart of FIG.

First, when the vehicle is running, the engine speed is read by the rotation sensor 2 (step a), then the accelerator opening is read by the accelerator sensor 3 (step b), and a target load corresponding to both of these data is data-mapped. (Step c). The target load is determined by this search (step d), and this is output from the processing device 1 and input to the comparator 5.

On the other hand, at this time, the load sensor 6 is reading the current load state every moment (step e), the current load value is calculated here (step f), and the result is input to the comparator 5 to obtain the target load. Calculate the error of.

That is, when it is determined that the current load is greater than the target load (step g), the step motor 7 is driven in the negative direction based on the error (step h), the control lever opening is reduced, and the fuel is opened. Reduce the injection amount. If it is determined that the current load is equal to the target load (step i), there is no error, so the driving of the step motor 7 is stopped (step j) and the current fuel injection amount is maintained. Further, except when the current load is greater than or equal to the target load, the step motor 7 is driven in the forward direction (step k), and the fuel injection amount is controlled to increase. Then, following the control of the step motor, the following steps of reading the output of the load sensor again are repeatedly executed, for example, every 2 msec.

As described above, the present invention gently changes the control lever opening with respect to the accelerator opening in order to prevent the engine from blowing up during clutch control when the vehicle starts, and improves the driving feeling when the vehicle is running. The responsiveness of the control lever opening with respect to the accelerator opening is improved, so that the riding comfort of the vehicle can be improved.

(Effects of the Invention) As described in detail above, according to the present invention, the engine rotation and the vehicle traveling at the time of oscillation are smoothly performed, and even when the vehicle is traveling in the low speed range in the traveling situation after starting. Regardless of this, sufficient acceleration performance can be obtained according to the amount of accelerator depression, and a good drive feeling can be obtained. As a result, it is possible to obtain a stable and good riding comfort at the time of starting the engine and over the entire traveling speed range after the starting.

[Brief description of drawings]

FIG. 1 is a characteristic diagram of a control lever opening degree in a conventional fuel injection amount control device, FIG. 2 is a block connection diagram for implementing the fuel injection amount control device of the present invention, and FIG. FIG. 4 is a flow chart showing the process of the fuel injection amount control device. 1 ... Processor, 2 ... Rotation sensor, 3 ... Accelerator sensor, 4 ... Memory, 5 ... Comparator, 6 ... Load sensor, 7 ... Stepping motor.

Claims (2)

[Claims] 1. A fuel injection amount control device for a diesel engine, which detects a depression amount of an accelerator pedal and operates a fuel injection control lever by an amount corresponding to the detected amount,
The first characteristic that the relationship of the fuel injection control lever opening degree with respect to the accelerator pedal depression amount from zero to the full depression amount is a linear proportional relation, and at least in the initial stage of the accelerator pedal depression, Is a map having a second characteristic in which the opening of the fuel injection control lever with respect to the accelerator pedal depression amount has a region smaller than the first characteristic, and the engine rotation speed for detecting the engine speed at the initial stage of accelerator pedal depression. The number detecting means and the first characteristic of the map is selected when the engine speed is at a predetermined value in the initial stage of depression of the accelerator pedal, and the engine speed detected by the engine speed detecting means is smaller than the predetermined value. In the state, the selecting means for selecting the second characteristic of the map and the characteristic selected by the selecting means are selected. There the fuel injection quantity control device for a diesel engine and adjusting the degree of opening of the fuel injection control lever relative to the change in the amount of depression of the accelerator pedal. 2. A map further comprising a third characteristic having a region where the opening of the fuel injection control lever with respect to the accelerator pedal depression amount is larger than the first characteristic at the initial depression of the accelerator pedal, When the engine speed is higher than a predetermined value in the initial stage of pedal depression, the third characteristic of the map is selected, and when the engine speed is the predetermined value in the initial stage of accelerator pedal depression, the first characteristic of the map is selected. The second characteristic of the map is selected when the engine speed detected by the engine speed detecting means is smaller than a predetermined value, and the second characteristic of the map is selected. Fuel injection amount control device for diesel engine.