JPH042784B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection amount control method for a diesel engine.

(Prior Art) Daycel engines use governors that automatically adjust the amount of fuel supplied in response to load fluctuations to improve torque characteristics. Recently, a system has been provided in which a stepping motor is connected to a control lever for adjusting the fuel injection amount as the governor, and the governor is controlled in a purely electronic manner.

This operates to obtain a control lever opening characteristic as shown by curve A in FIG. 4 in accordance with the amount of depression of the accelerator pedal. Furthermore, in such a system, not only engine speed control but also clutch control is performed by pressing the accelerator pedal. In other words, the accelerator opening versus control lever opening characteristic is such that in a half-clutch state where the accelerator opening is small, the control lever opening is made small to prevent the engine from revving up when the vehicle starts. Note that straight line B in FIG. 4 shows the control lever opening characteristic when the accelerator movement is transmitted to the control lever by a mechanical link or rod without using a stepping motor.

By the way, such a control lever drive device using a step motor is as shown in FIG. 3 and a full load switch 4 are provided, and an idle stopper 5 is provided on the other side.
and an idle switch 6 are provided. The control lever 2 is connected to a rotating arm 9 of a step motor 8 via a link 7, and the control lever 2 is configured to swing between a maximum full load stop 3 and an idle stop 5.

(Problem to be Solved by the Invention) In this control lever driving device, the step motor 8 is driven in response to a signal from the controller, and it seems that the signal is a signal (erroneous signal) with a value larger than the full load signal. In such a case, if the control lever 2 hits the full load stopper 3, a load torque greater than the drive torque of the step motor 8 will act on the slap motor, causing irregular rotation and eventually This causes the problem that the control lever 2 returns to the position of the idle stopper 5 due to the reaction force of a return spring (not shown).

In order to avoid such step-out, the full load switch 4 is turned on before the control lever 2 hits the full load stopper 3, and the position is adjusted so that the step motor 8 is stopped by this signal. However, in this case, since the control lever 2 cannot be moved to the full load position, there is a problem in that the engine output decreases despite the output of the full load signal.

The present invention solves such conventional problems,
When a full load signal is output, the control lever is brought into reliable contact with the full load stopper to ensure sufficient engine output and to prevent the step motor from stepping out.

(Means for Solving the Problems) The present invention includes a first means for detecting the engine rotation speed, a second means for detecting the accelerator opening degree, and an optimum means for the accelerator opening degree determined using the engine rotation speed as a parameter. a third means for obtaining a target load according to the detected engine speed and accelerator opening from a data map of the control lever opening; and a fourth means for detecting the current load using a load sensor linked to the control lever. , a fifth means for comparing the current load and the target load and driving the step motor in a direction according to the error;
When the target load is full load and the current load becomes full load, the step motor is further rotated in the forward direction by a certain amount within a range that does not step out and then stopped.

(Function) In the present invention, in the first to fifth means, the control lever opening degree relative to the accelerator opening degree is automatically adjusted to an optimum state according to the engine speed, and the drab feeling is improved. By means of step 5, the control lever is brought into contact with the full load stopper, and when the target load is full load, the controller determines that the current load has reached full load, and at this time, the stop motor is further rotated in the forward direction by a certain amount. This ensures sufficient engine output while preventing step-out.

(Embodiment) FIG. 1 is a block circuit diagram of one embodiment of the present invention. In the figure, reference numeral 11 denotes a processing device, including a rotation sensor 12 that detects the engine rotation speed and an accelerator sensor 1 that outputs a signal according to the accelerator opening degree.
3 is connected.

Reference numeral 14 denotes a memory (ROM) connected to the processing device 11, which stores a data map of the optimal control lever opening relative to the accelerator opening, using the engine speed as a parameter.
Accordingly, the processing device 11 searches the data map for a target load, that is, a control lever opening signal according to the outputs of the rotation sensor 12 and the accelerator sensor 13, and outputs the search result.

A comparator 15 compares the target load and the current load detected by the load sensor 16. The load sensor 16 is linked to the stepping motor 8 that adjusts the control lever opening degree via a link, etc., and controls the rotation of the stepping motor 8 in either the positive or negative direction based on the error output of the comparator 15. , automatically adjusts the fuel injection amount.

As shown in FIG. 2, the load sensor 16 detects the opening degree of the control lever 2 via the link 17.

The reason why the engine speed rises slowly in response to accelerator operation is to prevent the engine from revving up due to half-clutch control, etc., but when the clutch is fully engaged, the response of the engine speed and vehicle speed will be reduced. The faster the sex the better. Therefore, it is possible to switch the above response on the condition that the clutch is completely engaged, but here we will use a simpler method to control the control lever opening,
The engine output is determined.

In other words, the optimum control lever opening degree relative to the accelerator opening degree is determined in advance through engine tests using the engine speed as a parameter, and the control lever opening degree is controlled using this as a reference data map.

That is, for example, if the engine speed is 880 rpm
Until then, in order to control the clutch, the accelerator opening degree is adjusted gently in the small range, and the accelerator opening degree is quickly increased above 880 rpm when the clutch is engaged. And, in order to further improve the drive feeling at high speed rotation,
The control lever opening can be set sufficiently large even in a region where the accelerator opening is small.

Next, the operation of the fuel injection system for a diesel engine according to the present invention will be explained using the flowchart shown in FIG.

First, when the vehicle is running, the rotation sensor 12 reads the engine speed (step a), then the accelerator sensor 13 reads the accelerator opening (step b), and the target load corresponding to both of these data is displayed on the data map. Search from inside (step c). The target load is determined by this search (step d), which is output from the processing device 11 and input to the comparator 15.

Meanwhile, at this time, the load sensor 16 is reading the current load state every moment (step e), and calculates the current load value (step f).

Subsequently, it is determined whether the target load is full load or not (step g), and further it is determined whether the current load is full load or not. (Step h). Here, if the target load is not the full load or if it is determined that the target load is the full load and the current load is not the full load, the current load and the target load are input to the comparator 15 and the error is calculated. do.

That is, when it is determined that the current load is larger than the target load (step i), the step motor 7 is driven in the negative direction based on the error (step j), and the control lever opening degree is decreased.
Reduce fuel injection amount. Further, if it is determined that the current load and the target load are equal (step k),
Since there is no error, the drive of the step motor 7 is stopped (step 1) and the current fuel injection amount is maintained. In addition, unless the current load is greater than or equal to the target load, the step motor 7
is driven in the forward direction (step m), and the fuel injection amount is controlled to increase. Then, following such control of the step motor, the load sensor output is read again and the following steps are repeatedly executed, for example, every 2 msec.

In this way, when starting the vehicle, in order to prevent the engine from revving up during clutch control,
The control lever opening degree changes gradually in response to the accelerator opening degree, improving the responsiveness of the control lever opening degree to the accelerator opening degree in order to improve drive feeling when the vehicle is running, thereby improving vehicle ride comfort. be able to.

On the other hand, in step h, when the target load is full load (step g), when the current load becomes full load, the step motor 17 is driven to rotate in the forward direction, and the amount of rotation is also determined by a predetermined amount. 7 steps (step n).
These 7 steps are the amount of steps in which the control lever 2 comes into contact with the full load stopper 3 to enable fuel injection to provide sufficient output to the engine, and to prevent the step motor 8 from going out of step. It's summery. After rotating the step motor 17 by seven steps in this manner, the step motor 17 is stopped (step o). In addition,
Full load switch 4 instead of load sensor 16
When the step motor 8 is turned on, the step motor 8 is driven in the increasing direction by several steps after being turned on, and then the hold mode is entered. This control of the step motor 17 is repeatedly executed every 2 msec, and
Determine target load every 50msec.

In this way, the control lever 2 is driven by the step motor 8, and when the load is full, the control lever 2 is brought into contact with the full load stopper, and sufficient engine output can be obtained through fuel injection, and the step motor 17 is driven. When both the target load and the current load reach the full load, the rotation of the step motor 8 is held at a constant amount, thereby preventing a sudden drop in engine output due to step motor 8 stepping out. In the present invention, the load sensor 16 in the above embodiment is omitted, and a full load switch 4 like the conventional device is provided, and after the control lever 2 turns on the full load switch 4, the step motor 8 rotates by a predetermined amount. At this time, after the control lever 2 contacts the full load stopper 3, the control lever may be further pressed against the full load stopper 3 within a range that does not cause step-out.

(Effects of the Invention) According to the present invention, in the controller, when the target load is determined to be full load and the current load becomes full load, the step motor is further rotated by a set amount and then stopped. Since I configured it,
It is possible to reliably maintain the engine in a full load state, effectively prevent the step motor from stepping out when transitioning to the full load state, and improve diesel engine characteristics in a high speed operating range.

[Brief explanation of drawings]

Fig. 1 is a block connection diagram of the fuel injection system of the present invention, Fig. 2 is a schematic diagram of the related mechanism of the injection pump, Fig. 3 is a flowchart showing the process of the fuel injection system, and Fig. 4 is a diagram of the conventional fuel injection system. FIG. 5 is an opening degree characteristic diagram of a control lever in a fuel injection device, and is a schematic diagram showing a conventional related mechanism of an injection pump. 1... Injection pump, 2... Control lever, 3... Full load stopper, 4...
Full load switch, 8...Step motor, 1
1...Processing device, 14...Memory, 15...Comparator, 16...Load sensor.

Claims (1)

[Claims] 1. A means for detecting the current load using a load sensor linked to a control lever, a means for comparing the current load and a target load, and driving and controlling the step motor in a direction according to the error, 1. A fuel injection amount control system for a diesel engine, comprising means for further rotating a step motor by a predetermined amount in the forward direction when the current load reaches full load.