JP3095027B2 - Fuel injection control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for a diesel engine, and more particularly, to a fuel injection control device for controlling a fuel injection amount supplied to a diesel engine.

[0002]

2. Description of the Related Art It has been known that control of an injection amount in a diesel engine is performed by a mechanical governor, an electronic control governor, and the like added to an injection pump. For example, Japanese Utility Model Laying-Open No. 60-69336 discloses an injection device that controls a full rack control of a hydraulic governor by a step motor. In this configuration, it is necessary to always operate the step motor during operation of the diesel engine. is there. Japanese Patent Application Laid-Open No. 60-240834 discloses an injection device in which a minimum and a maximum injection amount are controlled using an actuator by a governor in a cam-driven unit injector. This configuration,
It is based on a unit injector and has a different variable mechanism from the mechanical governor of a row injection pump. Further, Japanese Patent Application Laid-Open No. 56-146027 discloses an injection device for duty-controlling a full rack control of a mechanical governor. However, in this configuration, position feedback control is mainly performed, and it is difficult to simplify the system. There is a problem that is.

In general, a mechanical governor has an advantage of lower cost than an electronically controlled governor, but has a problem in that the degree of freedom of a maximum injection amount for determining a full load performance of a diesel engine is small. As needs have increased due to stricter exhaust gas regulations and the like, the pattern of the maximum injection amount has become more complicated, and it is difficult to meet the required regulation values. On the other hand, the electronically controlled governor has a high degree of freedom in controlling the injection amount and has no particular problem in performance, but has a problem in that the cost is high.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a mechanical governor increases the degree of freedom of a maximum injection amount of a fuel injection pump, thereby achieving precise fuel injection control. It is an object of the present invention to provide a highly reliable fuel injection control device that enables the fuel injection control.

[0005]

A fuel injection control device according to the present invention for solving the above-mentioned problems comprises a fuel injection amount adjusting member for adjusting an amount of fuel injected from a fuel injection pump, and an operating state of the engine. Corresponding to the position of the fuel injection amount adjusting member.
A mechanical governor for adjusting the position, a sensor for detecting the actual position of the fuel injection amount adjusting member, and an engine when the sensor detects that the actual position of the fuel injection amount adjusting member is at the maximum injection amount position. A step motor for electrically adjusting the maximum injection amount position of the fuel injection amount adjusting member in accordance with the operation state of the fuel cell; and the sensor detects that the actual position of the fuel injection amount adjusting member is at the maximum injection amount position. when in, Ru and a control unit for outputting a signal for controlling the maximum injection quantity position of the fuel injection quantity adjusting member in accordance with the engine operating state to the step motor. And the fuel injection
The actual position of the amount adjusting member is the maximum injection amount position.
Drives the step motor when detected by the sensor
The fuel injection amount adjusting member according to the operating state of the engine.
Controlling the maximum injection position of the fuel injection amount adjusting member.
The sensor detects that the actual position is not the maximum injection amount position.
When it is issued, the drive of the step motor is shut off and
The fuel injection is controlled by the mechanical governor .

[0006]

According to the fuel injection control device of the present invention, the fuel injection
The actual position of the quantity adjusting member is detected by a sensor. This section
The actual position of the fuel injection amount adjustment member is the maximum injection amount
Position is detected, the fuel injection amount adjusting member
Is in the maximum injection position, the maximum injection position is
Adjusted by the step motor according to the operating condition
Therefore, precise control according to the operating state of the engine becomes possible.
It is detected that the fuel injection amount adjustment member is not at the maximum injection amount position
When the step motor is turned off, the mechanical
Governor controls the maximum injection amount adjustment member to control fuel injection
Is performed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the injection pump 1 includes a rack position sensor 2 for detecting the position of a control rack (not shown) and a switch 4 for detecting that the accelerator lever 3 is fully opened.
And a step motor 5 for controlling the full rack position by using a signal of the switch 4 as a trigger, and further, a signal indicating an operating state of the engine, for example, an engine speed signal, a boost pressure signal, a starter signal, an engine water temperature signal, etc. And a control device (ECU) 6 for controlling the full rack position. The step motor 5 has a built-in switch (not shown) for notifying the return to the zero point.

As shown in FIG. 2, the full rack control mechanism employs a system controlled by a step motor 5, and shows a typical half all speed mechanical governor link mechanism. The step motor 5 has a motor shaft 10
The eccentric cam 11 is attached to the tip of the. The arm 8 is directly connected to the control rack 7, and has a control pin 9 projecting in the axial direction of the motor shaft 10. When the accelerator lever 3 comes to the fully open position, the control pin 9 and the eccentric cam 11 come into contact. With this configuration, when the motor shaft 10 of the step motor 5 rotates, the control rack 7 moves, and the position of the accelerator lever 3 can be changed. If the accelerator lever 3 is lower than the fully open position, the control pin 9 moves away from the eccentric cam 11, so that the mechanical governor operates as it is, and the step motor 5 is independent.

FIG. 3 is a front view showing the step motor 5. A return spring 14 is attached to the eccentric cam 11, and the eccentric cam 11 contacts the stopper pin 12 when the step motor 5 is turned off. When the stopper pin 12 contacts the eccentric cam 11, a signal is generated (not shown). This position is the control start reference position (i) shown in FIG. Control is started based on this position, but in consideration of the step-out phenomenon peculiar to the step motor, a stopper pin 13 is also provided in the rack decreasing direction to protect the device. With this configuration, the stopper pin 1
The control rack 7 can be freely controlled when the accelerator lever 3 is at the fully open position within the range of the stop lever 2 and the stopper pin 13, that is, within the range of (i) to (ii) shown in FIG.

FIG. 5 is a block diagram showing a control circuit. Based on the signal obtained by the engine state detector 31, the mode of each of the full rack positions 32 to 33 is selected by the mode switching determiner 34, and the target full rack position is calculated by the arithmetic circuit 35. Next, from the target full rack position, the target number of steps, which is a command signal to the step motor 5, is calculated by the arithmetic circuit 36, and the pulse rate for driving the step motor 5 is calculated by the arithmetic circuit 37. In calculating the pulse rate,
The state of the engine is detected and corrected by the pulse rate switching determiner 40. This is because the torque generated in the step motor 5 changes due to the fluctuation of the power supply voltage, so that it is necessary to switch the pulse rate to always obtain the optimum torque. Further, even when the power supply voltage is constant, the sliding resistance of the control rack 7 and the like changes depending on the engine oil viscosity (depending on the temperature), so that the torque generated in the step motor 5 is changed to perform the optimal driving. Needs to switch the pulse rate. With this pulse rate, the stepping motor 5
Drive.

In the present embodiment, the step motor 5 is driven only when the accelerator lever fully open position detector 41 determines that the drive lever is in the fully open position by the drive determination circuit 42. In other cases, the step motor 5 is not driven. (No current flow)
Configuration. This is because the accelerator lever 3 is not always in the fully open position during engine operation, so the current is cut off when it is not necessary, and the heat generation of the step motor 5 itself and the heat generation of the power element in the control device 6 are reduced. This is to ensure the nature. This configuration also achieves a reduction in current consumption.

On the other hand, the actual rack position is detected by the detection circuit 43, and only when the accelerator lever 3 is fully opened, it is determined whether the actual rack position matches the target rack position calculated by the arithmetic circuit 35, that is, whether there is a step-out phenomenon. The determination is performed by the detection determination circuit 44. If it is determined that a step-out occurs, the number of correction steps is calculated by the arithmetic circuit 45 to generate a pulse rate.
Further, a zero point return circuit 46 is provided between the correction step number calculation circuit 45 and the drive circuit 38.

Next, a description will be given based on a flowchart shown in FIG. In step 51, it is determined whether or not the accelerator lever 3 is at the fully open position. If not, the process proceeds to step 61, in which the energization cut to the step motor 5 is continued. That is, it means that the full rack control is not entered. If the accelerator lever 3 is at the fully open position, step 5
From 1 the process proceeds to step 52, where it is determined whether or not the step motor 5 has returned to zero. If the step motor 5 has returned to the normal zero point, the step motor 5 is not energized and the return spring 14 causes the accelerator lever 3
Is always returned to the zero position, so that a zero signal is issued. However, if the step motor 5 does not return to the zero point for some reason, the reference position is different from that at the time of starting, and erroneous control is performed. In order to prevent such erroneous control, the presence or absence of a zero return signal is determined. Thereafter, at step 60, a warning lamp is turned on to notify a failure. Step 52
If the zero point return signal is detected in step (5), it is determined that the signal is normal, the process proceeds from step 53 to step 58, and the step motor 5 is driven to perform full rack control.

In this embodiment, the rack position sensor 2
The above describes a method of determining whether or not the step motor 5 is operating normally and making a correction, that is, a so-called closed loop control. However, if the rack position sensor 2 fails, it is also possible to switch to the open loop control. . In the present embodiment, the motor is monitored by the rack position sensor. Alternatively, a sensor may be mounted on the step motor side to directly monitor the motor position. In this case, the zero return switch is not required.

[0015]

As described above, according to the fuel injection control device of the present invention, since the control is started only when the fuel injection amount adjusting member is fully opened, the degree of freedom of the maximum injection amount of the fuel injection pump is increased. High precision injection control is possible,
This has the effect of saving current consumption and reducing heat generation of the motor and the power element of the control device.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a fuel injection control device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a full rack control mechanism of the fuel injection control device according to the embodiment of the present invention.

FIG. 3 is a front view showing a step motor according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between an engine speed and a rack position according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a control circuit of the fuel injection control device according to the embodiment of the present invention.

FIG. 6 is a flowchart illustrating a control example according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 injection pump (fuel injection pump) 2 rack position sensor 3 accelerator lever (fuel injection amount adjusting member) 4 switch 5 step motor 6 controller

Continuation of the front page (56) References JP-A-59-85514 (JP, A) JP-A-2-61330 (JP, A) JP-A-59-101558 (JP, A) JP-A-61-129423 (JP) , A) Hira 1-88043 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 1/00-1/18

Claims (1)

(57) [Claims] 1. A fuel injection amount adjusting member for adjusting an amount of fuel injected from a fuel injection pump, and a position of the fuel injection amount adjusting member in accordance with an operation state of an engine.
A mechanical governor for adjustment, a sensor for detecting the actual position of the fuel injection amount adjusting member, and operation of the engine when the sensor detects that the actual position of the fuel injection amount adjusting member is at the maximum injection amount position. photoelectrically maximum injection quantity position of the fuel injection amount adjustment member according to the state
A step motor that adjusts by a pneumatic operation , when the sensor detects that the actual position of the fuel injection amount adjusting member is at the maximum injection amount position, the maximum position of the fuel injection amount adjusting member according to the operating state of the engine. A control device for outputting a signal for controlling an injection amount position to the step motor , wherein the actual position of the fuel injection amount adjusting member is a maximum injection amount position.
Is detected by the sensor,
The motor is driven and the fuel injection is performed according to the operating state of the engine.
The maximum injection amount position of the injection amount adjustment member is controlled so that the actual position of the fuel injection amount adjustment member is the maximum injection amount position.
Is detected by the sensor,
The drive of the motor is shut off, and the fuel is injected by the mechanical governor.
The fuel injection control apparatus, characterized by elevation control.