JPS63150451A - Fuel feed amount control device - Google Patents

Abstract

PURPOSE:To facilitate execution of normally proper control, by a method wherein, in a device which controls the control rack of a fuel injection device with the aid of a stepping motor, a position relation between the number of pulses to a motor and the rack is properly corrected before the starting of an engine. CONSTITUTION:A control device varies an amount of fuel fed to an engine with the aid of a drive control means M2 for feeding a control pulse to a stepping motor M1, and a control rack M3 driven by means of the motor M1. In this constitution, a means M4 is provided for detecting whether the rack M3 before the starting of an engine is in a reference position. Further, means M5 for outputting a pulse to the motor M1 until the reference position of the rack M3 is detected by the means M4, and a means M6 for counting the number of pulses sent to the motor M1 by means of the means M5 are provided. Moreover, a means M7 is provided for correcting the number of control pulses outputted from the means M2 by means of the number of pulses counted by the M6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel supply amount control device that uses a stepping motor to control a control rack of a fuel injection device.

[Prior Art] A stepping motor can be controlled in an open manner without performing feedback control. In other words, the position can be determined by the number of pulses sent to the stepping motor. Therefore, if a stepping motor is used as the drive source of the control device, the configuration of the control device becomes very simple.

For this reason, conventional fuel injection devices for diesel engines include fuel supply amount control devices configured such that a stepping motor drives a control rack via a pinion (for example, Japanese Patent Application Laid-Open No. 160049/1983).

In this type of fuel supply amount control device, first, the movement amount Rw of the control rack is determined from the engine rotation speed Ne and the accelerator opening Acc according to the map shown in FIG. 4. Then, the design characteristics of the map shown in FIG. (solid line) is used to calculate the number of pulses X of the stepping motor required for the rack movement amount RW. Then, by sending pulses to the stepping motor by the number of pulses, the control rack is set at a predetermined position and the necessary fuel is supplied to the engine.

[Problems to be solved by the invention] However, for example, at low temperatures, the viscosity of the lubricating oil increases, making it difficult for the control rack to move. The stepping motor does not rotate properly, and the number of pulses to the stepping motor and the positional relationship with the control rack are incorrect.
In addition, the control rack position is generally at the fuel stop position before starting, but after the key switch is turned off, the engine is restarted before the control rack returns to this stop position, and the relationship between the number of pulses and the control rack is changed. If it does, the correct operation will no longer be performed since feedback control is not being performed.

For example, the accelerator opening Acc is 80% and the rotation speed Ne is N.
el, the required rack movement amount Rw from FIG.
It turns out that it is 1m. From the design characteristics shown in FIG. 5, it can be seen that the required number of pulses is x1. Here, if the rotation temporarily stops due to an excessive load, etc., and the number of pulses to the stepping motor and the control rack change, resulting in the actual characteristic relationship shown by the broken line in Figure 5, the stepping motor Even if x1 pulse is sent to , the control rack will only move up to R' 1m.

As a result, the engine is not supplied with the fuel it needs, so the engine cannot continue to rotate and stops. This causes a so-called engine stall.

If the number of pulses to the stepping motor and the control rack change in the opposite direction to the above example, more fuel than necessary will be supplied to the engine, resulting in a so-called overrun.

That is, even if there is a difference between the number of pulses applied to the stepping motor and the control rack, correct control cannot be performed.

[Measures for solving the problems fl11 The present invention is configured as follows as a means for solving the above problems.

That is, as illustrated in FIG. 1, the present invention includes a drive control means M2 that sends control pulses to the stepping motor M1 based on a preset reference pulse number, and a drive control means M2
In a fuel supply amount control device that changes the location of fuel supply to an engine using a stepping motor M1 controlled by a control rack M3 driven by a stepping motor M1 controlled by a stepping motor M1 controlled by a stepping motor M1 controlled by a stepping motor M1 controlled by a reference position detection means M4 for detecting the control rack; and a pre-start drive control means M5 for sending pulses to the stepping motor M1 until the reference position detection means M4 detects the reference position of the control rack M3 before starting the engine.
and the pre-start drive control means M5 is connected to the reference position detection means M4.
a counting means M6 for counting the number of pulses sent to the stepping motor M1 until the reference position of the control rack M3 is detected; and control output from the drive control means M2 using the number of pulses counted by the counting means M6. The fuel supply amount control device is characterized by comprising a correction means M7 for correcting the number of pulses.

Here, before the engine starts, the ignition key switch is turned on and power is supplied to the control means, etc.
This is a state in which the engine has not yet started operating. Before starting the engine, the control rack M3 moves a large amount.

The reference position detection means M4 includes a microswitch that detects a reference position, such as a starting position, when the control rack M3 moves a predetermined distance with its tip, and a stroke sensor such as a potentiometer that measures the amount of movement of the control rack M3. A sensor etc. can be used.

[Operation] The control rack M3 of the fuel supply system moves toward a predetermined reference position before starting the engine. The movement of the control rack M3 to the reference position before starting the engine is controlled by the pre-start drive control means M5,
The control rack M3 stops when the reference position of the control rack M3 is detected by the reference position detection means M4.

By counting the number of pulses required for this movement by the counting means M6, the actual number of pulses required for moving the control rack M3 to the reference position can be obtained. If the correction means M7 corrects the control pulse number of the drive control means M2 using this actual pulse number, even if the number of pulses to the stepping motor M1 and the control rack M3 are different before starting the engine, the correct fuel Injection amount control is possible.

[Example] Next, one embodiment of the present invention will be described with reference to the drawings.

The following example shows one embodiment of the invention, and the present invention includes other embodiments as long as they do not depart from the gist.

A diesel engine using the fuel supply amount control device of this embodiment will be explained based on the configuration diagram of FIG.

Fuel is drawn into the feed pump 20 from the tank 10,
After being filtered through a strainer 30, it is sent to an injection pump 40. The injection pump 40 pressurizes this fuel to a high pressure, sends it to the nozzle 60 through the injection pipe 50, and injects it into the combustion chamber 70. The fuel that has lubricated the needle of nozzle 60 and excess fuel in strainer 30 returns to tank 10 via overflow pipe 80 . Note that the strainer 30 has a pressure regulating valve 90 to prevent overpressure fuel from being sent to the injection pump 40. Therefore, when the oil pressure sent from the feed pump 20 becomes too high, this valve 90 opens and the oil flows to the overflow pipe 80.

The injection pump 40 discharges fuel under high pressure by driving a plunger of the injection pump 40 with a camshaft 95. The discharge location is determined by the position of the control rack 120 attached to the injection pump 40 and meshing with the pinion 110 of the stepping motor 100. Further, the stepping motor 100 is controlled by an electronic control circuit 130. Furthermore, injection pump 4
0 is equipped with an automatic timer 140 that automatically changes the injection timing in accordance with the increase in rotational speed.

The electronic control circuit 130 that controls the position of the control rack 120 via the stepping motor 100 has an input/output interface 180 connected to a well-known CPU 150, ROM 160, RAM 170, various sensors, etc.
, bus 190, etc. The input/output interface 180 also detects whether or not an accelerator opening sensor 200 attached to the accelerator, an engine rotation speed sensor 210 attached to the crankshaft, and a control rack 120 (described later) are at the starting position as a reference position. A microswitch 220 to be detected, an ignition key switch 230, and the like are connected.

In this embodiment, the electronic control circuit 130, various sensors 210 to 230 connected to the electronic control circuit 130,
, a stepping motor 100, and the like constitute a fuel supply amount control device.

The electronic control circuit 130 controls the position of the control rack 120 using the maps shown in FIGS. 4 and 5 stored in the ROM 160 as basic control during normal operation. That is, the control rack 12 is determined based on the engine speed Ne obtained from the engine speed sensor 210 and the accelerator opening Acc obtained from the accelerator opening sensor 200.
The movement amount Rw of 0 is obtained from a map (not shown in FIG. 4) stored in the ROM 160, and then this rack movement JilRw
The number of pulses X of the stepping motor 100 required for this is determined from the map shown in FIG. It supplies the necessary fuel to the engine.

Furthermore, before starting the diesel engine, the electronic control circuit 130 checks whether the number of pulses to the control rack 120 and the stepping motor 100 are inconsistent, and if there is a difference, it corrects the difference during the basic control. Perform processing.

This correction process will be explained using the flow chart of FIG.

First, when the key switch 230 is turned on and power is supplied to each part, it is checked in step 310 whether or not the engine is rotating. If the engine is rotating, control moves to step 370, which will be described later, and the basic control described above is performed.

If the engine is not running, steps 320-35
0, the control rack 120 is moved by the stepping motor 100 to the reference position before starting, and the number of pulses of the stepping motor 100 required to move the control rack 120 is counted.

That is, first, in step 320, the pulse number counter X
is set to 0, and then, in step 330, one pulse is output to the stepping motor 100, and at the same time, in step 340, the counter X is incremented by one. Then, in step 350, it is determined whether the control rack 120 has reached the reference position. If the control rack 120 has not reached the reference position, the operations of steps 330 to 350 are repeated, and if the reference has been reached, the process moves to step 360. . Here, whether or not the control rack 120 has reached the starting position in step 350 is determined by whether or not the microswitch 220 is turned on. That is, the microswitch 220
is set at a position corresponding to the position of the control rack 120 where the fuel discharge amount of the injection pump 40 at the time of startup is maximum, and the control rack 120 is turned on when it reaches this position.

When the number of pulses X required to move the control rack 120 to the starting position is measured through the above process, in step 360 the number of pulses xb serving as a reference for drive control of the stepping motor 100 is determined by the number of pulses Correct to. Then, the process moves to step 370, and basic control is performed with this correction taken into consideration.

In this embodiment, as described above, before starting the engine, the number of pulses X required for the control rack 120 to move to the starting position is counted, the reference number of pulses xb is corrected to the actually counted number of pulses X, The amount of fuel supplied is controlled by adding or subtracting, for example, the number of pulses in the subsequent basic control by adding or subtracting this correction (deviation between both numbers of pulses).

Therefore, due to excessive load etc., the stepping motor 1
00 does not rotate temporarily and the positional relationship between the number of pulses to the stepping motor 100 and the control rack 120 is distorted, the number of pulses to the stepping motor 100 and the positional relationship with the control rack 120 are corrected correctly. and normal operation is performed.

[Effects of the Invention] Since the fuel supply amount control device of the present invention has the above-described configuration, it is difficult to control the number of pulses to the stepping motor and the position of the control rack due to, for example, an excessive load due to increased viscosity. Even if the relationship is incorrect, the number of pulses to the stepping motor and the positional relationship with the control rack are correctly corrected before starting the engine, and normal operation is performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the configuration of the present invention, FIG. 2 is a block diagram explaining an embodiment of the present invention, FIG. 3 is a flowchart explaining the correction operation, and FIGS. 4 and 5 are This is a map used for fuel supply amount control. Ml... Stepping motor M2... Drive control means M3... Control rack M4... Reference position detection means M5... Pre-start drive control means M6... Counting means Ml... Correction means 40. ...1 injection pump 100...stepping motor 110...pinion 120...control rack 130...electronic control circuit 200...accelerator opening sensor 210...engine rotation speed sensor 220...micro Switch 230...Ignition key switch Fig. 1 Fig. 3 Fig. 4 Fig. 5 Pulse 4zx

Claims (1)

[Scope of Claims] A stepping motor, a drive control means for sending control pulses to the stepping motor based on a preset reference pulse number, and a control rack whose drive is controlled by the stepping motor controlled by the drive control means. and has
In the fuel supply amount control device that changes the amount of fuel supplied to the engine by moving the control rack, there is provided a reference position detection means for detecting whether or not the control rack is at a reference position before starting the engine; a pre-start drive control means for sending pulses to the stepping motor until the reference position detection means detects the reference position of the control rack; and the pre-start drive control means detects the reference position of the control rack using the reference position detection means. comprising a counting means for counting the number of pulses sent to the stepping motor until detection of the stepping motor; and a correction means for correcting the number of control pulses output from the drive control means using the number of pulses counted by the counting means. A fuel supply amount control device characterized by: