JPS59158335A - Idle speed controller of diesel engine - Google Patents

Abstract

PURPOSE:To prevent a speed from hunting, by setting the width of a control valve driving pulse on the basis of a weighted average in a case such that the weighted average of old and new detection values of battery voltage is larger than the newest detection value while setting the pulse width by the newest detection value of the battery voltage except when in said case. CONSTITUTION:When idle speed control (ISC) is performed, a target idle speed Ns predetermined from water temperature is referred by a target speed referring means 12. While a detection value of battery voltage is compared with the preceding detection value input from a register 16 in a comparing means 17. Next, a preset opening time, when solenoid valves 8A, 8B are opened, is referred by a pulse width referring means 19. And next, measuring an actual idle speed N by an actual speed measuring means 13, the target idle speed Ns is compared with the idle speed N by a comparing means 14. As the compared result, when Ns<N, a signal from the comparing means 14 causes a driving pulse transmitting means 15 to transmit a driving pulse, having the referred pulse width, to the solenoid valve 8B, and only the solenoid valve 8B is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aisle rotation speed control device for a diesel engine.

As a conventional engine speed control device for a diesel engine, there is one shown in FIGS. 1 to 3, for example.

Referring to FIG. 1, a fuel injection pump 1 is provided with two levers 3 and 4 fixed to the same shaft 2, and one lever 3
Idle stop horns 6 for regulating the idle position of the control leno-5 are attached to the tip of the control lever. An output port/nod 7a of the diaphragm actuator tough is connected to the tip of the other lever 4. The pressure working chamber of the diaphragm actuator tough is controlled by a control valve (VCM), which will be described later.
/\lube) 8 to a vacuum pump 9.

As shown in FIG. 2, the control valve 8 branches a line passing through the diaphragm actuator 7 into a negative pressure line 8a leading to the nozzle pump 9 and an atmospheric line 8b leading to the atmosphere.

8b has a structure in which solenoid valves 8A and 8B are interposed therebetween.

Each electromagnetic valve 8A, 8B of the control valve 8 is connected to the battery 1.
0 and is controlled by a control circuit 11 to which various information such as engine rotation speed, vehicle speed, and water temperature (engine cooling water temperature) is input.

This control will be explained based on flowchart 1 in FIG. 3. First, it is determined whether or not to perform the idle rotation control (Isc) based on the engine speed, vehicle speed, etc. (sl). When performing ISC, a predetermined target idle rotation speed Ns is searched based on the water temperature (S2). Next, 1. Measure the actual idle rotation speed N (S3), and compare the target idle rotation speed Ns with the actual idle rotation speed N (S4).

As a result of the comparison, when Ns<N, the solenoid valve 8A is closed and the solenoid valve 8B is opened (S5). As a result, the signal negative pressure to the diaphragm actuator 7 is decreased, the idle stopper 6 is moved in the direction of fuel reduction, and the idle rotation speed is decreased to be close to the target value.
and 8B are closed together (S6). As a result, the signal negative pressure within the diaphragm actuator 7 is maintained as it is, and the idle rotation speed is maintained at the target value.

Further, when N s > H, the solenoid valve 8A is opened and the solenoid valve 8B is closed (S7). As a result, the signal negative pressure to the diaphragm actuator 7 is increased, the i)-rust soaper 6 is moved in the fuel increasing direction, and the idle rotation speed is increased to approach the target value.

When opening the solenoid valves 8A and 8B, hunting occurs if they are turned on continuously, so they are turned on intermittently by applying a drive pulse with a predetermined pulse width.

If ISC is not performed, close solenoid valve 8A and close solenoid valve 8A.
Open B<(35).

However, in such a conventional idle speed control device, the solenoid valves 8A, 8B are opened for a predetermined period of time by applying a drive pulse with a predetermined pulse width to the solenoid valves 8A, 8B, and the battery voltage is When the battery voltage is high, the actual opening time becomes as shown in Figure 4 (A+) compared to the set opening time, and there is no problem. However, when the battery voltage decreases, the opening time changes as shown in Figure 4 (81). There was a problem that there was a lack of time and the responsiveness of rotation speed control deteriorated.

For this reason, a means is provided to control the pulse width of the drive pulse to the control valve based on the battery voltage, and when the battery voltage decreases, the pulse width of the drive pulse (set opening time) is increased. As shown in the figure, it is conceivable to make the actual opening time necessary and sufficient, thereby improving the responsiveness of control at low voltages.

However, in that case, the following new problem arises when the battery voltage fluctuates instantaneously, such as at the moment the power switch is turned on (or turned off), for example, as shown in FIG. In other words, if a drive pulse whose pulse width has been increased and corrected based on the voltage value read at point A when the voltage is falling is output at point B after the voltage has risen, the open time will actually change because the voltage has already risen. There were cases where the engine speed became excessive and the idle speed increased rapidly, resulting in engine speed hunting.

The present invention was made in view of the above points, and the present invention calculates a weighted average of new and old detected values of the battery voltage after the battery voltage starts to decrease, and calculates the weighted average value until the weighted average value is larger than the latest detected value. A diesel engine that solves the above problems by having a configuration that sets the pulse width of the control valve drive pulse based on the value, and sets the pulse width in other areas only based on the latest detected value of the battery voltage. The purpose of the present invention is to provide an idle speed control device.

An embodiment of the present invention will be described below.

The configuration of the mechanical part of the idle speed control device is the first
This is as shown in FIG. 2 and FIG. 2, and only the configuration of the control circuit 11 is different from the conventional one.

FIG. 6 is a functional block diagram of the control circuit 11, and the configuration of the control circuit 11 will be explained using this diagram. However, in FIG. 6, the means for determining whether or not to perform ISO is omitted.

A target rotation speed search means 12 that searches a predetermined target to idle rotation speed Ns based on the water temperature, and an actual rotation speed measurement means I3 that measures the actual idle rotation speed N.
are provided, and their output ends are connected to comparison means 14. The output end of the comparing means 14 is connected to the driving pulse transmitting means 15, and the output end of the driving pulse transmitting means 15 is connected to the electromagnetic valves 8A and 8B.

On the other hand, means is provided for controlling the pulse width of the driving pulse applied from the driving pulse transmitting means 15 to the electromagnetic valve 8A or 8B in accordance with the behavior of the battery voltage according to the comparison result of the comparing means 14.

That is, a register 16 temporarily stores a detected value of battery voltage detected at every predetermined sampling time, a comparing means 17 that compares the latest detected value of battery voltage with the previous detected value, and calculation means 18 for calculating a weighted average value of the latest detected value and the past detected value;
The corresponding pulse width is searched based on the latest detected value or weighted average value, and the search information is sent to the drive pulse transmitting means 1.
A pulse width retrieval means 19 is provided for transmitting the pulse width to the pulse width retrieval means 19.

Next, the operation will be explained with reference to the flowchart shown in FIG.

As a result of the determination (Sl) as to whether or not to perform ISO, if ISC is to be performed, target idle revolution speed Ns that is determined in advance from the water temperature in target revolution speed search means 12
(S2). In addition, the comparison means 17 uses the first detection value On of the battery voltage and the previous detection value U input from the register 16.

(S8). And if Un≧Uo, then U
The cent is n-+U (S9), and the process moves to the next step 312. In addition, when Un<Uo, the calculation means 18 calculates the weighted average value Um of Un and UO (=(n-1)/n-Uo
+Un) and set it to Urn-”U (
SIO). Next, the pulse width search means 19 searches for the pulse width of the drive pulse predetermined in accordance with the input signal S9 or 310, that is, the set opening time when opening the solenoid valve 8A or 8B. (Sll).

Next, the actual idle rotation speed N is measured by the actual rotation speed measuring means 3 (S3), and the target idle rotation speed Ns is compared with the actual idle rotation speed N by the comparison means 14 (S4).

As a result of the comparison, when Ns<H, the driving pulse transmitting means 15 transmits a driving pulse having the pulse width retrieved as described above to the solenoid valve 8B in response to the signal from the comparing means 14.
Only the solenoid valve 8B opens (S5). As a result, the signal negative pressure to the diaphragm actuator 7 decreases, the idle stopper 6 moves in the direction of decreasing fuel, and the idle rotation speed decreases and approaches the target value.

Furthermore, when N5=N, the drive pulse transmitting means 15 is not activated and the solenoid valves 8A and 8B are kept closed (S6).
. As a result, the signal negative pressure within the diaphragm actuator is maintained as it is, and the idle speed is maintained at the target value.

Further, when Ns>N, a drive pulse having the pulse width retrieved as described above is transmitted from the drive pulse transmitting means 15 to the solenoid valve 8A in response to a signal from the comparison means 14, and only the solenoid valve 8A is opened. (s7).

As a result, the signal negative pressure applied to the diaphragm actuator 7 increases, the idle stopper 6 moves in the fuel increasing direction, and the idle rotation speed increases and approaches the target value.

In this way, when the battery voltage drops, the weighted average of the detected values is calculated in S10 (see Figure 8), and the pulse width of the drive pulse is set based on this value. It is possible to improve control responsiveness by preventing valve opening delay of 8A or 8B, and even when the battery voltage suddenly changes from falling to rising, it is possible to suppress the sudden increase in pulse width due to excessive response, thereby preventing sudden changes in engine rotation. Changes can be prevented and hunting can be prevented from occurring.

As explained above, according to the present invention, it is possible to improve the responsiveness of engine speed control when the battery voltage drops, and also to prevent hunting of engine speed due to excessive response, resulting in stable driving performance. There is an effect.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional idle speed control device, Figure 2
The figure is a schematic diagram of the control valve in Figure 1, Figure 3 is a flowchart of the conventional control circuit, and Figure 4 (Al is the valve opening characteristic diagram at high voltage, and CB+ in the figure is the conventional valve opening characteristic diagram at low voltage. Figure 5 is a diagram showing the opening characteristics of the conventional control valve in response to a sudden change in battery voltage. FIG. 7 is a flowchart of the control circuit showing one embodiment, and FIG. 8 is a diagram showing the characteristics of read values with respect to changes in actual battery voltage. 1...Fuel pH- t pump 5...Control lever 6...Idle stopper 7...Diaphragm actuator 8...Control valve (VCM
Valve) 8A, 8B...Solenoid valve 9...Vacuum pump 10...Battery 11...Control circuit
12...Target rotation speed search means 13...Actual rotation speed measurement means 14...Comparison means 15...Drive pulse transmission means 16...Register 17...Comparison means 18...Calculation means 19 ...Pulse Width Search Means Utility Model Registration Applicant Japan Electronics Co., Ltd. Representative Patent Attorney Fujio Sasashima Figure 4 (A) (B) Figure 5 (C)

Claims (1)

[Claims] It is equipped with a pressure-responsive actuator connected to an idle stopper that regulates the idle position of the control lever of the fuel injection pump, and a control valve that controls the signal pressure to this actuator. In a diesel engine idle speed control device that controls the idle speed by comparing and controlling the transmission of drive pulses to the control valve, the battery voltage is detected at predetermined intervals, and the battery voltage is When the voltage drops, the new and old detected values of the battery voltage are weighted averaged, and when this weighted average value is larger than the latest detected value, the pulse width of the control valve drive pulse is set based on the weighted average value, and the pulse width of the control valve drive pulse is set based on the weighted average value. An idle rotation speed control device comprising: means for setting a pulse width based on the latest detected value of battery voltage.