JPS58143146A - Idle engine speed controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To slow down the fuel supply recovery revolutional speed to the extent of somewhere close to idle engine speed as well as to improve the fuel consumption and engine braking, by upping the output torque of an engine for a set time, immediately after resetting the fuel supply from being cut off during deceleration. CONSTITUTION:An engine control unit discriminates whether the fuel should be cut or not due to both a throttle valve on-off signal and an engine speed signal by means of a step 1 in the fuel routine as well as whether it is not during fuel cutting and being just after fuel supply recovering or not by a step 2. If it is just after the recovery, a flag FFCR is raised up by a step 3 and a timer value B is set by a step 4. In an idle engine speed control valve driving routine, if the value is disriminated to be FFCR=1 by a step 5, the timer signal B is subtracted by steps 6 and 7 whereby an idle engine speed control valve is opened up to A till the FFCR comes to ''0'', so that output torque is upped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an idle speed control device for an internal combustion engine.

In modern internal combustion engines, in order to improve efficiency and fuel efficiency during engine play, the fuel supply is cut off when the engine is decelerating, and the engine speed is reduced to a preset recovery speed. At times, the fuel supply may be restored to keep the engine running at idle. In addition, in order to improve fuel efficiency during idling, the intake air is adjusted to match the actual rotation speed with the target rotation speed calculated according to engine operating conditions, engine temperature, load fluctuations, etc. A control device may be added to set the idle speed of the engine by increasing or decreasing the engine speed.

However, in the past, the control value of the idle rotation speed was calculated only by correcting the basic characteristic value with the load fluctuation correction value, acceleration/deceleration correction value, and post-start correction value, so it was difficult to recover the idle speed after dialysis of the fuel supply. No corrections were made at all for the instability of the engine that sometimes occurs. For example, if the reset setting rotation speed is lowered to near the idle rotation speed, the recovery power of the engine rotation speed will decrease and the engine will become unstable.
In extreme cases, there was a risk that the engine would stall. Therefore, in the past, it was necessary to set the reset rotation speed sufficiently higher than the number of idle times to avoid engine instability and engine stall, which resulted in the problem that fuel efficiency could not always be improved sufficiently. there were.

The present invention has been developed by focusing on these conventional problems, and when the fuel supply is restored, the set value of the engine rotation speed is corrected upward to increase the generated torque and improve the recovery power of the rotation speed. The purpose of this is to avoid instability and engine stall that occur when fuel supply is restored, and thereby reduce the set rotation speed for recovery to near the idle speed, improving fuel efficiency and the effectiveness of the engine's 7° rake. The present invention will now be described in detail based on illustrated embodiments.

FIG. 1 is a system diagram showing one embodiment of the present invention, in which a signal disc plate 2a is fixed to the crankshaft (not shown) of an internal combustion engine 1, and the signal disc plate 2a is fixed to the crankshaft (not shown) of an internal combustion engine 1.
The output of the crank angle sensor 2 facing the engine a is supplied to the control unit 3 to calculate the engine speed N. Further, a throttle valve switch 4 is turned on when the intake throttle valve 4a provided in the intake passage 1a of the engine 1 is fully closed.
By supplying the output signal of the engine to the control unit 3, when the output signal of the throttle valve 4 is ON and the engine speed N is above a predetermined value, it is detected that the engine is in a deceleration operating state. On the other hand, an auxiliary air passage 5a is provided to provide bypass communication between the upstream and downstream sides of the intake throttle valve 4aO, and a negative pressure control pulp 6 The output signal of the control unit 3 is supplied to the negative pressure control pulp 6 to adjust the opening degree of the auxiliary air pulp 50, thereby increasing or decreasing the engine speed N during idling operation. There is.

A neutral switch 1 provided in the transmission T&, an air flow meter 8 provided in the intake passage 1aK, a water temperature sensor 9 provided in the engine cooling water passage, and a vehicle speed sensor 10
The outputs of and are respectively supplied to the control unit 3 to calculate the engine operating state, thereby controlling the strength of the signal negative pressure obtained by the voltage control valve 6 as described above, and at the same time controlling the intake port of the engine 1. A fuel injector 11 provided in the section is controlled to supply fuel, or to cut off and restore fuel supply.

In the above configuration, the intake throttle valve 4
When a is fully closed, the throttle valve switch 4 switches to the second
Turns on as shown by curve a in the figure.

Then, it is examined whether the engine speed N at this point is larger than the fuel cut setting speed Nz, and if N≧Nx, the width T1 of the drive pulse supplied to the fuel injector 11 is determined to be the minimum drive pulse width T3. fuel supply is cut off. When the engine rotation speed N decreases as shown by the curve in Figure 2 due to such cutoff of fuel supply and becomes smaller than the reset set rotation speed Nl, the width of the drive pulse supplied to the 7-uel injector 11 decreases. T1 is Ti
=TpXCOKFXALPHA+T,s (However, Tp=
KQ/N, = constant, Q = intake air amount.

C0EF=correction coefficient, ALPHA=λ control coefficient, 'l's=engine cooling water temperature), the supply of fuel from the fuel injector 11 is restarted (see FIG. 3).

When the fuel supply is restored at K as described above, the fuel supply restoration flag FFCR is set and the fuel supply restoration timer TMFCR is set to B. Then, in the routine of the idle speed control device (see FIG. 4), it is examined whether the fuel supply return flag FFCR is set. If the flag FFCR is set, the fuel supply return timer TMFCR is decremented by 1, and if this timer TMFCR is equal to or greater than "θ", the fuel supply return flag F
The duty of the idle speed control device is set to A without clearing the FCR, and the idle speed is controlled based on this value. Incidentally, A is the setting duty of the idle speed control device control which is set for a predetermined time after the fuel supply is restored according to the present invention, and B is the same set time, and if the fuel return flag FFCR is not set, the conventionally known duty is set. The idle rotation speed control program is executed.

Therefore, immediately after the fuel supply is restored, the auxiliary air pulp 5 provided as an idle speed control device, that is, a variable engine speed control device, is opened at duty A only during time B, thereby bypassing the intake throttle valve 4a. The amount of air increases, the generated torque increases, and a decrease in engine speed and engine stall are avoided. That is, in the past, the control signal supplied to the auxiliary air pulp 5 via the negative pressure control pulp 6 remained OFF even when the fuel supply was restored, but in the present invention, as shown by curve 4IC in FIG. Duty A for 8 hours only
Since the engine is turned ON, the engine intake air amount is increased by time B as shown by curve d in Fig. 2, so the engine speed N
The recovery power of the engine is improved, and a drop in rotational speed and engine stall are avoided. As a result, the fuel supply return setting rotation speed Ni
t can be lowered to near the set value of the idle speed, thereby preventing fuel wastage and improving the effectiveness of engine braking.

In the above embodiment, the engine rotation speed N is the return set rotation speed Ni+
Although the time and duty are uniquely determined when the engine speed becomes lower, as in the example shown in the vIN5 diagram, the set duty is determined according to the magnitude of the difference between the engine speed N and the set speed Nm. Two-stage AI with different sizes of people, Al
By switching to the value of , the engine resilience can be rationalized and the engine rotation can be stabilized.

In the 1M example shown in Fig. 6, the time change of the engine rotation speed N,
Engine speed deceleration ΔN due to fuel cut
The setting duty A is set in two stages according to the size of the 3. A4
In this case as well, there is an advantage that the recovery power of the engine rotational speed can be made appropriate and that changes over time due to the magnitude of the 7-rection can be canceled.

Further, in the above embodiment, the set interval is set to a constant time, but the same effect can be obtained by setting the set interval B to a constant rotation period (c period) as in the embodiment shown in FIG. FIG. 8 shows an idle rotation speed control routine during period control.

As explained above, according to the present invention, the set engine speed is corrected upward at the time of transition from the interruption of fuel supply due to deceleration operation to recovery, and the generated torque at the time of recovery is corrected to increase. Even if the reset set rotation speed is lowered, there is no risk that the engine rotation speed will drop excessively by FILK, resulting in instability or engine stall. Therefore, it is possible to improve the fuel efficiency of an internal combustion engine equipped with this type of control device, and also to improve the 1 engine play + 0 effectiveness.

[Brief explanation of drawings]

Fig. 1 is a control system diagram of the first embodiment of the present invention, Fig. 2 is a characteristic diagram of each part of the same as above, and JIK 3 is also a fuel supply O line disconnection/
The return routine, No. 41a is the same routine for variable engine speed control, FIG. 5 is the routine for variable engine speed control of the second embodiment, and Figure IK6 is the routine for variable engine speed control of the third embodiment, summary 7 The figure shows a routine for operating range control in the fourth embodiment, and FIG. 8 shows a routine for variable engine speed control. 1... Internal combustion engine 2... Crank angle sensor 3
...Control unit 4...Storage valve switch 5...Auxiliary air pulp 6...
Negative pressure control pulp T...neutral switch 8.
...Air flow meter 9...Water temperature sensor? 1
0...Vehicle speed sensor 11...Fuel engine injector patent applicant Fujio Shioji Sasajima, representative of Nido Jidosha Co., Ltd. Figure 2B: ISC Cositrono L/) ae4m Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] (υ Means for detecting deceleration operation of the engine, means for detecting the engine speed, and supply of fuel by inputting the deceleration operation signal and the rotation speed signal output from both of the above means. It is equipped with a fuel cut control device that turns off and returns the engine, and a variable engine speed control device that variably controls the engine speed, and outputs a return signal that is output in synchronization with the return of the fuel cut control device to the engine. An idle speed control device for an internal combustion engine, characterized in that the engine speed variable control device is supplied as a speed increase signal to the engine speed variable control device. (2) The engine speed variable control device is a device that variably controls the amount of intake air. An idle speed control device for an internal combustion engine according to claim 1, characterized in that: (3) the engine speed increase correction amount by the engine speed variable control device is a deceleration of the engine speed or an engine speed change control device; The idle speed control device for an internal combustion engine according to claim 1 or 2, characterized in that the idle speed control device is set in response to the magnitude of the difference between the rotation speed and the reset set rotation speed. (4) Engine The idle speed of an internal combustion engine according to any one of claims 1 to 3, wherein the engine speed increase correction section by the variable speed control device is a fixed period or time. Control device.