JPH01300036A - Idle rotational speed controller for engine - Google Patents

Abstract

PURPOSE:To make it possible to maintain the running performance at very low speed operation under loaded conditions well by changing the feedback rotational speed for enabling idle rotation speed control to the high rotational side when an engine and mission is under noninterlocked conditions. CONSTITUTION:A feedback control execution means B is provided to feedback- control the engine speed to the aimed speed when the engine speed detected by an engine speed detection means A becomes lower than the feedback rotational speed set before hand. According to this means B, the idle speed of engine is controlled by means of an idle speed control means C. A connection condition detecting means D is provided to detect the interlocked conditions of engine (a) and mission. The output thereof is sent out to a feedback rotational speed changing means E, and when the engine and mission are under noninterlocked conditions, the feedback rotation speed is changed to the higher rotation side than the position under the interlocked conditions.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine idle speed control device.

(Prior Art) Feedback control of the idle rotation speed of an engine to a target rotation speed set according to conditions such as water temperature has been proposed in the past. For example, Japanese Patent Application Laid-Open No. 56-44431 describes a device in which an electromagnetic bypass valve is provided in a bypass passage that bypasses a throttle valve, and the idle speed is feedback-controlled by controlling bypass air. There is. Other known idle speed control means include methods that utilize ignition timing control.

Such idle speed feedback control is normally performed on the condition that the engine is not in the starting zone, the throttle is fully closed, and the engine speed is below a preset feedback execution speed. executed when This feedback execution speed is several hundred revolutions (for example, 37
5 rpm) is set high. In contrast to the normal idle rotation speed in a warm-up state, the idle rotation speed is normally increased during warm-up, and the idle rotation speed is also increased when a load such as an air conditioner is applied. For this reason, the feedback execution rotation speed is set high so as to be able to cope with changes in the target rotation speed. In addition, since the feedback execution speed is set high in this way, when returning to normal idling after warming up, the ignition is activated while the engine speed drops below the actual rotation speed and drops to around the target rotation speed. There is a risk that the idle speed control means such as the timing control device will be operated in the direction of lowering the engine speed more and more, and the engine speed will drop significantly. Therefore, a condition may be added so that the feedback is executed after a predetermined period of time has elapsed after the engine speed has decreased and reached the feedback execution speed.

By the way, conventionally, the above-mentioned feedback execution speed in idle speed control is set to a certain constant speed, regardless of whether the engine and transmission are in a connected state, that is, regardless of whether they are in a loaded state or an unloaded state. It was set. However, in a loaded state, if the feedback execution speed is high, the engine speed will be close to the feedback execution speed when driving at very low speeds, resulting in a jerky feeling as the engine enters and exits the feedback execution zone. , the running performance deteriorates. On the other hand, under no-load conditions, the engine speed does not easily drop even when deceleration is performed because the engine is disconnected from the vehicle body. Therefore, when the feedback execution rotation speed is high, the idle recovery performance deteriorates. This phenomenon becomes even more remarkable in the case of an engine in which dashpot correction is performed to increase the amount of air 1 during deceleration. In addition, even if dashpot correction is not performed, it may be difficult to return to idle due to variations in air volume, etc., and if learning control is performed and there is incorrect learning, the engine speed will not reach the feedback execution range. There may be a situation where it does not fall. In this way, in the conventional idle speed control device, when the feedback execution speed is high, the running performance in a loaded state deteriorates, and when the feedback performance speed is low, it is difficult to return to idle in a no-load state. There is a problem in that the feedback execution speed cannot be set to an appropriate level for both loaded and unloaded conditions, as the performance deteriorates.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and is intended to prevent deterioration of running performance due to feedback when running at very low speeds in a loaded state, and to prevent deterioration of running performance in an unloaded state. ,
To provide an engine idle speed control device capable of quickly returning to idle even if there are factors that keep the engine speed at a high level, such as variations in intake air pressure.

(Structure of the Invention) The present invention is based on the knowledge that as long as the feedback execution rotation speed of idle rotation speed control is set uniformly, the optimal conditions for both the loaded state and the no-load state cannot be satisfied. , its configuration is shown in FIG. That is, the engine idle speed control device according to the present invention includes an idle speed control means for controlling the idle speed of the engine, an engine speed detection means for detecting the engine speed, and an engine speed that is set in advance. a feedback control execution means that outputs a feedback control signal to the idle rotation speed control means for feedback controlling the engine rotation speed to the target rotation speed when the rotation speed becomes equal to or lower than the feedback execution speed; and a connection state between the engine and the transmission. and feedback that changes the feedback execution rotation speed to a higher rotation side when the engine and the transmission are in the uncoupled state than when they are in the coupled state, based on the output of the coupled state detection means. The present invention is characterized by comprising an execution rotation speed changing means.

(Function) When the engine and transmission are connected (under load), the feedback execution speed is set low as shown in Figure 2, and when the engine returns to idle, the engine speed is set to this feedback execution speed. Feedback control is started after the rotational speed reaches the target rotational speed, and the rotational speed gradually converges to the target rotational speed. The feedback execution speed at this time can be set to a level sufficiently lower than the engine speed during normal very low speed driving, so the frequency of entering the feedback region during very low speed driving is low, and therefore the feedback is not performed. Deterioration of running performance due to not being carried out and sagging is less likely to occur.

On the other hand, when the engine and transmission are in a disconnected state (no load), the feedback execution rotation speed is changed to a higher value as shown in the figure.

In the uncoupled state, the engine speed decreases slowly during deceleration and does not easily reach the feedback execution speed level under load, but by changing the feedback execution speed to a higher level, the engine speed can be quickly fed back. Control is started to ensure return to idle.

(Example) Examples will be described below based on the drawings.

FIG. 3 is an overall system diagram of an embodiment of the present invention applied to an engine of a vehicle with an automatic transmission that controls the idle speed by adjusting the amount of bypass air.

In this embodiment, an injector 3 for fuel injection is provided in an intake passage 2 of an engine 1. Further, the upstream side of the intake passage 2 is connected to an air cleaner 5 via a surge tank section 4. A throttle valve 6 is provided upstream of the surge tank section 4, and an air flow meter 7 for detecting the amount of intake air is provided downstream of the connection section with the air cleaner 5.
An intake air temperature sensor 8 is provided. A bypass passage 9 that bypasses the throttle valve 6 is also formed in the intake passage 2, and an idle speed control valve (abbreviated as an ISO valve) 10 is provided in the bypass passage. The ISO pulp 10 is controlled by an engine control unit 11. The injector 3 and the engine's ignition device 142 are also controlled by this engine control unit.

The engine control unit 11 receives an engine rotation speed signal from a rotation sensor 14 attached to the camshaft 13 of the engine, a water temperature signal from a water temperature sensor 16 provided on the water jacket 15 of the engine l, and a water temperature signal from the air flow meter 7. intake air amount signal, and intake temperature signal from intake temperature sensor 8.

A throttle opening signal and an idle switch signal from a throttle sensor 17 provided on the throttle valve 6 are input, and a lock-up state signal and an inhibitor switch 20 from a lock-up switch 19 of an automatic transmission (A/T transmission) 18 are input. A shift lever position signal is input via the mission control unit 21. In addition, various load signals indicating on/off of air conditioners, electric fans, etc. are input. The engine control unit 11 determines whether it is loaded (D range) or unloaded (N range) from the shift lever position, and sets the feedback execution rotation speed according to the water temperature in response to each. Then, when the engine speed falls below the set feedback execution speed, feedback control of the idle speed by the ISO valve is started after a predetermined period of time. In other words, when the deviation between the actual rotation speed and the target rotation speed is greater than or equal to a predetermined value, the air amount feedback correction amount is calculated according to the deviation, and this feedback correction amount is added to the basic air amount at idle depending on the water temperature. Furthermore, the final intake air amount is calculated by adding correction amounts according to various load signals and dashpot correction amounts.

Then, based on this final air amount, the ISO valve is adjusted to converge the engine speed to the target rotation speed. The engine control unit 11 also controls the engine speed,
The fuel injection amount and ignition advance angle are calculated based on intake air pressure, water temperature, etc., and control signals are output to the injector 3 and ignition device 12, respectively.

FIG. 4 is a flowchart for controlling the ISO valve of this embodiment. Note that S1 to S ts represent each step.

Start and first read the engine speed N and water temperature THW (S,).

Next, it is determined whether there is a load (D range) or no load (N range) (S,).

If it is with a load, the basic air amount G for the load depending on the water temperature
B is called in (S3), and from the water temperature map, the feedback execution rotation speed N for the loaded system is determined.

Call in PLD (S4). And N<N0PLD,
In other words, the engine speed N is the feedback execution speed N
It is determined whether it has become lower than 0FLD (S5).

If N<N0PLD, reset the timer (zero value)
L(S,) and the feedback correction amount GFB are set to zero (S7). In other words, no feedback.

If N<N0PLD, the timer starts counting (T=T+1) (S8).

Then, check whether T>TFB, that is, the timer value or a predetermined value (SS), and if it is exceeded,
Deviation △N between actual engine speed N and target speed NO
Find (S + o).

Next, it is determined whether the absolute value of △N is greater than 2 Orpm (S,...), and if it is, then it is determined whether the idle switch is on (S,...).
,the law of nature. And if the idle switch is on, ΔN
Call in the feedback correction amount GFB according to (S
+, ).

When T>TFB, 1ΔNl>20rpm, or Sl! When the idle switch is not on, feedback is not performed, so the GF
Let B=0 (S,,).

Next, it goes to Sl and checks whether various loads such as an air conditioner are on, and if it is on, calls in a load correction amount GL corresponding to the load (S + S). Moreover, if various loads are not on, GL=0 is set (S17).

Next, in Sl, it is determined whether the dashpot (D/P) condition is on, that is, whether the dashpot is activated, and if yes, the dashpot correction amount GDP
(S, *). If the D/P condition is not on,
Let GDP=0 (St.).

And S! Go to I and calculate the final air amount GA as GA=
The calculation is performed in the form of CB+GFB+GL+GDP, and the ISO valve is controlled based on the calculation (S2.).

Also, if S is no, that is, no load, Sl3
to draw in basic air IIGB for no-load according to the water temperature,
At Sl4, retrieve the feedback execution rotation speed N0PLN from the no-load water temperature map.

Then, the process goes to S24, and it is determined whether N<N0PLN. If N<N0PLN, the process goes to S24, and the following steps are performed.
The ISO valve is controlled by S and ~Stl in the same way as when under load.

Also, if N<N0PLN is not established at So, the timer is reset at S, 6, and the process goes to S +4 to set GFB to zero.

Incidentally, even when there is no load, when the vehicle is running by inertia and the vehicle speed is, for example, 10 km/h or more, deterioration of running performance due to feedback still becomes a problem.

Therefore, when the vehicle speed is high even when there is no load, the feedback execution rotation speed may be lowered. This improves the running performance, especially in creep driving of automatic vehicles.

The present invention can be implemented in various other aspects, such as being applied to engines using other idle speed control means such as ignition timing control.

(Effects of the Invention) Since the present invention is configured as described above, when running at very low speed in a loaded state with the engine and transmission connected, the running performance is deteriorated due to feedback control of the idle rotation speed. In addition, under no-load conditions when the engine and transmission are separated, even if there are factors that maintain the engine speed at a high level during deceleration, such as variations in the amount of intake air, feedback is reliably executed and promptly It is possible to return to the idle state.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the present invention, Fig. 2 is an explanatory diagram of the operation of the present invention, Fig. 3 is a system schematic diagram of an embodiment of the present invention, and Fig. 4 is a flowchart for executing control of the embodiment. It is. ■=Engine, 9: Bypass passage, 10: ISC valve, II: Engine control unit, 14/Revolution sensor, I8: Automatic transmission. Agent Patent Attorney Jun Shinfuji - Figure 1 Figure 2 ↑

Claims (1)

[Claims] (1) Idle rotation speed control means for controlling the idle rotation speed of the engine; engine rotation speed detection means for detecting the engine rotation speed; Feedback control execution means for outputting a feedback control signal for feedback control of the rotation speed to the target rotation speed to the idle rotation speed control means, connection state detection means for detecting a connection state between the engine and the transmission, and the connection state Feedback execution rotation speed changing means changes the feedback execution rotation speed to a higher rotation side when the engine and transmission are in a disconnected state than when they are in a connected state, based on the output of the detection means. This is an engine idle speed control device.