JPH05280398A - Idle speed control device for engine - Google Patents

Abstract

PURPOSE:To restrict reduction of a discharge quantity of an oil pump, prevent increase of a time lag, and reduce a shock by controlling an idle rotation speed of an engine to be reduced in two stages in shifting from an N-range to a D-range. CONSTITUTION:In an idle rotation control device for an engine equipped with an automatic transmission, a shift position of the automatic transmission is detected by a detection means. Passage of a specified time after change of the shift position into a run range is recognized by a set means. An engine rotation speed is detected by a detection means. In the meanwhile, a first desired rotation speed is set when the shift position is at the run range in idle operation, a second desired rotation speed which is smaller for a specified time is set when the shift position is changed into the run range, and a third desired rotation speed which is smaller further is set after passage of a specified period respectively by set means. The engine is controlled by a control means to put the engine rotation speed at the desired rotation speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an engine equipped with an automatic transmission, and more particularly to an idle speed control device adapted to appropriately switch an idle target speed in accordance with a shift change. Regarding

[0002]

2. Description of the Related Art As a technique of this kind, JP-A-1-203
The one described in Japanese Patent No. 637 is known. In this technique, when the shift range of the automatic transmission is switched from the non-driving range (for example, N range) to the traveling range (for example, D range), the N range idle target rotation speed is changed to the D range idle target rotation speed. The switching is delayed from the shift time by a predetermined time.

According to this technique, the engine rotation speed when switching from the N range to the D range can be maintained at a high state, so that a large discharge amount of the oil pump of the automatic transmission can be secured, and the D range. It is said that it is possible to reduce the time lag of shift to (the delay time from the execution of the shift operation to the actual completion of the shift).

[0004]

However, since the shift is performed in the state where the engine speed is high, that is, in the state where the output is high in this technique, the amount of increase in the output shaft torque during the shift is large and the shift shock is large. Is a big problem.

The present invention has been made in view of such a conventional problem, and provides an idle speed control device capable of suppressing a shock while preventing an increase in a time lag for shifting to a running range. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention, and particularly the invention of claim 1, has an automatic idle speed controller for an engine equipped with an automatic transmission, as shown in FIG. 1 (a). Means for detecting the shift position of the transmission, means for confirming that a predetermined period has elapsed since the shift position of the automatic transmission was switched from the non-running range to the running range, and means for detecting the engine rotation speed, During idle operation, the first idle target rotation speed is set when the shift position is in the non-running range, and the first idle target rotation speed is set for the predetermined period when the shift position is switched from the non-running range to the running range. Means for setting a second idle target rotation speed that is smaller than the speed, and for setting a smaller third idle target rotation speed after the lapse of a predetermined period;
Means for controlling the engine so that the engine rotation speed becomes the idle target rotation speed is provided, thereby achieving the above object.

The invention of claim 2 further comprises means for detecting the oil temperature of the automatic transmission, as shown in FIG. 1 (b).
The object is achieved by providing means for setting the predetermined period to be longer as the oil temperature of the automatic transmission is higher.

According to the third aspect of the present invention, as shown in FIG. 1 (c), the measured value of the engine rotation speed is within a predetermined range in the vicinity of the second idle target rotation speed Ne2 for the predetermined period. The above-mentioned object was achieved by providing a means for setting the period until entering.

[0009]

In the invention of claim 1, the non-traveling range (N
There is a range, a P range, etc., but representatively from the "N range") to a driving range (a forward traveling range including the D range, an R range, etc., but representatively referred to as the "D range") During a shift, the engine idle speed decreases in two steps.

That is, when the shift operation is performed, the first idle target rotation speed Ne1 in the N range is switched to the second idle target rotation speed Ne2, and when a predetermined period elapses thereafter, the third idle speed is lowered. Switch to the target rotation speed. Therefore, the first idle rotation speed Ne1
From the second idle rotation speed Ne2 to the third idle rotation speed Ne3 at once, instead of immediately switching to the third idle rotation speed Ne2.
Therefore, the decrease in the discharge amount of the oil pump is suppressed and the increase in time lag is prevented.

Further, since the shift operation is executed mainly in the state of the intermediate second idle rotation speed Ne2, the shift operation is performed in the state of the engine output lower than that of the above-mentioned conventional example, and the shock is reduced. Planned.

Further, according to the second aspect of the invention, depending on the oil temperature of the automatic transmission, the higher the oil temperature, the longer the predetermined period, that is, the duration of the second idle rotation speed Ne2 is set. The relatively high idle rotation speed is maintained at the time of high oil temperature where the pump discharge amount is likely to be insufficient due to the increase in the leakage amount, and the increase in the shift time lag due to the decrease in the discharge amount is suppressed.

In the third aspect of the present invention, the actual engine speed is the second idle target engine speed Ne2.
It is considered that the shift from the N range to the D range is completed when approaching to. Then, at that point, the final idle target rotation speed Ne3 of the D range is set, and the engine rotation speed is controlled. Therefore, until the shift to the D range is achieved, the second idle target rotational speed Ne2, which is the intermediate speed, is reliably maintained, the decrease in the pump discharge amount during that time is suppressed, and the increase in the shift time lag is prevented. .. Further, when it is considered that the shift has been achieved, the final third idle target rotation speed Ne3 is set, so that the high rotation speed is not continued unnecessarily, which contributes to the improvement of fuel efficiency.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 is an overall schematic view of an engine with an automatic transmission to which the present invention is applied. This engine is an intake air amount sensing type electronic fuel injection engine for automobiles, and its output shaft is connected with an automatic transmission (hereinafter referred to as ECT) 900 shown in FIG.

The air sucked from the air cleaner 10 is
The air flow meter 12, the intake throttle valve 14, the surge tank 16, and the intake manifold 18 are sequentially sent. This air is mixed with fuel injected from the injector 22 in the vicinity of the intake port 20 and is further sent to the combustion chamber 26A of the engine body 26 via the intake valve 24. Combustion chamber 26
Exhaust gas generated as a result of combustion of the air-fuel mixture in A is an exhaust valve 28, an exhaust port 30, an exhaust manifold 32.
And to the atmosphere via an exhaust pipe (not shown).

The air flow meter 12 is provided with an intake air temperature 100 sensor for detecting the intake air temperature.
Further, the exhaust manifold 32 is provided with an exhaust temperature sensor 101 for detecting the exhaust temperature of the engine.
The intake throttle valve 14 rotates in conjunction with an accelerator pedal (not shown) provided in the driver's seat. The intake throttle valve 14 is provided with a throttle sensor 102 for detecting its opening.

A water temperature sensor 104 for detecting the engine cooling water temperature is provided on the cylinder block 26B of the engine body 26. Further, the distributor 38 having a shaft rotated by the crank shaft of the engine body 26 is provided with a crank angle sensor 108 for detecting a crank angle from the rotation of the shaft, from which the engine rotation speed is detected. It has become so.

Further, the ECT has a rotation speed N of its output shaft.
A vehicle speed sensor 110 for detecting the vehicle speed from 0, a C0 sensor 113 for detecting the rotational speed of the clutch C0, and a shift position sensor 1 for detecting the shift position.
12. Further, a sensor 111 for detecting the oil temperature in the oil pan of the automatic transmission is provided.

Each of these sensors 100, 101, 10
2, 104, 108, 110, 111, 112, 11
3 and the outputs of the pattern select switch 114, the overdrive switch 116, and the brake lamp switch 118 are the engine computer 40 or the ECT.
It is input to the computer 50.

The engine computer 40 calculates the fuel injection amount and the optimum ignition timing using the input signals from the respective sensors as parameters, and controls the injector 22 so that the fuel is injected for a predetermined time corresponding to the fuel injection amount. The ignition coil 44 is controlled so that the optimum ignition timing is obtained.

An idle rotation speed control valve 42 driven by a step motor is provided in a bypass passage that connects the upstream side of the intake throttle valve 14 and the surge tank 16.

The engine computer 40 uses the E
Information from each sensor on the automatic transmission side is received from the CT computer 50, and this idle speed control valve (ISCV) 4
By controlling 2, the idle speed of the engine is controlled.

This concrete control flow will be described later in detail.

On the other hand, the transmission section 900 of the ECT in this embodiment is provided with a torque converter 910, an overdrive mechanism 920, and an underdrive mechanism 930, as shown in FIG. The torque converter 910 is a known one including a pump 911, a turbine 912, and a stator 913, and includes a lockup clutch 914.

The overdrive mechanism 920 includes a sun gear 921, a planetary pinion 922 that meshes with the sun gear 921, a carrier 923 that supports the planetary pinion 922, and a ring gear 924 that meshes with the planetary pinion 922. Equipped with
The rotation state of this planetary gear device is controlled by the clutch C0, the brake B0, and the one-way clutch F0.

The underdrive mechanism 930 includes a common sun gear 931, planetary pinions 932 and 933 meshing with the sun gear 931, and the planetary pinion 9.
Carriers 934 and 935 supporting 32 and 933, and a ring gear 9 that meshes with planetary pinion 932 and 933.
Two sets of planetary gear units 36 and 937 are provided, and the rotation state of the planetary gear unit and the connection state with the overdrive mechanism are clutches C1 and C2 and brakes B1 to B1.
It is controlled by B3 and one-way clutches F1, F2. Since the transmission unit 900 is known per se, the connection state of each component will be described with reference to FIG.
In the figure, only the skeleton is shown and the detailed description is omitted.

The ECT in this embodiment is provided with the transmission section 900 as described above, and is provided with the throttle sensor 102 and the vehicle speed sensor 110 or the C0 sensor 1.
The electromagnetic valves S1 to S4 in the hydraulic control circuit 60 are driven and controlled by the ECT computer 50 to which signals such as 13 are input according to a preset shift pattern, and each clutch, brake, etc. as shown in FIG. The gear shift control is performed by combining the engagements. In FIG. 4, the mark ◯ indicates the operating state, and the mark ⊚ indicates the operating state only during driving.

Next, each example of a specific control flow of the idle rotation speed will be described with reference to FIGS.

FIG. 5 is a flowchart of the first control example.

When this flow starts, first, at step 200, it is judged if the shift position is in the D range or not. If it is not the D range, it is determined in step 202 whether it is the N range. In the case of the N range, the routine proceeds to step 204, where the first idle target rotation speed Ne1 is set as the idle target rotation speed of the N range. N
If it is not in the range, other control is performed in step 206.

When the N range is switched to the D range, the determination at step 200 changes from NO to YES,
Go to step 220. Then, the first idle target rotation speed N is set as the D range idle target rotation speed here.
A second idle target rotation speed Ne2 lower than e1 is set.

After the second idle target rotation speed Ne2 is set, it waits for the predetermined time T preset in steps 222 and 224 to elapse. When the predetermined time T has elapsed, the routine proceeds to step 226, where the third idle target rotation speed Ne3 which is lower than the second idle target rotation speed Ne2 is set as the D range idle target rotation speed.

On the other hand, in parallel with this control, the engine control computer 40 uses the idle target rotation speeds Ne1 to Ne3 thus set and the actual measurement value of the engine rotation speed obtained from the detected value of the crank angle sensor 108. The idle rotation speed control valve 42 is feedback-controlled to match the actual idle rotation speed with the target rotation speed.

FIG. 8 shows the relationship between the change in the idle target rotation speed and the timing of the shift operation.

FIG. 8A shows a conventional technique. In this device, the idle target rotation speed of the N range is maintained until a predetermined time elapses from the time when the N range is switched to the D range.

On the other hand, in the case of the present invention shown in (b), when the N range is switched to the D range, the first idle target rotation speed Ne1 is changed to the second idle target rotation speed Ne2 as a paragraph. The second idle target rotation speed Ne2 is maintained for a predetermined period, and the third idle target rotation speed Ne3 is switched to a lower value after the predetermined period has elapsed.

Therefore, as compared with the case where the first idle rotation speed Ne1 is immediately switched to the third idle rotation speed Ne3 by passing through the intermediate second idle rotation speed Ne2, the discharge amount of the oil pump is reduced. Since it can be suppressed and the idle speed itself is slightly reduced, the load at the time of engagement of the clutch C1 is correspondingly small, and therefore the shift tends to be completed earlier, so that the increase of the shift time lag is almost complete. Can be prevented.

Further, since the shift operation is mainly executed in the state of the intermediate second idle rotation speed Ne2, it becomes possible to perform the shift operation with a hydraulic pressure lower than the conventional one, and the shock at the time of shift. Is reduced.

Further, if the predetermined time T is determined so that the shift is surely completed while the second idle target rotation speed Ne2 is maintained, the time lag of the shift is practically not increased at all, and It is possible to set the third idle target rotation speed Ne3 (final D range idle target rotation speed) to a value that is lower than the conventional value, and it is possible to improve fuel efficiency.

The first idle target rotation speed Ne1
Needless to say, the values of the second idle target rotation speed Ne2 and the third idle target rotation speed Ne3 are actually more appropriately determined depending on, for example, the actual condition of use of the air conditioner or the warm-up condition. It goes without saying that you can set the changed value.

Next, a second control example will be described with reference to FIG. In this flow, the same parts as those in the steps of the flow of FIG. 5 are designated by the same reference numerals, and the description thereof may be omitted to avoid duplication.

When the flow of FIG. 6 starts, first, at step 200, it is judged if the shift position is in the D range or not. If it is not the D range, the same processing as the flow of FIG. 5 is performed (steps 202, 204, 206).

When the N range is switched to the D range, the determination at step 200 changes from NO to YES,
In step 208, the oil temperature a of the automatic transmission is detected. Then, in the next step 210, a predetermined time T until the idle target rotation speed of the D range is switched (switched from Ne2 to Ne3) is determined according to the detected oil temperature a of the automatic transmission.

This predetermined time T is the duration of the second idle target rotation speed Ne2, as will be understood from the following description, and is set longer as the oil temperature a is higher. That is, when the oil temperature a of the automatic transmission becomes high, the amount of oil leakage increases and the pump discharge amount tends to become insufficient. Therefore, in order to prevent the discharge amount from becoming insufficient, the relatively high idle target rotation speed is maintained for the time until the N → D shift is completed (set according to the actual result according to the oil temperature).

When the predetermined time T corresponding to the oil temperature a is determined, it is confirmed in step 212 whether the predetermined time T is zero. If it is not zero, the process proceeds to step 220. And
Here, as the D range idle target rotation speed, a second idle target rotation speed Ne2 lower than the first idle target rotation speed Ne1 is set.

After the second idle target rotation speed Ne2 is set, it waits for the predetermined time T previously determined in steps 222 and 224 to elapse. When the predetermined time T has passed, the routine proceeds to step 226, where the third idle target rotation speed Ne3 which is lower than the second idle target rotation speed Ne2 is set as the D range idle target rotation speed. If it is determined in step 212 that the predetermined time T = 0, the process directly proceeds to step 226 to set the third idle target rotation speed Ne3 as the D range idle target rotation speed.

As described above, the engine rotation speed converges to the target rotation speed set here.

In this way, the duration of the second idle target rotation speed Ne2 is adjusted according to the oil temperature of the automatic transmission, so that the duration of the second idle rotation speed is limited to the necessary minimum. Become so. As a result, it is possible to reduce the idle speed to the third idle speed at a more precise and accurate timing, which contributes to the improvement of fuel efficiency.

Next, a third control example will be described with reference to FIG. Also in this flow, the same parts as those in the steps of the flow of FIG. 5 are denoted by the same reference numerals, and the description thereof may be omitted to avoid duplication.

When the flow of FIG. 7 starts, first, at step 200, it is judged if the shift position is in the D range or not. If it is not the D range, the same processing as the flow of FIG. 5 is performed (steps 202, 204, 206).

When the N range is switched to the D range, the determination at step 200 changes from NO to YES,
In step 220, the second idle target rotation speed Ne2 lower than the first idle target rotation speed Ne1 is set as the D range idle target rotation speed. Next, at step 230, the timer t is set to "0" and the routine proceeds to step 232, where the actual engine speed Ne
To detect.

Next, at step 234, it is determined whether or not the previously detected actual measured engine speed Ne is within a predetermined range (within ± δn) near the second idle target rotational speed Ne2. If it is not within the predetermined range, the loop of steps 230 → 232 → 234 → 230 is repeated.
During this period, the idle target rotation speed remains the second idle target rotation speed Ne2.

Then, when the engine speed Ne falls within the predetermined range, the determination at step 234 becomes YES and the routine proceeds to step 222, where the value t of the timer is increased. Step 2 until the preset time T1 has elapsed
The loop of 30 → 232 → 234 → 222 → 234 → 230 is repeated. If the engine speed continues to fall within the predetermined range until the predetermined time T1 elapses, the determination at step 224 becomes NO at the time when the predetermined time T1 elapses, and the routine proceeds to step 226, where the D range idle target rotation speed is reached. The speed is switched to the third idle target rotation speed Ne3. If the engine speed N deviates from the predetermined range even once before the predetermined time T1 elapses, the process returns to step 230 at that time.

In this control, the engine speed is controlled at the second idle target rotation speed Ne2 as described above, and the actual engine rotation speed Ne is stably converged near the target value Ne2 for at least the predetermined time T1 or longer. Then, it is considered that the shift is completed at that time, and the speed is reduced to the third idle target rotation speed Ne3. Therefore, it is possible to reliably determine the actual shift completion, suppress the increase of the shift time lag, and further reduce the idle rotation speed to Ne3 promptly without maintaining the state of Ne2 longer than necessary.

[0056]

As described above, according to the present invention, N
When shifting from the range to the D range, the engine idle speed decreases in two steps. Therefore, the idle rotation speed does not change at once, but rather goes through an intermediate speed once, so that the decrease in the discharge amount of the oil pump is suppressed and the idle time speed itself is reduced, so that the increase of the shift time lag is almost complete. To be prevented. Also, the shift operation can be performed under low hydraulic pressure,
Shock is reduced.

Further, according to the invention of claim 2, the higher the oil temperature of the automatic transmission, the longer the duration of the intermediate idle rotation speed. Therefore, the high oil temperature is likely to cause the pump discharge amount shortage due to the increase of the leakage amount. At times, it is possible to effectively suppress an increase in time lag.

Further, according to the third aspect of the present invention, the control at the intermediate idle rotation speed is ended based on the state of the actual engine rotation speed, so that the increase of the shift time lag is surely performed. It can be suppressed, and can be reduced to the final D range idle rotation speed at the earliest possible timing. Therefore, it contributes not only to improvement of operation performance but also to reduction of fuel consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is an overall schematic diagram of an electronic fuel injection engine for an automobile to which the present invention is applied.

FIG. 3 is a schematic diagram of the automatic transmission shown in FIG.

FIG. 4 is a diagram showing an operating state of each friction engagement device of the automatic transmission.

FIG. 5: Engine control computer or E
Flowchart showing a first example of control executed by a CT computer

FIG. 6 is a flowchart showing another example of the same.

FIG. 7 is a flowchart showing still another example.

FIG. 8 is a diagram comparing the characteristics of the prior art (a) and the present invention (b).

[Explanation of symbols]

26 ... Engine main body, 108 ... Crank angle sensor (engine rotation speed sensor), 110 ... Vehicle speed sensor, 111 ... Automatic transmission oil temperature sensor, 112 ... Shift position sensor, 900 ... Automatic transmission, 42 ... Idle rotation speed control Valve, 40 ... Engine computer, 50 ... ECT computer.

Claims (3)

[Claims] Claim: What is claimed is: 1. In an engine idle speed control device having an automatic transmission, means for detecting a shift position of the automatic transmission, and after the shift position of the automatic transmission is switched from a non-running range to a running range. A means for confirming that a predetermined period has elapsed, a means for detecting the engine rotation speed, and a first idle target rotation speed is set when the shift position is in the non-running range during idle operation, and the shift position is not running. When the range is changed to the travel range, a second idle target rotation speed that is smaller than the first idle target rotation speed is set for the predetermined period, and a smaller third idle target rotation speed is set after the predetermined period has elapsed. And a means for controlling the engine so that the engine speed becomes an idle target speed. Idle speed control apparatus for an engine to be. 2. The method according to claim 1, further comprising means for detecting the oil temperature of the automatic transmission, and means for setting the predetermined period longer as the oil temperature of the automatic transmission is higher. Idle speed control device for engine. 3. The means according to claim 1, further comprising means for setting the predetermined period as a period until the output of the engine rotation speed detection means falls within a predetermined range near the second idle target rotation speed. Idle speed control device for engine.