JPH1150882A - Idle speed control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a fuel consumption by lowering an idle speed without causing the hydraulic pressure of a hydraulic pump to lower and the power generating capacity of an alternator to lower. SOLUTION: When a parking brake switch is turned off and the requirements for idle conditions are met, a target idle speed NSET is set at a low idle speed NLID until a set time is passed (S4). When a vehicle is stopped temporarily with the parking brake switch turned off, the idle operation is performed at low speed for the set time so as to improve a fuel consumption.

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 which improves fuel efficiency by lowering the idle speed under a predetermined condition for a set time.

[0002]

2. Description of the Related Art Generally, during idle operation, the amount of intake air is controlled independently of the throttle valve by controlling the opening of an idle speed control (ISC) valve interposed in an idle passage that bypasses the throttle valve. A desired idle speed is obtained. In an engine employing an electronically controlled throttle valve, a desired idle speed is obtained by controlling the opening of the throttle valve itself.

In such idle speed control, the target idle speed is set according to the engine operating conditions such as warm-up operation, or the increase in engine load due to accessories such as when an air conditioner switch is turned on. Is set high.

[0004] Incidentally, if the idle-up control is uniformly performed when the air conditioner switch is turned on, only the deterioration of fuel efficiency is caused. For example, in Japanese Patent Application Laid-Open No. 3-185241, the select lever is set to the travel range. A technology is disclosed in which when a parking brake is in an operating state in a state, unnecessary idle-up is prohibited even when the air conditioner switch is in an ON state to improve fuel efficiency.

[0005]

However, in the above-mentioned prior art, since the idle-up is merely prohibited, the fuel efficiency is not positively improved. On the other hand, if an attempt is made to improve fuel efficiency by actively reducing the idle speed, not only will the alternator's power generation capacity be reduced due to the reduced idle speed, but also automatic transmission will be used in engines that use an engine-driven oil pump. The hydraulic pressure supplied to the device is reduced, resulting in malfunction.

In order to cope with this, a sensor for detecting a decrease in the power generation capacity of the alternator and a decrease in the oil pressure of the automatic transmission is provided, and when the power generation capacity or the oil pressure decreases, the idle speed is returned to the normal idle speed. However, not only is the number of sensors increased and the control system becomes complicated, but also the cost is increased due to the increase in the number of parts, which is not feasible.

The present invention has been made in view of the above circumstances, and even when the idling speed is reduced, the alternator is hardly affected by a decrease in the power generation capacity and a decrease in the oil pressure of the oil pump. It is an object of the present invention to provide an idle speed control device for an engine that can perform the operation.

[0008]

According to a first aspect of the present invention, there is provided a first engine idle speed control apparatus for variably setting a target idle speed during idle operation according to an engine operating state. When the temporary stop state of the vehicle is determined, the target idle speed is set to a lower value for a set time.

A second engine idle speed control device is the first engine idle speed control device, wherein the vehicle is temporarily stopped when the parking brake is inactive and idle conditions are satisfied. It is characterized by being determined to be in a state.

A third engine idle speed control device is the first engine idle speed control device according to the first engine idle speed control device, wherein the vehicle is temporarily stopped when the select lever is in the travel range and the idle condition is satisfied. Is determined.

A fourth engine idle speed control device is provided in accordance with the first engine idle speed control device, wherein the vehicle speed has exceeded the set vehicle speed and the idle condition is satisfied. It is determined that the vehicle is in a temporary stop state.

A fifth engine idle speed control device is the first engine idle speed control device in which the vehicle speed is equal to or greater than the set vehicle speed and the idle time is satisfied when the vehicle speed exceeds the set time. It is determined that the vehicle is in a temporary stop state when the vehicle is in the stop state.

A sixth engine idle speed control device is the first engine idle speed control device, wherein the vehicle is temporarily stopped when the brake switch is on and the idle condition is satisfied. Is determined.

A seventh engine idle speed control device is the first to sixth engine idle speed control devices, wherein the setting of the target idle speed low value is prohibited while a predetermined engine load is operating. It is characterized by doing.

An eighth engine idling speed control apparatus for variably setting a target idling speed during idling operation according to the engine operating condition, wherein a predetermined engine load is operating and idling conditions are satisfied. During the operation, the target idle speed is set to a value lower by a set time.

According to a ninth engine idle speed control device, in the eighth engine idle speed control device, the predetermined engine load is an air conditioner.

A tenth engine idle speed control device is the eighth engine idle speed control device, wherein the predetermined engine load is a headlight.

That is, the first engine idle speed control device determines whether the vehicle is temporarily stopped,
The target idle speed is set lower by a set time.

In the idle speed control device for the second engine, the idle speed control device for the first engine may be configured to temporarily stop the vehicle when the parking brake is inactive and the idle condition is satisfied. to decide.

In the third engine idle speed control device, the first engine idle speed control device determines that the vehicle is in a temporarily stopped state when the select lever is in the travel range and the idle condition is satisfied. I do.

In the fourth engine idle speed control device, the vehicle is temporarily stopped when the vehicle speed has exceeded the set vehicle speed and the idle condition is satisfied in the first engine idle speed control device. Judge as the state.

In the fifth engine idle speed control device, the first engine idle speed control device has experience that the vehicle speed is equal to or higher than the set vehicle speed for a set time or longer and the idle condition is satisfied. When it is, it is determined that the vehicle is temporarily stopped.

A sixth engine idle speed control device is the same as the first engine idle speed control device, wherein the vehicle is temporarily stopped when the brake switch is on and the idle condition is satisfied. I do.

According to a seventh engine idle speed control device, in the idle speed control devices of the first to sixth engines, a low value of the target idle speed is prohibited while a predetermined engine load is operating. I do.

In the eighth engine idle speed control device, when a predetermined engine load is operating and idle conditions are satisfied, the target idle speed is set to a value lower by the set time.

According to a ninth engine idle speed control device, in the eighth engine idle speed control device, the predetermined engine load is an air conditioner.

According to a tenth engine idle speed control device, in the eighth engine idle speed control device, the predetermined engine load is a headlight.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention.

Reference numeral 1 in FIG. 2 denotes an engine. An intake manifold 3 is communicated with each intake port 2a formed in a cylinder head 2 of the engine 1, and an air chamber in which intake passages of respective cylinders are gathered. The throttle chamber 5 and the intake pipe 6 communicate with each other through the intake pipe 4, and an air cleaner 7 is attached to an intake air intake side of the intake pipe 6.

An intake air amount sensor 8 of a hot wire type or the like is interposed immediately downstream of the air cleaner 7 of the intake pipe 6. A throttle valve 5 a provided in the throttle chamber 5 is provided with a throttle opening degree. ON when the throttle opening sensor 9a that outputs a voltage corresponding to the throttle valve and the throttle valve is fully closed
And a throttle sensor 9 incorporating an idle switch 9b having an idle contact.

A bypass passage 10 which bypasses the throttle valve 5a and communicates between the upstream side and the downstream side.
The ISC valve 11 is interposed. Further, an injector 14 is located just upstream of each intake port 2a of each cylinder of the intake manifold 3, and an ignition plug 15 for exposing a firing portion at a tip end to a combustion chamber is attached to the cylinder head 2 for each cylinder. Have been.

The exhaust port 2 of the cylinder head 2
An O2 sensor 17 is provided at the gathering portion of the exhaust manifold 16 communicating with b, and a catalytic converter 18 is interposed downstream thereof.

A crank rotor 19 is mounted on a crankshaft 1b supported by the cylinder block 1a. An outer periphery of the crank rotor 19 includes an electromagnetic pickup for detecting a projection corresponding to a predetermined crank angle. A crank angle sensor 20 is provided opposite to a cam rotor 21 connected to a camshaft 1c that makes a half turn with respect to the crankshaft 1b. Has been established.

Reference numeral 30 shown in FIG. 3 is a control device for controlling the engine operating state, such as fuel injection amount control, ignition timing control, idle speed control, etc.
PU31, ROM32, RAM33, backup RA
M34, a counter / timer group 35, and an I / O interface 36 are configured around a microcomputer connected to each other via a bus line 37;
In addition, a constant voltage circuit 38 that supplies a stabilized voltage to each unit,
Peripheral circuits such as a drive circuit 39 for driving actuators by a signal from an output port of the I / O interface 36 and an A / D converter 40 for converting an analog signal from a sensor into a digital signal are incorporated. .

The counter / timer group 35 includes various timers such as a free-run counter, a counter for counting the input of a cam angle sensor signal, a fuel injection timer, an ignition timer,
Various timers such as a timer for generating a periodic interrupt, a timer for counting an input interval of an output signal of a crank angle sensor, and a watchdog timer for monitoring a system abnormality are collectively referred to for convenience. And various software counters and timers are used.

The constant voltage circuit 38 is connected to a battery 42 via a relay contact of a power supply relay 41, and a relay coil of the power supply relay 41 is connected to the battery 42 via an ignition switch 43. When the ignition switch 43 is turned on and the contact of the power supply relay 41 is closed, the constant voltage circuit 38 stabilizes the voltage of the battery 42 and controls the control device 30.
Supply to each part. Further, the backup RAM 34
, A battery 42 is directly connected via the constant voltage circuit 38, and the output of the ignition switch 43
Backup power is always supplied regardless of N / OFF.

The input port of the I / O interface 36 is connected to the vehicle speed sensor 23 and the idle switch 9.
b, the crank angle sensor 20, the cam angle sensor 22, the parking brake switch 24 that is turned ON when the parking brake is operated, and the select lever is set to P (parking).
Run range switch 2 that is turned ON when set to a drive range such as D (drive) range or R (reverse) range other than the range, N (neutral) range
5, an air conditioner switch 26, a lighting switch 27 for turning on a headlight, a brake switch 28 which is turned on when a brake pedal is depressed, are connected.
Intake air amount sensor 8, throttle opening sensor 9a, O2
The sensor 17 is connected via an A / D converter 40, and the terminal voltage VB of the battery 42 is input to the A / D converter 40 and monitored.

On the other hand, the ISC valve 1 is connected to the output port of the I / O interface 36 via the drive circuit 39.
1, the injector 14 and the like are connected.

The ROM 32 stores engine control programs, fixed data such as maps, and the like, and the RAM 33 stores data obtained by processing output signals of the sensors and switches, and CPU31
The data processed by the calculation is stored. The backup RAM 34 stores various learning maps, control data, trouble data corresponding to a failed part detected by the self-diagnosis function, and the like, and retains the data even when the ignition switch 43 is OFF.

The CPU 31 optimally controls engine control such as fuel injection control and idle speed control based on output signals from each sensor and switches according to a program stored in the ROM 32.

Hereinafter, the target idle speed setting routine executed by the control device 30 will be described with reference to the flowchart shown in FIG. This routine is executed every set cycle.

First, in steps S1 and S2, an idle down condition for reducing the idle speed is determined. That is, in step S1, the output value of the parking brake switch 24 is referred to, and in step S2, it is determined whether an idle condition is satisfied. The idle condition is determined based on, for example, the output of the idle switch 9b and the vehicle speed V. When the idle switch 9b is ON and the accelerator pedal is released and the vehicle speed V is equal to or less than the set vehicle speed for determining whether the vehicle is stopped, the idle condition is determined. It is determined to be established.

If it is determined in step S1 that the parking brake switch 24 is OFF and the parking brake is not operated, and if it is determined in step S2 that the idle condition is satisfied, the process proceeds to step S3 because the idle-down condition is satisfied. If it is determined in step S1 that the parking brake switch 24 is ON and the parking brake is ON, or if it is determined in step S2 that the idle condition is not satisfied, the process branches to step S5 because the idle-down condition is not satisfied.

When the process proceeds from step S2 to step S3, the continuation time “time” for satisfying the idle-down condition is compared with the set time T. When the duration time exceeds the set time T (t
im> T), that is, when the idle-down condition is satisfied for more than the set time T, the flow branches to step S5. The duration time is started when the idle-down condition is satisfied from when the idle-down condition is not satisfied, and is cleared when the idle-down condition is not satisfied again. Further, the set time T is set based on a delay time until a malfunction occurs due to a decrease in the power generation capacity of the alternator and a decrease in the hydraulic pressure discharged from the oil pump of the automatic transmission by setting the idle speed to be low, The delay time is set to be equal to or slightly shorter than the delay time.

When the process proceeds from step S3 to step S4, the target idle speed NSET is set at a preset low idle speed NLID (NSET ← NLI).
D), exit the routine. This low idle speed NLID
Is set to a rotation speed that does not cause engine malfunction such as misfire even if the idle rotation speed is set low.

In step S5, the target idle speed NSET is set to the normal idle speed NID (NSET ← NID), and the routine exits.

Then, in the ISC valve opening control, the valve opening of the ISC valve 11 is controlled so that the engine speed N converges on the target idle speed NSET.

As described above, in this embodiment, when the duration time “idle down condition is satisfied” is within the set time T, the target idle speed NSET is set to the low idle speed NLID. When the vehicle is temporarily stopped, such as when waiting for a traffic light, the idle speed is set low, and the fuel efficiency is improved accordingly. Furthermore, since the duration time of the low idle speed is limited to the set time T, not only the alternator's power generation capacity and the hydraulic pressure supplied to the automatic transmission device are effectively prevented from malfunctioning but also durable. The performance is improved. Furthermore, since the maximum continuation time (set time T) of the low idle speed is set in advance,
Since a sensor for detecting a decrease in the power generation capacity of the alternator and a decrease in the hydraulic pressure of the automatic transmission is not required, and the parking brake switch 24 is normally provided, manufacturing costs can be suppressed.

FIG. 4 shows a target idle speed setting routine according to the second embodiment of the present invention. In the present embodiment, the select lever of the automatic transmission is set to the travel range (P
(A range other than the range and the N range) is defined as one of the idle down conditions.

That is, in step S11, the set position of the select lever provided in the automatic transmission is determined with reference to the output value of the travel range switch 25. If the travel range switch is set to a range other than the N range, the process proceeds to step S2. If the travel range switch 25 is OFF and the select lever is set to the P range or the N range, the process proceeds to step S5. Then, the same processing as in the first embodiment is performed in steps S2 to S5.

As described above, in this embodiment, the temporary stop state of the vehicle is determined based on the fact that the select lever is set to the travel range and the idle condition is satisfied. This makes it possible to easily detect a temporary stop state of the vehicle without newly adding sensors and switches.

Next, FIG. 5 shows a target idle speed setting routine according to a third embodiment of the present invention. In the present embodiment, one of the idle-down conditions is that the vehicle speed V has ever exceeded the set vehicle speed VO even once.

That is, in step S21, it is determined whether or not the vehicle speed V has exceeded the set vehicle speed VO. If there is experience, the process proceeds to step S2 to determine whether or not the idle condition is satisfied. If there is no experience, proceed to step S5.

Then, in steps S2 to S5, the same processing as in the above-described first embodiment is executed.

As described above, in the present embodiment, it is determined that the vehicle is temporarily stopped and the idling condition is satisfied after the vehicle speed V exceeds the set vehicle speed VO even once. By setting the target idle speed NSET low, it is possible to prevent a decrease in oil pressure of the oil pump when shifting to the low idle speed, and to reduce the power generation load on the alternator.

In this case, the duration of the state in which the vehicle speed V exceeds the set vehicle speed VO (V ≧ VO) is measured, and it is determined that the vehicle has experienced the state where V ≧ VO has continued for the set time Tv or more. It is good also as a condition.

That is, as shown in FIG.
In, it is determined whether there is any experience that the duration of V ≧ VO has reached the set time Tv, and if there is such experience, the process proceeds to step S2. If it is determined in step S31 that the user has no experience, the process branches to step S5.

Next, FIG. 7 shows a target idle speed setting routine according to a fourth embodiment of the present invention. In the present embodiment, the state where the air conditioner is off is one of the idle down conditions.

That is, in step S41, the output value of the air conditioner switch 26 is referred to, and the air conditioner switch 26
If it is F, the process proceeds to step S2, and if the air conditioner switch 26 is ON, the process branches to step S5. And
In steps S2 to S5, the same processing as in the first embodiment is executed.

As described above, in the present embodiment, the ON / OFF of the air conditioner which greatly affects the engine load during the idling operation is detected, and the air conditioner switch 26 is turned off.
The target idle speed is set low only when the idle condition is satisfied. Therefore, even if the idle speed is set low, the power generation capacity of the alternator and the hydraulic pressure supplied to the automatic transmission can be effectively reduced. Can be avoided.

FIG. 8 shows a target idle speed control routine according to a fifth embodiment of the present invention. In the present embodiment, one of the idle-down conditions is that the headlight is off.

That is, in step S51, it is determined whether or not the headlight is turned off by referring to the output value of the lighting switch 27 for turning on the headlight. In the case of, the process proceeds to step S2, and when it is determined that the headlamp whose lighting switch 27 is ON is turned on, the process branches to step S5. Then, in steps S2 to S5, the same processing as in the first embodiment is executed.

As described above, in the present embodiment, one of the requirements is that the headlight is turned off as the idle-down condition.
The target idle speed is not set low during the night when power consumption is relatively large,
During nighttime operation, there is no shortage of alternator power generation capacity.

Next, FIG. 9 shows a target idle speed setting routine according to a sixth embodiment of the present invention. In the present embodiment, the braking state is one of the idle down conditions.

That is, in step S61, the output value of the brake switch 28 is referred to, and the brake switch 28
When the brake is applied to N, the process proceeds to step S2. When the brake switch 28 is OFF and the brake is not applied, the process branches to step S5. Then, in steps S2 to S5, the first
The same processing as in the embodiment is executed.

As described above, in the present embodiment, since the braking state is one of the requirements as the idle-down condition, the temporary stop state of the vehicle can be detected more accurately.

The present invention is not limited to the above embodiments, and the idle down conditions in the first to sixth embodiments may be combined as needed.
For example, in an engine employing an electronically controlled throttle valve, the idle speed may be set by controlling the opening of the throttle valve itself instead of controlling the opening of the ISC valve.

[0068]

As described above, according to the present invention,
The idle speed is temporarily reduced in the state where the effect of the engine load during idling and the effect of the oil pressure drop of the oil pump are small, so that the fuel consumption can be reduced without affecting each peripheral device. It is possible to improve the cost, and it is not necessary to load a new component, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a target idle speed setting routine according to a first embodiment;

FIG. 2 is an overall configuration diagram of the engine.

FIG. 3 is a circuit configuration diagram of the control device.

FIG. 4 is a flowchart showing a target idle speed setting routine according to a second embodiment;

FIG. 5 is a flowchart showing a target idle speed setting routine according to a third embodiment;

FIG. 6 is a flowchart showing a target idle speed setting routine according to another embodiment of the present invention;

FIG. 7 is a flowchart showing a target idle speed setting routine according to a fourth embodiment;

FIG. 8 is a flowchart showing a target idle speed setting routine according to a fifth embodiment;

FIG. 9 is a flowchart showing a target idle speed setting routine according to a sixth embodiment;

[Explanation of symbols]

 24 parking switch 25 running range switch 26 air conditioner switch 27 lighting switch 28 Brake switch NSET target idle speed T ... set time V ... vehicle speed VO ... set vehicle speed

Claims (10)

[Claims] An engine idling speed control device for variably setting a target idling speed during idling operation according to an engine operating state, wherein the target idling speed is set for a set time when a temporary stop state of the vehicle is determined. An idle speed control device for an engine, characterized in that the idle speed control device is set to a low value only. 2. The engine idle speed control system according to claim 1, wherein the vehicle is determined to be in a temporary stop state when the parking brake is in a non-operating state and an idle condition is satisfied. . 3. The engine idle speed control system according to claim 1, wherein the vehicle is determined to be in a temporary stop state when the select lever is in a travel range and an idle condition is satisfied. 4. The engine idle speed according to claim 1, wherein the vehicle is judged to be in a temporary stop state when the vehicle speed has exceeded the set vehicle speed and an idle condition is satisfied. Control device. 5. The vehicle according to claim 1, wherein the vehicle is temporarily stopped when the vehicle speed is equal to or higher than the set vehicle speed for a set time or more and the idle condition is satisfied. Engine idle speed control device. 6. The engine idle speed control device according to claim 1, wherein when the brake switch is on and the idle condition is satisfied, the vehicle is determined to be in a temporary stop state. 7. An idle speed control device for an engine according to claim 1, wherein a low value of said target idle speed is prohibited while a predetermined engine load is operating. . 8. An idle speed control system for an engine for variably setting a target idle speed during idling according to an engine operating state, wherein a predetermined engine load is in an operating state and idle conditions are satisfied. An engine idle speed control device, wherein the target idle speed is set to a value lower by a set time. 9. An engine idle speed control device according to claim 8, wherein said predetermined engine load is an air conditioner. 10. An engine idle speed control device according to claim 8, wherein said predetermined engine load is a headlight.