JPH07180588A - Idling engine speed control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the increase of the idling engine speed of an internal combustion engine in a state produced during no-load being non-running and to improve fuel consumption. CONSTITUTION:When during idling, it is decided by an electronic control unit (ECU) 51 based on signals from a throttle sensor 31 and an L4 range switch 40 that a vehicle is run in a LOW range being a four-wheel drive state, updating of an ISC learning value for idle speed control (ISC) control is prohibited. When a clutch is engaged, an increased air amount is added to the target value of the idling engine speed of a base and ISC control is then carried out by the ECU 51. When it is decided that the clutch is not engaged, ISC control is applied on the number of idle revolutions based on the target idling engine speed of a base.

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 controlling an idle speed of an internal combustion engine mounted on an automobile or the like.

[0002]

2. Description of the Related Art In an internal combustion engine, in order to stabilize the internal combustion engine at the time of idling, an intake air amount is controlled to be increased and corrected. As a device for this purpose, there is conventionally known a bypass passage that bypasses the throttle valve and connects the upstream side and the downstream side of the intake passage, and an idle speed control valve (ISCV) is provided in the bypass passage. ing. Then, at the time of idling when the throttle valve is fully closed, learning for ISCV control is performed based on the engine cooling water temperature, vehicle speed, etc. input from various sensors. Based on this result, the opening of the ISCV and the valve opening time are controlled, and the amount of intake air to the internal combustion engine is adjusted to control the idle speed to the target speed.

By the way, as disclosed in Japanese Patent Laid-Open No. 60-88855, in a four-wheel drive vehicle, when traveling on an off-road (rock road, rubble road, etc.), it is possible to drive at an idle speed. Since it becomes the main, the larger the torque,
Since the off-road running performance is improved, it has been proposed that the idle speed is increased in the four-wheel drive state. In this technique, the idle speed is increased even when there is no load, which is when the vehicle is not running.

[0004]

However, if the idle speed is increased even when there is no load, that is, when the vehicle is not running, there is a problem that fuel consumption is deteriorated.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to increase the idle speed when a running state is detected, and to increase the internal combustion speed in a non-loading state where the vehicle is not traveling. An object of the present invention is to provide an idle speed control device for an internal combustion engine, which can prevent an increase in engine speed and improve fuel efficiency.

[0006]

In order to achieve the above-mentioned object, the present invention is provided with a control means M1 for controlling an engine M4 of a vehicle to a predetermined target rotational speed during idling, as shown in FIG. In the engine control device,
A running state detecting means M2 for detecting a running state of the vehicle at the time of idling, and a target value increasing means M3 for increasing a target rotational speed at the time of idling based on the detection of the running state by the running state detecting means M2. The point is to have prepared.

[0007]

According to the above construction, as shown in FIG. 1, when the traveling state detecting means M2 detects the traveling state of the vehicle at the time of idling, the target value increasing means M3 is operated by the traveling state detecting means M2 at the time of idling. When the vehicle is in the traveling state based on the detection of the traveling state, the target rotational speed during idling is increased. The control means M1 controls the engine M4 of the vehicle to the increased target rotation speed during idling. When the vehicle is in the non-traveling state based on the detection of the traveling state at the time of idling by the traveling state detecting means M2, the target rotational speed at the time of idling is not increased. Therefore, the control means M1 controls the engine to a predetermined target rotation speed at which the target rotation speed is not increased.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the engine idle speed control device according to the present invention is embodied in a gasoline engine of a four-wheel drive vehicle equipped with a manual transmission will be described in detail below with reference to FIGS.

FIG. 2 is a schematic configuration diagram showing an engine control device in this embodiment. An engine 1 mounted on an automobile has a plurality of cylinders, and a cylinder block 2 constituting the engine 1 has cylinder bores 3 for the number of cylinders. A cylinder head 4 is attached to the upper side of the cylinder block 2 so as to close each cylinder bore 3. A piston 5 is provided in each cylinder bore 3 so as to be vertically movable, and the piston 5 is connected to a crankshaft (not shown) via a connecting rod 6. And
Inside the cylinder bore 3, a space surrounded by the piston 5 and the cylinder head 4 is a combustion chamber 7.

The cylinder head 4 is provided with spark plugs 8 corresponding to the respective combustion chambers 7. Further, the cylinder head 4 is provided with an intake port 9 and an exhaust port 10 which communicate with the combustion chambers 7, respectively, and an intake passage 11 and an exhaust passage 12 are connected to the ports 9 and 10, respectively. There is. An intake system is constituted by the intake port 9 and the intake passage 11. Further, an intake valve 13 and an exhaust valve 14 for opening and closing are provided at the respective open ends of the intake port 9 and the exhaust port 10 which communicate with the combustion chamber 7. The intake valve 13 and the exhaust valve 14 are adapted to be opened and closed by interlocking with the rotation of the crankshaft by a valve operating device including a camshaft (not shown). Also, each of these valves 1
The opening and closing timings of 3, 14 are opened and closed in synchronization with the rotation of the crankshaft.

An air cleaner 1 is provided on the inlet side of the intake passage 11.
5 are provided. A surge tank 16 for smoothing the pulsation of air passing through the intake passage 11 is provided in the intake passage 11. Further, on the downstream side of the surge tank 16, injectors 17 for fuel injection are provided near the intake port 9 for each cylinder. Fuel of a predetermined pressure is supplied to these injectors 17 from a fuel tank (not shown) by a fuel pump. On the other hand, on the outlet side of the exhaust passage 12, a catalytic converter 18 including a three-way catalyst for purifying exhaust gas is provided.

The engine 1 has an air cleaner 15
The outside air taken in from is introduced through the intake passage 11 including the surge tank 16. Further, the fuel is injected from each injector 17 at the same time as the introduction of the outside air, so that the mixture of the outside air and the fuel is taken into the combustion chamber 7 in synchronization with the opening of the intake valve 13 in the intake stroke.
Further, the air-fuel mixture taken into the combustion chamber 7 is ignited by the ignition plug 8, so that the air-fuel mixture explodes and burns to provide the engine 1 with a driving force. Then, the exhaust gas after the explosion / combustion is guided to the exhaust passage 12 in synchronization with the opening of the exhaust valve 14 in the exhaust stroke, and is discharged from the exhaust passage 12 to the outside through the catalytic converter 18 and the like.

On the upstream side of the surge tank 16, there is provided a throttle valve 19 which opens and closes in conjunction with the operation of an accelerator pedal (not shown). Then, by opening and closing the throttle valve 19, the intake amount of outside air into the intake passage 11, that is, the intake air amount Q is adjusted.
A throttle sensor 31 for detecting the opening of the valve 19, that is, the throttle opening TA is provided near the throttle valve 19. The throttle sensor 31 outputs a signal of the throttle opening TA and also outputs an idle signal IDL by an idle contact which is turned on only when the throttle valve 19 is at the fully closed position. Further, on the downstream side of the air cleaner 15, an air flow meter 3 for detecting an intake air amount Q into the intake passage 11 is provided.
Two are provided. Between the air cleaner 15 and the air flow meter 32, an intake air temperature sensor 33 that detects the temperature of the air taken into the intake passage 11, that is, the intake air temperature THA.
Is provided.

Further, in the middle of the exhaust passage 12, there is provided an oxygen sensor 34 for detecting the oxygen concentration in the exhaust, that is, for detecting the exhaust air fuel consumption in the exhaust passage. or,
In the cylinder block 2, the temperature of the cooling water of the engine 1,
That is, a water temperature sensor 35 that detects the cooling water temperature THW is provided.

The ignition signal distributed by the distributor 20 is applied to the ignition plug 8 for each cylinder. The distributor 20 is for distributing the high voltage output from the igniter 21 to each spark plug 8 in synchronization with the rotation of the crankshaft, that is, the crank angle. The ignition timing of each spark plug 8 is determined by the high voltage output timing from the igniter 21.

The distributor 20 has a built-in rotor (not shown) that rotates in association with the rotation of the crankshaft. Then, the distributor 20
A rotation speed sensor 36 for detecting the rotation speed of the engine 1, that is, the engine rotation speed NE from the rotation of the rotor is provided. Similarly, the distributor 20 is provided with a cylinder discriminating sensor 37 that detects the crank angle reference signal GP of the engine 1 at a predetermined rate according to the rotation of the rotor. In this embodiment, the crankshaft rotates twice for a series of strokes in the engine 1, and the rotation speed sensor 36 detects the crank angle at a rate of 30 ° CA per pulse. The cylinder discrimination sensor 37 detects the crank angle at a rate of 360 ° CA per pulse. Further, a transmission (not shown) drivingly connected to the engine 1 is provided with a vehicle speed sensor 38 for detecting a vehicle speed, that is, a vehicle speed SP. Similarly, the transmission (not shown) is provided with an L4 range switch 40 that is turned on in the L0W range by four-wheel drive and turned off in other cases. The switch 40 is used, for example, during off-road traveling.

A throttle valve 19 is provided in the intake passage 11.
A bypass passage 22 that bypasses the valve 19 and connects the upstream side and the downstream side of the valve 19 to each other is provided. A known linear solenoid type idle speed control valve (ISCV) 23 is provided in the middle of the bypass passage 22.
Is provided. The bypass passage 22 is opened and closed by driving and controlling the ISCV 23 based on a predetermined control signal. This ISCV2
When the engine 1 is idling when the throttle valve 19 is fully closed, the valve 3 is operated to stabilize the idling. Therefore, when the engine 1 is idle, I
By controlling the opening degree of the SCV 23 and its valve opening time, that is, by performing the ISC control, the amount of air flowing through the bypass passage 22 is adjusted, and the intake air amount Q to the combustion chamber 7 is adjusted.

The engine 1 is provided with a starter 24 for imparting a rotational force to the engine 1 by cranking when starting the engine 1. Also, this starter 24 has
A starter switch 39 for detecting the operation / non-operation is provided. The starter switch 39 is turned on / off by operating an ignition switch (not shown). Since the starter 24 is operated while the ignition switch is being operated, the starter switch 39 outputs an “on” starter signal. STS is output.

Each injector 17, igniter 21, and ISCV 23 are electronic control units (hereinafter simply referred to as "EC
U ”) 51, and their drive timing is controlled by the operation of the ECU 51. The ECU 51 constitutes a target value increasing means and a control means, and the ECU 51 includes the above-mentioned throttle sensor 3
1, air flow meter 32, intake air temperature sensor 33, oxygen sensor 34, water temperature sensor 35, rotation speed sensor 36, cylinder discrimination sensor 37, vehicle speed sensor 38, starter switch 39
, And the L4 range switch 40 are respectively connected. The ECU 51 controls the ignition timing of the engine 1,
In order to control the fuel injection amount control, the ISC control, etc., based on the output signals from the sensors 31 to 38 and the starter switch 39, the injectors 17, the igniters 21, and I
The SCV 23 is preferably driven and controlled.
Further, the ECU 51, the throttle sensor 31, and the L4 range switch 40 constitute a traveling state detecting means.

The electrical configuration of the ECU 51 will be described with reference to the block diagram of FIG. The ECU 51 is a central processing unit (CP
U) 52, a read-only memory (ROM) 53 that stores a predetermined control program and the like in advance, and a random access memory (RAM) 5 that temporarily stores the calculation result of the CPU 52 and the like.
4. Backup RAM 5 to save the stored data
5, a timer counter 56, etc., and each of these units, an external input circuit 57, an external output circuit 58, etc. are connected by a bus 59 as a logical operation circuit. In this embodiment, the ROM 53 stores in advance a control program such as an "idle rotation speed control routine" described later and a map of ignition timing. In addition, the timer counter 56
Outputs an interrupt signal every predetermined time and simultaneously performs a plurality of counting operations.

The external input circuit 57 includes the throttle sensor 31, the air flow meter 32, and the intake air temperature sensor 3 described above.
3, oxygen sensor 34, water temperature sensor 35, rotation speed sensor 3
6, a cylinder discrimination sensor 37, a vehicle speed sensor 38, a starter switch 39, an L4 range switch 40, etc. are connected to each other. Further, the injector 17, the igniter 21, and the ISCV 23 are connected to the external output circuit 58, respectively.

Then, the CPU 52 reads the respective signals from the sensors 31 to 38, the starter switch 39 and the L4 range switch 40, which are input via the external input circuit 57, as input values. In addition, the CPU 51 uses the read input values to inject each injector 17 and igniter 21.
And ISCV23 are suitably drive-controlled.

Next, the processing operation for the idle speed control in the engine control device configured as described above will be described with reference to FIG. The ECU 51 executes the "idle speed control routine" for other fuel injection control, IS
The control routine is appropriately repeated along with various control routines such as C control.

Further, the ECU 51 has its timer counter 5
Idle signal ID from the throttle sensor 31 at the timing of the interrupt signal output every 6 hours from 6
The starter signal STS from the L and starter switches 39 and the signal from the L4 range switch 40 are repeatedly read. Then, the ECU 51 sends the idle signal IDL
Is "ON", the idle flag XIDL is "1", and when the idle signal IDL is "OFF", the idle flag XIDL is "0". further,
The ECU 51 sets the L4 range flag L4F to "1" when the signal from the L4 range switch 40 is "on", and the L4 range flag L4 when the signal is "off".
Let F be "0".

Also, the ECU 51 sometimes
The throttle opening TA, the engine speed NE, the intake air amount Q, and the vehicle speed SP are read based on the signals from the throttle sensor 31, the rotation speed sensor 36, the air flow meter 32, and the vehicle speed sensor 38, respectively.

FIG. 4 is a flow chart for explaining the "idle rotation speed control routine" executed by the ECU 51, and this routine is executed by a regular interruption every predetermined time. When the processing shifts to this routine, first, at step (hereinafter, step is referred to as S) 100, it is determined whether or not the idle flag XIDL is "1".
Here, when the idle flag XIDL is not "1", it is determined that the throttle valve 19 is opened and the engine is not idling, and the process proceeds to S108. On the other hand, S10
At 0, if the idle flag XIDL is "1", it is assumed that the throttle valve 19 is fully closed, and S
The process proceeds to step 101, and the determination in step S101 is performed. That is,
In S101, the L4 range flag L4F is "1".
Or not.

Here, the L4 range flag L4F is "1".
If not, it is determined that the vehicle is traveling other than the LOW range in the four-wheel drive state, and the process proceeds to S108. On the other hand, in S101, the L4 range flag L4F
Is “1”, the vehicle is running in the four-wheel drive LO
Assuming that the vehicle is traveling in the W range, the process proceeds to S102. In S102, the update of the ISC learning value for ISC control is prohibited, and the process proceeds to S103.

In the ISC control, the ECU 51 updates the ISC learning value based on various signals from the rotation speed sensor 38, the water temperature sensor 35, the vehicle speed sensor 38, etc., and the target rotation speed is calculated based on the ISC learning value. The setting is done. Then, the ECU 51 sends a control signal corresponding to the engine speed to the target engine speed IS.
The idle speed is controlled by outputting to the CV 23.

The reason why the updating of the ISC learning value is prohibited is that the vehicle speed becomes low from the signal SP from the vehicle speed sensor 38 because the vehicle speed is low in traveling in the LOW range in the four-wheel drive state, and the ISC learning value updating This is because one parameter for can not be used.

At S103, the air amount increase α_i-1
From the judgment value a
It is determined whether or not it is larger. This judgment is ISC opening DO
The relationship between P and engine speed NE is shown in FIG.
There is. Note that the increase in air amount α _i-1Is the inhalation obtained this time
Calculated from the difference between the air amount Q and the intake air amount obtained last time
The engine speed increase ΔNE is the rotation obtained this time.
Calculated from the difference between the number NE and the rotational speed NE obtained last time
It

If this ratio is larger than the judgment value a, it is judged that the load of the engine 1 is light, that is, the clutch is not engaged, and the routine proceeds to S109. If this ratio is less than or equal to the determination value a, it is determined that the clutch is engaged, that is, the vehicle is running, and the process proceeds to S104.

At S104, since the clutch is engaged, the increase amount β is added to the previous air amount increase amount α _i−1 ,
A new air amount increase amount α _i is set, and the process proceeds to S105. S
In 105, the new air amount increase α _i is the upper limit value K.
It is determined whether or not it exceeds. Upper limit value K in S105
If it is determined that it is less than, the process proceeds to S107. S1
At 07, the air amount increase α _i (previous air amount increase α _i−1 and increase β) is added to the ISC learning value DG to calculate the ISC opening DOP, and this routine is exited. Then, the ECU 51 drives and controls the ISCV 23 based on the calculated ISC opening DOP. That is, I increased by the added amount of increased air amount α _i
Based on the SC opening DOP, the idle target engine speed will be made higher than the base idle target engine speed.
The CU 51 uses the ISCV to achieve this increased target speed.
Control 23.

If it is determined in S105 that the value is equal to or more than the upper limit value K, the process proceeds to S106. The upper limit value K is regulated in order to prevent an excessive increase in the new air amount increase α _i . In S106, the upper limit value K is set as the air amount increase amount α _i, and in S107, the air amount increase amount α _i is added to the ISC learning value DG to obtain the ISC opening DOP.
And then exit this routine. And the ECU 5
1 is I based on the calculated ISC opening DOP
The SCV 23 is drive-controlled.

When the process proceeds from S100 and S101 to S108, the air amount increase α _i is increased in S108.
Is set to 0, the process proceeds to S107, and this processing routine ends. Therefore, when the vehicle is not in the idle state or when the vehicle is traveling outside the LOW range of the four-wheel drive state, the ISC opening DOP is calculated based on the learned value DG of the base ISC, and the ISCV 23 Drive control is performed. That is, the idle target rotation speed becomes the base idle target rotation speed based on the ISC opening DOP, and the ECU 51 sets the IS target opening rotation speed to the IS target opening rotation speed.
Control CV23.

When it is determined in S103 that the clutch is not engaged and the process proceeds to S109, the increase β (> 0) is determined to be the air amount increase α _i in S109, and in S107. The air amount increase α _i (= increase β) is added to the learned value DG of the base ISC, and this processing routine ends. The reason why the increase amount β is made the air amount increase amount α _{i in} S109 is that the neutral determination is always performed in S103 when the next processing routine is executed when the clutch is in neutral. is there. If the increase β is set to 0, hunting occurs in the idle, and S109 is a process for preventing this.

As described above, in this embodiment, the update of the ISC learning value is prohibited when the vehicle is in the LOW range of four-wheel drive, and in step 107, the air amount increase α is gradually increased.
_i will be added. Therefore, the target rotation speed for ISC control is gradually increased, and the idle rotation speed is increased based on the gradually increased target rotation speed. Therefore, as a result, the amount of air that can be added can be increased, and the driving performance can be improved. Further, since the idle rotation speed gradually increases based on the gradually increased target rotation speed, the vehicle can be prevented from jumping out even if the cranking start is performed.

When the clutch is not engaged, that is, when the vehicle is in a non-running state, the target engine speed during idling does not increase, so fuel consumption can be improved.

Further, in this embodiment, whether or not the clutch is engaged is determined by the ratio between the engine speed increase ΔNE and the air amount increase α _i-1. Since it is not necessary to provide a sensor for detecting, and the number of assembling steps and the number of parts for the sensor do not increase, the cost can be reduced.

The present invention is not limited to the above-described embodiments, but may be implemented by appropriately modifying a part of the configuration without departing from the spirit of the present invention. (1) In the above embodiment, the ECU 51 determines and detects whether or not the clutch is engaged, but it is determined whether or not the clutch is engaged based on the detection signal of the sensor that detects the engagement of the clutch. May be.

(2) In the above embodiment, the embodiment is applied to the four-wheel drive vehicle equipped with the manual transmission, but it may be applied to the four-wheel drive vehicle equipped with the automatic transmission.

[0041]

As described above in detail, according to the present invention, the idling speed is increased when the running state is detected, and the speed of the internal combustion engine is increased in the non-running state where there is no load. It is possible to prevent the increase of fuel consumption and improve fuel efficiency.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing an engine control device in an embodiment embodying the present invention.

FIG. 3 is a block diagram showing a configuration of an ECU and the like in the embodiment.

FIG. 4 is a flowchart illustrating an “idle rotation speed control routine” executed by the ECU in the embodiment.

FIG. 5 is a graph showing a relationship between an ISC opening and an engine speed for determining whether or not a clutch is engaged.

[Explanation of symbols]

1 ... Engine, 9 ... Intake port, 11 ... Intake passage (9,
Reference numeral 11 constitutes an intake system), 19 ... Throttle valve, 31 ... Throttle sensor, 32 ... Air flow meter, 40 ... L4 range switch, 51 ... ECU (or ECU which constitutes target value increasing means and control means) Together with the throttle sensor and the L4 range switch 40 constitute a traveling state detecting means).

Claims (1)

[Claims] 1. An engine control device comprising a control means for controlling an engine of a vehicle to a predetermined target rotation speed during idling, the running state detecting means for detecting a running state of the vehicle during idling, and the running state. An idle speed control device for an internal combustion engine, comprising: a target value increasing means for increasing a target speed during idling based on detection of a running state during idling by the detecting means.