JP2679210B2 - Idle speed control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an idle speed control device, and in particular, when changing from idle operation to another operation state, the IS
The control value of the C valve is stored and updated as a learning value, and the fixed duty or opening of the ISC valve that compensates the flow rate of the air valve at that time is also stored and updated as a water temperature correction value, and the operating state shifts to idle operation again. At some times, an idle speed control device that starts the ISC valve control with a fixed duty or opening that adds the updated learning value and the updated water temperature correction value and controls the idle speed from the cooling to the warm-up process Regarding

[Prior Art] In recent years, there have been increasing demands for lower fuel consumption of automobiles due to energy circumstances, and various measures for lowering fuel consumption and purifying exhaust gas have been proposed in combination with stricter exhaust gas regulations. ing. One of the measures is to precisely control the idle speed according to various conditions of the engine, such as intake air temperature and engine cooling water temperature.

The idle speed control device of this measure is usually called the idle speed control (ISC), and adjusts the amount of air flowing through the passage that bypasses the throttle valve when idling to set the idle speed to the target value, that is, the target speed. It is something to control.

As the idle speed control device, Japanese Patent Laid-Open No. 61-15
Some are disclosed in Japanese Patent No. 5638. The idle speed control method disclosed in this publication obtains the deviation between the target engine speed and the current engine speed, and changes the ratio of changing the opening area of the air passage according to the deviation depending on the engine warm-up state. It is variable to prevent hunting of the engine rotation when the engine is cold, improve responsiveness after warming up, and maintain a stable idling state.

[Problems to be Solved by the Invention] By the way, in the conventional idle speed control device, the idle switch is turned on immediately after starting regardless of the cooling water temperature, and the water temperature is adjusted according to the water temperature when the idle switch is turned on. Feedback control is performed to achieve the target engine speed.

At this time, the air valve operates with a somewhat large intersection, but there is a system that supplements this intersection with an idle speed control valve (also called "ISC valve").

In this system, the above-mentioned control value at the time of feedback control is stored as a learning value, and when the idle switch is turned off or the accelerator switch is turned on and the idle switch is turned on again after traveling,
The learned value is used as a fixed duty or opening for the idle speed control (ISC), that is, a control value only while the vehicle speed is equal to or higher than a predetermined speed, and the engine speed is controlled by this control value.

At this time, the control value α changes according to the water temperature, and generally, a table is set so that the control value α is reduced by the water temperature correction value Δα as the water temperature rises. (See FIG. 3 (e)).

The idle speed control device operates as in the idle speed control flowchart shown in FIG.

That is, the program is started (200) by the driving of the internal combustion engine, and after the start, the idle switch (IDSw) remains in the ON operation for a specified time, for example, 3 to 5 seconds, that is, whether the learning start condition is satisfied. The decision (202) is made. If this judgment (202) is YES, the control value which is the feedback value of the idle speed control (ISC) valve is learned (204), and the judgment (202)
When is NO, the idle speed is not controlled.

Further, the idle switch (IDSw) is turned off or a judgment (206) is made as to whether or not the vehicle speed is equal to or higher than a predetermined vehicle speed. If the judgment (206) is YES, the idle operation is changed to another operation state. The control value α of the ISC valve at the time of performing is stored and updated in the RAM as the learning value I (208), and the determination (206) is N
When it is O, the idle speed is not controlled.

Then, a judgment (210) is made as to whether or not the idle switch (IDSw) has been turned on to enter the deceleration state. If the judgment (210) is YES, the water temperature obtained from the table according to the water temperature during the deceleration. The correction value Δα is added to the learned value I stored and updated, and the water temperature correction value Δα is added to the learned value I stored and updated. The idle speed is determined by the fixed duty or opening of the ISC valve. Control (212). When the determination (210) is NO, the idle speed control is not performed.

Further, it is judged (214) whether or not the vehicle speed is lower than a predetermined vehicle speed. If the judgment (214) is YES, the process returns to the learning of the control value of the ISC valve (204), and the judgment (214). But
If NO, the idle speed is not controlled.

However, when performing idle speed control, if the flow rate of the air valve at the start of the cooler is large, or if the temperature of the cooling water rises quickly due to various running conditions and the operation of the wax in the air valve is delayed, the idle During operation, the learning value I ₂ becomes small up to the minimum guard position of about 10%, as indicated by the broken line in FIG.

After restarting from this minimum guard position and increasing the duty or opening of the idle speed control (ISC), when the idle state is restored again, the duty or opening of the idle speed control (ISC) The control value α becomes small up to the previous learning value I ₂ .

Therefore, when the water temperature is low, the control value α is equal to the water temperature correction value Δ
Even if the value is set to a large value by α, the water temperature correction value Δα alone becomes insufficient depending on the off-operation time of the idle switch, that is, the length of the running time and the acceleration state, and the broken line in FIG. As shown, the engine speed drops (see arrow A), which eventually causes engine stall.

More specifically, referring to FIG. 3, the water temperature Tw is T ₃ during the first deceleration (deceleration), and the water temperature correction value Δα ₃ that is Δα of the water temperature T ₃ is changed from the previous idle operation to another operation state. The value is added to the learning value I ₁ stored and updated at the time of transition to obtain the duty or opening of the idle speed control (ISC), that is, the control value α.

Also stored updated added to the learning value I ₂ as a control value α when migrating water temperature correction value [Delta] [alpha] ₆ by the second deceleration (deceleration) sometimes water temperature T ₆ in the other operating conditions from the previous idling operation.

At this time, when the learning value I ₂ becomes a very small value,
Since the cooling water temperature is water temperature T ₄ <water temperature T ₆ ,
Water temperature correction value [Delta] [alpha] _{is, Δα 4> Δα 5> Δα} 6 , and the water temperature correction value [Delta] [alpha] ₆ water temperature T ₄ at the temperature T ₆
Is extremely smaller than the water temperature correction value Δα ₄ at
The above-mentioned inconvenience occurs.

Therefore, in order to eliminate the above-mentioned inconvenience, an object of the present invention is to store and update the control value of the ISC valve at the time of transition as a learning value at the time of transition from idle operation to another operating state, and at that time. The fixed duty or opening of the ISC valve that compensates the flow rate of the air valve is stored and updated as the water temperature correction value, and the updated learning value and updated water temperature correction value are It is controlled to start the ISC valve control with a fixed duty or opening that has been added, and even if the learning value becomes small to the minimum guard position during the process from cold to warm-up, it depends on the length of running time and the acceleration state. An object of the present invention is to realize an idle speed control device capable of reliably preventing the engine speed from dropping and preventing the engine stall at the worst time.

[Means for Solving Problems] In order to achieve this object, the present invention provides an ISC valve and an air valve that opens and closes in accordance with the cooling water temperature in a bypass passage of a throttle valve, and achieves a target rotation speed during idle operation. While performing feedback control of the ISC valve as described above, when shifting from idle operation to another operating state, the control value consisting of the fixed duty or opening of the ISC valve at the time of transition is stored and updated as a learning value, and other operation is performed. In the idle speed control device that starts the control of the ISC valve by the control value of the updated learning value when shifting from the state to the idle operation again, when shifting from the idle operation to another operating state, the transition time The control value of the ISC valve is stored as a learning value and updated, and the ISC valve's fixed value that compensates the flow rate of the air valve at that time is fixed. A constant duty or an opening is stored and updated as a water temperature correction value, and when the operation is shifted to the idle operation again from the other operating state, the updated learning value and the updated water temperature correction value are read out, and the learning value and the water temperature correction are performed. And a control unit for controlling the ISC valve to start the control with a fixed duty or an opening that is added to the value.

[Operation] With the above-described configuration, when the idle operation is changed to another operation state, the ISC valve control value at the time of the change is stored and updated as the learning value, and the air valve flow rate at that time is compensated. The fixed duty or opening of is stored and updated as the water temperature correction value, and when shifting from another operating state to the idle operation again, the fixed duty or opening obtained by adding the updated learning value and the updated water temperature correction value The ISC valve is controlled to start, and feedback control of the idle speed is performed to reliably prevent the engine speed from dropping due to the length of running time and the acceleration state, and to prevent the worst engine stall. I'm avoiding it.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. 2, 2 is an internal combustion engine, 4 is an air cleaner, 6 is a throttle body, 8 is a body intake passage, 10 is a fuel injection valve, 12 is a throttle valve, 14 is an intake manifold, 16 is a manifold intake passage, and 18 is intake air. Port, 20 is combustion chamber, 22
Is an exhaust manifold, 24 is a manifold exhaust passage, 26 is an exhaust pipe, 28 is a pipe exhaust passage, and 30 is a catalytic converter.

The fuel injection valve 10 constituting a fuel control device, for example, a fuel injection type fuel control device 32, is disposed in the body intake passage 8 on the upstream side of the throttle valve 12. Fuel injection valve
The fuel in the fuel tank 34 is supplied to 10. That is, the fuel in the fuel tank 34 is filtered by the fuel filter 40 through the fuel supply passage 38 by the fuel pump 36 and supplied to the fuel injection valve 10.

The fuel supply passage 38 is provided with a fuel pressure regulator 42 for regulating the fuel pressure acting on the fuel injection valve 10 at a constant level. The fuel pressure regulator 42 is operated by the intake pipe pressure from a fuel pressure passage 44 that opens into the manifold intake passage 16 downstream of the throttle valve 12.

An exhaust gas recirculation device (EG)
(R device) 46, an exhaust intake port 50 which is one end of an EGR recirculation passage 48 is open. An exhaust gas recirculation port 52, which is the other end of the EGR recirculation passage 48, opens to the manifold intake passage 16 downstream of the throttle valve 12. An EGR regulating valve 54 is provided in the middle of the EGR recirculation passage 48. This EGR regulating valve
An operation pressure passage 58 of the EGR regulating valve 54 is provided in the pressure chamber 56 of
Has contacted.

The operating pressure passage 58 communicates the pressure chamber 56 of the EGR regulating valve 54 with the body intake passage 8 upstream of the throttle valve 10. A control pressure switching valve 60 (VSV) is provided in the middle of the operating pressure passage 58. The control pressure switching valve 60 is operated by a control unit 74 described later,
The operation pressure passage 58 is opened and closed.

A pressure sensor passes through a detection pressure passage 62 to detect an intake pipe negative pressure which is an intake pipe pressure in the manifold intake passage 16.
64 are provided. Further, the intake manifold 14 is provided with a water temperature sensor 68 for detecting the cooling water temperature in the cooling water passage 66 formed in the intake manifold 14, and the exhaust manifold 22 is provided with O2 for detecting the oxygen concentration in the exhaust gas. The sensor 70 is attached.

Further, the throttle valve 10 has a throttle opening sensor for detecting the throttle opening of the throttle valve 10.
72 are provided.

The fuel injection valve 10, the fuel pump 36, the pressure sensor 64, the water temperature sensor 68, the O2 sensor 70, the throttle opening sensor 72 and the like are in communication with a control unit 74 which is a control means.

This control unit 74, when changing from the idle operation to another operation state, controls the control value α of the ISC valve 82 at the time of the change.
Is stored as a learning value I, and at the same time, a fixed duty or opening of the ISC valve 82 for compensating the flow rate of the air valve 92, which will be described later, is stored and updated as a water temperature correction value Δα, and the operating state is changed to idle operation again. At this time, the updated learning value I and the updated water temperature correction value Δα are read out, and the control is performed to start the control of the ISC valve 82 with a fixed duty or opening obtained by adding the learning value I and the water temperature correction value Δα. Has a configuration.

In other words, when shifting from idle operation to another operating state, a fixed duty or opening control value α for idle speed control (ISC) for feedback control of idle speed during transition is stored as a learning value I. At the same time as updating, the water temperature Tw at the time of shifting from the idle operation to another operating state and a value corresponding to the water temperature Tw are stored and updated as the water temperature correction value Δα. Then, after the start of traveling, that is, at the time of shifting from another driving state to the idle operation again, the updated learning value I and the updated water temperature correction value Δα are read out and fixed by adding the water temperature correction value Δα to the learning value I. The control of the ISC valve 82 is started by the duty or the opening.

Further, in the control section 74, one end is opened in the ignition coil 76 for detecting an ignition signal, engine speed, etc., the battery 78, the manifold intake passage 16 on the downstream side of the throttle valve 12, and the other end is opened in the air cleaner 4. Negative pressure control valve (hereinafter referred to as "ISC valve") 82, which is a negative pressure switching valve installed in the bypass passage 80, and an adjusting screw 86 installed in parallel with the ISC valve 82 in the middle of the short-circuit passage 84 communicate with each other. doing.

Reference numeral 88 is a blow-by gas passage, 90 is a PCV valve, 9
2 is an air valve. The air valve 92 is opened and closed according to the temperature of the cooling water, and is provided in the bypass passage 80. That is, as is clear from FIG.
The air valve 92 is provided in the middle of a bypass air passage 94, one end of which opens on the downstream side of the throttle valve 12 and the other end of which opens on the air cleaner 4 side. At this time, the bypass air passage 94 bypasses the ISC valve 82 and the adjusting screw 86.

Next, the operation of this embodiment will be described with reference to the flow chart for controlling the increase in acceleration shown in FIG.

When the internal combustion engine 2 is driven, the program in the control unit 74 starts (100), and after starting, the idle switch (I
A determination (102) is made as to whether or not a predetermined time, for example, 3 to 5 seconds has elapsed while DSw) is still in the ON operation, that is, whether or not the learning start condition has been satisfied. If this determination (102) is YES, the control value that is the feedback value of the idle speed control (ISC) is learned and the water temperature is also learned.
The water temperature correction value Δα corresponding to Tw or the water temperature Tw is learned from the table (104), and if the determination (102) is NO, the idle speed control is not performed.

Further, the idle switch (IDSw) is turned off or a judgment (106) is made as to whether or not the vehicle speed has become equal to or higher than a predetermined vehicle speed. If the judgment (106) is YES, the idle operation is changed to another operation state. When Idle Speed Control (ISC) feedback control value is set to learning value I, water temperature when transitioning from idle operation to another operating state
The water temperature correction value Δα corresponding to Tw or the water temperature Tw is read from the table, and the learning value I and the water temperature correction value Δα are stored and updated in the RAM (108). If the judgment (106) is NO,
The idle speed is not controlled.

Then, a judgment (110) is made as to whether or not the idle switch (IDSw) is turned on and is in a deceleration state. When the judgment (110) is YES, when the idle operation shifts to another operation state. The water temperature correction value Δα obtained and stored from the table according to the water temperature Tw of the idle temperature control (ISC) learning value I that was stored and updated when shifting from idle operation to another operating state
The idle speed is controlled by the fixed duty or the opening obtained by adding the updated learning value I and the updated water temperature correction value Δα (112). Also, the judgment (110)
If NO, the idle speed is not controlled.

Further, a judgment (114) is made as to whether or not the vehicle speed is lower than a predetermined vehicle speed, and if the judgment (114) is YES, a control value which is a feedback value of the idle speed control (ISC) is learned. With water temperature Tw or water temperature
The process returns to the process (104) of learning the water temperature correction value Δα corresponding to Tw from the table, and when the determination (114) is NO, the idle speed control is not performed.

As a result, as shown by the solid line in FIG. 3 (a), even if the learning value I ₂ becomes small to the minimum guard position of about 10% in the first deceleration (deceleration), the idle operation is changed to another operation state. After the second running after re-running, the learning value I ₂ stored and updated at the time of the second deceleration (deceleration) when the idle operation is performed again is changed to the other operation state when the idle operation is performed.
The water temperature correction value Δα ₄ stored and updated at the time of shifting from the idle operation to another operation state is added, and the added fixed duty or opening is made larger than the conventional value, as shown by the solid line in FIG. 3 (c). Even if the learning value I becomes small to the minimum guard position in the process from cold to warm-up, it surely prevents the engine speed from dropping due to the length of running time and the acceleration state, causing the engine stall at the worst time. Can be avoided.

Further, it is possible to improve the drivability of the vehicle because it is possible to reliably prevent the engine speed from dropping when the operating state is changed from the other operating state to the idle operating state again, which is practically advantageous.

[Effects of the Invention] As described in detail above, according to the present invention, when shifting from idle operation to another operating state, the control value of the ISC valve at the time of transition is stored and updated as a learning value, and the air valve at that time is also updated. The fixed duty or opening of the ISC valve that compensates for the flow rate is stored and updated as the water temperature correction value, and when the operating state shifts to the idle operation again from another operating state, the updated learning value and the updated water temperature correction value are read out,
Since the control unit is provided to start the control of the ISC valve with a fixed duty or opening that adds the learned value and the water temperature correction value, the learned value is the minimum guard position in the process from cold to warm up. Even if it becomes small, it is possible to reliably prevent the engine speed from dropping due to the length of traveling time and the acceleration state, and it is possible to avoid causing the engine stall at the worst time and to improve the drivability of the vehicle. It can be improved and is practically advantageous.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a flowchart for idle speed control of an idle speed control device, FIG. 2 is a schematic diagram of the idle speed control device, and FIG. 3 is idle speed. It is a time chart of a number control device. FIG. 4 is a flow chart for idle speed control of the idle speed control device showing the prior art of the present invention. In the figure, 2 is an internal combustion engine, 4 is an air cleaner, 8 is a body intake passage, 10 is a fuel injection valve, 12 is a throttle valve, 16 is a manifold intake passage, 24 is a manifold exhaust passage, 28 is a pipe exhaust passage, and 32 is a fuel. Control device, 34 is a fuel tank, 46 is an exhaust gas recirculation device (EGR device), 60 is a control pressure switching valve (VSV), 64 is a pressure sensor, 66 is a cooling water passage, 68
Is a water temperature sensor, 70 is an O2 sensor, 72 is a throttle opening sensor, 74 is a control unit, 76 is an ignition coil, 80 is a bypass passage, 82 is an ISC valve, 84 is a short-circuit passage, 86 is an adjusting screw, 88 is a blow-by gas. A passage, 90 is a PCV valve.

Claims (1)

(57) [Claims] 1. An ISC valve and an air valve that opens and closes according to the cooling water temperature are provided in a bypass passage of a throttle valve,
While performing feedback control of the ISC valve so that the target rotation speed is achieved during idle operation, when shifting from idle operation to another operating state, a control value consisting of a fixed duty or opening of the ISC valve at the time of transition is learned. Is stored and updated, and when shifting from another operating state to idle operation again, the control value of the updated learning value
In the idle speed control device for starting the control of the ISC valve, when shifting from the idle operation to another operating state, the control value of the ISC valve at the time of transition is stored and updated as a learning value, and the flow rate of the air valve at that time. The fixed duty or opening of the ISC valve that compensates for is stored and updated as a water temperature correction value, and when transitioning to the idle operation from the other operating state again, the updated learning value and the updated water temperature correction value are read out, The fixed duty or the opening obtained by adding the learning value and the water temperature correction value
An idle speed control device comprising a control unit for controlling the control of the ISC valve.