JPH04303151A - Idle rotation number controlling device for internal combustion engine - Google Patents

Abstract

PURPOSE:To maintain an idling condition preferably, and take counter-measures to freezing of a muffler by controlling an electromagnetic valve for a predetermined control time at a fixed duty ratio when an intake air temperature reaches a first set value, and actuation controlling it alternately at duty ratios for fixing and rotation feedback till reaches the intake air temperature after the time. CONSTITUTION:A control means 112 controls an ISC valve 76 at a fixed duty ratio for a predetermined control time set by timer 110 when an intake air temperature detected by an intake air temperature sensor 106 gets to be less than a first set value on the lower side. After the predetermined time and before the intake air temperature gets to a second set value over the first set value, the ISC valve 76 is actuation-controlled alternately at the fixed duty ratio and a duty ratio for rotation feedback. The rotation number can thus be increased only by operating the electromagnetic valve preferably without delaying an ignition timing only when the intake air temperature is low, thereby an exhaust temperature can be increased.

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 internal combustion engine, and more particularly to an idle speed control device for an internal combustion engine that can remove water from a muffler while stabilizing the idling state.

0002

2. Description of the Related Art Some internal combustion engines are equipped with an idle speed control device in order to control the idle speed during idling operation.

[0003] This idle speed control device for an internal combustion engine generally includes a bypass passage that bypasses a throttle valve in the intake passage, and an ISC valve (idle speed control valve), which is a solenoid valve, provided in the middle of this bypass passage. By controlling the duty of this ISC valve using a duty ratio depending on the idling operating state, the engine rotational speed in the idling operating state is controlled by increasing or decreasing the amount of intake air in the bypass passage. In order to prevent the muffler from freezing, this idle speed control device performs control to retard the ignition timing and increase the exhaust temperature when idling operation is set for a certain period of time.

[0004] Further, as for ignition timing control during idling, for example, Japanese Patent Laid-Open No. 60-60
It is disclosed in Japanese Patent No. 272. The system described in this bulletin detects fluctuations in engine speed within a predetermined period of time in order to control ignition timing during idling after warming up, and ignites when the fluctuation in engine speed/air-fuel ratio exceeds a predetermined value. By retarding the ignition timing and retarding the ignition timing when the fluctuation in engine speed is less than a predetermined value, combustion is stabilized during idling and the fuel ratio is improved.

[0005]

[Problems to be Solved by the Invention] However, in the past, the ignition timing was retarded to prevent muffler freezing, and the ignition timing was retarded even when the intake air temperature was not low. , there was an inconvenience that the idling condition deteriorated.

[0006]

[Means for Solving the Problems] Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides a bypass passage that bypasses the intake throttle valve in the intake passage of an internal combustion engine, and has a duty ratio controlled part in the middle of the bypass passage. In an idling speed control device for an internal combustion engine, a solenoid valve for opening and closing the bypass passage is provided, and the solenoid valve is operated to increase or decrease the amount of intake air in the bypass passage to control the engine speed during idling operation. is less than a first set value on the low side, the solenoid valve is controlled with a fixed duty ratio for a predetermined control time, and a second set value at which the intake air temperature is equal to or higher than the first set value after the elapse of the predetermined control time; The present invention is characterized in that a control means is provided for controlling the operation of the electromagnetic valve alternately at the fixed duty ratio and the rotational feedback ratio until the rotational feedback ratio is reached.

[0007]

[Operation] According to the configuration of the present invention, the control means controls the solenoid valve at a fixed duty ratio for a predetermined control time when the intake air temperature becomes less than the first set value on the low side, and after the predetermined control time has elapsed. The solenoid valve is controlled to operate alternately with a fixed duty ratio and a rotational feedback duty ratio until the intake air temperature reaches a second set value that is equal to or higher than the first set value. As a result, only when the intake air temperature is low, by skillfully operating the solenoid valve, the engine speed is increased and the exhaust temperature is raised, without retarding the ignition timing. The water in the muffler can be removed while maintaining good conditions, and the muffler can be prevented from freezing.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail and specifically below with reference to the drawings. 1 to 3 show embodiments of this invention. In FIG. 1, 2 is an internal combustion engine, 4 is an internal combustion engine, and 4 is an internal combustion engine.
is a cylinder block, 6 is a cylinder head, 8 is a piston, 10 is a combustion chamber, 12 is an intake valve, 14 is an exhaust valve, 16
1 is an intake port, 18 is an exhaust port, 20 is an intake manifold, 22 is a manifold intake passage, 24 is an exhaust manifold, 26 is a manifold exhaust passage, 28 is an air cleaner, 3
0 is an intake pipe, 32 is a pipe intake passage, 34 is a throttle body, 36 is a body intake passage, 38 is an intake throttle valve, 40 is a surge tank, 42 is an exhaust pipe, 44 is a pipe exhaust passage, 46
is a muffler.

The intake manifold 20 includes a combustion chamber 10.
A fuel injection valve 48 is mounted so as to be oriented in this direction.

This fuel injection valve 48 has a fuel tank 50.
The fuel inside is pumped out. That is, the fuel in the fuel tank 50 is force-fed by the fuel pump 52 to the fuel supply passage 56 via the oil strainer 54, filtered by the fuel filter 58, and the pressure is adjusted by the fuel pressure regulator 60 to the fuel injection valve. 46.

Body intake passage 3 of throttle body 34
The fuel vapor passage 62 has one end communicating with the upper part of the fuel tank 50, and the other end thereof communicates with the fuel vapor passage 62. A separator 64, a two-way valve 66, and a canister 68 are interposed in this evaporative fuel passage 62 in this order from the fuel tank 50 side.

A bypass air passage 70 is provided to communicate between the body intake passage 36 and the inside of the surge tank 40, bypassing the intake throttle valve 38. That is, the bypass air passage 70 has an air inlet 72 at one end communicating with the body intake passage 36 on the upstream side of the intake throttle valve 38, and an air outlet 74 at the other end communicating with the surge tank 40. An ISC valve (VSV) 76, which is a solenoid valve, opens and closes the bypass air passage 70 to adjust the amount of intake air. As a result, the bypass air passage 70 becomes the first bypass passage 70-1.
and a second bypass passage 70-2.

The first bypass air passage 70-1 and the second bypass air passage 70-2 via the ISC valve 76 are communicated by an air conditioner bypass air passage 78. An air conditioner solenoid valve (VSV) 80 is interposed in the middle of this air conditioner bypass air passage 78. This air conditioner solenoid valve 80 is connected to an air conditioner switch 82 .

An ignition-side pressure introduction passage 86 is connected to the throttle body 34 for introducing the pressure within the body intake passage 36 to a distributor 84 of the ignition mechanism.

The surge tank 40 includes a pressure sensor 8.
8 is connected to a detection pressure introduction passage 90 that guides the pressure inside the surge tank 40.

An EGR valve 94 held by a valve holder 92 is attached to the intake manifold 20 . This EGR valve 94 is connected to an EGR inlet 96 formed in the exhaust manifold 24 and an EGR inlet 96 formed in the intake manifold 20.
The EGR amount is adjusted by opening and closing an EGR passage 100 that communicates with the R reflux port 98.

A cooling water passage 102 through which cooling water flows is formed in the intake manifold 20, and a water temperature sensor 104 for detecting the temperature of the cooling water is also attached.

Furthermore, an intake temperature sensor 106 is attached to the intake manifold 20 on the side of the surge tank 40 to detect the intake air temperature within the manifold intake passage 22.

Furthermore, an idle switch 108 is provided which detects the opening state of the intake throttle valve 38 to determine the idle rotation state of the internal combustion engine 2 and turns it on and off.

The fuel pump 52, the fuel injection valve 48, and the I
The SC valve 76, the pressure sensor 88, the water temperature sensor 104, the intake air temperature sensor 106, and the idle switch 108 are connected to a control means 112 having a timer 110. Further, the control means 112 is connected to a battery 118 via a fuse 114 and a main switch 116, and is also connected to an ignition coil 120.

The control means 112 controls the ISC valve 76 for a predetermined control time T set by a timer 110 when the intake air temperature detected by the intake air temperature sensor 106 becomes less than a first set value A on the low side. In addition to controlling with a fixed duty ratio, the ISC valve 76 is controlled with a fixed duty ratio and a rotation feedback duty ratio until the intake air temperature reaches a second set value B that is higher than the first set value A after a predetermined control time T seconds has elapsed. The operation is controlled alternately, that is, the rotation feedback control is performed for a time of t seconds and the fixed duty ratio control is performed for a time of T seconds.

Next, the operation of this embodiment will be explained based on the flow chart of FIG. 2 and the time chart of FIG. 3.

When the internal combustion engine 2 starts, the control means 112
The program starts (step 202), and it is determined whether the idle switch 108 is on or off (step 202).
Step 204). If the idle switch 108 is off in step 204, this determination is continued.

In step 204, the idle switch 108
is on, the idle time is counted (step 206), and it is determined whether the idle time has reached a predetermined time t seconds (the time from X1 to X2 of the rotation feedback control in FIG. 3) (step 206). 208). If NO in step 208, this determination is continued.

If YES in step 208, it is determined whether the intake air temperature has become lower than the first set temperature A on the low side (step 210). If NO in this step 210, this determination is continued.

If YES in step 210, the intake air temperature is lower than the first set value A at the position shown in FIG.
Control of the C valve 76 is started at a fixed duty ratio (shown in FIG. 4), that is, a duty ratio higher than the rotational feedback duty ratio (step 212).

[0027] Then, the predetermined control time (TD) of this fixed duty ratio control is counted by the timer 110 (step 214), and then it is determined whether the intake air temperature is less than the second set value B (step 216). .

If YES in step 216, it is determined whether the predetermined control time TD is greater than the set fixed duty control time T (step 218). In other words, the first
Between the set value A and the second set value B, the timer 110 resets the ISC valve 76 and alternately controls the operation of the rotation feedback duty ratio and the fixed duty ratio until the intake air temperature reaches the second set value. .

If NO in step 218, the determination in step 216 is continued.

On the other hand, if NO in step 216 or YES in step 218, the process returns to step 216.

As a result, during idling, only when the intake air temperature is low, the ISC valve 76 is actuated to increase the engine speed, thereby increasing the exhaust temperature and removing water in the muffler 46. At this time, since there is no need to control the ignition timing to the retarded side by only controlling the operation of the ISC valve 76, it is possible to maintain a good idling state.

[0032]

[Effects of the Invention] As is clear from the above detailed description, according to the present invention, when the intake air temperature becomes less than the first set value on the low side, the solenoid valve is controlled at a fixed duty ratio for a predetermined control time, and By providing a control means that alternately controls the operation of the solenoid valve with a fixed duty ratio and a rotational feedback duty ratio until the intake air temperature reaches a second set value that is equal to or higher than the first set value after a predetermined control time has elapsed. By setting conditions for the intake air temperature, only when the intake air temperature is low, the engine speed is increased and the exhaust temperature is increased by skillfully operating the solenoid valve without retarding the ignition timing, resulting in a good idling condition. Water in the muffler can be removed while maintaining the muffler to prevent freezing of the muffler.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of an idle rotation speed control device.

FIG. 2 is a flowchart explaining the operation of the embodiment.

FIG. 3 is a time chart explaining the operation of the embodiment.

[Explanation of symbols]

2 Internal combustion engine 38 Intake throttle valve 70 Bypass air passage 76 ISC valve 106 Intake temperature sensor 108 Idle switch 112 Control means

Claims (1)

[Claims] 1. A bypass passage that bypasses an intake throttle valve in an intake passage of an internal combustion engine is provided, and a solenoid valve that opens and closes the bypass passage under duty ratio control is provided in the middle of this bypass passage. In an idling speed control device for an internal combustion engine that controls the engine speed during idling operation by increasing or decreasing the amount of intake air in a bypass passage, the solenoid valve is set to a predetermined value when the intake air temperature becomes less than a first set value on the low side. The solenoid valve is controlled at a fixed duty ratio for the control time, and the solenoid valve is controlled at the fixed duty ratio and the rotation feedback duty ratio until the intake air temperature reaches a second set value that is equal to or higher than the first set value after the predetermined control time has elapsed. 1. An idle speed control device for an internal combustion engine, characterized in that it is provided with a control means for alternately controlling the operation.