JPS6085235A - Method of controlling idling speed of internal- combustion engine - Google Patents

Abstract

PURPOSE:To prevent remarkable decrease in engine rotational speed in an internal-combustion engine for a vehicle, by allowing a bypass of a throttle valve to be communicated for a predetermined period from a timing when a compressor of an air conditioner in operation is made unoperational. CONSTITUTION:When an engine rotational speed detected by a sensor 26 becomes higher than an upper limit of a predetermined range, a control circuit 30 acts to block a bypass 3 of a throttle valve 4 by an electromagnetic valve 5, while when the engine rotational speed becomes lower than a lower limit, the control circuit 30 acts allow communication of the bypass 3, thus controlling an idling speed within the predetermined range. Further, when operation of a compressor for an air conditioner is detected by an air conditioner switch 25, an electromagnetic valve 9 is opened to allow communication of a passage 7 thereby to increase the engine rotational speed. When the compressor is made unoperational, the passage 7 is blocked and the bypass 3 is communicated for a predetermined period. Thusly, it is possible to prevent remarkable decrease in the engine rotational speed upon unoperation of the compressor for the air conditioner.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the idle speed of an internal combustion engine, and more particularly, the present invention relates to a method for controlling the idle speed of an internal combustion engine, and more particularly, to a method for controlling the engine speed within a predetermined range by communicating and blocking a detour provided by bypassing a throttle valve. The present invention relates to an idle speed control method for an internal combustion engine, in which the above-mentioned control is stopped when a compressor of a near conditioner is activated, and a detour path is communicated with another passage to increase the engine speed.

Modern internal combustion engines tend to have low idle speeds in order to improve fuel efficiency, so small and lightweight internal combustion engines in particular require a small load due to driving the dynamic fan that lights up the high beam when idling. Even if this is applied, the engine speed may drop and the engine speed may become unstable during idling. Furthermore, if deposits are deposited on the throttle valve due to changes over time, the engine speed may gradually decrease and the engine speed during idling may become unstable.

For this purpose, a detour is provided that bypasses the throttle valve and communicates the upstream side of the throttle valve with the downstream side of the throttle valve, and a solenoid valve is installed to cut off and communicate this detour. When the engine speed exceeds the upper limit of the range, a solenoid valve shuts off the detour, and when the engine speed falls below the lower limit of the specified range, the solenoid valve opens the detour, allowing the engine to flow to the detour. The idle speed of the engine is controlled within a predetermined range by controlling the amount of air. Additionally, when the compressor of the near conditioner is operating, a load is applied to the engine, so it is possible to increase the idle speed (idle up) by keeping the detour open and closed and communicating the detour with another passage. It is being done. In this method, the near conditioner compressor that was operating was at fault.

When the engine moves, the idle-up passage is blocked and idle speed control is started to control the air flow to the detour.

However, when the compressor is operating, the engine speed is high, and even when the compressor is not operating, the engine speed does not drop suddenly and remains high for a while, so the engine speed does not exceed the upper limit of the specified range. If the detour is exceeded, the detour is blocked. Therefore, if the engine speed is within a predetermined range with the detour connected due to deposits on the throttle valve (due to changes over time), the operating compressor will become inactive. When this occurs, the detour is blocked, resulting in a lack of air volume and a significant drop in engine speed, causing the problem that in the worst case scenario, the engine stalls.

The present invention has been made to solve the above problems, and prevents the intake air amount from decreasing, resulting in a significant drop in engine speed when the operating near conditioner compressor becomes inactive. An object of the present invention is to provide a method for controlling the idle speed of an internal combustion engine.

In order to achieve the above object, the present invention has a detour that bypasses the throttle valve and communicates the upstream side of the throttle valve with the downstream side of the throttle valve when the engine speed exceeds the upper limit of a predetermined range. When the engine speed becomes lower than the lower limit of the predetermined range, the bypass path is opened to control the engine speed during idle link to a value within the predetermined range, and also to control the engine speed during idle link to a value within the predetermined range. In the idle speed control method for an internal combustion engine, the method for controlling the idle speed of an internal combustion engine increases the engine speed by keeping the bypass path closed and in communication when the near conditioner is in operation, and communicating the detour path with another passage to increase the engine speed. The detour is characterized in that the detour is communicated for a predetermined period from the time when the compressor becomes inoperable.

As a result, even if the compressor of the near conditioner that was operating becomes inactive and the passage is blocked, the amount of air flowing through the detour is not reduced.

Therefore, according to the above configuration of the present invention, it is possible to prevent the engine speed from significantly decreasing when the compressor of the near conditioner becomes inactive.

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

FIG. 1 is a schematic diagram of an internal combustion engine equipped with an idle speed control system to which the present invention is applied. An intake temperature sensor 2 is installed downstream of the air cleaner 1 to detect the temperature of intake air and output an intake air temperature signal. A throttle valve 4 is disposed downstream of the intake air temperature sensor, and a throttle switch 6 is attached which is interlocked with the throttle valve 4 and turns on when the throttle valve is fully closed and turns off when the throttle valve opens.

A surge tank 8 is provided downstream of the throttle valve 4, and a pressure sensor 1 is installed in the surge tank 8 to detect the intake pipe pressure downstream of the throttle valve and output an intake pipe pressure signal.
0 is attached. Detour path 3 with one end opening upstream of the throttle valve 4 and the other end opening into the surge tank 8
is provided so as to bypass the throttle valve 4,
A first Vat valve 5 is attached to the detour 3 and opens and closes the detour 3 for communication and isolation.

The first electromagnetic valve 5 may have a small flow rate that can compensate for a decrease in the idle rotation speed due to the electrical load. Further, a passage 7 having one end open to the upstream side of the throttle valve 4 and the other end opening to the surge tank 8 is provided so as to bypass the throttle valve 4 and the first electromagnetic valve 5. Attached to 7 is a second solenoid valve 9 that is opened when the near conditioner compressor is activated and closed when the compressor is not activated.

The surge tank 8 is communicated with the combustion chamber of the engine via an intake manifold 12. A fuel injection valve 16 is attached to the intake manifold 12 for each cylinder. The combustion chamber of the engine is communicated via an exhaust manifold 11 to a catalytic converter 15 filled with a three-way catalyst. Further, a water temperature sensor 20 is attached to the engine block to detect the engine cooling water temperature and output a water temperature signal. A tip of a spark plug projects into the combustion chamber of the engine, and a distributor 24 is connected to the spark plug.

An engine rotational speed sensor 26 is attached to the distributor 24 and includes a pickup fixed to the distributor housing and a signal rotor fixed to the distributor shaft. This engine rotation speed sensor 26 outputs a crank angle signal to the control circuit 30, for example, every 30° CA. In addition, 23 is a 0□ sensor that detects the residual oxygen concentration in exhaust gas and outputs the air-fuel ratio (N), 25 is an air conditioner switch that is turned on when the near conditioner is activated, and 27 is a switch. .

As shown in FIG. 2, the control circuit 30 includes a central processing unit (C
PU) 36, read-only memory (ROM) 38, random access memory (RAM) 40, backup 2 memory (BU-RAM) 42, input/output capo) (Ilo)
44, an analog-to-digital converter (ADC) 46, and a bus such as a data path control bus for connecting these. l1044 has a crank angle signal, an air ratio signal, an air conditioner switch (No. W,
A throttle signal output from the throttle switch 6 is input, and the first electromagnetic valve 5 is
- A solenoid valve control signal for opening and closing, a fuel injection signal for controlling the opening/closing time of the fuel injection valve 16, and an ignition signal for controlling the on/off time of the igniter are output. Also, A
An intake pipe pressure signal, an intake temperature signal, a battery signal, and a water temperature signal are input to the DC 46 and converted into digital signals.

The above crank angle signal is passed through a waveform shaping circuit to l104.
4, and a digital signal representing the engine speed NE is formed from the 2-ink angle signal.

Next, a processing routine according to an embodiment of the present invention will be explained.

FIG. 3 shows an interrupt routine that is implemented at predetermined time intervals, and in step 102, it is determined whether the near conditioner compressor is operating based on the air conditioner switch signal, that is, whether idle up is being executed. to judge. When the compressor is operating, the count value T is set to 0 in step 104, and when the compressor is not operating, the count value T is incremented by 1 in step 106.

Fourth! lt shows the main routine executed when the throttle switch is on, that is, when the engine is idling. First, in step 202, the engine rotation speed NE is increased and the engine rotation voltage V is taken in, and in the next step 204, the engine rotation speed NE is increased and the rotation voltage V is below the lower limit of a predetermined range, and the engine rotation speed NK is a predetermined value. In other words, it is determined whether the solenoid valve 50 opening condition is satisfied or not.If it is determined in step 204 that the solenoid valve opening condition is satisfied, step 206 is performed. outputs a solenoid valve control signal to open the solenoid valve.

On the other hand, when it is determined in step 204 that the electromagnetic valve opening condition is not satisfied, in step 210 it is determined whether the battery voltage v is greater than or equal to the upper limit of the predetermined range and the engine speed NE is greater than or equal to the upper limit of the predetermined range. That is, solenoid valve 5
It is determined whether the valve closing conditions are satisfied. When it is determined in step 210 that the closing condition for the electromagnetic valve is satisfied, it is determined in step 212 whether the count value T incremented in step 106 is greater than or equal to a predetermined value Tα. Then, only when the count value °r is greater than or equal to a predetermined value Tα, a solenoid valve control signal is output in step 214 to close the solenoid valve. On the other hand, when it is determined in step 210 that the closing condition for the electromagnetic valve is not satisfied, that is, when the battery voltage V and the engine speed NE are within the predetermined ranges, and when the count value T is less than the predetermined value Tα That is, if a predetermined period of time has elapsed since the compressor of the near conditioner became inactive, the main routine is immediately terminated, and the previous open/closed state of the solenoid valve is maintained.

As a result of the above, if the solenoid valve is opened when the compressor of the near conditioner is operating, even if the solenoid valve closing condition is met, the solenoid valve will be closed after a predetermined period of time has passed from the time when the compressor is not operating. Ru.

Next, the control characteristics of this embodiment are shown in FIG. 5 in comparison with the conventional example. As can be understood from the figure, when the solenoid valve is open during idle up, the engine speed drops significantly after the compressor stops, as shown by curve A. On the other hand, in this embodiment, since the solenoid valve is opened within a predetermined period after the compressor stops in the above case, no significant decrease in the engine speed is observed as shown by curve B.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an internal combustion engine to which Kitoaki is applied, Fig. 2 is a block diagram showing the specific structure of the control circuit 3o in Fig. 1, and Fig. 3 is an interrupt routine that is activated at regular intervals. FIG. 4 is a flowchart showing the contents of the main routine, and FIG. 5 is a diagram showing a comparison between the control characteristics of this embodiment and the conventional example. 3... Detour path, 5... First solenoid valve, 7... Passage, 9... Second solenoid valve ~ 30... Control circuit. Agent Tatsuyuki Unuma (and 1 other person)

Claims (1)

[Claims] (1) When the engine speed exceeds the upper limit of a predetermined range, the detour that bypasses the throttle valve and communicates the upstream side of the throttle valve with the downstream side of the throttle valve is cut off, and the engine speed reaches the upper limit of a preset range. When the temperature falls below the lower limit of the predetermined range, the detour is opened to control the engine speed during idling to a value within the predetermined range, and when the near conditioner compressor is activated, the detour is closed and In the idle speed control method for an internal combustion engine in which the engine speed is increased by maintaining the communication state and communicating the detour path with another path, from the time when the compressor of the air conditioner that was in operation becomes inactive. A method for controlling the idle speed of an internal combustion engine, characterized in that the detour is communicated for a predetermined period of time.