JPH06101459A - Rotational speed control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Object] In an internal combustion engine having an electrically heated catalytic converter device, a voltage drop that occurs when the electrically heated catalytic converter device is heated during idle operation is prevented. [Composition] An idle switch 17 and an EHC switch 9 for turning ON / OFF the heating of the electric heating catalytic converter device and a FICD valve 16 for increasing and controlling the intake air flow rate during the idling operation are provided, and the heating operation of the electric heating catalytic converter device is performed during the idling operation. When the state is detected, the FICD valve 16 is opened to increase the idle rotation speed, thereby increasing the amount of energy generated and preventing a voltage drop.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed control device for an internal combustion engine having an electrically heated catalytic converter device.

[0002]

2. Description of the Related Art An exhaust gas purification catalytic converter device for purifying pollutants such as CO, HC, and NOx contained in exhaust gas by being installed in an exhaust passage of an internal combustion engine is not in a state of being heated until a predetermined activation temperature is reached. Therefore, a sufficient catalytic action cannot be achieved, and for example, immediately after a cold start of the engine, it takes a considerable time for the exhaust gas purification performance to reach a sufficient level.

Therefore, it has been conventionally considered to incorporate an electric heater for heating the catalyst carrier carrying the catalyst in a cold state, or to make the catalyst carrier itself an electric heater structure.
On the other hand, in recent years, it has been considered that a catalyst carrier made of metal, which is advantageous in terms of heat capacity and pressure loss, is applied as the catalyst carrier. Since the catalyst carrier made of metal is composed of a metal plate, the metal plate itself An exhaust gas purifying catalytic converter device has been proposed in which is used as a heating resistor, that is, an electric heater. (See, for example, Japanese Utility Model Laid-Open No. 63-67609).

[0004]

However, such an electric heating catalytic converter device of the related art, in particular, a device having an electric heater structure of a metallic catalyst carrier consumes a large amount of electric energy, so that it is in idle operation. However, there is a problem in that the power consumption exceeds the power generation capacity of the generator, so that the battery is discharged and a voltage drop is caused.

The present invention has been made in view of the above-mentioned conventional problems, and when the heating operation of the electric heating catalytic converter device is detected during the idle operation, the idle speed (hereinafter, the rotation speed is represented by the rotation speed) is detected. It is an object of the present invention to provide a rotation speed control device for an internal combustion engine having an electrically heated catalytic converter device capable of increasing the amount of power generation energy of a generator and preventing a voltage drop by increasing (. And

[0006]

Therefore, as shown in FIG. 1, an internal combustion engine revolution speed control apparatus according to the present invention is charged with a generator driven by the internal combustion engine and energy generated from the generator. And a heating operation state of the electric heating catalytic converter device, in an internal combustion engine having an electric heating catalytic converter device installed in an exhaust passage and heated by electric power of the battery when cold. And a means for controlling the increase of the intake air flow rate when the heating operation of the electrically heated catalytic converter device is detected during idle operation.

[0007]

With this structure, the intake system is provided when the heating operation of the electrically heated catalytic converter device is detected during the idle operation by detecting the idle operation state and the heating operation state of the electrically heated catalytic converter device. The idle speed can be increased by the means for increasing the intake air flow rate.

Therefore, since the rotational speed of the generator driven by the internal combustion engine can be increased, the amount of energy generated by the generator can be increased and a voltage drop can be prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, an electrically heated metal monolith catalytic converter device (hereinafter referred to as EH) is provided in an exhaust passage 2 of an internal combustion engine 1.
C) 3 is provided upstream of the main monolith catalyst 4. The EHC 3 is provided so that it can be electrically heated by the power of the battery 5. The battery 5 is provided so that it can be charged by a generator 8 driven by a crank pulley 6 of the internal combustion engine 1 via a belt 7. In addition, EH that heats EHC3 when the engine is cold
A C switch 9 is provided.

On the other hand, the intake side of the internal combustion engine 1 is provided with an air cleaner 10, an intake duct 11, a throttle chamber 12 and an intake manifold 13, through which air is sucked. The throttle chamber 12 is provided with a throttle valve 14 that works in conjunction with an accelerator pedal (not shown) to control the intake air flow rate. Throttle valve 1
4 is provided in the middle of the auxiliary air passage 15 during the idling operation with a large load amount.
A fast idle control device (hereinafter referred to as FICD) valve 16 whose opening is adjusted according to the duty ratio of a pulse signal sent from
Thus, by controlling the auxiliary air flow rate, the idle speed when the load amount is large is controlled. The throttle valve 14 is additionally provided with an idle switch 17 which is turned on at its fully closed position.

Although the duty ratio of the pulse signal is controlled by the control unit 21, signals from various sensors are input to the control unit 21 for the idle speed control according to the present invention. A crank angle sensor 18 is provided as each of the various sensors, and the engine speed RPM is calculated based on the signal from the crank angle sensor 18. A water temperature sensor 20 that outputs a voltage signal corresponding to the engine cooling water temperature (hereinafter referred to as water temperature) is provided facing the water jacket 19 of the internal combustion engine 1, and the water temperature detected by the water temperature sensor 20 is a predetermined value. In the following cold state, the EHC switch 9 is turned on by a control signal from the control unit 21.

Next, the idle speed control by the control unit 21 will be described with reference to the flow chart shown in FIG. Step 1 (denoted as S1 in the figure).
In the following), the idle switch 17 detects whether or not the engine is in an idle operation state, and if NO, the process exits from this flow. If YES, go to step 2. Here, the idle switch 17 and the function of step 1 constitute an idle operation state detecting means.

In step 2, the water temperature sensor 20 detects the cold state of the engine and, for example, the EHC switch 9 is set to O when the water temperature is below 60 ° C.
Based on the N / OFF signal, it is determined whether the EHC 3 is heating. If NO, the process exits this flow.
If YES, go to step 3. Here, the EHC switch 9 and the function of this step 2 constitute the heating operation state detecting means of the electric heating catalytic converter device.

In step 3, it is determined whether or not the heating operation state detection of the EHC 3 is the first time. If YES, go to step 4. If NO, go to step 6. In step 4, since it is immediately after the heating operation state of the EHC 3 is detected, it is determined that the idle speed needs to be rapidly increased, and the target duty ratio (Duty shown in FIG. 3 and FIG. 4) and the target engine are immediately determined. Rotation speed (rpm shown in FIG. 3
) Is calculated, and then the process proceeds to step 5, where F
The Du is used as a solenoid drive signal for the ICD valve 16.
Initially set ty, immediately start energizing the FICD valve 16 to open it.

In step 6, EHC in step 3
When it is judged that the heating operation state detection of 3 is not the first time,
The detected engine speed RPM and the target engine speed rpm are compared in order to converge the increased idle speed to the minimum required target value within a range in which fluctuations in the speed can be suppressed well. Then, if RPM> rpm, proceed to step 7, and if RPM <rpm, proceed to step 8.

Step 7 is for RPM> rpm and reduces the ON time of the duty pulse signal, while step 8 is for RPM <rpm and increases the ON time of the duty pulse signal. By sending a signal, the opening operation time of the FICD valve 16 is controlled to perform feedback control of the idle speed. The intake air flow rate increase control means is configured by the functions from step 3 to step 8 and the FICD valve 16.

According to this control method, the EH during idle operation is
During the heating operation of C3, the idle rotation speed can be immediately increased by the control of the initially set Duty, and the amount of energy generated by the generator 8 can be increased.
Further, it is possible to stabilize the idle speed by performing feedback control of the idle speed thereafter.

Next, a second embodiment of the present invention will be described. This embodiment is a case where an air conditioner is attached to the first embodiment. FIG. 5 showing the configuration of the present embodiment has an air conditioner (hereinafter referred to as A / C) 22 and an air conditioner switch 23 added to FIG. The A / C 22 is driven by a crank pulley 6 of the internal combustion engine 1 via a belt 7. Air conditioner switch 23
Turns ON / OFF the A / C 22 and detects its operating state. The signal of the air conditioner switch 23 is input to the control unit 21 in addition to the signals described in the first embodiment. Other configurations are the same as those described in the first embodiment.

Next, the idle speed control by the control unit 21 will be described with reference to the flowchart shown in FIG. In steps 1 and 2, as in the above embodiment, the idle operation state is detected and the heating operation of the EHC 3 is determined by the ON / OFF signal of the EHC switch 9. If the judgment in step 2 is NO, step 9
Proceed to. If YES, go to step 12.

In step 9, it is determined whether the A / C 22 is operating. In the case of NO, the routine proceeds to step 11, where the FICD valve 16 is closed and the process exits from this flow. If YES, go to step 10. Step 10 is a case where only the A / C 22 is operating in the idle operation state, and the target duty ratio (Du shown in FIGS. 6 and 7) according to the load when only the A / C 22 is operating.
ty), and the target engine speed (rpm shown in FIG. 6) is calculated.

Similarly, in the idling state, when it is determined that the EHC 3 is heating in step 2 and the A / C 22 is not operating in step 12, only the EHC 3 is heating in step 13. Target duty ratio according to the load at the time (Du shown in FIGS. 6 and 7
ty), and the target engine speed (rpm shown in FIG. 6) is calculated.

When it is determined that the EHC 3 is heating in step 2 and the A / C 22 is operating in step 12 in the idle operation state, it is determined in step 14 that these two are in operation. Target duty ratio (Duty shown in FIGS. 6 and 7) according to the load of
The target engine speed (rpm shown in FIG. 6) is calculated.

After obtaining the duty ratios corresponding to the respective loads, the process proceeds to step 3, and it is judged whether or not the operation state of each load device is detected for the first time, and if it is the first time, the process proceeds to step 5. move on. If it is not the first time, go to step 6. In step 5, the duty ratio (denoted as Duty (n) in FIG. 6) corresponding to each load is initially set as the solenoid drive signal of the FICD valve 16, and the FIC is set.
The energization of the D valve 16 is started and the D valve 16 is opened.

After step 6, feedback control of the idle speed is performed as in the above embodiment. According to the present embodiment, the idle speed can be variably set according to the load, so that the idle speed can be finely controlled and the fuel consumption amount can be reduced. Next, the control of the third embodiment in which the duty pattern of the control method is learned and controlled to improve the responsiveness will be described with reference to the flowchart of FIG. 8 is added to the flowchart shown in FIG. 6, and proceeds to step 15 after steps 7 and 8,
Learning is done.

That is, if it is determined in step 15 that the duty ratio decrease or duty ratio increase is repeated five times, Duty, is updated, and the engine operating state and the duty pattern are stored in the non-volatile memory. According to this method, since the duty is updated to a more appropriate value by learning, it is possible to increase the idle speed immediately after the EHC3 heating operation in a short time and improve the convergence of the engine speed. Is. Furthermore, it is possible to absorb the fluctuation of the rotational speed due to the change with time of the engine.

In each of the above embodiments, the means for increasing and controlling the auxiliary air flow rate is not limited to the control of the FICD valve 16, but an auxiliary such as an AAC valve for performing idle speed control when the load amount is small. The capacity of the air control valve may be increased so as to be able to cope with a large load amount, or may be controlled so as to directly control the fully closed state of the throttle valve.

[0027]

As described above, the rotation speed control device for an internal combustion engine having the electrically heated catalytic converter device according to the present invention is provided with an intake system provided in the intake system when the electrically heated catalytic converter device is heated during idle operation. Since the amount of energy generated by the generator can be increased by increasing the idle speed by means of increasing air amount control, it is possible to prevent voltage drop and also to prevent idle speed fluctuations due to increased load. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration and functions of the present invention.

FIG. 2 is a system diagram of a rotation speed control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 3 is a flowchart of the rotational speed control of the internal combustion engine according to the first embodiment of the present invention.

FIG. 4 is an example of a pulse signal for driving a FICD valve at the duty ratio according to FIG.

FIG. 5 is a system diagram of a rotation speed control device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 6 is a flowchart of the rotational speed control of the internal combustion engine according to the second embodiment of the present invention.

7 is a FICD at a duty ratio according to FIG.
An example of pulse signal for valve drive

FIG. 8 is a flowchart regarding learning control according to the flowchart of FIG.

[Explanation of symbols]

 1 Internal Combustion Engine 3 Electric Heated Catalytic Converter (EHC) 5 Battery 8 Generator 9 EHC Switch 15 Auxiliary Air Passage 16 FICD Valve 17 Idle Switch 18 Crank Angle Sensor 21 Control Unit

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location F02D 43/00 301 L 7536-3G T 7536-3G 45/00 312 D 7536-3G 395 A 7536-3G

Claims (1)

[Claims] 1. A generator driven by an internal combustion engine, a battery for charging energy generated by the generator, and an electrically heated catalytic converter device provided in an exhaust passage and heated by the battery power when the engine is cold. In the internal combustion engine having, while providing the means for detecting the idle operation state and the means for detecting the heating operation state of the electric heating catalytic converter device, when detecting the heating operation of the electric heating catalytic converter device during the idle operation, An engine speed control device for an internal combustion engine, wherein an intake system is provided with means for increasing and controlling an intake air flow rate.