JPH0914030A - Idle rotation control method by electric load control - Google Patents

Abstract

PURPOSE: To maintain a stable idle running state by detecting the power generation amount of an alternator, calculating the change amount of the power generation amount of the alternator at the throw in time of an electric load and setting the correction amount of an intake air amount based on the change amount. CONSTITUTION: In the detection state of the power generation work amount FDUTY of an alternator during idle running, it is judged whether an electric load is changed from time off state to on state, in other words, whether the electric load is thrown in or not (S1). At the thrown in time, the electric load calculates the power generation work amount FDUTY at the point of time when the electric load is thrown in and reads the number of engine rotation NE (S2). Then, the change amount ΔFD of power generation work amount FDUTY is calculated from the power generation work amount FDUTY just before the throw in of the electric load and the power generation work amount FDUTY just after the thrown in. A secondary map is detected and an air correction amount is calculated (S3) from the read number of engine rotation NE and the change amount ΔFD. A flow rate control valve is controlled based on the calculated air correction amount (S4).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle rotation control method applied to an engine of an automobile or the like by electric load control.

[0002]

2. Description of the Related Art Conventionally, in an automobile engine, an automatic transmission (A / T), an air conditioner (A / C), an electric load such as a headlight, a car stereo, etc. are external factors that affect idle rotation. There is. Here, it is known that when an electric load is applied, a request for charging the alternator occurs, and the intake air amount is corrected according to the state of the alternator that has become the load of the engine. For example, as in Japanese Patent Laid-Open No. 2-291444, when an external load is applied to the engine, a control valve provided in an auxiliary air passage bypassing the throttle valve is opened and the load is cut off from the engine. There is known a control method in which a control valve is maintained as it is for a predetermined time and then closed.

[0003]

By the way, in the above configuration, the amount of air corrected for the electric load is a constant amount regardless of the size of the electric load. For this reason,
In the case of an electric load having a small capacity such as a small light, the amount of air to be corrected is large, and the engine speed may increase due to an excessive amount of correction. On the contrary, in the case of a large electric load such as a headlight,
The engine speed may temporarily decrease because the correction amount is too small. Therefore, when the correction amount is not optimal for the electric load, the engine rotation fluctuates due to the electric load being turned on during idle rotation.

An object of the present invention is to solve such a problem.

[0005]

In order to achieve the above object, the present invention takes the following measures. That is, the idle rotation control method by electric load control according to the present invention is mechanically driven by the engine,
And the amount of intake air of the engine when the electric load is turned on during idle operation is corrected based on the amount of power generated by the alternator, which changes the amount of power generated according to the voltage change of the drive power source to which the electric load is selectively connected. An idle rotation control method by electric load control, which detects the power generation amount of the alternator, calculates the change amount of the power generation amount of the alternator when the electric load is turned on, and based on at least the change amount, the intake air amount The feature is that a correction amount is set.

[0006]

With the configuration of the present invention, the change in the amount of power generated by the alternator when the electric load is turned on is calculated to detect the change in the load on the alternator, that is, the change in the load on the engine. Then, since the correction amount of the intake air amount is set based on the change amount, it becomes possible to accurately grasp the intake air amount required before and after the application of the electric load. Therefore, the correction amount required at that time can be accurately set according to the magnitude of the applied electric load, and the engine speed during idle operation can be maintained without changing.

[0007]

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

The engine schematically shown in FIG. 1 is for an automobile, and its intake system 11 is provided with a throttle valve 12 that opens and closes in response to an accelerator pedal (not shown), and bypasses this throttle valve 12. A bypass passage 13 for controlling the idle speed is provided in the bypass passage 13. The flow control valve 14 is of an electromagnetic switching type, which is abbreviated as VSV, and its substantial opening can be changed by controlling the duty ratio of the drive voltage applied to its terminal 14a. The air flow rate of the bypass passage 13 can be adjusted by the above.

The intake system 11 is further provided with a fuel injection valve 15, and the fuel injection valve 15 and the flow rate control valve 14 are controlled by the electronic control unit 4. The electronic control unit (E / GECU) 4 also detects the power generation work FDUTY of the alternator 1 shown in FIG.

The electronic control unit 4 includes a central processing unit 4a.
, A storage device 4b, an input interface 4c, and an output interface 4d. Then, to the input interface 4c, the intake pressure signal a output from the intake pressure sensor 17 that detects the pressure in the surge tank 16 and the rotation speed output from the rotation speed sensor 18 that detects the engine rotation speed NE. A signal b, a vehicle speed signal c output from a vehicle speed sensor 19 for detecting the vehicle speed, a throttle signal d output from an idle switch 20 for detecting the open / closed state of the throttle valve 12, and an engine cooling water temperature The water temperature signal e output from the water temperature sensor 21 and the crank angle signal f output from the crank angle reference position sensor 23 incorporated in the distributor 22 are input, and the alternator 1
The control signal g is input from the IC regulator 2 that controls the power generation of the.

The alternator 1 shown in FIG. 2 is driven to rotate at a rotation speed corresponding to the rotation speed of the engine by a pulley and a belt (not shown).
The C regulator 2 is connected and the battery 3 is connected. This alternator 1 includes three stator coils L1 wound in a groove of a stator and three-phase star-connected.
To L3 and a field coil Lf wound in a rotor rotatably supported inside the stator, the three-phase alternating current output from the stator coils L1 to L3 is full-wave rectified by the diodes D1 to D6. Then, the output is performed. The cathodes of the diodes D1, D3, D5 are connected to the positive electrode of the battery 3 and the charging terminal B of the IC regulator 2. Also, the diodes D2, D
The anodes of D4 and D6 are grounded.

The IC regulator 2 has its power input terminal IG connected to its positive electrode for monitoring the terminal voltage of the battery 3, and its field coil control terminal F connected to the field coil Lf of the alternator 1 and electronically controlled. It is connected to the device 4 and the phase signal input terminal P is connected to the stator coil L1. The two transistors Tr1 and Tr2 of the IC regulator 2 are turned on / off by a signal output from the IC 2a, and one transistor Tr1 is turned on / off to perform a known regulation operation. That is, in this embodiment, by turning on the transistor Tr1, an exciting current is passed through the field coil Lf of the alternator 1 (corresponding to the ON signal Son being output to the electronic control unit 4), The stator coils L1 to L of the alternator 1
A current is induced in 3 to generate electricity. Further, by turning on the other transistor Tr2, a charging lamp (not shown) (connected to the terminal L) is turned on.
That is, turning on / off the transistor Tr1 controls the power generation of the alternator 1 so that the terminal voltage of the battery 3 becomes constant, and is set to the terminal voltage of the battery 3 input to the power input terminal IG and IC2a. A target voltage (for example, 14.5 V) is compared, and when the terminal voltage is lower than the target voltage, it is turned on, and when it is higher, it is turned off. As described above, when the transistor Tr1 is turned on, the on signal Son is output from the field coil control terminal F to the electronic control unit 4 and is turned off to turn off the off signal S.
off will be output. The diode D1
The series connection body 5 composed of two diodes D7 and D8 provided in parallel with D1 to D6 is a neutral point diode, and reduces the potential fluctuation generated at the neutral point of the stator coils L1 to L3 when the alternator 1 operates. It is intended to effectively use energy.

The electronic control unit 4 determines the fuel injection valve opening time based on signals from the intake pressure sensor 17 and the rotation speed sensor 18 as main information, and controls the fuel injection valve 15 according to the determination time to control the engine. A program for injecting fuel according to the load from the fuel injection valve 15 into the intake system 11 is incorporated. In addition, the electric load was turned on during the idle operation based on the power generation amount of the alternator that is mechanically driven by the engine and selectively changes the power generation amount according to the voltage change of the driving power supply to which the electric load is selectively connected. It corrects the intake air amount of the engine at the time, detects the power generation amount of the alternator, calculates the change amount of the power generation amount of the alternator when the electric load is turned on, and at least based on the change amount There is a built-in program to set the correction amount of the air amount. In this program,
Using the engine speed NE and the power generation work FDUTY as parameters, the opening degree of the flow rate control valve 14 during idling, that is, the air correction amount is set by a two-dimensional map.
FIG. 3 shows the relationship between the electric power generation work FDUTY and the air correction amount when an electric load is applied at a certain engine speed NE.

Usually, the power generation work FDU of the alternator 1
There is a relationship as shown in FIG. 4 between TY, the engine speed NE and the generated current, and between the engine speed NE and the load torque of the alternator 1. That is, at a certain engine speed N, the power generation work FDUTY is 60%.
From 100% (from A1 to A2 in the figure),
The load torque similarly changes (B1 to B2 in the figure). With this in mind, it is possible to determine the increase / decrease in the load torque of the alternator 1, that is, the magnitude of the electric load, based on the change amount ΔFD of the power generation work FDUTY. Moreover, when the electric load is applied, the power generation work amount FD
Since UTY generally shifts from a certain value to 100%, it is possible to associate it with the air correction amount as shown in FIG. Note that FIG. 5 shows the relationship between the power generation work FDUTY, the engine speed NE, and the air correction amount when the electric load is applied.

The outline of this idle rotation control program is as shown in FIG. First, the power generation work FDU of the alternator 1 performed before the correction of the intake air amount
The detection of TY will be described. To detect the generator work FDUTY of the alternator 1, the ON signal S per unit time is detected.
This is performed by the on / off ratio of the FDUTY signal including the on signal and the off signal Soff. Specifically, the unit time is from the top dead center TDC of the piston to the next top dead center TD.
The time to C is performed as one division. This is because the energy consumed by the spark plug is larger than that consumed by the electronic control unit 4, the fuel injection valve, the fuel pump or the like in the idling state or the state in which the electric load is small, and the FD from the field coil control terminal F is increased.
This is because the on / off switching timing of the UTY signal is almost synchronized with the ignition timing. The detection of the top dead center TDC is performed using an N (cylinder discrimination) signal indicating the compression top dead center output from the crank angle reference position sensor. Then, the electronic control unit 4 turns on / off the FDUTY signal from the field coil control terminal F, which is input to the input interface 4c by the built-in counter, and has respective durations tonα and toffα.
(Α is a positive integer) is measured. In this case, the number of counters is two in order to individually measure the respective duration times tonα and toffα, and each counter is capable of counting the time by integrating the time and is cleared at the timing of the top dead center TDC. To do. This duration ton α,
As shown in FIG. 7, the measurement of toffα is performed at the top dead center TDC.
From the next to the top dead center TDC, the sum of the duration time tonα of the on signal Son and the sum of the duration time toffα of the off signal Soff during that period are determined by the energization time Ton of the field coil Lf and the disconnection. The time Toff is used to detect the power generation work described later.

Power generation work FDUTY of the alternator 1
Is detected by the ratio of the energization time Ton to the time Tmp (= Ton + Toff) of the section MP, and is calculated by the following formula.

FDUTY (%) = Ton × 100 / Tmp = Ton × 100 / (Ton + Toff) In the case shown in FIG. 7, ignition (indicated by arrow I in the figure)
Corresponding to the ON signal Son is output, the alternator 1
There is a case where the power generation of the alternator 1 is stopped because there is an intermediate timing from the previous ignition to the next ignition in the middle of the section Tmp, and the off signal Soff is output at that portion. is there. The electronic control unit 4 measures the duration of these ON signal Son and OFF signal Soff output from the IC regulator 2 with a counter. In this case, the counter measures the duration of the ON signal Son1 in response to the input of the signal of the top dead center TDC to the input interface, and then the OFF signal S1.
The duration of off is measured, and the duration of the ON signal Son2 is measured until the next signal of the top dead center TDC is input. Then, the obtained respective signals Son1, S
Based on the durations of on2 and Soff, the power generation work FDUTY of the alternator 1 is calculated as follows.

Ton = Son1 + Son2 Toff = Soff FDUTY (%) = Ton × 100 / (Ton + Toff) = (Son1 + Son2) × 100 / (Son1 + Son2 + Soff) By repeating these calculations, the alternator 1 of the engine is running. The power generation work FDUTY is detected in real time, and its value is temporarily stored in the storage device 4b.

In the state in which the power generation work FDUTY of the alternator 1 is detected as described above, first in step S1, the electric load is switched from the off state to the on state, that is, whether the electric load is turned on or not. It is determined whether or not the electric load is turned on, the process proceeds to step S2, and if not, the process proceeds to another routine. The electric load may be applied by, for example, taking a signal from a switch of each electric load or by making a decision by detecting the presence or absence of a power generation request signal in the IC regulator 2. In step S2, the power generation work FDUTY at the time when the electric load is turned on is calculated, and the engine speed NE is read. In step S3, a change amount ΔFD of the power generation work FDUTY is calculated from the power generation work FDUTY immediately before the electric load is applied and the power generation work FDUTY immediately after the electric load is applied, and the read engine speed NE is calculated.
Then, the air correction amount is calculated by searching the two-dimensional map from the change amount ΔFD. In step S4, the flow rate control valve 14 is controlled based on the calculated air correction amount, and the engine speed NE during idle operation is controlled to be maintained at the target speed.

Now, the idle switch 20 is turned on to detect that the engine is idling, a load other than an electric load is applied to the alternator 1, and the power generation work FDUTY is, for example, 4
Assuming 0%, when a headlight as an electric load is turned on, the power generation work FDUTY becomes 1 at the same time when the headlight is turned on.
Move to 00%. In this case, the control is step S1 →
The process proceeds from S2 to S3 to S4, calculates a correction air amount according to the engine speed NE with respect to an increase amount of 60% which is the change amount ΔFD of the power generation work FDUTY, and controls the opening of the flow control valve 14 to suck the intake air. Increase the amount of air and correct it. That is, the calculated correction air amount is the intake air amount that becomes insufficient when the electric load is turned on, in other words, the intake air amount that is required by judging from the state of the alternator 1 at that time when the electric load is turned on, This is different from the one in which a fixed amount of air is corrected by the application of an electric load. Therefore, the corrected air amount is an appropriate amount that reflects the operating state of the engine at the time when the electric load is applied, and the fluctuation of the load torque of the alternator 1 and the engine speed that occur due to the change of 60% of the power generation work FDUTY. Sufficient to absorb NE variations. Therefore, it is possible to efficiently prevent the engine rotation from fluctuating due to an excessive correction amount of the intake air amount or an excessively small correction amount.

The present invention is not limited to the embodiment described above. For example, in the above embodiment,
Power generation work FDUTY for calculating the corrected air amount
Although the engine speed NE and the engine speed NE are parameters, for example, cooling water temperature, atmospheric pressure, etc. may be added as parameters. By adding the parameters in this manner, more detailed control of idle rotation can be performed.

In addition, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0023]

As described in detail above, the present invention corrects the necessary and sufficient intake air amount according to the operating condition of the engine when an electric load is applied. It is possible to control the engine speed during idle operation in accordance with the above. Therefore, it is possible to reliably prevent the engine speed from fluctuating due to the excess or deficiency of the correction air amount, and it is possible to maintain a stable idle operation state without being influenced by the application of the electric load.

[Brief description of the drawings]

FIG. 1 is a schematic configuration explanatory view showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a portion related to the alternator of the embodiment.

FIG. 3 is a graph showing a relationship between a power generation work amount and a correction air amount in the same embodiment.

FIG. 4 is a graph showing the relationship between the work of power generation and the load torque of the alternator in the same embodiment.

FIG. 5 is a graph showing the relationship between the work of power generation and the corrected air amount when the engine speed is different in the embodiment.

FIG. 6 is a flowchart showing a control procedure of the embodiment.

FIG. 7 is a waveform chart showing the detection timing of the power generation work of the embodiment.

[Explanation of symbols]

 1 ... Alternator 2 ... IC regulator 3 ... Battery 4 ... Electronic control device 4a ... Central processing unit 4b ... Storage device 4c ... Input interface 4d ... Output interface 14 ... Flow control valve

Claims (1)

[Claims] 1. An electric load during idle operation based on the power generation amount of an alternator that is mechanically driven by an engine and that changes its power generation amount according to a voltage change of a driving power source to which an electric load is selectively connected. It is an idle rotation control method by electric load control that corrects the intake air amount of the engine when it is turned on.It detects the power generation amount of the alternator and calculates the change amount of the power generation amount of the alternator when the electric load is turned on. Then, the idle rotation control method by electric load control is characterized in that a correction amount of the intake air amount is set based on at least the change amount.