JPH05248278A - Control device for engine - Google Patents

Abstract

PURPOSE:To prevent an engine from its unnecessary output increase and blow up by limiting increase of a engine output at the time of large viscosity of operating oil, in the case of increasing the engine output, when a pressure of the operating oil for power steering is in a trend of rising. CONSTITUTION:An engine 1 is provided with an idle speed control valve (ISCV) 8 which bypasses a throttle valve 5 to control an amount of air at the time of fully closing this throttle valve. A control unit 13 controls the ISCV8, fuel injection valve 9 and an ignition coil 11 based on intake air amount and temperature signals detected by each sensor 6, 7, crank angle signal of a distributor 12, power steering switch signal which is a pressure of operating oil, etc. In this case, when large viscosity of operating oil is detected by a water temperature sensor 15, the ISCV8 is controlled by the control unit 13 so as to limit increase of an engine output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for limiting an unnecessary increase in engine output caused by an increase in viscosity of hydraulic oil for power steering of an automobile.

[0002]

2. Description of the Related Art Generally, in a hydraulically operated power steering device, the power of a hydraulic pump for generating hydraulic pressure is obtained from an engine. Then, when the power steering is operated, the output of the hydraulic pump increases, so that the load on the engine also increases and the output of the engine decreases.

Therefore, a hydraulic switch is provided in the hydraulic system of the power steering, and when the hydraulic pressure exceeds a predetermined value by the hydraulic switch, the engine output is increased.
For example, in Japanese Utility Model Laid-Open No. 57-20536, when the power steering is operated, the opening of the throttle valve is increased to increase the engine output.

[0004]

However, after the cold start of the engine, the hydraulic pressure of the oil for operating the power steering is erroneously determined to be ON because the oil viscosity increases even when the power steering is not operating. However, there was a problem that the torque increased more than necessary and the rotation increased.

In view of the above problems, the present invention provides a means for limiting the increase of the engine output when the operation of the power steering is erroneously determined to be ON when the power steering is not operated, thereby preventing the engine from being blown up. It is an object of the present invention to provide a control device for an engine that aims at

[0006]

SUMMARY OF THE INVENTION The present invention is directed to an operating oil pressure detecting means for detecting the oil pressure of hydraulic oil for power steering, and an engine for increasing the engine output when the oil pressure detected by the operating oil pressure detecting means tends to rise. In an engine control device having an output increasing means, a hydraulic oil viscosity detecting means for detecting the viscosity of the hydraulic oil, and when the hydraulic oil viscosity detected by the hydraulic oil viscosity detecting means is large,
And an engine output increase limiting unit configured to limit an increase in engine output by the engine output increasing unit when the engine output is small.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is an engine body, 2 is a combustion chamber, 3 is an intake passage, and 4 is an exhaust passage. A throttle valve 5 is provided in the intake passage 3, and an air flow sensor 6 and an intake air temperature sensor 7 are provided upstream of the throttle valve 5. Further, an idle speed control valve (I which controls the intake air amount when the valve 5 is fully closed by bypassing the throttle valve 5
SCV) 8 is provided.

Further, a fuel injection valve 9 is provided on the downstream side of the throttle valve 5, and a fuel-air injected by the valve 9 and the air introduced from the intake passage 3 form an air-fuel mixture. Supply. On the other hand, the voltage generated in the ignition coil 11 is distributed to the plug 10 provided in the combustion chamber 2 via the distributor 12 according to the crank angle.

The idle speed control device is provided with a control unit 13 for controlling the engine speed, and the control unit 13 has an intake air amount signal detected by an air flow sensor 6 and an intake air temperature sensor 7. And the intake air temperature signal, and the crank angle signal of the distributor 12 is also input. The control unit 13 outputs a drive signal to the ISCV 8, a fuel injection signal to the fuel injection valve 9, and an ignition advance signal to the ignition coil 11. Further, a water temperature sensor 15 is provided in the cooling water passage 14 of the engine body 1, and the cooling water temperature signal detected by the sensor 15 is input to the control unit 13.

In the present embodiment, the water temperature sensor 15 is used as a substitute for the hydraulic oil viscosity detecting means because the temperature of the hydraulic oil is low and the viscosity is high when the engine water temperature is low, and conversely the engine temperature is low. It is known that when the water temperature is high, the temperature of the hydraulic oil is high and the viscosity is low.

In addition to the above input signals, the control unit 13 also receives a power steering switch signal, a cooler switch signal, an idle switch signal, etc., which are operating oil pressure detecting means. The ignition advance signal, the fuel injection signal, and the IS signal output to the ignition coil 11 based on the various signals input to the control unit 13 are output.
The drive signal of the CV8 is controlled to control the idle speed of the engine.

Further, the ISCV 8 and the control unit 13 constitute an engine output increasing means and an engine output increasing limiting means.

The control executed by the control unit 13 will be described below with reference to FIGS. Figure 2
3 is a flow chart for executing the device of the present invention. In FIG. 2, it is determined in step S1 whether or not the power steering switch is ON, and when the switch is ON (power steering switch flag XPST [i] = 1), that is, whether the power steering is turned off or the viscosity of the hydraulic oil is high. In either case, the process proceeds to step S2.

In step S2, it is judged whether or not the water temperature increase (GSW) for correcting the intake air amount corresponding to the change in the engine water temperature after the engine is started, that is, whether or not the increase correction is made, is made. If not (YES), the process proceeds to step S3.

In step S3, it is determined whether or not the intake air temperature increase (GSA) for correcting the intake air amount is corrected according to the change in the intake air temperature, and if the correction is not performed (YE
For S), the process proceeds to step S4.

In step S4, a basic correction amount (TMG) is applied to the engine load generated by turning on the power steering switch.
PL) is increased by the set value.

Next, in step S5, it is determined whether or not the power steering switch was previously turned on (XPST [i-1] = 0.
? ) Is determined and the power switch is turned on (NO), the process proceeds to step S6.

In step S6, it is judged whether or not the control of this time (i) is more than the value of the last time (n), and if i is more than n, that is, if the one-shot increase correction is completed,
Only the basic correction amount (TMPGL) in step S4 is increased and corrected, and the process ends. If i is less than n in step S6 (NO), that is, if the one-shot increase correction is being performed, the process proceeds to step S7.

In step S7, the one-shot increase correction (SP [i]) is the basic increase correction (TM) in step S4.
PGL), and its value is gradually reduced from the initial value by the attenuation value until the value of i becomes n. In step S5, if it is determined that the power steering switch is not turned on last time (XPST [i-1] = 0) (YES), the process proceeds to step S8, and the one-shot increase correction is set to the initial value and finished.

On the other hand, if it is determined that the power switch is OFF (= O) in the initial step S1, step S
The process proceeds to step 9 and the basic increase correction (TMPGL) becomes zero, and the one-shot increase correction in step S10 also becomes zero.

In step S2, the water temperature is increased (GSW).
Is corrected (NO), or if the intake air temperature increase (GSA) is not corrected in step S3 (NO), the process proceeds to step S9. At this time, the reason why the increase correction is not carried out is to prevent the engine from being blown up by further increasing the correction.

If NO is determined in step S2, that is, when the water temperature increase correction is being performed, it can be determined that the engine water temperature is low and the viscosity of the power steering hydraulic oil is high. Even if it is determined that the steering is in operation, step S9,
In S10, the increase correction for power steering is prohibited.

Here, the temporal change of GSW and GSA when the engine is idling will be described with reference to FIG. 3. The amount is corrected when the engine is started, and then gradually decreased. At this time, the hydraulic pressure of the power steering is H in the graph.
When the power steering switch is ON, that is, when the power steering switch is ON, conventionally, the graphs of GSW and GSA also project as shown by the solid line, that is, the increase correction is performed, and the engine pops up. Therefore, when the GSW and GSA are corrected, the engine output is originally increased by the GSW and GSA correction, so that no further correction is performed as indicated by the dotted line of the present invention to prevent the engine rotation from rising. Details of the GSW and GSA are shown in FIG. From this, it is understood that the protrusion of the GSW and GSA graphs is the sum of the TMGPL set value increase and the one-shot increase correction.

As described above, during idle rotation within a predetermined period after the engine is started, the power steering is turned off or the viscosity of the operating oil is detected by the detecting means (water temperature sensor 15) to be a predetermined value or more, that is, the operating oil pressure. When the detection means detects that the oil pressure is high, the engine output increase limiting means (control unit 13 and ISCV8) prevents the engine output increasing means (control unit 13 and ISCV8) from increasing the air amount by the GSW and GSA. Can be suppressed.

That is, while the GSW and GSA remain, the one-shot increase correction (SP [i]) is prohibited, and the engine torque is increased more than necessary to prevent the engine speed from rising.

This will be explained with reference to FIG. 5. It is desirable that the initial idling speed after the engine is started suddenly rises and gradually decreases as shown by the rear dotted line showing the _first peak P _1. A second peak P ₂ due to the uphill is shown.

[0027]

According to the present invention, the power steering is erroneously determined to be in the operating state due to the increase in the viscosity at the beginning of the operation of the power steering pump, even though the power steering is not in operation after the cold start of the engine, and thus it is unnecessary. It is possible to prevent an excessive increase in output.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an engine to which the device of the present invention is applied.

FIG. 2 is a flow chart for executing control of the device of the present invention.

FIG. 3 GS at idle rotation after engine start
It is a graph of W, GSA, etc.

FIG. 4 is an enlarged view of a peak portion of the graph of GSW and GSA in FIG.

FIG. 5 is a graph showing the number of rotations when the engine is cold started.

[Explanation of symbols]

 6 Air flow sensor 7 Intake air temperature sensor 8 Idle speed control valve (ISCV) 13 Control unit 15 Water temperature sensor

Claims (4)

[Claims] 1. A control of an engine having an operating oil pressure detecting means for detecting an oil pressure of hydraulic oil for power steering and an engine output increasing means for increasing an engine output when the oil pressure detected by the operating oil pressure detecting means tends to increase. In the device, when the viscosity of the working oil detected by the working oil viscosity detecting means for detecting the viscosity of the working oil is high, the engine output is increased by the engine output increasing means more than when the working oil viscosity is small. An engine control device comprising: an engine output increase limiter configured to limit the engine output. 2. The engine output increase limiting means limits an increase in engine output by the engine output increasing means when the viscosity of the hydraulic oil detected by the hydraulic oil viscosity detecting means is a predetermined value or more. 1. The engine control device according to 1. 3. The engine control device according to claim 1, wherein the engine output limiting means limits an increase in the engine output by the engine output increasing means within a predetermined period after the engine is started. 4. The engine control device according to claim 1, wherein the hydraulic oil viscosity detecting means is configured to detect the viscosity of the hydraulic oil based on the water temperature of the engine cooling water.