JPS59546A - Idling control device for engine attached with turbocharger - Google Patents

Abstract

PURPOSE:To prevent an engine failure at the time of starting the engine by compensating for the worsening of rising of the output of the engine with respect to the opening degree of a throttle valve by a method wherein the output of the engine at the time of idling is increased when the temperature of sucked air on the downstream side of a blower is higher than a predetermined value. CONSTITUTION:A turbine 26 is provided in an exhaust gas passage 14 and the blower 28 is provided in a sucked air passage 16. Both of the turbine 26 and the blower 28 are connected to each other with a rotary shaft 30 to thereby constitute a turbocharger 18. When the engine is idling, the temperature Tx of sucked air detected by a sucked air temperature sensor 46 is higher than a predetermined temperature Ts, the amount of injection of a fuel from a fuel injection valve 24 is increased by an engine control circuit 22 and the output of the engine is increased by increasing the amount of projection of a plunger 50 of a proportional solenoid 48, that is, the opening degree of the throttle valve 20 so that the idling number of revolutions of the engine is made higher than the case when Tx<Ts. Thus, by the increase of the output of the engine at the time of idling operatin, it is made possible to prevent the engine failure at the time of starting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an idling control device for a turbocharged engine, and more specifically, increases the engine output during idling when the intake air temperature downstream of the blower of the turbocharger is equal to or higher than a set value. The present invention relates to an idle control device for a turbocharged engine.

Conventionally, fuel supply systems include turbo superchargers, in which a turbine installed in the exhaust passage and a blower installed in the intake passage are connected by a rotating shaft, and a fuel injection system, which controls the amount of fuel injection using a microcomputer, etc. As an engine control system that combines this with the
It is known that the engine output is improved and the intake air flow rate is detected by the above-mentioned sensor to control the air-fuel ratio well (for example, Japanese Patent Laid-Open No. 56-16573
(See No. 0).

By the way, as mentioned above, in an engine equipped with a turbo supercharger, when it enters idling operation after high-load operation,
Heat from the turbine installed in the exhaust passage superheats the blower or the blower housing via the rotating shaft and the turbine housing, thereby heating the intake air. For this reason, there is a problem in that the intake air density becomes low downstream of the turbocharger, and the charging efficiency decreases, and the idling engine output decreases and the idling rotation speed decreases, as shown by arrow Arl in FIG. 1.

For this reason, it is common practice to control the idle speed of the engine to a constant value using idle speed control, feedback control, etc., but if this is done, the idle speed, that is, as shown by arrow Ar2 in FIG. Although the engine output during idling is controlled to be constant, since the intake air density is low, the engine output relative to the throttle opening changes as shown by the solid line 10 in Figure 1 when the intake temperature is low. On the other hand, when the intake temperature is high, it changes slowly as shown by the dotted line l2 in FIG. Therefore, when the intake temperature is high, the rise of the engine output becomes difficult, and the engine may stop when starting the vehicle.

The present invention has been made in view of the above circumstances, and its purpose is to increase the output during idling in an engine equipped with a turbocharger when the intake air temperature downstream of the blower is equal to or higher than a set value. The purpose is to catch the deterioration of the engine output from idling with respect to the throttle opening and prevent the engine from stopping.

To summarize the present invention, the present invention provides an engine equipped with a turbocharger in which a turbine disposed in an exhaust passage and a blower disposed in an intake passage are connected by a rotating shaft. an intake air temperature sensor that detects the intake air temperature of the engine; and an output increase device that receives the output of the intake air temperature sensor and increases engine output during idling when the intake air temperature IW downstream of the blower is equal to or higher than a set value. This is an idling control device for a turbocharged engine, which is characterized by:

Hereinafter, the present invention will be specifically described with reference to the accompanying drawings.

In FIG. 2, 12 is an engine, and 14 is the engine 1.
2 an exhaust passage; 16 an intake passage of the engine 12;
8 is a turbo supercharger that supplies supercharged air to the engine 12 using the exhaust energy of the engine 12, 2o is a throttle valve that controls the amount of intake air juice of the engine 12, and 22 is a microcomputer that controls the engine 12. An engine control circuit composed of, etc., 24
is the fuel injection valve.

The turbocharging ja18 includes a turbine 26 installed in the exhaust passage 14 and a blower 28 installed in the intake passage 16.
and a rotating shaft 30 connecting the turbine 26 and the blower 28, the turbine 26 is driven by the energy of the exhaust gas of the engine 12 discharged from the exhaust passage 14, and the rotating shaft 30 is connected to the turbine 26. The blower 28 is rotated to compress the air taken in through the air cleaner 32 and the air flow sensor 34, and supplies supercharged air to the engine 12 through the intake passage 16.

On the other hand, the engine control circuit 22 has a configuration as shown in FIG. 3, which will be explained later. output signal of a pickup 44 for detecting the engine rotation speed provided near the crank pulley 42 of the crankshaft 40, and an intake signal for detecting the intake air temperature in the intake passage 16 downstream of the blower 28 of the turbocharging 4@18. The output signals of the temperature sensors 46 are inputted respectively.

The engine control circuit 22 includes an air flow sensor 34,
The output signals output from the pickup 44 and the intake humidity sensor 46 are processed, and based on the processing results, the fuel injection valve A1 installed near the end of the intake passage 16 is controlled to inject fuel. In addition to controlling the injection cap, during idling operation of the engine 12, when the intake air condition detected by the intake air temperature sensor 46 is equal to or higher than a set value, the amount of protrusion of the plunger 50 of the proportional solenoid 48 is controlled;
This constitutes an output increasing device that increases the engine output by increasing the opening degree of the throttle valve 20.

As shown in FIG. 4, the plunger 50 of the proportional solenoid 48 is attached to an abutting portion 54a at the tip of a throttle lever 54, which is rotatably supported in the intake passage 16 by a support shaft 52 along with the throttle valve 20. The opening of the throttle valve 20 during idling is determined by the protrusion of the plunger 50.

As already mentioned, the engine control circuit 22 has the configuration shown in FIG. 3.

In FIG. 3, 62 is an intake air temperature calculation circuit, 64 is a setting lightning generation circuit, 66 is a comparison circuit, and 68.70 is a function circuit.

The intake air crystal change calculation circuit 62 is connected to the intake air flattening sensor 46.
This circuit calculates the intake air temperature downstream of the blower 28 of the turbocharger 18 based on the temperature signal input from the intake air temperature calculation circuit 62, and the intake air temperature signal output from the intake air temperature calculation circuit 62 is output to the comparison circuit 66.

The comparison circuit 66 compares the intake air temperature signal inputted from the intake air temperature calculation circuit 62 with the set voltage inputted from the set city pressure generation circuit 64, and calculates the intake air temperature Tx downstream of the blower 28. When the intake air temperature Tx is equal to or higher than the set temperature Ts corresponding to the set voltage (Tx≧Ts), the intake air temperature Tx reaches the set temperature Ts
A fuel increase signal in which the fuel increase rate is set higher in the idling function circuits 68 and 70 and a set rotation speed signal in which the rotation speed is set higher than when the engine output is increased when the engine output is less than (Tx (Ts)). Outputs a command signal that commands output.

The fuel increase signal output from the function circuit 68 is combined with the intake air amount signal output from the intake air amount output circuit 72, which is a circuit for calculating the intake air amount of the engine 12 based on the signal input from the air flow sensor 34. It enters the arithmetic circuit 74.

The calculation circuit 74 calculates the optimal pulse width of the fuel injection pulse based on the intake air amount signal input from the intake air condition calculation circuit 72 and the fuel increase signal input from the function circuit 68, and calculates the optimal pulse width of the fuel injection pulse, ] signal to the injection pulse generation circuit 76.

The injection pulse generation circuit 76 generates a fuel injection pulse based on the pulse width signal inputted from the arithmetic circuit 74, and sends a synchronous pulse inputted from the pickup 44 in synchronization with the rotation of the crankshaft 4o of the engine 12 as a fuel injection command. As a signal, the fuel injection valve 24 is caused to inject fuel.

On the other hand, the set rotation speed signal output from another function circuit 7o is output from the pickup 44. The signal is input to the differential amplification circuit 80 along with the several signals.

The differential amplification circuit 80 outputs a difference signal between the engine rotation speed signal and the set rotation speed signal to the addition circuit 82 .

On the other hand, the basic control wheel pressure generation circuit 84 outputs a basic control signal corresponding to the set rotational speed signal output from the function circuit 70. The adder circuit 82 combines the difference signal of the differential amplification circuit 80 with the basic 4++ of the basic control signal generating circuit described in
control signal and output to the drive circuit 86.

The F11 movement circuit 86 drives the proportional renoid 48 to control the amount of protrusion of the plunger 50 based on the signal input from the addition circuit 82, and controls the amount of protrusion of the plunger 50. Controls the dollar rotation speed to the set rotation speed.

By doing the above, the engine 12 enters idling operation after high-load operation, and the intake air temperature Tx is equal to or higher than the set temperature Ts (
When Tx≧Ts), command signals are output from the comparator circuit 66 in FIG. 3 to the function circuits 68 and 70, respectively.
and 70 output a fuel increase signal with a higher increase rate and a set rotation speed signal with a higher rotation speed, and the fuel injection valve 24 injects the increased amount of fuel, and the plunger 50 of the proportional solenoid 48 The amount of protrusion, that is, the amount of rotation of the throttle valve 20 is set so that it matches the engine rotation speed signal output from the engine rotation speed calculation circuit 78 or the set rotation speed signal output from the function circuit 70. ``The rx power is controlled so that the crystallinity is higher than that when the crystallinity is less than Ts (1'x(Ts) (;!).

Therefore, the intake air temperature Tx is higher than the set temperature Ts (Tx>TS
), the output increases as shown by arrow Ar3 in Fig. 1, and this increase in output during idling compensates for the deterioration in the rise of engine output relative to the throttle opening, so the engine power increases even when starting. No stops occur.

In addition, in the above embodiment, the intake air temperature Tx is the set temperature T.
s or more (Tx≧Ts), in order to increase the engine output during idling operation, the amount of fuel is increased and the idling speed is increased. However, the present invention is not limited to this, and the point is that the intake air Temperature 'rx is set temperature Ts
It is sufficient if the engine output during idling operation when the above ('rx≧Ts) is greater than the engine output during idling operation when the intake air temperature Tx is less than the set temperature 11ijTs, and the idling speed can be made higher. By setting this, you can omit increasing the amount of fuel.

As is clear from the detailed description above, the present invention increases the engine output during idling when the intake air temperature downstream of the blower is higher than a set value in a turbocharged engine. By increasing the engine output, it is possible to compensate for the deterioration in the rise of the engine output with respect to the throttle opening, and it is possible to prevent the engine from stopping at the time of starting.

[Brief explanation of the drawing]

FIG. FIG. 3 is a block diagram of the engine control device shown in FIG. 2, and FIG. 4 is an explanatory diagram of an operating mechanism of a throttle knob using a proportional solenoid. 12...Engine, 14...Exhaust passage, 16...
Intake passage, 18... Turbo supercharger, 20... Throttle nozzle, 22... Engine control circuit, 24...
Fuel UG injection valve, 26... Turbine, 28... Blower, 30... Rotating shaft, 46... Intake sensor. -241-

Claims (1)

[Claims] {1) In an engine equipped with a turbocharger in which a turbine disposed in the exhaust passage and a blower disposed in the intake passage are connected by a rotating shaft, the intake air temperature downstream of the blower is A turbo supercharger equipped with an intake air temperature sensor that detects the intake air temperature, and an output increase device that receives the output of the air intake air temperature sensor and increases the engine output during idling when the intake air temperature downstream of the blower exceeds a set value. Engine idling control device.