JPS63120822A - Supercharge control method for engine with car-mounted exhaust turbosupercharger - Google Patents

Abstract

PURPOSE:To prevent the generation of a black smoke, by controlling an exhaust bypass valve to be opened when the condition of its full opening is detected to continue for the fixed time or more, so that a differential delay of closing of the exhaust bypass valve is eliminated in the time of acceleration after a speed change control. CONSTITUTION:If an exhaust temperature detector 19 reads its detection value lower than the preset value, a driving control circuit 16, which decides an engine to be placed in a light loaded condition, controls each intake and exhaust bypass valve 14, 15 to be opened. As the result, the engine, which prevents a main flow of exhaust gas from passing through a driving impeller chamber 9 while a main flow of new charge air from passing through a driven impeller chamber 4, stops a supercharger. Here the engine provides a timer device 20 to be arranged between the exhaust temperature detector 19 and the driving control circuit 16. And before the fixed time of the exhaust temperature detector 19 detecting its detection value lower than the preset value, the engine is controlled by the timer device 20 so as to prevent the exhaust temperature detector 19 from transmitting a temperature detection signal to the driving control circuit 16.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine equipped with an exhaust turbine supercharger, and in particular to an exhaust turbine supercharger that suspends supercharging when the engine load is relatively low. This invention relates to a supercharging control method for an engine equipped with a charger.

(Prior art) In general, in engines equipped with a supercharger, the supercharger acts as resistance at light loads, increasing fuel consumption. Therefore, in order to save fuel consumption, the supercharger is turned off at light loads to create a non-supercharging state. It is now possible to drive.

Conventionally, there is a supercharging device that stops supercharging when the load is light, as disclosed in, for example, Japanese Utility Model Publication No. 53-46404.

This creates a bypass in the engine's exhaust system by short-circuiting the turbine section of the supercharger, and a directional control valve is placed at the branch between the exhaust path to the turbine chamber and the bypass, allowing the flow to flow through the exhaust manifold. The temperature of the exhaust gas is detected by an exhaust temperature detector, and when the detected temperature is high, it is determined that high-load operation is in progress, and the actuator switches the directional control valve to the state that sends the exhaust gas to the turbine chamber, thereby generating supercharging. On the other hand, when the detected temperature is low, the turbocharger applies back pressure to the combustion chamber by determining that the load is light and switching the directional control valve to a state where exhaust gas flows into the bypass. The structure is designed to prevent exhaust gas from blowing back into the combustion chamber during the overlap period of the intake and exhaust valves.

(Dot the time when you are trying to solve the problem.) However, when a vehicle is equipped with a conventional supercharged engine that controls switching of the directional valve when the exhaust gas in the exhaust system is at a high temperature, As the exhaust gas temperature changes, the exhaust bypass will be opened and closed frequently.

As a result, the operation of the supercharger is delayed during repeated accelerations after a gear shift operation, and black smoke is likely to be produced.In addition, in vehicles that frequently switch the exhaust bypass, switching the supercharging state does not reduce fuel consumption. Ta.

(Problems to be Solved) The present invention is designed to prevent the generation of black smoke that accompanies gear shifting, and for this purpose, focuses on the fact that gear shifting is completed within a short period of time. , in which the opening and closing of the exhaust bypass is controlled based on the exhaust temperature, a timing means is attached to the drive control system of the bypass valve, and the timing means detects that the bypass valve is fully open for a certain period of time or more. Based on this, a configuration in which the bypass valve is opened is considered to be a vP symptom.

(Function) The present invention provides a timing means in the drive control system of the bypass valve, and opens the bypass valve based on the timing means detecting that the bypass valve fully open condition continues for a certain period of time or more. Therefore, when the exhaust gas temperature is lower than the set temperature and is only open for a short time, such as when changing gears, the bypass valve is kept closed and the engine is kept in the supercharging state. to hold. This eliminates the delay in closing the bypass valve during acceleration after a gear change operation, and prevents the generation of black smoke during false acceleration.

(Example) FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In the figure, (1) is a diesel engine installed in a vehicle, (2) is an intake port, (3) is an exhaust port, (C
) indicates the exhaust turbine supercharger, and the exhaust turbine supercharger PI
The driven impeller chamber (4) of i(C) and the intake port (2) are communicated through an air supply pipe (5), and this air supply Ir! The intake bypass (6) is branched out from the middle of (5').

This intake bypass (6) bypasses the fresh air discharge port (7) of the exhaust turbine supercharger R (C>) and returns to the exhaust turbine supercharger (C).
It communicates with the fresh air suction chamber (8).

On the other hand, the drive impeller chamber of exhaust turbine supercharging +fi (C) (
9) and exhaust port (3) are exhaust? F(10) is connected to the exhaust pipe (10), and an exhaust bypass (11) is branched out from the middle of this exhaust pipe (10). This exhaust bypass (1
1) is the exhaust gas blowing chamber (1) of the exhaust turbine supercharger (C).
2), the exhaust gas of the exhaust turbine supercharging Iff (C) communicates with the gas discharge chamber (13).

The intake bypass (6) and the exhaust bypass (11) are equipped with bypass valves (14) and (15), respectively, and each bypass valve (14) and (15) is connected to a drive control circuit (described later).
16), the output from 7 actuators (such as solenoids)
17) It can be opened and closed repeatedly by (18).

A large exhaust temperature detector (19) is arranged in the part of the exhaust W (10) near the exhaust port (3), and this exhaust large temperature detector (19) connects the bypass valves (14) (15). When the set temperature for opening and closing is detected, the temperature detection signal (
K).

A drive control circuit (16) for the bypass valves (14) and (15) receives the temperature detection signal (K) and controls the actuator (1).
7) Output a drive signal (D) to drive and control (IS). That is, if the exhaust temperature detector (19) detects a temperature higher than the set temperature (T) in the non-supercharging state, it is determined that the load is heavy and the bypass valves (14) and (15) are closed. By operating the valve, exhaust gas is transferred to the drive impeller chamber (9
), and at the same time, fresh air is introduced into the driven impeller chamber (4) to operate the supercharger (C). In addition, in the supercharging state, the exhaust temperature detector (19) is lower than the set temperature (T).
By detecting a low temperature, it is determined that the load is light, and by opening the bypass valves (14) and (15), the exhaust bypass (11) is opened and the main flow of exhaust gas is directed to the drive impeller. The main flow of fresh air is prevented from passing through the driven impeller chamber (9), and the intake bypass (6) is also opened to prevent the main flow of fresh air from passing through the driven impeller chamber (4).
pause. Note that this drive control circuit (16) has a data table stored therein containing a fuel consumption curve and a set temperature that vary with changes in engine speed, and the bypass valve is activated in response to changes in engine speed. (1
4) The opening/closing drive signal (D) of (15) is generated.

In the drive system of the bypass valves (14) and (15), a timer device (20) is disposed between the exhaust temperature detector (19) and the drive control circuit (16).

This timer device (20) is an exhaust temperature detector (19)
is detecting a temperature lower than the set temperature for a certain period of time (
For example, the temperature detection signal (K
) is not transmitted to the drive control circuit (16). Therefore, when the exhaust temperature detector (19) continuously detects a temperature lower than the set temperature for a certain period of time or more, the temperature detection signal (K) is input to the drive control circuit (16), and the bypass valve (14) (15) will be operated to close the valve.

Figure ptS2 is a control flow diagram related to on-off valve control of the bypass valves (14) and (15), in which the first judgment means determines whether the exhaust gas temperature detected by the exhaust temperature detector (19) is higher or lower than the set temperature. (21), and if the exhaust gas temperature is higher than the set temperature, the drive control device (16) issues a valve closing signal for the bypass valves (14) and (15), and the bypass valves (6) and (11) Fully close to put the supercharging inactive. Also, if the temperature is lower than the set temperature, a timer device (20
), the second determining means (22) determines whether or not the large exhaust temperature remains lower than the set temperature for a certain period of time (for example, 20 to 30 seconds), and the detected temperature is determined. If the temperature remains lower than the set temperature for a shorter time than the set time, the drive control device (16) is not moved and the bypass valves (14) and (15) are kept fully closed, and the detected temperature is If the temperature remains lower than the set temperature for longer than the set time, the drive control device (16) issues a bypass valve opening activation signal, fully opens the bypass valves (14) and (15), and prevents the supercharger from malfunctioning. It will be put into use.

Therefore, when the accelerator is operated during gear shift vibration, the accelerator pedal deceleration operation, the gear change operation of the transmission, and the accelerator pedal acceleration operation are performed in a short period of time. Even if the temperature drops significantly, if the exhaust gas temperature remains below the set temperature within the set time, the bypass valves (14) and (15) in the bypasses (6) and (11) remain closed. Therefore, a supercharging delay does not occur during the acceleration operation that is performed continuously after the gear change operation, and black smoke is not emitted during the acceleration operation.

(Effects) In the present invention, in an apparatus that detects fluctuations in exhaust temperature due to changes in engine load and uses an exhaust turbine supercharger as a switching source, a timing means is attached to the drive system of the bypass valve, The configuration is such that the bypass valve is opened based on the timing means detecting that the bypass valve is fully open for a certain period of time or more, so that it is possible to perform a speed change cycle in which deceleration and acceleration are performed in a short period of time. Even if the exhaust gas temperature becomes lower than the set temperature during operation, the supercharging will not be suspended. As a result, it is possible to prevent the generation of black smoke due to the delay in switching the bypass valve during repeated acceleration after a gear shift operation, and also because the bypass valve does not have to be opened and closed frequently. The durability of the valve is also improved.

[Brief explanation of the drawing]

Figure vJ1 is a schematic diagram showing one embodiment of the present invention, and Figure 2 is a 70-chart of bypass valve opening/closing control. C...Exhaust turbine supercharger, 1...Engine, 3.
...Exhaust port, 11...Bypass, 12...(C
) exhaust gas inlet chamber, 15...bypass valve, 19...
- Exhaust temperature detector, 20... timing means.

Claims (1)

[Claims] 1. An engine with an exhaust turbine supercharger mounted on a vehicle (
A bypass (11) is provided in a branched manner from the exhaust path portion between the exhaust port (3) of 1) and the exhaust gas inlet chamber (12) of the exhaust turbine supercharger (C), and a bypass valve is installed in the bypass (11). (15) is provided so as to be openable and closable, and an exhaust temperature detector (19) is provided in the exhaust system path of the engine (1), and based on the fact that the exhaust temperature detector (19) detects a temperature higher than the set temperature,
The bypass valve (15) is closed to operate the exhaust turbine supercharger (C), and the bypass valve (15) is closed while the temperature detected by the exhaust temperature detector (C) is lower than the set temperature.
In a vehicle-mounted engine with an exhaust turbine supercharger configured to stop the exhaust turbine supercharger (C) by opening the valve, a timing means (20) is provided in the drive control system of the bypass valve (15).
An on-vehicle exhaust system characterized in that the bypass valve (15) is opened based on the timing means (20) detecting that the bypass valve fully open condition continues for a certain period of time or more. Supercharging control method for an engine with a turbine supercharger