JPS6019919A - Supercharged pressure control device in turbo-supercharger - Google Patents

Abstract

PURPOSE:To lower supercharged pressure even though the temperature of intake- air rises in the case of, for example, a high ambient air temperature condition, to avoid the occurrence of knocking, by changing the supercharged pressure along three stage characteristics thereof. CONSTITUTION:When the temperature of intake-air is lower than, for example, 70 deg.C, a temperature switch 14 closes a first solenoid valve 12 so that the pressure from a second pressure take-out port is introduced as the control pressure into an actuator 8 to take a characteristic as shown by the broken line I . When the temperature of intake-air is higher than, for example, 90 deg.C the temperature switch 14 closes a second solenoid valve 13 so that the pressure from a first pressure port 10 is introduced as the control pressure into the actuator 8 to take a characteristic as shown by the one-dot-chain line II. When the temperature of intake-air is between both set temperatures, both first and second solenoid valves 12, 13 open so that mixed value of both pressures from the first and second pressure take-out ports 10, 11 is introduced as the control pressure into the actutor 8 to take a characteristic shown by the solid line III.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boost pressure control device for a turbocharger attached to an internal combustion engine.

In a turbocharger that is driven by engine exhaust energy, an exhaust bypass valve is generally installed upstream of the turbine, and when the pressure at the compressor outlet exceeds the set pressure, the exhaust bypass valve is opened to allow exhaust to escape. Specifically, the pressure derived from the pressure outlet provided at an appropriate position in the compressor housing is used as the control pressure, and the diaphragm type or piston type of the exhaust bypass valve is used as the control pressure. This control pressure is guided to a type actuator to control the opening and closing of the exhaust bypass valve.
(Refer to "Service Bulletin No. 479")O However, in this conventional boost pressure control device,
Since the boost pressure is controlled regardless of the intake air temperature, knocking is more likely to occur when the outside temperature is high. FIG. 1 shows changes in the knocking limit of boost pressure with respect to changes in intake air temperature, and FIG. 2 shows changes in the knocking limit of ignition timing with respect to changes in intake air temperature. In addition, all +00
0 rpm and full load. In the case of Fig. 1, the ignition timing is constant (38° BTDO), and in the case of Fig. 2, the boost pressure is constant (4501 uLHg). As is clear from both figures, knocking is significantly more likely to occur when the intake moisture layer is high. It was necessary to install a knock avoidance device that retards the ignition timing when king is detected.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a supercharging pressure control device that can change supercharging pressure according to intake air temperature, and to reduce the temperature when the intake air temperature is high. The objective is to both avoid knocking in the engine and ensure sufficient boost pressure when the intake air temperature is low.

That is, the supercharging pressure control device for a turbocharger according to the present invention has a first pressure outlet formed in the compressor housing of the turbocharger from which a relatively high control pressure can be derived, and a relatively low pressure control device. A second pressure outlet from which pressure can be derived, an exhaust bypass valve provided upstream of the turbine of the turbocharger, and an actuator of the exhaust bypass valve and the first pressure outlet and the second pressure outlet. It is equipped with an on-off valve arranged in each of the two on-off valves, and a valve control mechanism that controls the opening and closing of both on-off valves according to the engine intake air temperature, and selectively uses either one of the pressures of 10,000 or a mixed pressure of both. be.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 schematically shows the configuration of the boost pressure control device according to the present invention, in which 1 is an internal combustion engine, 2 is an intake manifold,
3 is an exhaust manifold, 4 is a turbo supercharger consisting of a compressor 5 and a turbine 6, 7 is an exhaust bypass valve provided upstream of the turbine 6, and 8 is this exhaust bypass valve 7.
The figure shows a diaphragm actuator that opens and closes the door. The actuator 8 introduces control pressure from the compressor 5 through a passage 9, and has two pressure outlet ports, namely, the first pressure outlet port 1() and the second pressure outlet port.
A pressure outlet port 11 is formed in the compressor housing, and a normally open first valve is provided between each pressure outlet port 10, 11 and the passage 9. 2nd'llt magnetic valve 1
2 and 13 are provided, respectively. In the intake manifold 2, the first. , second 'dt magnetic valve 12,
A two-contact temperature switch 14 is provided as a valve control mechanism for the valve 13. Note that 15 indicates a battery.

The first pressure outlet IO is provided at a position where a relatively high control pressure can be derived, specifically, as shown in FIG. , is provided at a location where relatively low control pressure can be derived, specifically near the outlet of the combustor scroll. Further, as shown in FIG. 4, the temperature switch 14 has a structure in which a pair of fixed contacts 17 and 18 are disposed with a movable contact 16 made of metal.
A contact 17 that conducts at high temperatures is connected to the second solenoid valve 13, and a contact 18 that conducts at low temperatures is connected to the first solenoid valve 12.

Next, the operation of the above configuration will be explained. First, when the intake air temperature is lower than the set temperature on the low temperature side (for example, 70"C), the movable contact 16 of the temperature switch 14 is electrically connected to the fixed contact A1B, and the first electromagnetic In order for the valve 12 to close,
The pressure of the second pressure outlet 11 is introduced to the actuator 8 as a control pressure. Therefore, a relatively rich supercharging pressure characteristic as shown by the broken line (1) in FIG. 5 can be obtained. On the other hand, when the intake air temperature is higher than the high temperature constant temperature setting (for example, 90° C.), the movable contact 16 of the temperature switch 14 is electrically connected to the fixed contact 17 and the second Vt magnetic valve 13 is closed. In this case, the pressure of the first pressure outlet 10 is introduced as a control pressure. Therefore, a relatively low supercharging pressure characteristic as shown by the dashed line (n) in FIG. 5 can be obtained. Further, when the intake air temperature is between the constant temperatures of both membranes, the movable contact 16 is at the neutral position and the first. Since both the second solenoid valves 12 and 43 open, the actuator 8 has both pressure outlets io
, n is derived as the control pressure. Therefore, an intermediate supercharging characteristic as shown in the caustic line (11) in FIG. 5 is obtained.

In other words, the boost pressure characteristics can be changed in three stages depending on the intake air temperature, and even if the intake air temperature rises due to high outside air temperature, the boost pressure will be lowered as described above. The occurrence of knocking can be reliably avoided.

On the other hand, the torque characteristic of the engine is the boost pressure characteristic (I) described above.
, , (...) , (1) in Fig. 6 corresponding to (1), respectively.
I), ω), the characteristics shown in (1) are obtained. As is clear from this, it is possible to perform sufficient supercharging when the outside temperature is low to ensure the torque characteristics shown in (1), and it is possible to achieve a significant increase in the output direction compared to the conventional one. It can be done.

As is clear from the above explanation, according to the turbocharger boost pressure control device according to the present invention, it is possible to obtain three stages of boost pressure characteristics depending on the intake air temperature, and therefore, when the intake air temperature is high, It is possible to reliably avoid knocking, and it is also possible to apply a higher boost pressure than before when the intake air temperature is low, improving the way the engine comes out.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the relationship between the knocking limit of boost pressure and intake air temperature, Figure 2 is a characteristic diagram showing the relationship between the knocking limit of ignition timing and intake air temperature, and Figure 3 is a characteristic diagram showing the relationship between the knocking limit of boost pressure and intake air temperature. An explanatory diagram of the configuration of the boost pressure control device, Figure 4 is an explanatory diagram of its main parts, Figure 5 is a characteristic diagram showing boost pressure characteristics under various wet layer conditions, and Figure 6 is a characteristic diagram showing torque characteristics. It is a diagram. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Intake manifold, 4... Turbo supercharger, 5... Compressor, 6... Turbine, 7... Exhaust bypass valve, 8... Actuator, l
()...First pressure outlet, 11...Second pressure outlet, 12...First solenoid valve, 13...Second solenoid valve, 14
...Temperature switch. Figure 4 Figure 5 Engine rotation level (r, P, m) Figure 6 Engine rotation (r, 9.m)

Claims (1)

[Claims] (1) A first pressure outlet from which a relatively high control pressure can be derived, a second pressure outlet from which a relatively low control pressure can be derived, and which are formed in the compressor housing of the turbocharger. An exhaust bypass valve provided upstream of the turbine of the feeder, an on-off valve provided between the actuator of the exhaust bypass valve and the first pressure outlet and the second pressure outlet, respectively, and an exhaust bypass valve provided upstream of the turbine of the feeder; A supercharging pressure control device for a turbocharger, comprising a valve control mechanism that controls the opening and closing of both on-off valves accordingly and selectively uses either pressure or a mixture of both pressures.