JPS6019916A - Engine provided with turbo-supercharger - Google Patents

Abstract

PURPOSE:To enhance the accelerating response of an engine with a simple structure without the necessity of a check valve, by disposing compressors, respectively in two intake-air passages separately opened to a combustion chamber, and also by providing turbines in series in an exhaust passage. CONSTITUTION:First and second branched intake-air passages 18 through 21, 22 through 25 are separately opened to the combustion chambers of cylinders 1 through 4 thorough surge tanks 16, 17. With this arrangement, upon intake- stroke no blow-off of intake-air occures even if they are communicated with each other through the combustion chambers whose pressure becomes negative during intake-stroke. Further, the turbines 26, 27 of first and second turbo-superchargers 10, 10 are disposed in series in an exhaust passage 32, and therefore, the turbines 26, 27 receives all volume of exhaust gas so that they rotate high- responsively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a turbocharged engine.

(Prior Art) Generally, engines with a turbocharger are known that use exhaust gas to rotate a turbine in an exhaust passage and rotate a compressor directly connected to the turbine in an intake passage to perform supercharging.

Conventionally, in the case of a multi-cylinder engine, one turbocharger M compressor and turbine were installed for each of the main intake passage, which branches into the intake passage of each cylinder, and the main exhaust passage, where the exhaust passages of each cylinder merge. Because of this configuration, it was necessary to increase the capacity of the turbo supercharger, which caused the problem that the amount of exhaust gas did not suddenly increase during acceleration, especially during sudden acceleration, resulting in poor acceleration response. .

Therefore, as disclosed in Japanese Patent Application Laid-open No. 171777/1987, at least two exhaust turbines are arranged in the exhaust system of an internal combustion engine, and a supercharging system is arranged in the intake system of the internal combustion engine and driven by the exhaust turbine. The operation of at least seven of the exhaust turbines is controlled according to the load condition of the internal combustion engine, so that the exhaust turbines can operate with high efficiency from the low speed range to the high speed range of the engine. An internal combustion engine with a turbo supercharging device has been proposed which can provide a sufficient supercharging effect.

However, in such an engine, the operation of at least seven exhaust turbines is controlled according to the load condition of the internal combustion engine, so the engine exhaust pressure, supply air pressure, engine speed, or engine intake throttle valve opening is controlled. The structure was complicated, as it required a control valve to be controlled by the temperature, etc., and a check valve to prevent backflow of air supply.

(Object of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to provide a turbocharged engine that does not require a check valve in the intake system, has a simple structure, and has improved acceleration response. The purpose is to

(Structure of the Invention) The present invention relates to an improvement of a turbocharged engine, in which first and second turbochargers are provided in first and second intake passages that open independently into the combustion chamber of the engine. The present invention is characterized in that a compressor for the engine is provided, and the turbines of the first and second turbochargers are provided in series in an exhaust passage.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

In the engine shown in FIG. 1, 1. ．． 2, 3°4 are the 1st. Second. Third. The th cylinder, 5, is a main intake passage, in which an air cleaner 6 and an air flow meter 7 are arranged in order from the upstream side, and downstream of the air flow meter 7, it branches into first and second intermediate intake passages 8 and 9, which are independent from each other. There is. The first and second intermediate intake passages 8, 9 are connected to the compressors 12, 13 . 7th and 2nd intercooler 14゜1
5 (Cooler), 1st and 2nd surge tank 16.17
are arranged in sequence, the first and second surge tanks 16.
17, each cylinder 1, 2. First and second branch intake passages 18, 19, 20, 21 that open independently into the combustion chambers of
and 22,2ro.

It branches to 24.25.

26.27 is the turbine of the first and second turbo supercharger 10゜11, which is formed by merging branch exhaust passages 28, 29, 30, 31 that open into the combustion chamber of each cylinder 1, 2, 3.4. They are arranged in series in the main exhaust passage 32.

Reference numeral 36 denotes a cooling water passage through which engine cooling water cooled by the radiator 35 is circulated by the water pump 34 to the second ink cooler 15 and the first intercooler 14 according to the arrows.

As a result, the intake air is cooled from the side of the second intermediate intake passage 8, where the temperature increase due to the increase in intake pressure due to supercharging is larger, so that the intake air can be efficiently cooled and the charging efficiency can be increased.

36.37 are the first and second throttle valves;
It is arranged upstream of the surge tank 16.17. Second
The throttle valve 67 is linked to the first throttle valve 36, and the first throttle valve 36 opens during high load after a certain period of time.

38 is a first communication passage connecting the upstream and downstream sides of the first turbocharger 10, and 69 is a second communication passage connecting the upstream and downstream sides of the second turbocharger 11.

40 and '41 are the first and second communication passages 68 and 9, respectively.
The first and second on-off valves are interposed in the first and second on-off valves.
It opens when the pressure inside the surge tank 16, 17 exceeds a set value. That is, the pressures p, , p6 of the first and second surge tanks j 6 , 17 are kept at constant values. However, p, < ps.

With the above configuration, the first and second branch intake passages 18, 19, 20, 21 and 22, 2.

24.25 are opened independently into the combustion chambers of each cylinder 1, 2, and 3.4, so during the intake stroke, even if they are communicated through the combustion chambers that are in a negative pressure state during the intake stroke. , so-called intake air blow-through does not occur. That is, both the intake passages 18, 19, 20° 21 and 22, 23, . 24
．． There is no need to provide a valve on the reverse 1 between 25 and 25.

Further, since the turbines 26.27 of the first and second turbochargers 10.11 are arranged in series in the exhaust passage 62, each turbine 26.27 can be used without any special means such as a control valve. receives the full amount of exhaust gas and rotates with good response.

Also, each cylinder 1, 2. 4, as shown in FIG. 2, the second branch intake passages 22, 23, .
24.25 intake port 22a.

The boat opening degree B of 23a, 24a, 25a is the intake port 18a of the first branch intake passage 18, 19, 20, 21,
Since the opening degree of the ports 19a, 20a, and 21a is set to reach its maximum later than the opening A of the ports 19a, 20a, and 21a, the filling efficiency of the intake air is increased in conjunction with the cooling effect of the intake air by the first and second intercoolers 1.4.15. be enhanced.

(Effects of the Invention) Since the present invention is configured as described above, a check valve is not required in the intake system, and acceleration response can be improved with a simple structure.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is an overall configuration diagram of a turbocharged engine, and FIG. 2 is a diagram showing the relationship between the boat opening and the crank rotation angle. 1...First cylinder, 2...Second cylinder, 3
...3rd cylinder, 4th cylinder, 5th cylinder...
...Main intake passage.

Claims (1)

[Claims] (/) A turbocharger compressor is installed in each of the two intake passages that open independently into the combustion chamber of the engine.
A turbocharged engine characterized in that the turbocharger turbines are arranged in series in an exhaust passage.