JPS59147823A - Exhaust turbo-supercharger type four-cycle engine - Google Patents

Abstract

PURPOSE:To enhance the performance of an internal combustion engine having each cylinder provided with two intake valves and as well having more than two turbo-superchargers, by providing independent intake pipes to the two intake valves, respectively, and as well by controlling the supercharging in one of the intake pipes in accordance with the operating condition of the engine. CONSTITUTION:In the case of a four-cycle engine provided with two turbo-superchargers, one exhaust valve 21 and two intake valves 310, 320 are fitted in the cylinder head 11 of each cylinder, and exhaust gas is discharged into an exhaust pipe 20 from each exhaust valve 21 so that first and second turbines 41, 42 are driven. Meanwhile the feed of air is conducted to the intake valves 310, 320 through two independent intake pipes 31, 32, and discharged air from first and second compressors 51, 52 is fed into the intake pipes 31, 32. Further, an exhaust gas parting valve 60 is disposed in an exhaust passage between the exhaust pipe 20 and the second turbine 42, and as well an intake-air parting valve 70 is disposed, as occassion demands, in an intake-air passage between the second intake pipe 32 and the second compressor 52, both parting valves 60, 70 being opened only upon high speed operation of the engine.

Description

[Detailed description of the invention] The present invention relates to an exhaust turbocharged four-stroke engine.

Conventional exhaust turbocharged 4-stroke engines are equipped with two or more turbochargers consisting of a compressor and a turbine.
In the low speed range of the engine, one (or more) of the turbochargers is deactivated and a smaller number of turbochargers are used.

A so-called one-turbo cut operation has been proposed that improves the performance of the engine in the low-speed range by performing supercharging.

However, since the air supply pipe that receives the discharge air from multiple compressors is common, when turbocharger B, which is stopped at two partial loads, is started to operate as the engine speed increases, the turbocharger B, which is already in operation, is Since high pressure is maintained in the air supply pipe by the compressor of charger A, the compressor of turbocharger B, which started operating later, has a certain pressure in order to avoid backflow from the air supply pipe and surging phenomenon. The discharged air cannot be sent to the air supply pipe until a certain rotation, and this requires a special switching device and time for switching, which hinders the practical implementation of this type of partial load performance improvement measure. ing.

The purpose of the present invention is to provide an exhaust turbocharged 4-cycle engine that can change the number of turbochargers operated according to the rotational speed and load of one engine, and that allows for easy and quick switching. The main feature of this system is that each cylinder has two intake valves, each of which is configured to be able to remain closed for a required period of time during engine operation in an exhaust turbocharged four-stroke engine. A first air supply pipe that supplies air to the cylinder through one air supply valve of each cylinder, the other air supply valve of each cylinder, and a second air supply pipe that supplies air to the cylinder through one of the air supply valves of each cylinder. Trachea, No. 1 above. at least one compressor directly connected to an exhaust turbine that supplies air to only one of the second air supply pipes, and an exhaust turbine of the compressor that supplies air to the second air supply pipe and an exhaust pipe of the engine; An exhaust gate valve is provided in the exhaust passageway between the two to open and close the passageway.

Embodiments of the present invention will be described below with reference to the drawings.

The first tooth is an explanatory diagram showing a main part of an exhaust turbocharged four-cycle engine according to an embodiment of the present invention.

In the figure, 10 is the engine body, 1 is the cylinder head, 20 is the exhaust pipe, 21 is the exhaust valve, 31 is the first set of trachea, 3
] 0 is the first air intake valve, 32 is the second air intake pipe, 320 is the second air intake valve, 41 is the first turbine, 42 is the second turbine, 51
is a first compressor, 52 is a second compressor, 60 is an exhaust gate valve,
70 is an air supply gate valve.

In this case, the present invention is applied to a four-cylinder engine.

Exhaust valve 2 is provided in the cylinder head 11 of each cylinder.
1 and the first air supply valve 310. A second air supply valve 320 is provided. The exhaust gas from each exhaust valve 21 is discharged to the exhaust pipe 20.

The first air supply valve 310 receives air supply from the first air supply pipe 31,
The second air supply valve 320 receives air from a second air supply pipe 32 that is independent of the first air supply pipe 31 .

The first compressor 51 is connected to send its discharged air to the first air supply pipe 3], and the second compressor 52 is connected so as to send its discharged air to the second air supply pipe 32.

Both the first turbine 41 and the second turbine 42 operate by receiving exhaust gas from the exhaust pipe 20, and are operated by the first compressor 5, respectively.
The first and second compressors 52 are configured to be driven by direct connection or the like.

The exhaust passage between the first trachea 20 and the second turbine 42 is connected by an exhaust gate valve 60, and the air supply passage between the second air supply pipe 32 and the second compressor 52 is connected by an air supply gate valve 70 (if necessary). (not necessarily necessary).

Each passage can be opened and closed.

Further, the second air introduction valve 320 can be maintained in a closed state by stopping its normal opening and closing operation by appropriate means.

The operation in the case of the above configuration will be described.

When the engine is running at low speed, the exhaust gate valve 60 and the air supply gate valve 7
0 is closed, and the second air supply valve 320 is always kept closed.

Therefore, no exhaust gas is introduced into the second turbine 42,
The second turbine 42 and the second compressor 52 do not operate at all.

Each cylinder of the engine is connected to the first compressor 51 → the first air supply pipe 31 →
The first air supply valve 310 receives air supply.

The entire amount of exhaust gas introduced into the exhaust pipe 20 through the exhaust valve 21 is discharged from the first turbine 41.

When the engine rotates at high speed, the exhaust gate valve 60 and the air supply gate valve 7
0 is open, and the second air supply valve 320 normally opens and closes.

Therefore, in addition to the above-mentioned supply air and exhaust flow at low rotation speeds,
In addition, supply air is supplied to each cylinder from the second compressor 52 and the second air supply pipe 32, and exhaust gas is introduced from the exhaust pipe 20 to the second turbine 42.

The above case has the following effects.

As the engine speed increases, the bleed gate valve 60. Air supply gate valve 7
The second turbine 42 and the second compressor 5 are stopped with 0 open.
2, the pressure in the second air supply pipe 32, which is the destination of the discharge air of the second compressor 42, is kept sufficiently low, and the backflow from the second air supply pipe 32 to the second compressor 52 side is prevented. There is no occurrence of surging or surging of the second compressor 52, and very stable switching is possible.

Therefore, there is no need to set a complicated control mechanism or waiting time for this switching mechanism.

As described above, optimum supercharging conditions are provided for each of the low rotational speed range and high rotational speed range of the engine, so that a quadratic improvement in engine performance is achieved.

(1) Prevention of smoke generation and improvement of acceleration in the low rotation range.

(2) Improved fuel efficiency and reduced heat load in high rotation range.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the main parts of an exhaust turbocharged four-stroke engine according to the present invention. DESCRIPTION OF SYMBOLS 11... Cylinder, 20... Exhaust pipe, 31... First air supply pipe, 32... Second air supply pipe, 41... First turbine. 42... Second turbine, 51... First compressor, 52
...Second compressor, 310...First air supply valve, 320.
...Second air supply valve. Figure 1

Claims (1)

[Claims] 1. In a υ-air turbocharged 4-cycle engine having two air intake valves in each cylinder, one air intake valve of each of the cylinders is configured to be able to remain closed for a required period of time during two-engine operation. , a first air supply pipe that supplies air to the cylinder via the other air supply valve of each cylinder; a second air supply pipe that supplies air to the cylinder via one of the air supply valves of each cylinder;
．． at least one compressor directly connected to an exhaust turbine that supplies air to only one of the second air supply pipes, and an exhaust turbine of the compressor that supplies air to the second air supply pipe and an exhaust pipe of the engine; An exhaust turbocharged four-stroke engine characterized by comprising an exhaust gate valve provided in an exhaust passageway between the exhaust passageways to open and close the passageway.