DESC:Field of the invention:

The present invention relates to an exhaust system and more particularly, to the exhaust system consisting of a turbocharger with anticlockwise rotating turbine wheel for a three cylinder common rail diesel engine.

Background of the invention:

Combustion engines such as diesel engines, gasoline engines and gaseous fuel-powered engines are supplied with a mixture of air and fuel for combustion within the engine that generates a mechanical power output. In order to maximize the power output generated by this combustion process, the engine is often equipped with a turbocharged air induction system.

Efforts are being made in the prior art to develop an exhaust system equipped with a turbocharger. For example, US Patent No. 7571717B2 to Caterpillar Inc. discloses a two turbocharger design for V-type engine. One impeller rotates clockwise and another rotates counterclockwise. Due to V type engine, one turbocharger has to rotate in a clockwise and other in a counter clock wise direction and this is a result of packaging constraints.

As shown in figure 1a, for the same overhang (‘X’) of the turbocharger, pressure drop of exhaust gas with clockwise (hereinafter “CW”) turbocharger is high as compared to counterclockwise (hereinafter “CCW”) turbocharger. This high pressure drop adversely effects the fuel consumption.

Now referring to figure 1b, for the same pressure drop, if the CW turbocharger is used, the overhang of the turbocharger (‘X’) from manifold face will be two times more than that of the CCW turbocharger. With the CW turbocharger, packaging of the engine, intake and exhaust system in a vehicle is not possible. With such overhang turbocharger, more than one support bracket is required.

Also, the conventional turbocharger turbine wheel rotates in the clockwise direction and in conventional exhaust systems pressure drop in the exhaust gas passage is more.

Accordingly, there is a need to provide an exhaust system that overcomes the above mentioned drawbacks of the prior art.

Objects of the invention:

An object of the present invention is to make an exhaust gas passage significantly smooth.

Another object of the present invention is to provide an anticlockwise rotating turbine wheel that allows maximum energy transfer thereto thereby reducing overall pressure drop of an exhaust system.

Summary of the invention:

Accordingly, the present invention provides an exhaust system for a diesel engine. The diesel engine comprises a cylinder head. The cylinder head comprises a plurality of ports configured therein.

The exhaust system comprises an exhaust manifold, a turbocharger and an actuator. The exhaust manifold is mounted on a cylinder head of the diesel engine. The exhaust manifold includes a plurality of runners configured therein.

The turbocharger is mounted on the exhaust manifold. The turbocharger comprises a turbine housing, a turbine wheel, a compressor housing, a compressor wheel and a bearing shaft. The turbine wheel is positioned inside the turbine housing. The turbine wheel is designed to rotate in an anticlockwise direction when viewed from a front end of the diesel engine. The turbine housing comprises an inlet connected to the exhaust manifold via an exhaust pipe and an outlet adapted to carry exhaust gas therefrom. The compressor wheel is positioned inside the compressor housing. The compressor wheel is connected to the turbine wheel through the bearing shaft. The actuator is mounted on the compressor housing for controlling geometry of the turbine wheel and thus controlling the rotation of the bearing shaft.

During an exhaust stroke of a combustion cycle, the exhaust gas leaves a cylinder and via the plurality of ports in the cylinder head comes in to the exhaust manifold and through the plurality of runners enters into the turbine housing of the turbocharger through the inlet. The exhaust gas then gives complete pressure energy thereof to the turbine wheel resulting in rotation of the turbine wheel in the anticlockwise direction and maximum energy transfer thereto thereby reducing overall pressure drop of the exhaust system.

Brief description of the drawings:

Figures 1a and 1b illustrate pressure drop and overhang of a turbocharger of the prior art;

Figure 2 illustrates a perspective view of an exhaust system for a diesel engine, in accordance with the present invention;

Figures 3a and 3b illustrate a front end view of the exhaust system of figure 2;

Figure 4 illustrates an exhaust gas passage through an exhaust port to an exhaust manifold, in accordance with the present invention;

Figure 5 shows components of a turbocharger of the exhaust system of figure 2; and

Figure 6 illustrates the exhaust gas passage in an anticlockwise flow, in accordance with the present invention.

Detailed description of the invention:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides an exhaust system for a diesel engine. The exhaust system comprises a turbocharger having an anticlockwise rotating turbine wheel. The anticlockwise rotating turbine wheel allows maximum energy transfer thereto thereby reducing overall pressure drop of the exhaust system.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring now to figures 2 to 6, an exhaust system (100) for a diesel engine (not shown) in accordance with the present invention is shown. In an embodiment, the diesel engine is a three cylinder common rail diesel engine. Specifically, the exhaust system (100) is primarily used for 1.2 liter three cylinder in-line internal combustion diesel engine with a turbocharger intercooler (not shown). The diesel engine includes a cylinder head (150). The cylinder head (150) is mounted over a crankcase/cylinder block (not shown). The cylinder head (150) includes a plurality of ports (110) configured therein.
The exhaust system (100) comprises an exhaust manifold (40), a turbocharger (80) and an actuator (90).

The exhaust manifold (40) is mounted on the cylinder head (150) using studs and nuts (not shown). The exhaust manifold (40) includes a plurality of runners (20) configured therein. The plurality of runners (20) is gas passages adapted to carry exhaust gas from the cylinder head (150) to the turbocharger (80).

The turbocharger (80) is mounted on the exhaust manifold (40) using studs and nuts (not shown). The turbocharger (80) includes a compressor housing (42), a turbine housing (44), a compressor wheel/impeller wheel (46) (hereinafter “the compressor wheel (46)”), a turbine wheel (48) and a bearing shaft (50).

The compressor wheel (46) is positioned inside the compressor housing (42). The turbine housing (44) includes an inlet (43A) and an outlet (43B). The inlet (43A) is connected to the exhaust manifold (40) via an exhaust pipe (not shown). The outlet (43B) is adapted to carry out the exhaust gas from the turbine housing (44). The turbine wheel (48) is positioned inside the turbine housing (44). The turbine wheel (48) and the compressor wheel (46) are connected through the bearing shaft (50).

In an embodiment, the exhaust system (100) is designed with the turbine wheel (48) of the turbocharger (80) rotating in an anticlockwise/counter clockwise direction when viewed from a front end (not shown) of the diesel engine.
The anti-clockwise rotation of the turbine wheel (48) gives following benefits:
• Reduced pressure drop of the exhaust system (100) before the turbine wheel (48)
• High efficiency and less brake specific fuel consumption (BSFC)
• Reduced overhang of the turbocharger (80)
• Compact packaging of the exhaust system (100)

The actuator (90) is mounted on the compressor housing (42) of the turbocharger (80). The actuator (90) controls opening and closing of vanes (not shown) inside the turbine housing (44) thereby controlling boost pressure. As the exhaust gas flow is less at low speeds, the actuator (90) closes the vanes to increase velocity of the exhaust gas thereby rotating the turbine wheel (48) faster to give the required boost pressure.

The actuator (90) controls geometry of the turbine wheel (48) for controlling the maximum rotation of the bearing shaft (48). The plurality of runners (20) of the exhaust manifold (40) directs the exhaust gas pulse onto the turbine wheel (48) smoothly thereby reducing overall pressure drop of the exhaust system (100).

Again referring to figures 2-6, in an operation, during an exhaust stroke of a combustion cycle, the exhaust gas leaves the cylinder and via the plurality of ports (110) in the cylinder head (150) comes into the exhaust manifold (40). The exhaust gas moves through the plurality of runners (20) in the exhaust manifold (40) just after exiting from the plurality of ports (110). Thereafter, the exhaust gas enters into the turbine housing (44) of the turbocharger (80) through the inlet (43A). After entering inside the turbine housing (44), the exhaust gas gives complete pressure energy thereof to the turbine wheel (48) resulting in rotation of the turbine wheel (48) in the anticlockwise direction and maximum energy transfer thereto thereby reducing overall pressure drop of the exhaust system (100).

Advantages of the invention:
1. Energy loss of the exhaust gas before reaching the turbine wheel (48) is very less.
2. Improved performance of the turbocharger (80).
3. The plurality of runners (20) is designed such that the exhaust gas passes smoothly onto the turbine wheel (48) of the turbocharger (80).

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.
,CLAIMS:We claim:

1. An exhaust system (100) for a diesel engine, the diesel engine having a cylinder head (150), the cylinder head (150) having a plurality of ports (110) configured therein, the exhaust system (110) comprising:
an exhaust manifold (40) positioned on the cylinder head (150), the exhaust manifold (40) having a plurality of runners (20) configured therein;
a turbocharger (80) mounted on the exhaust manifold (40), the turbocharger (80) having,
a turbine wheel (48) positioned inside a turbine housing (44), the turbine housing (44) having an inlet (43A) connected to the exhaust manifold (40) via an exhaust pipe and an outlet (43B) adapted to carry exhaust gas therefrom, and
a compressor wheel (46) positioned inside a compressor housing (42), the compressor wheel (46) connected to the turbine wheel (48) through a bearing shaft (50); and
an actuator (90) mounted on the compressor housing (42) for controlling geometry of the turbine wheel (48) and thus controlling rotation of the bearing shaft (50),
characterized in that, the turbine wheel (48) rotates in an anticlockwise direction when viewed from a front end of the diesel engine,
wherein, during an exhaust stroke of a combustion cycle, the exhaust gas leaves a cylinder and via the plurality of ports (110) in the cylinder head (150) comes in to the exhaust manifold (40) and through the plurality of runners (20) enters into the turbine housing (48) of the turbocharger (80) through the inlet (43A) thereafter, the exhaust gas gives complete pressure energy thereof to the turbine wheel (48) resulting in rotation of the turbine wheel (48) in the anticlockwise direction and maximum energy transfer thereto thereby reducing overall pressure drop of the exhaust system (100).