GB2478008A

GB2478008A - Cylinder head with an integral turbine housing

Info

Publication number: GB2478008A
Application number: GB1003053A
Authority: GB
Inventors: Christer Sten Blom
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2010-02-23
Filing date: 2010-02-23
Publication date: 2011-08-24
Anticipated expiration: 2030-02-23
Also published as: GB2478008B; GB201003053D0

Abstract

The cylinder head 12, exhaust manifold and turbine housing 14 of an internal combustion engine 10, 60 are integrally made from aluminium, and the exhaust manifold may be cast within the cylinder head. The compressor housing 16, bearing housing 18 and the turbine housing 14 assembly may be connected together by screws 20 connected to the turbine and compressor housings, and the axis defined by the compressor, bearing, and turbine housings may be aligned vertically or horizontally and/or parallel or perpendicular to the axes of the cylinders of the internal combustion engine. Additionally the outlet 26 of the turbine housing 14 may be connected to an exhaust pipe by means of a partial turn connection, such as a bayonet fitting.

Description

Internal. Combustion Engine with Turbo Installation The present invention relates to an internal combustion engine having a turbo installation.

Existing internal combustion engines in automobile applications typically comprise a cylinder head, which may be of aluminium, an exhaust manifold of stainless steel, an exhaust turbine housing of stainless steel, a bearing housing of steel and a compressor housing of aluminium. The stainless steels employed in the exhaust manifolds and turbine housings of such engines have a high content of metals such as nickel and chromium. This leads to expensive, heavy and bulky engines. In addition, the engines operate at high temperatures which means that measures, such as heat shields, are necessary to thermally protect adjacent components.

The housing for the turbine wheel collects the engine exhaust gases from the exhaust manifold. The gases are accelerated in a turbine volute and directed on to the turbine wheel to rotate it. The wheel is attached to an output shaft and the kinetic energy of the exhaust gases and some of their thermal energy is converted into an output drive torque at the shaft.

Fixed to the other end of the shaft is a compressor wheel which operates within a compressor housing having its own volute. The compressor wheel acts to pump fresh air to the engine inlet system. The rotating parts of the turbo installation, i.e. the shaft and the wheels, are supported in a central bearing housing between the turbine housing and the compressor housing.

The bearings are lubricated by pressurised oil taken from the engine's own lubrication system and, if the exhaust gas temperatures are higher than 950 °C, the housing also must be connected to the engine's cooling system. This protects the engine oil from coking (i.e. destroying the oil additives) and blocking the oil channels. Today's diesel engines have exhaust gas temperatures of 850 -950 00 and petrol engines 900 -1050 00. Higher exhaust gas temperatures have the advantage of leading to savings in fuel.

Existing exhaust manifolds and turbine housings for petrol engines are, because of the very high temperatures, made of stainless steel. They are expensive to produce and they are heavy and bulky from the packaging point of view. They also spread a lot of heat in the engine compartments. Heat shields are needed to protect other components around the hot side of the engine and a lot of expensive materials need to be used also in the parts located close to the turbine.

Moreover, a substantial number of expensive screws, nuts and gaskets are needed to assemble all the parts to each other.

They are expensive because they have to be made of specific materials to withstand the high temperatures.

The turbine housing is usually connected to the engine's exhaust manifold, either by being cast together in one piece or bolted together.

Aspects of the present invention seek to overcome or at least reduce one or more of the above problems.

According to the present invention, there is provided an internal combustion engine comprising a cylinder head and an exhaust turbine housing, the cylinder head and turbine housing being of integral construction.

The employment of such a monoblock design provides a component which is cheaper, lighter, more compact and operates at lower external temperatures. In addition, the screws, nuts and gaskets in expensive materials are no longer required to interconnect the various components. Lubricating oil and cooling water tubes are no longer needed.

The exhaust manifold of the engine may also be integrally connected between the exhaust valves and the turbine housing.

In particular it may be cast within the body of the cylinder head.

The engine may further comprise a compressor housing with a bearing housing being arranged between the turbine housing and the compressor housing. The bearing housing provides bearings for a shaft extending between the turbine and compressor wheels. The housing may be disposed so that the axis of the shaft extends either parallel to or perpendicular to the axes of the cylinders of the internal combustion engine, i.e. the shaft extends either vertically or horizontally.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a side perspective view of parts of an internal combustion engine in accordance with a first embodiment of the present invention, with the turbine installation in a vertical disposition.

Figure 2 is a front view of parts of an internal combustion engine in accordance with a second embodiment of the present invention, in which the turbine installation is in a horizontal disposition.

Returning to the drawings, Figure 1 shows a vehicle internal combustion engine 10 comprising a cylinder head 12 integrally formed with an exhaust turbine housing 14. This integral or monoblock construction is made of aluminium. An exhaust manifold of the engine is integrally cast within the cylinder head 12 to convey the exhaust gases from the engine's cylinders to a turbine volute and wheel within the turbine housing 14. The turbine wheel drives a compressor wheel within a compressor housing 16 by means of a shaft mounted in a central bearing housing 18. The compressor housing 16 and bearing housing 18 are separate components made of aluminium.

The housings 14, 16 and 18 are firmly held together by four long screws 20, the ends of which are connected to the housings 14 and 16.

Fresh air, having passed through an air cleaner, enters the compressor housing at inlet 24 and, having been compressed, leaves at outlet 22 for engine 10. When the exhaust gases emerging from engine 10 have passed through the turbine housing, they are fed to an exhaust system via outlet 26.

A turbine-speed control arrangement 30 is contained in a housing 32. The unit comprises a pneumatic actuator or an electric solenoid and is respectively controlled by means of overpressure from the compressor or electrically. It operates a control rod 34 to operate a by-pass valve to allow some of the exhaust gases to by-pass the turbine. The housing 32 has a flange 36 which is attached by bolts 38 to the integrated cylinder head 12 and turbine housing 14.

The above-described arrangement has numerous advantages. For example it provides a compact construction. In particular, the need for a bulky exhaust manifold component is avoided.

The overall saving of space fits in well with the current trend towards smaller vehicles and smaller engine compartments. The total weight of the power train is also significantly reduced. The total cost is also reduced.

The construction also allows an improved cooling system e.g. by providing a direct coupling between the bearing housing 18 and the cylinder block of the engine, so that cooling can be provided by the engine's own cooling system. Although more heat has to be removed, improved cooling efficiency can be achieved to reduce the temperature of the power train. The highest temperature in the engine compartment can be as low as 110°C. There is also a reduction in the number of cooling components required. Furthermore, the risk of leakage is reduced.

More heat is produced and provided to the cooling system than in a conventional system. This has the advantages of facilitating the rate at which the engine warms up after starting. Fuel consumption and exhaust emissions are also reduced. In view of the compact arrangement, the catalytic converter in the exhaust pipe is closer to the exhaust valves of the engine, thus bringing the catalytic converter into action more quickly. Lower exhaust emissions are produced directly after engine start up, so that the need for a secondary air injection system can be avoided.

To cope with higher ambient temperatures in the summer, the extra heat output typically requires more engine coolant.

The extra weight of this is far exceeded by the weight saving in the turbine installation itself.

In addition there is a reduction in the number of components required for lubrication.

The provision of the long screws 20 provides a secure assembly arrangement which is quick and easy to assemble and can also be taken apart easily for the purposes of maintenance and possible replacement.

Various modifications can be made to the above arrangement.

For example the integral turbine housing and cylinder head can be made of a metal other than aluminium. Also, if desired, the compressor housing 16 and the bearing housing 18 may be made of other suitable materials.

Instead of being arranged vertically, as in Figure 1, the axis of the housings 14, 18 and 16 can be arranged horizontally as shown in the internal combustion engine 60 of Figure 2. Corresponding parts to Figure 1 have the same reference numerals and function in the same way.

Housing 32 of the control arrangement 30 has a flange 66 which is attached by bolts 68 to the compressor housing 16.

The outlet 26 of the turbine housing 14 is connected to an exhaust pipe (an end section of which is indicated schematically at 70 in Figure 2) by a connection arrangement 80. This connection arrangement is disclosed in co-pending application filed on even date and entitled "Exhaust System Connection Arrangement", which is hereby incorporated by reference. The outlet 26 is formed with L-shaped members or tracks defined by circumferentially-extending tapering members 82 which interact with projections 84 on the interior of a connector ring 86 to form a partial-turn connector. The arrangement is initially attached manually or with a tool by a push-and-rotate movement and then firmly secured by tightening a screw member 88 passing through a hole in lug 90 on the outside of ring 86 and then into a threaded hole or bore 92 on the cylinder head 12.

Instead of extending tangentially to the ring 86, the securing screw 88 may extend axially of the ring, in which case lug 90 and threaded hole 92 are suitably relocated.

The connection arrangement 80 may be constructed by any type of partial turn device, including a bayonet-type fitting.

The same modifications may be made to the embodiment of Figure 2 as to the embodiment of Figure 1.

The embodiment of Figure 1 can be provided with the connection arrangement of the output of its turbine housing 14.

Reference Numerals internal combustion engine 10 cylinder head 12 turbine housing 14 compressor housing 16 bearing housing 18 screws 20 compressor outlet 22 compressor inlet 24 turbine outlet 26 control arrangement 30 control arrangement housing 32 control rod 34 flange 36 bolts 38 internal combustion enginee 60 flange 66 bolts 68 exhaust pipe 70 connection arrangement 80 tapering member 82 projections 84 connector ring 86 screw 88 lug 90 threaded hole 92

Claims

CLAIMS1. An internal combustion engine (10, 60) comprising a cylinder head (12) and an exhaust turbine housing (14), the cylinder head and turbine housing being of integral construction.
2. An internal combustion engine according to claim 1, wherein the cylinder head (12) and turbine housing (14) are of aluminium.
3. An internal combustion engine according to claim 1 or 2 further comprising a compressor housing (16), wherein a bearing housing (18) is provided between the turbine housing (14) and the compressor housing (16), the three housings defining an axis which is parallel to the axes of the cylinders of the internal combustion engine.
4. An internal combustion engine according to claim 1 or 2 further comprising a compressor housing (16), wherein a bearing housing (18) is provided between the turbine housing (14) and the compressor housing (16), the three housings defining an axis which is perpendicular to the axes of the cylinders of the internal combustion engine.
5. An internal combustion engine according to claims 3 or 4 wherein the housings (14, 16, 18) are connected together by a plurality of screws (20) which are connected to the turbine and compressor housings.
6. An internal combustion engine according to any preceding claim, wherein an exhaust manifold is integrally cast within the cylinder head (12)
7. A vehicle comprising an internal combustion engine according to claim 1 or 2 further comprising a compressor housing (16), wherein a bearing housing (18) is provided between the turbine housing (14) and the compressor housing (16), the three housings defining an axis which is substantially vertical.
8. A vehicle comprising an internal combustion engine according to claim 1 or 2 further comprising a compressor housing (16), wherein a bearing housing (18) is provided between the turbine housing (14) and the compressor housing (16), the three housings defining an axis which is substantially horizontal.
9. A vehicle comprising an internal combustion engine according to any of claims 1 to 6 and an exhaust system, the outlet (26) of the turbine housing (14) being connected to an exhaust pipe (70) of the exhaust system by means of a partial turn connection arrangement (80)