Internal combustion engine with compressor, intercooler and intake manifold in an integrally cast housing

Abstract: An internal combustion engine with a mechanically driven charge-air compressor (13), which is connected to the engine intake manifold (18) by way of an intercooler (14). The characteristic feature of the engine is that the compressor, the intercooler and the intake manifold have a common, integrally cast housing part (8).

Description: The present invention relates to an internal combustion engine, comprising an engine block with a plurality of cylinders, a cylinder head connected to the engine block, with combustion air inlet ports to each cylinder, an intake manifold with at least one branch pipe to each cylinder and a mechanically driven compressor, which is connected to the intake manifold by way of an intercooler. US-A-6.029.637 shows such a supercharged internal combustion engine. Supercharged engines with charge-air cooling usually have a radiator in the form of a plate heat exchanger mounted in the engine compartment at a distance from the engine. The heat exchanger is connected by way of pipes and/or hoses to the compressor outlet and the intake manifold inlet. This means that the volume of air between the compressor outlet and the intake manifold inlet is relatively large, which where a mechanically driven compressor, such as a screw compressor, is used tends to generate noise due to resonance in the system. Large volumes of air between the compressor outlet and the inlet to the engine cylinders also have a negative effect on engine response. The object of the present invention is to produce an engine of the type specified in the introductory part, with a very compact compressor and intercooler installation, which results in more efficient cooling and silencing and improved response than previously known supercharged engines with charge-air cooling described above. According to the invention this is achieved in that the compressor and the intercooler have a common, integrally formed housing part, which is connected to the intake manifold. In a preferred embodiment the intake manifold is also integrally formed with the housing part of the compressor and the intercooler, the housing part preferably being composed of cast metal, for example, aluminium. Integrating the compressor, the intercooler and the intake manifold in this way provides a very compact and stable unit with very small air volume between the compressor outlet and the inlet into the cylinders of the engine. As an example the said volume of air may be as little as 2.5 litres in an engine of corresponding cylinder capacity. The invention is described in more detail below with reference to exemplary embodiments shown in attached drawings, in which Fig. 1 shows an end view of an embodiment of a five-cylinder, in-line engine, Fig. 2 shows a side view of the engine in Fig. 1, Fig. 3 shows a side view of the engine's integrated compressor, intercooler and intake manifold unit, Fig. 4 shows the unit in Fig. 3 turned through 90 degrees, Fig. 5 shows an end view of the unit in Fig. 3 viewed from the right, Fig. 6 shows an end view of the unit in Fig. 3 viewed from the right but with its right end removed, Fig. 7 shows a cross section through the unit in Fig. 3, Fig. 8a shows a side view of a cooler element, Fig. 8b shows an end view of the cooler element in Fig. 8a, Fig. 8c shows an enlargement of the area inside the circle A in Fig. 8a, and Fig. 9 shows a block diagram of an exemplary embodiment of a cooling circuit for the intercooler. In Fig. 1, 1 denotes the cylinder block, 2 the cylinder head and 3 the oil sump of a five-cylinder in-line engine with fuel injection known in the art. The engine has twin overhead camshafts, which support pinions 4, which are driven by a common toothed belt 5 from a pinion 6 on the engine crankshaft 6a. An integrated compressor, intercooler and intake manifold unit, generally denoted by 7, which will be described in more detail below with particular reference to Figs. 3-7, is shown on the right-hand side of the cylinder block 1 and the cylinder head 2, seen in Fig. 1. The unit 7 has an integrally cast housing body 8, preferably of aluminium, which forms a housing, closed at the ends by the end pieces 9, 10 and 11, for a screw compressor 13 and an intercooler 14, the housing part 15 enclosing the rotating screws 15a of the compressor 13, the axes 13a of which screws are parallel with the engine crankshaft 6a, whilst the housing part 16 defines three cylindrical, elongated chambers, parallel to the crankshaft 6a, for cooler elements of the intercooler, which will be described in more detail below. The housing part 16 of the intercooler merges into an intake manifold 18 with five intake pipes 19, which is therefore integrally cast with the compressor and intercooler housing parts 15 and 16. The intake pipes 19 are designed with threaded seats 20 for fuel injectors (not shown further). The air is drawn into the housing part 15 of the compressor 13 through an inlet pipe 21, intended to be connected to a line with an air filter. The compressed air flows through an outlet 22 from the compressor (see Fig. 7) into an enclosed space 23, which is separated from the interior 24 of the manifold 18 by three cast-in cylinders 25 with intervening wall elements 26. The cylinders 25 define the above-mentioned cylindrical chambers 17 and are arranged so that each encloses a cooler element in the form of a pipe with external cooling flanges. In a preferred embodiment cooling fins 27 of a type known in the art are used, as shown in Fig. 8a-8c and marketed under the name Laminovastavar ®. The walls of the cylinders 25 are perforated by slits 28 and 29 distributed along the length of the cylinders, so that air that is forced into the enclosed space 23 can flow in through the slits 28, pass between cooling gills 30 of the fins 27 and flow out through the slits 29 into the intake manifold 18. In a vehicle with air conditioning system the refrigerant of the air conditioning system is preferably used for cooling the cooling fins 27, as illustrated in Fig. 9, in which a conventional cooling system with compressor 40, storage reservoir, 41, cooler element 42 and condenser 43 are shown diagrammatically. The cooling circuit 44 for the cooling fins 27 is connected in parallel over the cooler element 42. In addition to the fins 27, the circuit 44 comprises a throttle 45, an electrically controlled valve 46 and a storage reservoir 47. In the embodiment shown in Fig. 1 and 2 the air conditioning system cooling compressor 40 is suspended in the housing 8 of the compressor, intercooler and intake manifold unit 7, a power steering hydraulic pump 48 also being fitted in the housing. By suspending the cooling compressor 40 in the housing 8, short lines will suffice to carry refrigerant to cooling fins 27 of the intercooler. The embodiment described enables the charge-air compressor 13, the cooling compressor 40 and the hydraulic pump 48 to be driven by one and the same drive belt from the engine crankshaft, as indicated by the dotted and dashed line 49 in Fig. 1 Altogether, the embodiment described provides an extremely compact and stable installation, which affords very efficient cooling, low noise level and good response. The invention has been described above with reference to an installation with a screw compressor, but it is naturally also feasible to use other types of mechanically driven compressors, such as a Roots compressor®. Nor is the invention confined to cooling of the cooling fins 27 using the refrigerant in an air conditioning system. Without departing from the scope of the invention, the cooling fins 27 may alternatively be cooled by coolant, which is in turn cooled in an air-cooled heat exchanger.

Claims: An internal combustion engine, comprising an engine block with a plurality of cylinders, a cylinder head connected to the engine block, with combustion air inlet ports to each cylinder, an intake manifold with at least one branch pipe to each cylinder and a mechanically driven compressor, which is connected to the intake manifold by way of an intercooler, wherein the compressor (13) and the intercooler (14) have a common, integrally formed housing part (8), which is connected to the intake manifold (18), characterized in that the intake manifold (18) is integrally formed with the housing part (8) of the compressor (13) and the intercooler (14). Internal combustion engine according to Claim 1, characterized in that the housing part (8) is composed of cast metal. Internal combustion engine according to Claims 1 or 2, characterized in that the compressor (14) is arranged with its axes of rotation (13a) parallel with the engine crankshaft (6a) and that the intercooler (14) has at least one elongated chamber (17) parallel to the axes of rotation of the compressor, which chamber contains a cooler element (27) with a cooling medium flowing through it and has an inlet (28) from the compressor and outlet (29) to the intake manifold (18). Internal combustion engine according to Claim 3, characterized in that the intercooler (14) has a plurality of parallel cylindrical chambers (17), which each contain a cooler element (27) in the form of a pipe with external cooling flanges (30) and a flow of cooling medium passing through it, and which have diametrically opposed inlets (28) and outlets (29) for intake air in their cylindrical wall. Internal combustion engine according to Claim 3 or 4, characterized in that the cooler element (27) is connected to a refrigerant circuit in an air conditioning system. Internal combustion engine according to any of Claims 1 to 5, characterized in that the common housing part (8) of the compressor (13) and the intercooler (14) forms a suspension element for additional units (40; 48). Internal combustion engine according to Claim 7, characterized in that a cooling compressor (40) in a refrigerant circuit in an air conditioning system and/or an oil pump (48) for power-assisted steering are fitted in the housing (8). Internal combustion engine according to Claim 6 or 7, characterized in that the compressor (13) and the additional unit(s) (40, 48) are driven by a common belt (49) or chain driven by the engine crankshaft (6a).

Inventors: WIIK JAN-ERIK, WIIK, JAN-ERIK
Applicants: VOLVO CAR CORP, VOLVO CAR CORPORATION
Application year: 2001
Main classification: F02B29
IPC codes: F02B67, F02B29, F02B75