GB2060772A

GB2060772A - Fluid-cooled internal combustion engine

Info

Publication number: GB2060772A
Application number: GB8031996A
Authority: GB
Original assignee: Bayerische Motoren Werke AG
Current assignee: Bayerische Motoren Werke AG
Priority date: 1979-10-05
Filing date: 1980-10-03
Publication date: 1981-05-07
Also published as: FR2468736A1; IT1132766B; JPS5914604B2; JPS5654919A; DE2940427C2; IT8024934A0; DE2940427B1

Abstract

A coolant circulating pump has a housing (3) connected to engine crankcase (2), and a coolant flow duct (13) connects a cylinder head (1) to a chamber (6) of the pump housing (3), the cylinder head (1) having a cylindrical opening (10), and the duct having a cylindrical end region (11) which fits into the opening (10) and is sealed relative to it by an 'O'-ring (12). <IMAGE>

Description

SPECIFICATION Fluid-cooled internal combustion engine This invention relates to a fluid-cooled internal combustion engine comprising a cylinder head, a crankcase, a coolant circulating pump having a housing connected to the crankcase, and a coolant flow duct connecting the cylinder head to a chamber of the pump housing.

In a known fluid-cooled internal combustion engine of this construction (Mercedes*Benz 350 SEL), the pump housing is screwed on to an end face of the crankcase, and the upper end of the duct lies in a plane separating the cylinder head from the crankcase. This construction calls for great precision and close tolerances for its assembly in order to achieve a reliable seal between the cylinder head and the duct.

An aim of the present invention is to provide a fluid-cooled internal combustion engine of the construction set forth in the opening paragraph wherein the pump housing can be secured easily and rapidly in place while ensuring fluid tight connections. With this aim in view, the invention is directed to an engine of the construction set forth in the opening paragraph in which the cylinder head has a cylindrical opening, and the duct has a cylindrical end region which fits in to the cylinder head opening and is sealed relative to it by an '0'-ring.

The fitting of the end of the duct into the cylinder head opening automatically centres the pump housing. The pump housing should be connected to the crankcase by means designed to allow for dimensional tolerances. For example, in a preferred embodiment, a flange on the pump housing is connected to the crankcase by bolts which pass through oversize holes in the flange.

In an embodiment described below, the duct is a short circuit duct for returning coolant direct from the cylinder head to the pump by-passing a radiator for cooling the coolant, the pump housing having mounted in it a thermostat disposed in a chamber of the pump housing into which the duct discharges, the thermostat serving to control fluid flow through the duct, the upstream end of the duct being disposed generally at right angles to a plane in which the pump housing joins the crankcase.

A preferred embodiment of engine according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, in part, an end of a fluid-cooled internal combustion engine with a pump housing, also shown in part only, secured thereto; and Figure 2 is a section through the pump housing along the line Il-Il in Figure 1.

The illustrated fluid-cooled internal combustion engine, which is not shown in detail, comprises a cylinder head 1 and a crankcase 2, to which a pump housing 3 is secured by means of a connecting flange 4. The pump housing 3 accommodates a coolant pump 5 and thermostat, i.e. a thermostatic control insert 7, arranged in an integrated control chamber 6. Integraily formed with the cylinder head 1, i.e. by casting, is a lug 8 which has an outlet opening 9' formed by a cylindrical bore 9. The pump housing is formed with an integral pipe 13 which serves for the return of coolant from the cylinder head direct to the chamber 6, the pipe 13 thus being a shortcircuit duct. An end 11 of the pipe 13 is accommodated in the outer enlarged portion 10 of the bore 9 and is sealed off by means of an O-ring 12.The O-ring need only be small as it does not have to compensate for tolerances, and as shown the ring 12 seats between the outer surface of pipe 1 3 and the inner surface of the cylinder head opening. Also connected to the control chamber 6 is the suction duct 14 of the coolant pump 5. The control chamber 6 is closed off by a cover 1 5 which has an inlet port 16 for collant emanating from a radiator, not illustrated.

The connecting flange 4 of the pump housing 3 has three eyes 17. The holes 18 in the eyes 17 for receiving fixing bolts 1 9 are made oversize in order to offset dimensional differences between the cylinder head 1 and the crankcase 2. The end 11 of the pipe 1 3 forming the inlet to the shortcircuit duct is disposed at right angles to the lane 4' of the connecting flange 4. The connecting flange 4 surrounds the outlet 5' of the coolant pump 5, which outlet discharges directly into the water jacket of the crankcase 2.

When assembling the internal combustion engine or when carrying out repairs, the pump housing 3 can be very easily fitted, the procedure being as follows: the O-ring 1 2 is fitted on the end 11 of the short-circuit pipe 13 of the pump housing 3, and thus end 11 is pushed into the enlarged portion 10 of the cylindrical bore 9 in the lug 8 of the cylinder head 1. In this way the end 11 is accurately located in the cylinder head 1 and the pump housing 3 simply requires to be aligned with the aid of oversize holes for receiving the fixing bolts 1 9. Then, after interposing an optional seal between the connecting flange 4 and the crankcase 2, the fixing bolts 19 can be pushed through the eyes 1 7 of the flange and can be tightened.

1. A fluid-cooled internal combustion engine comprising a cylinder head, a crankcase, a coolant circulating pump having a housing connected to the crankcase, and a coolant flow duct connecting the cylinder head to a chamber of the pump housing, in which the cylinder head has a cylindrical opening, and the duct has a cylindrical end region which fits into the cylinder head opening and is sealed realtive to it by an '0'-ring.

2. An engine according to claim 1, in which the pump housing is connected to the crankcase by means designed to allow for dimensional tolerances.

3. An engine according to claim 2, in which a flange on the pump housing is connnected to the crankcase by bolts which pass through oversize holes in the flange.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fluid-cooled internal combustion engine This invention relates to a fluid-cooled internal combustion engine comprising a cylinder head, a crankcase, a coolant circulating pump having a housing connected to the crankcase, and a coolant flow duct connecting the cylinder head to a chamber of the pump housing. In a known fluid-cooled internal combustion engine of this construction (Mercedes*Benz 350 SEL), the pump housing is screwed on to an end face of the crankcase, and the upper end of the duct lies in a plane separating the cylinder head from the crankcase. This construction calls for great precision and close tolerances for its assembly in order to achieve a reliable seal between the cylinder head and the duct. An aim of the present invention is to provide a fluid-cooled internal combustion engine of the construction set forth in the opening paragraph wherein the pump housing can be secured easily and rapidly in place while ensuring fluid tight connections. With this aim in view, the invention is directed to an engine of the construction set forth in the opening paragraph in which the cylinder head has a cylindrical opening, and the duct has a cylindrical end region which fits in to the cylinder head opening and is sealed relative to it by an '0'-ring. The fitting of the end of the duct into the cylinder head opening automatically centres the pump housing. The pump housing should be connected to the crankcase by means designed to allow for dimensional tolerances. For example, in a preferred embodiment, a flange on the pump housing is connected to the crankcase by bolts which pass through oversize holes in the flange. In an embodiment described below, the duct is a short circuit duct for returning coolant direct from the cylinder head to the pump by-passing a radiator for cooling the coolant, the pump housing having mounted in it a thermostat disposed in a chamber of the pump housing into which the duct discharges, the thermostat serving to control fluid flow through the duct, the upstream end of the duct being disposed generally at right angles to a plane in which the pump housing joins the crankcase. A preferred embodiment of engine according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, in part, an end of a fluid-cooled internal combustion engine with a pump housing, also shown in part only, secured thereto; and Figure 2 is a section through the pump housing along the line Il-Il in Figure 1. The illustrated fluid-cooled internal combustion engine, which is not shown in detail, comprises a cylinder head 1 and a crankcase 2, to which a pump housing 3 is secured by means of a connecting flange 4. The pump housing 3 accommodates a coolant pump 5 and thermostat, i.e. a thermostatic control insert 7, arranged in an integrated control chamber 6. Integraily formed with the cylinder head 1, i.e. by casting, is a lug 8 which has an outlet opening 9' formed by a cylindrical bore 9. The pump housing is formed with an integral pipe 13 which serves for the return of coolant from the cylinder head direct to the chamber 6, the pipe 13 thus being a shortcircuit duct. An end 11 of the pipe 13 is accommodated in the outer enlarged portion 10 of the bore 9 and is sealed off by means of an O-ring 12.The O-ring need only be small as it does not have to compensate for tolerances, and as shown the ring 12 seats between the outer surface of pipe 1 3 and the inner surface of the cylinder head opening. Also connected to the control chamber 6 is the suction duct 14 of the coolant pump 5. The control chamber 6 is closed off by a cover 1 5 which has an inlet port 16 for collant emanating from a radiator, not illustrated. The connecting flange 4 of the pump housing 3 has three eyes 17. The holes 18 in the eyes 17 for receiving fixing bolts 1 9 are made oversize in order to offset dimensional differences between the cylinder head 1 and the crankcase 2. The end 11 of the pipe 1 3 forming the inlet to the shortcircuit duct is disposed at right angles to the lane 4' of the connecting flange 4. The connecting flange 4 surrounds the outlet 5' of the coolant pump 5, which outlet discharges directly into the water jacket of the crankcase 2. When assembling the internal combustion engine or when carrying out repairs, the pump housing 3 can be very easily fitted, the procedure being as follows: the O-ring 1 2 is fitted on the end 11 of the short-circuit pipe 13 of the pump housing 3, and thus end 11 is pushed into the enlarged portion 10 of the cylindrical bore 9 in the lug 8 of the cylinder head 1. In this way the end 11 is accurately located in the cylinder head 1 and the pump housing 3 simply requires to be aligned with the aid of oversize holes for receiving the fixing bolts 1 9. Then, after interposing an optional seal between the connecting flange 4 and the crankcase 2, the fixing bolts 19 can be pushed through the eyes 1 7 of the flange and can be tightened. CLAIMS

4. An engine according to any preceding claim, in which the duct is a short circuit duct for returning coolant direct from the cylinder head to the pump by-passing a radiator for cooling the coolant, the pump having mounted in it a thermostat disposed in a chamber of the pump housing into which the duct discharges, the thermostat serving the control fluid flow through the duct, the upstream end of the duct being disposed generally at right angles to a plane in which the pump housing joins the crankcase.

5. An engine according to any preceding claim, in which the 'O'-ring seats between an outer surface of a pipe which comprises the duct and an inner surface of the opening in the cylinder head.

6. A fluid-cooled internal combustion engine substantially as described herein with reference to the accompanying drawings.