GB1564692A - Cooling circuit for the cylinder heat of an internal combustion engine - Google Patents

Description

(54) COOLING CIRCUIT FOR THE CYLINDER HEAD OF AN INTERNAL COMBUSTION ENGINE (71) We, FIAT SOCIETA PER AZIONI, an Italian joint stock company, of Corso Marconi, 10, Turin, Italy do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an improvement in a cooling circuit for the cylinder head of an internal combustion engine of the type cooled by forced circulation of liquid coolant and particularly, but not exclusively, to such an improvement for a Diesel engine.

Various systems have been developed to increase the efficiency of the cooling circuits of internal combustion engines in order to ensure the perfect operation of the engines and to prolong the life of the various components. One such system involves pumping coolant, by means of a known centrifugal pump, to the lower part of the cylinders and then letting it rise to the cylinder head. This solution is, however, rather ineffective, especially in Diesel engines, which have very high and rapidly fluctuating working temperatures.

In order to overcome this difficulty, in the prior art the coolant is passed directly to the cylinder head and, after having performed its cooling function, is withdrawn, by forced re-circulation by means of a pump, through a suitable conduit located adjacent the row of cylinders.

It is found, however, that coolant stagnates in the portion of the said conduit, corresponding to the part of the cylinder head farthest from the pump, and consequently fails to recycle, preventing completion of the required cooling. This results in various problems after the engine has been working for a short time, such as cracking of the valve seats and a thermal imbalance which causes the deposition of calcareous sediments on those components which, together with the combustion chambers, are more exposed to the high temperatures of the thermal cycle.

The object of the present invention is to eliminate these serious problems and to ensure the necessary degree of cooling efficiency for the whole of the cylinder head, by means of a simple machining operation on the coolant conduit which can be effected without any great alteration in the manufacturing costs and without the addition of further accessories.

According to the present invention there is provided a cooling circuit for the cylinder head of an internal combustion engine of the type cooled by forced circulation of liquid coolant in the circuit by a pump supplying the liquid coolant directly to the coolant space of the cylinder head wherein the circuit further comprises a duct disposed in the region of the cylinder head at which a pair of valve seats of each cylinder is located and conduits connecting said ducts to the pump so that in use coolant is also drawn by the pump through the ducts and from the cylinder head through the conduits and returned to the coolant space of the cylinder head.

The rapid and intense re-cycling of the coolant due to the forced circulation and the addition to the traditional installation of the ducts and conduits communicating with the water pump is able to ensure thorough cooling.

One embodiment of the invention will now be more particularly described, by way of example, with reference to the attached, purely diagrammatic drawing, which is a plan view of the cylinder heads and cooling circuit of an internal combustion engine.

Referring to the diagram, a cylinder head assembly of an internal combustion engine is shown, generally indicated 14, in which exhaust valve seats 1, 2, 3, 4 and corresponding inlet valve seats, 5, 6, 7, 8 respectively, located in the upper part of the four cylinders of the engine, are indicated diagrammatically.

The assembly 14 is connected into the normal cooling circuit of the engine by means of a conduit 13 which opens into a valve chamber 24 containing a thermostat 11. A further conduit 12 opens from the conduit 13 into a radiator 9 which is itself connected to the chamber 24 by means of a conduit 10.

The thermostat is arranged to operate a valve which allows cold coolant (water) flowing from the assembly 14 through the conduit 13 to flow directly into the chamber 24, bypassing the radiator 9, but which closes the outlet from the conduit 13 into the chamber 24 when the water becomes hot, forcing the water to circulate through the radiator 9 to be cooled therein before entering the valve chamber 24.

The normal cooling circuit is completed by a pump inlet conduit 13a which conducts water from the chamber 24 to the low pressure side of a pump 1S, comprising a rotary impeller 16, arranged to pump water into the cylinder head assembly 14 to cool the cylinder head by forced circulation of water.

The engine may have an inlet manifold with a water jacket, in which case the manifold jacket could be connected to the pump inlet conduit 13a.

In addition to the normal cooling circuit for the cylinder head, described above, ducts 17, 18, 19, 20 and conduits 21, 22, 23 are provided in accordance with this invention for recirculating part of the water from the assembly 14 to the low pressure side of the pump 1S to improve the cooling efficiency of the system. Accordingly, the ducts 17, 18, 19, 20 lead from the assembly 14 and are located between respective pairs of inlet and exhaust valve seats 1-5, 2-6, 3-7 and 4-8, the ducts 17, 18 opening into the conduit 21 which leads into the inlet conduit 13a, and the ducts 19, 20 opening into the conduit 23 which leads into a conduit 22 connected to the inlet conduit 13a.

In use of the engine, the low pressure in the conduits 22, 23, due to the operation of the pump 13, causes water to be drawn through the ducts 17, 18, 19, 20 from the cylinder head assembly 14. The water thence passes into the inlet conduit 13a through the conduits 21 and 23, 22 respectively, to be recirculated back into the assembly 14 by the pump 15, as shown by the arrows in the drawing.

The present invention thus provides a simple, practical and economical device which increases the cooling efficiency of the cooling circuit of an internal combustion engine having forced coolant circulation.

WHAT WE CLAIM IS: 1. A cooling circuit for the cylinder head of an internal combustion engine of the type cooled by forced circulation of liquid coolant in the circuit by a pump supplying the liquid coolant directly to the coolant space of the cylinder head wherein the circuit further comprises a duct disposed in the region of the cylinder head at which a pair of valve seats of each cylinder is located and conduits connecting said ducts to the pump so that in use coolant is also drawn by the pump through the ducts and from the cylinder head through the conduits and returned to the coolant space of the cylinder head.

2. A cooling circuit according to Claim 1, in which each said duct is interposed between the inlet and the exhaust valve seats of a respective pair of valve seats.

3. A cooling circuit for the cylinder head of an intemal combustion engine of the type cooled by forced circulation of liquid coolant in a circuit including a pump supplying the liquid coolant directly to the cylinder head, substantially as herein described with reference to, and as shown in, the accompanying drawing.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. The thermostat is arranged to operate a valve which allows cold coolant (water) flowing from the assembly 14 through the conduit 13 to flow directly into the chamber 24, bypassing the radiator 9, but which closes the outlet from the conduit 13 into the chamber 24 when the water becomes hot, forcing the water to circulate through the radiator 9 to be cooled therein before entering the valve chamber 24. The normal cooling circuit is completed by a pump inlet conduit 13a which conducts water from the chamber 24 to the low pressure side of a pump 1S, comprising a rotary impeller 16, arranged to pump water into the cylinder head assembly 14 to cool the cylinder head by forced circulation of water. The engine may have an inlet manifold with a water jacket, in which case the manifold jacket could be connected to the pump inlet conduit 13a. In addition to the normal cooling circuit for the cylinder head, described above, ducts 17, 18, 19, 20 and conduits 21, 22, 23 are provided in accordance with this invention for recirculating part of the water from the assembly 14 to the low pressure side of the pump 1S to improve the cooling efficiency of the system. Accordingly, the ducts 17, 18, 19, 20 lead from the assembly 14 and are located between respective pairs of inlet and exhaust valve seats 1-5, 2-6, 3-7 and 4-8, the ducts 17, 18 opening into the conduit 21 which leads into the inlet conduit 13a, and the ducts 19, 20 opening into the conduit 23 which leads into a conduit 22 connected to the inlet conduit 13a. In use of the engine, the low pressure in the conduits 22, 23, due to the operation of the pump 13, causes water to be drawn through the ducts 17, 18, 19, 20 from the cylinder head assembly 14. The water thence passes into the inlet conduit 13a through the conduits 21 and 23, 22 respectively, to be recirculated back into the assembly 14 by the pump 15, as shown by the arrows in the drawing. The present invention thus provides a simple, practical and economical device which increases the cooling efficiency of the cooling circuit of an internal combustion engine having forced coolant circulation. WHAT WE CLAIM IS:

1. A cooling circuit for the cylinder head of an internal combustion engine of the type cooled by forced circulation of liquid coolant in the circuit by a pump supplying the liquid coolant directly to the coolant space of the cylinder head wherein the circuit further comprises a duct disposed in the region of the cylinder head at which a pair of valve seats of each cylinder is located and conduits connecting said ducts to the pump so that in use coolant is also drawn by the pump through the ducts and from the cylinder head through the conduits and returned to the coolant space of the cylinder head.

2. A cooling circuit according to Claim 1, in which each said duct is interposed between the inlet and the exhaust valve seats of a respective pair of valve seats.

3. A cooling circuit for the cylinder head of an intemal combustion engine of the type cooled by forced circulation of liquid coolant in a circuit including a pump supplying the liquid coolant directly to the cylinder head, substantially as herein described with reference to, and as shown in, the accompanying drawing.