Claims:We claim:

1. A cooling arrangement for cooling the cylinder head in an Internal combustion engine, wherein water jacket around each cylinder is provided with a cooling tube and a cooling passage for cooling the region between the valve bridge and injector nozzle bore.

2. Cooling arrangement as claimed in claim 1, wherein the cooling tube and cooling passage are linearly connected and the cooling passage is a machined cooling passage.

3. Cooling arrangement as claimed in claim 2, wherein the machined passage is configured between the valves and up to the injector nozzle housing and appropriately profiled to direct the coolant around the water jacket for efficiently cooling the region between the valve bridge and the injector nozzle bore.

4. Cooling arrangement as claimed in claim 2, wherein the cooling tube has a central passage for directing the coolant flow towards the valve bridge area and the injector nozzle bore, a bottom hole for cooling the fire deck and an inclined hole for cooling the area around the exhaust port.

5. Cooling arrangement as claimed in claim 4, wherein the first end of the cooling tube is the guide portion, which is closed by a plug and the front end of the cooling tube is aligned with the inlet of the machined passage.

6. Cooling arrangement as claimed in claim 5, wherein an offset is configured between the guide portion axis and the front-end axis of the cooling tube for ensuring a correct orientation of the cooling tube and to avoid reverse fitting thereof in the water jacket.

7. A cooling arrangement for cooling the cylinder head in an Internal combustion engine, the arrangement comprising:

• the cylinder head made with a water jacket having a lower portion and an upper portion;

• a profiled cooling tube inserted in the lower water jacket for directing the coolant therethrough; and

• a profiled machined passage made between the upper water jacket and the lower water jacket.

8. Cooling arrangement as claimed in claim 7, wherein the profiled cooling tube comprises:

• a guide portion end and front end with a linear cooling passage made therebetween;

• a first hole made at the bottom thereof as an inlet for the incoming coolant;

• a second hole made at the bottom thereof for directing a portion of the coolant towards the fire deck; and

• an inclined hole made for cooling the exhaust port;

wherein an offset is configured between the axis of the guide portion and the axis of the front-end of the cooling tube for ensuring a correct orientation of the cooling tube and to avoid reverse fitting thereof in the water jacket.

9. Cooling arrangement as claimed in claim 8, wherein the first hole allows the coolant entry from the cylinder head water jacket to be delivered to the valve bridge area and passing through the central passage and the machined passage.

10. Cooling arrangement as claimed in claim 8, wherein the wall thickness around the machined passage is at least in the range of 4 to 5 mm, preferably 4.5 mm.

11. Cooling arrangement as claimed in claim 8, wherein the inner diameter of the cooling tube is selected to maintain the velocity of the coolant flowing around the valve bridge area in the range of 1 to 2 m/s, preferably 1.5 m/s.

12. Cooling arrangement as claimed in claim 8, wherein the hole diameter at the front-end of the cooling tube are selected to maintain the velocity of the coolant in the range of 2.0 to 2.5 m/s.

13. Cooling arrangement as claimed in claim 8, wherein the cooling tube thickness is in the range of 1 to 2 mm, preferably 1.5 mm.

14. Cooling arrangement as claimed in claim 8, wherein the outer diameter of the cooling tube and the inner diameter of the corresponding machined passage made in the cylinder head have a radial clearance in the range of 0.02 to 0.05 mm.

15. Cooling arrangement as claimed in claim 8, wherein the inner diameters at the guiding portion end and the front end of the cooling tube are suitably chamfered to ensure a complete opening of cooling tube inner diameter into the machined passage.

Dated: this day of 22nd February, 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to a nozzle cooling tube for an internal combustion engine (ICE). In particular, the present invention relates to a cooling tube for valve bridge and injector nozzle in the cylinder head of an ICE. More particularly, the present invention relates to a cooling tube for valve bridge and injector nozzle in the cylinder head of a heavy-duty diesel engine.

BACKGROUND OF THE INVENTION

The cylinder head is one of the primary components in an internal combustion (IC) engine and the following are the main functions thereof:

• Cylinder head acts as a top cover for the cylinders and seals the combustion gases within the cylinders.

• Cylinder head houses the valve train components such as intake and exhaust valves, valve springs and/or rocker arms and camshafts.

• Cylinder head houses the fuel injector nozzles.

• Cylinder head accommodates the bolts connecting the cylinder heads to the crankcase and transfers the bolt load to cylinder head gaskets.

• Cylinder head accommodates the passages for coolant and oil.

• Cylinder head provides sealing lands for the cylinder head gaskets.

Apart from the abovementioned functions, the cylinder head also supports the components like intake and exhaust manifolds, engine covers, thermostat housings etc. It may also be used as a structural support for several other engine components/parts of the vehicle.

DISADVANTAGES WITH THE PRIOR ART

The face of the cylinder head exposed to the combustion gases (known as the fire deck) and the subsequent cooling passage located above it, are subjected to enormous amounts of mechanical and thermal loads.
In the existing design of the cylinder head, the area between the valves and the injector nozzle (referred to as “valve bridge”) is cooled by conventional cooling passages formed during the casting of the cylinder head.

The valve bridge region has small cross-sections and it is subjected to highest temperatures and pressures, since it is disposed at the center of the cylinder bore. These small cross-sections at the valve bridge have the following disadvantages:

a) Cooling efficiency is reduced in the valve bridge area, thereby affecting the working life and/or efficiency of the valve seats, valves and injector nozzles,

b) Manufacture through casting is made difficult, which leads to higher defect rates of the casted cylinder head, and

c) Due to the limitation to the valve size and structural rigidity required for withstanding the combustion forces acting on the fire deck, it is not possible to increase the cross-section in the valve bridge area.

Therefore, there is an existing need to eliminate the abovementioned disadvantages of the conventional cylinder head design, while at the same time meeting the twin objectives of achieving an efficient cooling and providing sufficient strength/rigidity in the valve bridge region.

OBJECTS OF THE INVENTION

Some of the objects of the present invention satisfied by at least one embodiment of the present invention are as follows:

An object of the present invention is to provide cooling passage for an efficient cooling of the valve bridge area in the cylinder head of an ICE.

Another object of the present invention is to provide cooling passage which provides sufficient strength and rigidity to withstand the combustion forces acting on the fire deck.
Another object of the present invention is to improve the fatigue life of the cylinder head.

Another object of the present invention is to improve the fatigue life of the valves, valve seats and injector nozzles.

Another object of the present invention is to induce sufficient coolant flow around the exhaust port of the cylinder head.

Another object of the present invention is to efficiently cool the injector nozzles in order to reduce its coking and thus to avoid durability issues thereof.

A further object of the present invention is to reduce the complexity of manufacturing process of the cylinder head.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE PRESENT INVENTION

The present invention relates to a heavy-duty diesel engine cylinder head architecture, which involves a cooling tube for cooling the valve bridge and injector nozzles. The invention offers to channel the coolant entering the lower water jacket of the cylinder head via cooling tube and machined passage to the valve bridge area. The cooling tube is inserted into the machined passage in the cylinder head and closed by a respective plug (Figs. 6, 7). The cooling tube has a bottom hole to allow the coolant entry from the cylinder head water jacket. This coolant is subsequently delivered to the valve bridge area through the central hole and the machined passage. The cooling tube has additional holes at the end to direct some of the coolant towards the fire deck and around the exhaust port region for cooling the high temperature regions around this region.
Therefore, the requirement of a cast cooling passage as used in the conventional cylinder heads is completely eliminated and the aforementioned objects of the present invention are successfully achieved.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a cooling arrangement for cooling the cylinder head in an Internal combustion engine, wherein water jacket around each cylinder is provided with a cooling tube and a cooling passage for cooling the region between the valve bridge and injector nozzle bore.

Typically, the cooling tube and cooling passage are linearly connected and the cooling passage is a machined cooling passage.

Typically, the machined passage is configured between the valves and up to the injector nozzle housing and appropriately profiled to direct the coolant around the water jacket for efficiently cooling the region between the valve bridge and the injector nozzle bore.

Typically, the cooling tube has a central passage for directing the coolant flow towards the valve bridge area and the injector nozzle bore, a bottom hole for cooling the fire deck and an inclined hole for cooling the area around the exhaust port.

Typically, the first end of the cooling tube is the guide portion, which is closed by a plug and the front end of the cooling tube is aligned with the inlet of the machined passage.

Typically, an offset is configured between the guide portion axis and the front-end axis of the cooling tube for ensuring a correct orientation of the cooling tube and to avoid reverse fitting thereof in the water jacket.

In accordance with the present invention, there is also provided a cooling arrangement for cooling the cylinder head in an Internal combustion engine, the arrangement comprising:
• the cylinder head made with a water jacket having a lower portion and an upper portion;

• a profiled cooling tube inserted in the lower water jacket for directing the coolant therethrough; and

• a profiled machined passage made between the upper water jacket and the lower water jacket.

Typically, the profiled cooling tube comprises:

• a guide portion end and front end with a linear cooling passage made therebetween;

• a first hole made at the bottom thereof as an inlet for the incoming coolant;

• a second hole made at the bottom thereof for directing a portion of the coolant towards the fire deck; and

• an inclined hole made for cooling the exhaust port;

wherein an offset is configured between the axis of the guide portion and the axis of the front-end of the cooling tube for ensuring a correct orientation of the cooling tube and to avoid reverse fitting thereof in the water jacket.

Typically, the first hole allows the coolant entry from the cylinder head water jacket to be delivered to the valve bridge area and passing through the central passage and the machined passage.

Typically, the wall thickness around the machined passage is at least in the range of 4 to 5 mm, preferably 4.5 mm.

Typically, the inner diameter of the cooling tube is selected to maintain the velocity of the coolant flowing around the valve bridge area in the range of 1 to 2 m/s, preferably 1.5 m/s.

Typically, the hole diameter at the front-end of the cooling tube are selected to maintain the velocity of the coolant in the range of 2.0 to 2.5 m/s.

Typically, the cooling tube thickness is in the range of 1 to 2 mm, preferably 1.5 mm.

Typically, the outer diameter of the cooling tube and the inner diameter of the corresponding machined passage made in the cylinder head have a radial clearance in the range of 0.02 to 0.05 mm.

Typically, the inner diameters at the guiding portion end and the front end of the cooling tube are suitably chamfered to ensure a complete opening of cooling tube inner diameter into the machined passage.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows perspective view of a conventional cylinder head of a 4-cylinder automobile engine.

Figure 2 shows the top view of the cylinder head of Figure 1 representing a section line A-A cutting the cylinder head of the IC engine along Y axis thereof.

Figure 3 shows a cross-sectional view of the conventional cylinder head of Figure 2 sectioned along section line A-A depicting the cooling passages around the valve bridge and the injector nozzle area.

Figure 4 shows another sectional view of the cylinder head of Figure 1 with its area around the valves and the injector bore thereof.

Figure 5 shows a conventional configuration of the water jacket and the coolant flow pattern around the valve bridge and the injector bore area in the cylinder head of Figure 1.
Figure 6 shows a sectional view of the cylinder head configured in accordance with the present invention provided with the water jacket with the cooling tube for cooling the valve bridge and the injector nozzle area.

Figure 7 shows an enlarged view of the valve bridge and injector nozzle bore area depicted in Figure 6.

Figure 8 shows the tube construction and the position of the cooling tube inserted inside the cylinder head of Figure 6.

Figure 9a shows constructional details of the injector nozzle cooling tube of Figure 6 depicting the position of holes used for cooling the valve bridge, fire deck and injector nozzle bore.

Figure 9b shows the constructional details of the cooling tube assembly configured in accordance with the present invention.

Figure 10a shows the constructional details of the injector nozzle cooling tube of Figure 9a depicting the position of holes used for cooling the injector nozzle bore.

Figure 10b shows the constructional details of the injector nozzle cooling tube of Figure 9a depicting the position of holes used for cooling the valve bridge.

Figure 11a shows the constructional details of the guidance bore for injector nozzle bore cooling tube of the cooling tube assembly of Figure 9b configured for ensuring a correct orientation of cooling hole on the cooling tube.

Figure 11b shows the constructional details of the cooling tube configured for the cooling tube assembly of Figure 9b.

Figure 11c shows further constructional details of the cooling tube assembly of Figure 9b to ensure an interference in case of a reverse fitment thereof.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows perspective view of a 4-cylinder automobile engine with a conventional cylinder head 10 including a top section 12 for enclosing the valve train and rocker cover and a bottom section 14 with cooling jacket 16 and the fire deck 18. The cylinder head 10 provides a housing for enclosing the valve train, rocker cover and breather system.

Figure 2 shows the top view of the cylinder head 10 of Figure 1 representing a section line A-A cutting it along the Y axis thereof and providing the valve train components and injectors.

Figure 3 shows a cross-sectional view of the conventional cylinder head 10 of Figure 2 sectioned along section line A-A depicting the cooling passages 20 around the valve bridge 30 and the injector nozzle bore area 40. It depicts the water jacket 16 around the valve bridge 30 and injector nozzle bore area 40 disposed in a vertical direction.

Figure 4 shows another sectional view of the cylinder head of Figure 1 with its area around the intake port 50 and exhaust port 60 of the corresponding valves and the injector nozzle bore area 40 thereof in a horizontal direction. It depicts the cooling jacket 16 in the cylinder head 10 to ensure the cooling of the fire deck 18 and the valve bridge 30.

Figure 5 shows a conventional configuration of the water jacket 16 and the coolant flow pattern formed in the cooling passage 20 configured around the valve bridge 30 and the injector nozzle bore area 40 in the cylinder head 10 of Figure 1. It depicts the cast narrow passage 32 to ensure cooling around the valve bridge 30 and the injector nozzle bore area 40. The arrows show the flow path of the coolant coming in from the coolant jacket 16.

Figure 6 shows a sectional view of the cylinder head 100, which is configured with water jacket 116 in accordance with the present invention and provided with cooling tube 180 for cooling the valve bridge 130 and the injector nozzle area 140 by means of the cooling passage 120 configured around the same. The machined passages 170 are formed in the injector nozzle bore area 140, i.e. into the lower water jacket 116 of the cylinder head 100. Respective cooling tubes 180 are inserted into machined passages 170 in the lower water jacket. The cooling tubes eliminate the process criticality and ensure proper cooling of valve bridge and nozzle bore area.

Figure 7 shows an enlarged view of the region around the valve bridge 130 and injector nozzle bore area 140 depicted in Figure 6.

Figure 8 shows the tube construction and the position of the cooling tube inserted inside the cylinder head 100 in the lower water jacket 116 thereof. This cooling tube 180 construction ensures proper cooling of the cylinder head 100 especially in the areas of the valve bridge 130 and the injector nozzle bore area 140. Each cooling tube 180 is inserted into a respective machined passage 170 in the lower water jacket 116 and closed by a respective plug 175 (not shown).

Figure 9a shows the constructional details of the injector nozzle cooling tube 180 depicting the position of the holes and alignment with the cylinder head lower water jacket 116. The coolant enters the water jacket 116 from the bottom thereof and channeled into the cooling tube 180 through the hole 200. The coolant is further channeled and directed through the central passage 182 of the tube 180 towards the valve bridge 130 and injector nozzle bore area 140 and then passed through the machined passages 170 into the upper water jacket 126. This results in an effective cooling of the valve bridge 130 and the injector bore 140. Some of the coolant also flows through a hole 184 made near the front end of the cooling tube 180 and runs towards the fire deck 118 for cooling thereof.

Figure 9b shows the constructional details of the cooling tube assembly 180 configured in accordance with the present invention. It includes a central passage 182 for directing the flow towards valve bridge area 130 and injector nozzle bore area 140, a bottom hole 184 for cooling the fire deck 118 and an inclined hole 186 for cooling the area around the exhaust port 160 (Figure 7).

Figure 10a shows the constructional details of the injector nozzle cooling tube 180 of Figure 9a depicting the coolant flow through the central passage 182 towards the valve bridge 130 and injector nozzle bore 140. An inclined hole 186 is also provided directing the coolant flow towards the area around exhaust port 160 and the arrows indicate the coolant flow pattern to achieve effective cooling thereof.

Figure 10b shows the constructional details of the injector nozzle cooling tube 180 of Figure 9a depicting the coolant flow through the central passage 182 towards the valve bridge 130 and injector nozzle bore 140 and a hole 184 directing the coolant flow towards the fire deck 118 and the arrows indicate the coolant flow pattern for achieving effective cooling thereof.

Figure 11a shows the constructional details of the guidance bore 188 for injector nozzle bore cooling tube 180 of the cooling tube assembly of Figure 9b and another bore 190 configured at the other end for supporting the end of the injector nozzle cooling tube 180, both bores are configured to ensure correct orientation of the cooling hole on the cooling tube.

Figure 11b shows the constructional details of the cooling tube 180 configured for the cooling tube assembly of Figure 9b. There is an offset 192 configured between axis C1 of the guide portion 194 and axis C2 of the front end 196 of the cooling tube 180. This offset ensures the correct orientation of the tube 180 as explained in Figure 11c.

Figure 11c shows the constructional details of the cooling tube assembly of Figure 9b to ensure an interference 198 in case of a reverse fitment thereof. Here, the offset 192 configured between the guide portion 194 and the front end 196 of the cooling tube 180 (Fig. 11b) ensures correct orientation of the cooling hole on the cooling tube 180.

WORKING OF THE INVENTION:

With the water jacket 116 made with the cooling tube 180 and the machined passage 170 configured in accordance with the present invention, it is possible to properly configure the region of the cylinder head 100 around the valve bridge 130 and the injector nozzle bore 140 according to the following analysis conducted by the applicant:

• Analyzing the coolant passage to estimate the coolant velocity, pressure drop and heat transfer co-efficient in the surrounding regions, and

• Estimating the fatigue factors of safety in the region around the valve bridge.

This results in an optimal design for ensuring sufficient structural strength and rigidity as well as excellent coolant flow characteristics in the new configuration.

Although, the present invention is disclosed and explained in terms of the cooling tube for valve bridge and injector nozzle cooling in IC engine cylinder head, the same idea can be extended to similar applications with small cross-sections and coolant circulation is necessary therein.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The water jacket with the cooling tube and machined passages configured in accordance with the present invention for cooling the valve bridge and injector nozzle bore area has the following advantages:

• Ensures an efficient cooling in the valve bridge area and injector nozzle bore area.

• Improves the durability and service life for the component by keeping the operating temperature lower.

• Increases the ease of manufacture of the cylinder head.

• Improves stiffness and rigidity of the cylinder head in the valve bridge area.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept.

Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

It is to be understood that the phraseology or terminology employed herein is for the purpose of description and the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the above description.
The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in accordance with the present invention.

Therefore, while the embodiments herein have been described in terms of preferred embodiments, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments described herein and can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.