FIELD OF INVENTION:-
The present invention is related to the cylinder head of an engine. More particularly the present invention is related to the light weight cylinder head structures with internal EGR passage for an internal combustion engine.
BACKGROUND OF THE PRESENT INVENTION:-
With two valves per cylinder and single over camshaft configuration of the engine, the cylinder head stiffness will be non uniform. It will be stiff in the oil room area and weak in other areas. Strengthening the cylinder head will ask for addition of lot of material and this will increase the cost. Due to non uniform stiffness of the cylinder head, sealing pressure of cylinder head bolt load will not be uniform over the cylinder head gasket bead around cylinder bore. This calls for topography of welded stopper around cylinder bore. This also increases the cost. To solve the problem of weight addition and low stiffness, cylinder head design has been optimized with ribs and weight reduction concepts.
The existing cylinder heads with 2 valves per cylinder have a weight of at least 1.5 times of the weight of the cylinder head disclosed in the present invention. Compromising the cylinder head stiffness and using topography in the cylinder head gasket for welded stopper to get uniform distribution of bolt load around cylinder bore.
OBJECT OF INVENTION:-
It is object invention to make light weight cylinder reducing weigh by providing weight reduction pocket at less loaded areas with strengthening by means ribs.
It is also object of invention to optimize volume water jacket for effective cooling. It is also object invention to provide ribs for effective transfer of bolt load from bolt boss to fire deck and middle deck.
It is also another object of invention to provide internal EGR passage.

STATEMENT OF 1NVENTION:-
Accordingly the invention provides a light weight cylinder head with internal EGR passage for an internal combustion engine provided with improvements comprising:-
a. ribs provided for effective transfer of bolt load from bolt boss to fire
deck and middle deck;
b. the said ribs are connected diagonally from bolt boss to middle deck
and fire deck of cylinder head;
c. provided with weight reduction pocket at less loaded areas;
d. provided with ribs and inserts with internal EGR passage; and
e. Optimized volume of water jackets which imparts the technical
advantage of weight reduction without deviating from the performance
output.
BRIEF DESCRIPTION OF THE F1GURES:-
Figure 1 and Figure 2 shows the perspective view of the cylinder head.
Figure 3 shows the assembly view of the cylinder head in accordance with the present invention.
Figure 4 shows the sectional view of the cylinder head showing the ribs in lower oil core to support cylinder head bolt load.
Figure 5 shows the sectional view of the cylinder head showing the cooling passage, intake port and exhaust port of the engine.
Figure 6 shows the sectional view of the cylinder head showing weight reduction pockets and ribs in water jacket to support bolt load.
Figure 7 shows the sectional view of the cylinder head showing weight reduction pockets in accordance with the present invention.

Figure 8 shows the sectional view of the cylinder head with EGR passage and water jacket in accordance with the present invention.
Figure 9 shows the sectional view of the cylinder head with stiff bolt bosses to take cylinder head bolt load.
Figure 10 shows the sectional view of the cylinder head with horizontal rib connecting all the bolt bosses together.
Figure 11 shows bottom view of the cylinder head disclosing oil drain passage, blow by passage and weight reduction pockets in accordance with the present invention.
Figure 12 shows the temperature plot for fire deck temperatures
DESCRIPTION OF THE INVENTION:-
An Innovative design of Ultra Low Weight Cylinder head with internal EGR passage for an internal combustion engine addresses the various weight reduction concepts followed to make light weight cylinder head which is manufactured in aluminum. The cylinder head for two valves per cylinder engine configuration has been designed for diesel application. The said cylinder head has been reinforced with ribs wherever required and weight reduction pockets provided at less loaded areas. Referring to the figure 4 the cylinder head showing the ribs in lower oil core to support cylinder head bolt load. The water jacket volume has been optimized in such a way that the fire deck is cooled effectively and the strength of fire deck is sufficient to take care of firing loads. Referring to Figure 5 which shows the sectional view of the cylinder head showing the cooling passage, intake port and exhaust port of the engine.
Referring to figure 6 which shows the sectional view of the cylinder head showing weight reduction pockets and ribs in water jacket to support bolt load. The cylinder head weiaht reduction done bv Droviding weight reduction pockets as shown in figure 7.The figure 11 also shows weight reduction features with

disclosing oil drain passage, blow by passage and weight reduction pockets in accordance with the present invention.
The purpose of bolt force is to seal the top face of cylinder block against combustion loads. So, effective transfer of bolt force from bolt bosses to fire deck and middle deck is necessary for proper sealing. The bolt force from bolt bosses is not transferred to the middle of cylinder bore as there are no connecting members from bolt boss to fire deck and middle deck. As there is no restraining force acting on middle deck and fire deck, they are deforming under combustion loads. This leads to high stresses in cylinder head and leakage of combustion gases. Hence ribs are required for effective transfer of bolt load from bolt boss to fire deck and middle deck.
Referring to figure 9 which shows the sectional view of the cylinder head with stiff bolt bosses to take cylinder head bolt load.
Ribs are connected diagonally from bolt boss to middle deck and fire deck of cylinder head. These ribs start from bolt boss and end at the middle of cylinder bore where combustion load is acting on cylinder head. So the bolt load is transferred via ribs from cylinder head bolt boss to middle of cylinder bore where combustion load is acting. As these ribs are stiff, they will not allow the fire deck to deform under combustion loads and they will transfer bolt loads effectively from bolt boss to fire deck resulting in effective sealing and low stresses in cylinder head. The features are clear from the figure 10 which shows the sectional view of the cylinder head with stiff bolt bosses to take cylinder head bolt load.
The unique feature of the present invention is providing cylinder head with ribs and inserts with internal EGR passage and optimized water jackets which imparts the technical advantage of weight reduction without deviating from the performance output. The figure 8 shows the sectional view of the cylinder head with EGR passage and water jacket in accordance with the present invention.

The weight of the ultra low weight cylinder head with internal EGR (Exhaust gas recirculation) passage of the present invention is 26% to 40% less than prior art cylinder heads of the same category available in public domain. Referring to Fig. 12, the maximum temperature on bottom face of the cylinder head is 248 degree centigrade. The safe working limit is 260 degree centigrade. Thus, the effective cooling of the fire deck is achieved.

WE CLAIM:-
1. A light weight cylinder head with internal EGR passage for an internal
combustion engine provided with improvements comprising:-
a. ribs provided for effective transfer of bolt load from bolt boss to fire
deck and middle deck;
b. the said ribs are connected diagonally from bolt boss to middle deck
and fire deck of cylinder head;
c. provided with weight reduction pocket at less loaded areas;
d. provided with ribs and inserts with internal EGR passage; and
e. Optimized volume of water jackets which imparts the technical
advantage of weight reduction without deviating from the performance
output.
2. The light weight cylinder head as claimed in claim 1 wherein the said ribs start from bolt boss and end at the middle of cylinder bore where combustion load is acting on cylinder head so that the bolt load is transferred via ribs from cylinder head bolt boss to middle of cylinder bore where combustion load is acting.
3. The light weight cylinder head as claimed in claims 1 and 2 wherein the said optimized volume of water jacket is made capable of cooling the fire deck effectively and the strength of fire deck is sufficient to take care of firing loads.