FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Cylinder head for two cylinder IC engine
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Narendra Kumar Jain, Hemant Ambadas Malekar
Kedar Digambar Gokhale & Sameer Madhukar Nagarkar all Indian nationals
of TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification describes the invention

FIELD OF INVENTION:
This invention relates to IC engine and more particularly this relates to cylinder head with mechanical bucket tappets used for two cylinder, inline, four stroke, Gasoline / LPG / CNG / Ethanol / Methanol / Multi point fuel injection / Gasoline direct injection, reciprocating piston, naturally aspirated / supercharged / turbocharged / turbocharged inter-cooled and single overhead camshaft engine, intended for passenger car, light commercial vehicle and other transport / mobility / stationary applications.
BACKGROUND OF INVENTION:
Conventionally, not many of the passenger cars & light commercial vehicles are powered with inline, two cylinder, four stroke reciprocating piston internal combustion engine fueled with Gasoline / LPG / CNG / Ethanol / Methanol. Though very few engines with such configuration are available, the cylinder head of these engines are not optimized for low cost, compact in size, low weight, lower oil consumption & low blow-by / ventilation gases.
OBJECTS OF THE INVENTION:
A) The main object of the invention is to have inline, two cylinder, low pressure die cast/ gravity die cast, aluminium cylinder head with following features:
1) Suitable for inline, two cylinder application.
2) Suitable for housing two valves per cylinder head with mechanical bucket tappet.
3) Capable of housing single overhead camshaft.
4) Capable of housing two fuel injectors and fuel rail.
5) Single main oil gallery supplying oil to three camshaft bearings.
6) Dedicated blow-by / ventilation passages on front and rear sides.
7) Capable of housing low oil pressure switch.
8) Having provision for mounting intake manifold with throttle body.


9) Having provision for mounting exhaust manifold.
10) Capable of mounting timing belt tensioner.

B) To have the cylinder head for two cylinder internal combustion engine which can be manufactured with gravity die casting process or alternatively with low pressure die casting process.
C) To have cylinder head for inline, two cylinder internal combustion engine adoptable for various alternate fuels viz. Gasoline, Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG), Ethanol, Methanol for single fuel / bi fuel operation.
D) To have cylinder head for an internal combustion engine with reduced NVH and low pass by noise level when assembled on passenger cars, light commercial vehicles and other transport / mobility / stationary applications.
E) To have cylinder head for an internal combustion engine that can be naturally
aspirated, selectively supercharged / turbocharged and/or inter-cooled depending
upon the application.
F) To have cylinder head for two cylinder internal combustion engine with blow-by /
ventilation gases circuit optimized for 0-360 firing order of pistons.
G) To have cylinder head for an internal combustion engine with minimum usage of
material, least cost, compact and light weight.
H) To have cylinder head for two cylinder internal combustion engine with positive crankcase ventilation system & reduced pressure fluctuations in cylinder crankcase specifically for 0-360 firing order of pistons.


I) To have cylinder head for an internal combustion engine with rear end closed for reduced oil leakage.
BRIEF DESCRIPTION OF INVENTION:
The novel inline, two cylinder, low pressure die cast / gravity die cast cylinder head with two valves per cylinder housing single overhead camshaft, fuel injectors & fuel rail is designed for following innovative features:
The shape of the cylinder head designed such that minimum material is used for the casting, with minimum possible wall thickness around coolant jacket, oil jacket, combustion chamber and camshaft housing. The shape of the cylinder head is probably smallest in size while meeting all performance requirements. It is also optimized low cost small size cylinder head cover. The cylinder head bolts are outside the top profile which results in their shorter length. The machined faces of the cylinder head are designed for minimum machining setting for reduced machining costs. The cylinder head is designed for the low cost and weight.
The cylinder head is designed for housing single overhead camshaft with mechanical bucket tappets, so as to reduce number of components in cylinder head assembly & valve train, there by reducing the part counts, cost & improving the reliability of the system.
The injectors are directly mounted on cylinder head as against the conventional method of mounting the injectors on intake manifold. The cooling passages surrounding injectors are optimized in such way that the injectors are cooled & no vapor locks are formed in hot condition. This arrangement provides better emissions due to proper injector spray targeting & reduced wall wetting & also provides better fuel economy & lower CO2 emissions. Direct mounting of injectors on cylinder head has made it possible to control injector position precisely there by greater consistency in the performance & less variation in performance in production.
The said cylinder head is specifically designed for reduction in the blow-by / ventilation gases from inline, two cylinder internal combustion engine, with 0-360 firing order. The


oil return passage is separated from blow-by / ventilation gases to avoid mixing of the two, and hence reducing the engine oil consumption. The blow-by / ventilation gases passage in the cylinder head. It is capable of housing the oil separating baffle plate, if required, for further reduction of blow-by gases. The reed valve provided in the blow-by circuit at the cylinder head top face helps to maintain negative crankcase pressure in the cylinder crankcase which required by regulation in gasoline engines. The rear end of the cylinder head is completely closed for reduction of oil / blow-by ventilation gases leakage to atmosphere. Due to closed rear end, the requirement of sealing plug at the rear is avoided. This results in reduction of machining & component costs & rejection at assembly line.
The intake & exhaust port location, size & shape is optimized to get better torque, power, emissions & fuel economy.
Combustion chamber shape, valve locations, valve sizes & the spark plug position is optimized using in cylinder CFD analysis so that almost complete burning of charge takes place, reduced emissions, better fuel economy, low CO2 emissions & reduced knocking tendency.
The coolant entry into cylinder head, the hole shape, size, numbers & locations are optimized for effective cooling of the combustion chamber, spark plug, injectors, valve seats & exhaust ports. The size of water core is optimized low cost
The oil cores in the cylinder head are optimized for proper oil supply to cam bearings, bucket tappet & return of oil back to oil sump. The oil cores shape is optimized so that no dead oil pockets are formed inside the cylinder head.
DETAILED DESCRIPTION OF INVENTION:
Referring now to the drawings wherein the showings are for the purpose of illustrating
a preferred embodiment of the invention only, and not for the purpose of limiting the
same,
Figure 1 shows an isometric view of cylinder head, looking from the front & left hand
side


Figure 2 shows an isometric view of cylinder head looking from the front & right hand side,
Figure 3 shows an isometric view of cylinder head looking from the rear & right hand side,
Figure 4 shows an isometric view of cylinder head looking from rear & left hand side,
Figure 5 shows an isometric view of cylinder head looking from top side,
Figure 6 shows an isometric view of cylinder head looking from bottom side,
Figure 7 shows sectional view of cylinder head through centerline of camshaft,
Figure 8 shows sectional view of cylinder head through intake port,
Figure 9 shows sectional view of cylinder head through exhaust port,
Figure 10 shows supply of oil to main oil gallery,
Figure 11 shows delivery of oil from main oil gallery to camshaft bearings,
Figure 12 shows sectional view of cylinder head through coolant temperature sensor housing,
Figure 13 shows sectional view of cylinder head through thermostat valve housing.
Now with reference to figures,
Figure 1 shows exhaust manifold mounting face (1), Housing for nipple for radiator coolant inlet hose (2) , Interface for timing belt tensioner mounting (3), Interface for timing cover mounting (4), Interface for lifting hook mounting (5), Cylinder head mounting bolt hole (6)


Figure 2 Interface for mounting thermostat valve & thermostat cover (7), Boss for mounting coolant temperature sensor (8), Intake manifold mounting face (9), Interface for mounting lifting hook rear (10), Interface for mounting dipstick bracket (11), Front camshaft cap seal housing (12), Opening for Main coolant flow circuit in thermostat cover (13).
Figure 3 shows main oil gallery (14), Interface for mounting fuel rail (15), Fuel injector housing (16), Bosses for mounting throttle body support bracket (17), Low oil pressure switch housing (18), Oil supply gallery from cylinder crankcase to main oil gallery (19), Cylinder head mounting bolt hole (20).
Figure 4 shows Spark plug housing (21), Camshaft housing which follows the contour of cam lobe for complete rotation of camshaft (22), Blow-by / ventilation gases opening for cylinder head cover (23).
Figure 5 shows Front camshaft bearing (24), Oil return passage (25), Tappet bore (26), Valve guide bore (27), Cylinder head top profile with interface for mounting cylinder head cover, reed plate & camshaft caps (28), Spring seat housing (29), Oil groove for camshaft bearings (30), Threaded hole for mounting reed plate in blow-by / ventilation gases circuit (31).
Figure 6 shows Blow-by / ventilation gases passage opening to cylinder crankcase (32), Intake valve seat insert housing (33), Coolant jacket entry holes (34), Squish type combustion chamber (35), Exhaust valve seat insert housing (36), Coolant outlet for heater take off (37), Oil return passage opening to cylinder crankcase (38), Spark plug opening in combustion chamber (39).
Figure 7 indicates cross section showing Oil return passage (40), Exhaust port for first cylinder (41), Intake port for first cylinder(42), Coolant jacket between intake & exhaust port (43), Blow-by / ventilation gases passage (44), Valve guide bore for second cylinder (45), Tappet bore for first cylinder (46), Oil drain passage (47).


Figure 8 shows cross sectional view through intake port. It shows Coolant jacket around intake port (48), Intake port (49), Fuel injector housing (50), Main oil gallery (51), Valve spring seat housing (52), Contour of camshaft housing (53).
Figure 9 shows cross sectional view through exhaust port. It shows Coolant jacket around exhaust port (54), Oil jacket around exhaust port & valve guide bore (55), Exhaust port (56).
Figure 10 shows arrangement of oil supply to main oil gallery. It shows Oil supply hole from cylinder crankcase to main oil gallery (57) and Main oil gallery (58).
Figure 11 shows Coolant jacket around spark plug (59), Threaded hole for camshaft cap mounting (60), Camshaft bearing (61), Oil delivery hole from main oil gallery to camshaft bearing (62), Main oil gallery (63).
Figure 12 shows Coolant outlet for heater take off / water pump (64), Coolant temperature sensor mounting (65).
Figure 13 shows Housing for single acting thermostat valve (66), Coolant passage for main coolant flow circuit to radiator (67), Housing for nipple for radiator coolant inlet hose (68).