FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
A novel crank case for Inline 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 & Laus Deo Lynd 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 Internal combustion engine and more particularly this relates to Crank case for inline two cylinder internal combustion engine and further more particularly to a two cylinder inline, four stroke, Gasoline / Diesel / LPG / CNG / Ethanol / Methanol / Gasohol, Multi Point Fuel Injection / Gasoline and Diesel Direct Injection, reciprocating pistons, naturally aspirated / supercharged / Turbocharged / Turbocharged intercooled, and single / double overhead camshaft engine intended for passenger car, light commercial vehicle and other transport / mobility / stationary applications.
BACKGROUND OF INVENTION:
Conventionally most of the passenger cars and light commercial vehicles are powered by 3 or 4 cylinder, internal combustion, four stroke, and reciprocating piston engines with diesel, gasoline or other suitable alternate fuel having conventional cylinder crankcase. Whereas no engine in two cylinder inline configuration along with primary balancer shaft having inline two cylinder open deck, deep skirt, high pressure die cast crankcase housing single primary balancer shaft, with suitable interface at front for integral oil & water pump and separate blow by and oil return passage at rear and or front of cylinder crankcase used on cars and or for stationary application. This invention will serve the diverse requirements of latest engines at the least possible cost by leveraging the expertise available and applying lean manufacturing methods, which previously were not used.
OBJECTS OF THE INVENTION:
A) The main object of the invention is to have high pressure die cast aluminium two cylinder crankcase with following features.
1) Suitable for inline two cylinder application.


2) Suitable for having single primary balancer shaft.
3) Capable of supporting balancer shaft either on two / three bearings.
4) Front side interface suitable for using integrated oil and water pump.
5) With provision for driving water pump by balancer shaft.
6) Having as cast cylinder liners with 2-4 mm aluminium on top of liner, for ease of machining and avoiding machining of two dissimilar material (as in conventional case).
7) Single main oil gallery supplying oil to balancer shaft and crank shaft bearings.
8) Open deck cylinder crankcase suitable for high pressure die cast process.
9) Deep skirt, no bed plate, oil sump directly mounted on crankcase, low cost design.

10) Dedicated oil return and blow by passage at front and or rear sides.
11) Oil return passages dipped into oil sump, below oil level there by preventing crankcase ventilation gases to pass through it, & crankcase pressure being applied to cylinder head. It also avoids return oil to be mixed into crankcase gases.
12) Cylinder crankcase width is reduced by providing blow by passage at the rear side of crankcase, simultaneously maintaining the rear cover position closer to crankcase by providing flange directed inside for oil sump mounting onto rear cover.
13) Suitable for housing drive gears for balancer shaft.
14) Housing dipstick and tube for measuring oil levels in oil sump.
15) Having separate / combined caps for main bearing and balancer bearing.
16) Having two shell bearings and one bush bearing for balancer shaft.
17) Having starter motor mounted on cylinder block, crankcase.
18) Having provision for mounting oil filter.
19) Having provision for mounting alternator along with brackets.
20) Having provision for mounting AC compressor along with brackets.


21) Having provision for TDC locking pin.
22) Having optimized shape of skirt following locus of crank shaft and connecting
rod for low cost and high stiffness design of better NVH.
23) Having optimized shape of skirt following locus of balancer shaft for low cost
and high stiffness design of better NVH.
B) To have cylinder crankcase for an internal combustion 2 cylinder engine suitable for various transmissions viz. manual gearbox, Continuously Variable Transmission (mechanical as well as electronic), infinitely variable transmission, and automatic transmission.
C) To have cylinder crankcase stiffened for better NVH properties by suitable contouring and ribs.
D) To have cylinder crankcase 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 crankcase for an internal combustion engine adoptable for
various alternate fuels viz. ethanol, methanol, gasohol, Diesel, Gasoline, Liquid
Petroleum Gas (LPG), Compressed Natural Gas (CNG) and suitable for single
fuel / bi-fuel operation.
F) To have cylinder crankcase for an internal combustion engine that can be
naturally aspirated, selectively supercharged / turbocharged and/or intercooled
depending on the application requirements.
G) To have cylinder crankcase for an internal combustion engine that can be
adoptable for hybrid vehicle applications / operation.


BRIEF DESCRIPTION OF INVENTION:
Novel inline two cylinder open deck, deep skirt, high pressure die cast aluminium crankcase housing single primary balancer shaft with front side interface suitable for adopting integral oil and water pump is designed for four-stroke reciprocating piston internal combustion spark ignition engine.
The cylinder crankcase is designed for high pressure die cast (aluminium) process for high volume production. The crankcase designed in such a way that the die should not have complex cores & too many moving sides. There are one fixed side die, four side dies moving in perpendicular direction to fixed die and one top die moving in the direction of bottom die. The cylinder crankcase design is optimized for mold filling & solidification. In this design cylinder liners are casted in situ. At top of liner, aluminium wall is provided, high volume machining process. This avoids machining of two dissimilar materials as is in conventional design. The only aluminium at top deck of cylinder liner helps in better sealing and improved reliability by avoiding expansion of dissimilar material as in conventional designs. Cooling water jacket surrounding cylinder liners are open deck for ease of manufacturing.
The shape of crankcase follows the locus of connecting rod and crankshaft on one side and other side it follows the locus of balancer shaft. The special countering on crankcase provide the high stiffeness and reduced material content.
In this invention crankcase is with deep skirt design and does not require bed plate or ladder frame. The oil sump can be sheet metal or aluminum. Oil sump is directly mounted on bottom of block.
In this invention wall thickness and ribs are optimized using structural and NVH analysis.
The cylinder crankcase is designed for low cost by optimizing wall thicknesses, removing the material from non functional area.


The cylinder crankcase is designed to house single primary balancer shaft & drive gears for the balancer shaft. The design is such that balancer shaft can be supported on two bearings for low cost design, and for high speed design balancer shaft can be supported on three bearings. The three bearing support design is very innovative. The two bearing out of three bearing are supported using shell bearing and third bearing is housed in rear wall and uses bush bearing.
In this i cylinder crankcase front end is designed to have interface with integral oil and water pump. The oil pump is driven by crankshaft & water pump is balancer shaft.
To reduce oil consumption separate passages are provided for crankcase ventilation and oil return from cylinder head. The ventilation path in cylinder crankcase houses the innovative oil separation device. The provision is made at front side of cylinder crankcase for return oil to be delivered at bottom of crankcase.
In this cylinder crankcase design very simple lubrication passages are provided for ease of manufacturing and low cost machining. The main oil gallery is as cast, only drill is passed to clear flashes. Cross drills are made for lubrication to main bearing and balancer bearing from single main oil gallery. As cast oil passage is provided in cylinder crankcase from main gallery matching to oil passage in cylinder head. Return oil from cylinder head is connected to cylinder crankcase as cast passage at front side. Part of oil return passage is split between cylinder crankcase and integral oil pump which is sealed by liquid or paper gasket. At crankcase bottom provision is made for connecting oil drain to be which delivers return oil at bottom of oil sump.
The cylinder crankcase has innovative provision of dipstick which passes through oil return passage in to oil sump.
The cylinder crankcase has provision for mounting starter motor, oil filter, alternator, compressor etc. auxiliaries.


DETAILED DESCRIPTION OF PREFERRED EMBODIMENT:
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 looking from the front & right hand side of the
cylinder crankcase,
Figure 2 shows an isometric view from the front & left hand side of the cylinder crankcase,
Figure 3 shows an isometric view of the rear & left hand side of the cylinder crankcase,
Figure 4 shows an isometric view of the cylinder crankcase from bottom side,
Figure 5 shows an isometric view of the cylinder crankcase from top side,
Figure 6 shows sectional view of the cylinder crankcase showing lubrication to main bearing and balancer bearing,
Figure 7 shows passages for crankcase ventilation & oil return passages,
Figure 8 shows delivery of return oil below oil level in oil sump,
Figure 9 shows right hand side view of crankcase for continuously variable transmission version,
Figure (10) shows mounting arrangement for dipstick and dipstick tube,
Figure (11) shows separate caps for main bearing and balancer bearing,
Figure (12 ) shows combined caps for main bearing and balancer bearing,
Figure 13 shows arrangement for supporting balancer shaft on two bearings and


Fig 14 shows arrangement for supporting balancer shaft on three bearings.
Now with reference to figures,
Figure 1 shows crank shaft axis (1) and balancer shaft axis (2). Interface for integral oil and water pump (3), water entry to cylinder block (4), unfiltered pressurized oil entry to oil gallery (5), main oil gallery (6), oil return passage (7), provision for oil filter mounting (8), provision for starter motor mounting (9), As cast oil gallery for supplying oil to cylinder head (10), shows contoured profile for balancer shaft locus (11), skirt (13) below crankshaft centerline (deep skirt), ribs (14) for stiffness and better NVH provision for AC compressor mounting bosses (15), provision for 'C arm (12).
Figure (2) shows front and left hand side view, it shows mounting bosses (16) for A arm, used for engine mounting through rubber isolation, three bosses (17) on left side are for alternator mounting, (18) shows contoured profile for crankshaft and connecting rod locus.
Figure (3) shows rear side of cylinder crankcase, ribbed flange (19) is for supporting transmission gear box; it also shows spigot location (20) for starter motor mounting, passage for blow by (21) is sealed by rear cover.
Figure (4) shows bottom side of crankcase, it shows housing for crankshaft (22), housing for balancer shaft (23), oil return passage (24), passage for blow by gases (21), As cast cylinder liner shown by (25). (26) Shows holes for mounting oil sump.
Figure (5) shows inline two cylinders (27), aluminum materials at top of liners (28), shows open deck water jacket surrounding cylinder liner(29) , (24) oil return passage , (21) passage for crankcase gases.
Figure (6) section shows cross drill holes for oil supply to main bearing (30) and balancer bearing (31) from single main oil gallery.


Figure (7) section showing dedicated oil return passage front side of engine and passage for crankcase gases at rear side of engine. The reverse arrangement i.e. passage for blow by at front and oil return passage at rear is also possible option in this design.
Figure (8) shows arrangement for delivery of returned oil below oil level and at bottom of oil sump.
Figure (10) shows mounting arrangement for dipstick and dipstick tube.
Figure (11) shows separate caps for main bearing and balancer bearing.
Figure (12) shows combined caps for main bearing and balancer bearing.
Figure (13) shows arrangement for supporting balancer shaft on two bearings.
Figure (14) shows arrangement for supporting balancer shaft on three bearings, i.e. on two shell bearing and one bush bearing.