FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THR PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
A novel Inline two cylinder Multi Point Fuel Injection four-stroke reciprocating piston internal combustion naturally aspirated or turbocharged or turbocharged intercooled spark ignition 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
and Kedar Digambar Gokhale 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
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FIELD OF INVENTION:
This invention relates to internal combustion spark ignition engine and more particularly to a two cylinder inline, four stroke, Multi Point Fuel Injection reciprocating piston type, naturally aspirated or supercharged or turbocharged or turbocharged intercooled engine intended for passenger car, light commercial vehicle and other transport / mobility applications.
BACKGROUND OF INVENTION:
Conventionally most of the passenger cars and light commercial vehicles are powered by three or four cylinder internal combustion four stroke, and reciprocating piston engines with diesel, gasoline or other suitable alternate fuel. Mostly the engine is mounted in the front portion of the vehicle and rarely on the rear side. Whereas no engine in two cylinder inline configuration along with primary balancer shaft and Multi Point Fuel Injection (in intake ports) or direct fuel injection (in combustion chamber) which is suitable for rear mounting is in use for passenger cars and/or light commercial vehicles application. This invention will serve the diverse requirements of latest passenger cars as well as those of light commercial vehicles at the least possible cost by leveraging the expertise available and applying lean manufacturing methods.
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PRIOR ART
US 4174698 relates to an inline two cylinder engine comprising a crankshaft having 360 Degrees setting and balancing means comprising a first counterweight rotating oppositely to, but at the same speed as, the crankshaft and designed to develop a centrifugal force equal to half the maximum amplitude of the reciprocating rectilinear inertia force'3 of the engine. Means in the form of additional counterweight are provided for compensating for the resultant of the centrifugal force of first counterweight and of the reciprocating rectilinear inertia forces.
OBJECTS OF THIS INVENTION:
A) The main object of this invention is to provide a high performance deliverable, compact.& robust internal combustion, spark ignition engine especially suitable for transverse / longitudinal mounting at rear of passenger cars / light commercial vehicles and other transport / mobility applications.
B) Another object of this invention is to provide an internal combustion, spark ignition engine suitable for various transmissions viz. manual gearbox, Continuously Variable Transmission (mechanical as well as electronic), Infinitely variable transmission, and automatic transmission. .. . .
C) Another object of this invention is to provide an internal combustion, spark ignition engine with high fuel efficiency and reduced emissions by better matching of engine performance with the vehicle inertia.
D) Another object of this invention is to provide an internal combustion, spark ignition engine with reduced pass by noise level when assembled on passenger cars, light commercial vehicles and other transport / mobility applications.
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E) Another object of this invention is to provide an internal combustion, spark
ignition engine adoptable for various alternate fuels viz. ethanol, methanol,
ga.30.hol.. Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG) and
suitable for single fuel / bi-fuel operation.
F) Another object of this invention is to provide an internal combustion, spark
ignition engine with naturally aspirated or selectively supercharged or
turbocharged or turbocharged intercooled,
G) Another object of this invention is to provide an internal combustion, spark
ignition engine adoptable for hybrid vehicle applications / operation.
SUMMARY OF INVENTION:
The novel Inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, naturally aspirated or turbocharged or turbocharged intercooled, spark ignition engine basically comprises of cylinder crankcase, cylinder head, crankshaft, balancer shaft, camshaft, piston, connecting rod, intake and exhaust manifolds, engine management system and valve train components.
The cylinder crankcase is an open deck type, the cylinder head is cross flow type and connecting rod is steel forging without the small end bush. The crankshaft is designed for forged steel with fillet rolling and without any induction hardening. The direct acting mechanical tappjts are used with single overhead camshaft as a best compromise between cost and performance. The coolant pump is driven by the balancer shaft and is integrated with the crankcase front cover and oil pump. This simplifies the timing belt drive for the camshaft. A common crankcase facilitates the mounting of Manual transmission, Automatic transmission as well as Continuously Variable Transmission (CVT). The mounting provision is made for all the accessories such as alternator, A/c Compressor required for various applications.
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This novel inline two cylinder Multi Point fuel Injection four stroke reciprocating pistons internal combustion spark ignition engine consists of integration of following key features:
360Degrees - 360 Degrees OK 180 Degrees - 540 degrees crank disposition: The crank spacing is selected as 360 degrees to achieve uniform firing interval and better gas dynamics 'of intake system. This leads to the unbalanced primary inertia forces, which can be balanced by employing either one or two primary balancer shafts driven at equal speed but in opposite direction by the crankshaft. As a cost -balancing trade-off, only single primary balancer shaft is used in this engine, which gives rise to unbalanced primary couple due to inertia force and centrifugal force induced by the counterweights on the primary balancer shaft. The effect of this couple and the unbalanced secondary inertia forces is reduced by using appropriate engine mounts.
Electronically controlled multipoint fuel injection system: Spark ignition engine being Quantity governed is highly sensitive towards the gas flow dynamics of intake system. The various stringent requirements on emissions and fuel economy increase the challenges further. The electronically controlled fuel injection in multiple intake ports addresses these challenges and optimized performance can be achieved.
Reed valve controlled crankcase ventilation; For 360 Degrees crank configuration, the crankcase ventilation becomes critical since both pistons move in unison leading to the high pressure fluctuations inside the crankcase. A reed valve which allows the flow of blow-by gases only in one direction is employed in this engine to ensure the positive crankcase ventilation to meet emission legislations.
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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
engine,
Figure 2 shows an isometric view from the front Sc left hand side of the engine. Figure 3 shows an isometric view from the rear & right hand side of the engine,
Figure 4 shows a view from front side in vehicle mounted condition.
Figure 5 shows a section A-A marked in figure 4
Figure 6 shows a section B-B marked in figure 5,
Now with reference to figure 1, where in Cylinder Crankcase [1] is an Aluminium High Pressure Die casting (HPDC) provided with two bores in the inline configuration The front side of the cylinder crankcase [1] is covered by an integrated oil pump and coolant pump [34]. The coolant pump cover [37] facilitates axial entry of engine coolant to the coolant pump. The flow optimized Cylinder Head [2] is a cross flow type design having intake manifold [11] mounted on its left hand side, whereas integrated exhaust manifold with catalytic converter [12] mounted on its right hand side. The cylinder head cover [6] made up of plastic with a provision for oil separation. The high tension / i;5nition coil [32] is mounted on the cylinder head cover [6]. The oil filler cap [16] is also provided on the cylinder head cover [6] and the timing gear" cover [28] cnclose-5 the timing belt drive on the front side of the engine. The alternator [29] is mounted on the right hand side of the cylinder crankcase [1] using suitable cast Aluminium / Iron bracket. The A/c compressor [31] is mounted on the left hand side of the cylinder crankcase [1] using suitable A/c compressor mounting bracket [38]. "The alternator belt [21] and A/c Compressor belt
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[22] are used to drive the respective accessories by taking drive from the front pulley [20].
The oil sump [13] made up of steel sheet is mounted on the bottom side of the cylinder crankcase [1]. which forms the reservoir for the engine oil. A drain plug [17] is provided on the oil sump [13] for draining the engine oil from sump during field service. The assembly flywheel with ring gear [33] is mounted on the rear side of the engine, which facilitates starring as well as forms an interface for the transmission.
Engine "A" mounting arm [35] made up of ductile iron / forged Aluminium is bolted on the front face of the cylinder crankcase [1] to have rigid mounting. It also facilitates the support for the top mounting of the Alternator [29].
With reference to Figure 2, the oil dipstick [36] for checking nil level in the oil sump [13]. The starter motor [30] is mounted oil cylinder crankcase [1] with spigot location underneath the intake manifold [11.]. The oil filter [15] is mounted directly on the cylinder crankcase [1] close to the oil pump discharge to the main oil gallery.
The throttle body [25] is mounted on inlet of the intake manifold [11] plenum. The fuel rail [23] made up of plastic / aluminium is mounted on the cylinder head [2]. The fuel injectors [24] are assembled on the fuel rail [23] using clips and are inserted inside the intake port in the cylinder head [2] in an optimized orientation and location. The Thermostat valve is housed near the engine coolant outlet in the cylinder head. The thermostat valve is covered by the thermostat cover [27] screwed on the cylinder head [2]. The engine coolant temperature sensor [43], which is one of the important input of the electronic Engine Management System (EMS) is mounted on cylinder head [2], just before (upstream) the thermostat valve.
With reference to Figure 3, where in the crankshaft [3] is forged steel / ductile iron / Spheroidal graphite Iron with fillet rolling and which facilitates the mounting of the assembly flywheel with ring gear [33] and various types of transmissions. The rear
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flange [1A] of the cylinder crankcase [1] is designed for having a common mounting interface for various types of transmissions such as Continuously Variable Transmission (CVT), Manual Transmission ;MT), Infinitely Variable Transmission (IVT), and Automatic Transmission. The power shaft required for the CVT mounting on the rear end of the crankshaft is retreated with crank shad [3].
The alternator mounting bracket [39] made up of cast iron / aluminium facilitate the bottom mounting of alternator where it is hinged and swiveled for tensioning the drive belt [21]. The spark plugs [26] are mounted on the cylinder head [2], The engine coolant outlet [40] on the cylinder head is provided with a steel pipe insert to facilitate the radiator hose fitment.
Figure 4 shows the front view of the engine when assembled on vehicle. The illustrated engine is designed for the inclination of 14 degrees with the vertical, however, the same engine can be modified to cater various inclinations depending upon the packaging constraints of the applications.
Figure 5 depicts the internal construction of the engine from section A-A of figure 4 wherein the oil strainer [14] acts as a coarse filter for the engine oil. It collects the engine oil from close to the bottom of the oil sump [13] and helps to ensure the a\ ailability of engine oil during various driving conditions. The single main oil gallery in the cylinder crankcase [I] directly supplies pressurized oil to crankshaft main journal bearings as well as to the balancer shaft journal bearings. It also supplies the piessurized oil to the oil gallery in the cylinder head [2], the flow to which is controlled by optimized diameter for the supply hole. The-low oil pressure switch [44] is located on the rear end of the oil gallery In cylinder head (2J.
The illustrated crankshaft [3] is of 5-60 degrees - 360 degrees configuration, however it can also be designed with 180 degrees - 540 degrees configuration with suitable changes in the engine design. The crank gear [18] is mounted on the front end of the
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crankshaft [3] and the timing gear [19] is mounted on the front end of the camshaft [5j. The timing belt runs over these gears for providing the drive for camshaft [5].
Pistons [7] made up of Aluminium alloy move in unison with the 360 degrees - 360 degrees configuration thereby inducing the unbalanced primary inertia forces. These forces need to be balanced using balancer shaft(s). Further, with this there is a large fluctuation in the crankcase pressures. To ensure positive crankcase ventilation, the blow-by passage [41] and the oil return passage [42] in the cylinder crankcase [1] are totally isolated from each other. Further, a reed valve [41A] is introduced in the blowby passage which ensures unidirectional flow of blowby gases.
The connecting rods [8] are made up of forged steel. The big end of which can be machine split or serrated or fracture split. The big end uses suitable thin wall bearing, whereas the small end bush is eliminated.
The intake valves [9] and the exhaust valves [10] are actuated by the camshaft [5] through the direct acting mechanical tappets arrangement [5AJ.
Figure 6 Shows the section B-B marked in figure 5, wherein a single balancer shaft [4] is located adjacent to the crankshaft [3], The crankshaft drives the balancer shaft at exactly same speed but in the opposite direction to achieve primary inertia force balancing. Half of the primary inertia force balance is achieved in the crankshaft [3] through the crank-webs and remaining half inertia force balance is achieved in the balancer shaft [4] through the counterweights provided. This single balancer shaft system leads to an imbalanced inertia couple, however it can be taken care by appropriate engine mounting system design.
The present invention provides the' compact, quiet, robust and cost effective engine especially suitable for rear mounting in small passenger cars and/ or light commercial vehicles and other transport / mobility applications, with focus on the
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best fuel economy along with the upgradeability to meet the future emission norms with comfortable margins
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration
only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing; from the spirit and scope of the invention. It is intended that all such modification and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.
Dated this 30th day, of March 2007.
TATA MOTORS LIMITED By their Agent & Attorney

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