WO2008120239A1

WO2008120239A1 - A novel inline two cylinder multi point fuel injection four-stroke reciprocating piston internal combustion spark ignition engine

Info

Publication number: WO2008120239A1
Application number: PCT/IN2008/000200
Authority: WO
Inventors: Narendra Kumar Jain; Hemant Anbadas Malekar; Kedar Digambar Gokhale
Original assignee: Tata Motors Ltd
Current assignee: Tata Motors Ltd
Priority date: 2007-03-30
Filing date: 2008-03-28
Publication date: 2008-10-09
Anticipated expiration: 2009-09-30

Abstract

This invention relates to a novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine, comprising of cylinder crankcase (1), cylinder head (2), crankshaft (3), flywheel assembly (33), balancer shaft (4), pistons (7), connecting rods, camshaft (5), valve train components, cylinder head cover, intake and exhaust manifolds (11), oil sump (13) and engine management system, said cylinder crankcase (1) is provided to act as a structural member to house said crankshaft (3), balancer shaft (4), pistons (7) and connecting rods, said pistons (7) are assembled in said cylinder crankcase (1) and are connected to said crankshaft (3) through connecting rods, said cylinder head (2) is having cross flow type compact design with overhead camshaft (5) and direct acting tappets, said cylinder head (2) is assembled on said cylinder crankcase (1), said cylinder head (2) cover is provided on top of said cylinder head (2), said intake and exhaust manifolds (11) are provided on said cylinder head (2), said flywheel assembly (33) is mounted on said crankshaft (3), said oil sump (13) is provided at the bottom of said cylinder crankcase (1) wherein said cylinder crankcase (1) is having extended skirt to house said balancer shaft (4), said crankshaft (3) is provided with 360 degree crank disposition and is supported on said cylinder crankcase (1) through plurality of main bearings, said balancer shaft (4) is provided with balancing means in such a way that the centre of gravity of said balancing means lies away from the axis of rotation of said balancer shaft (4) said balancer shaft (4) is supported on said cylinder crankcase (1) through plurality of bearings in such a way that the axis of rotation of said balancer shaft (4) is parallel to said crankshaft (3) axis, said engine management system is provided with hardware units and software to manage the overall operation of said engine.

Description

A NOVEL INLINE TWO CYLINDER MULTI POINT FUEL INJECTION FOUR-STROKE RECIPROCATING PISTON INTERNAL COMBUSTION SPARK IGNITION ENGINE

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 engine primarily 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, four stroke reciprocating piston internal combustion 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. There also exist few vehicles with two cylinder engine; however these engines are either with two balancer shafts or without any balancer shaft.

The drawbacks associated with said vehicle having two cylinder engine with two balancer shafts are higher engine weight, complexity, low fuel economy and difficulty in packaging.

The drawback associated with said vehicle having two cylinder engines without any balancer shaft is high vibration levels associated with engine which leads to passenger discomfort. This invention is devised to incorporate optimized features in a most economical way along with addressing the said drawbacks.

It is also found that no engine in two cylinder inline configuration along with single 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.

PRIOR ART

US 4174698 teaches 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 forces 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.

Drawbacks associated with said cited prior art are higher engine weight, complexity, low fuel economy and difficulty in packaging.

OBJECTS OF THIS INVENTION:

> The main object of this invention is to provide a high performance deliverable, compact, robust and low cost internal combustion spark ignition engine with best possible fuel economy and reduced emissions. > Yet another object of this invention is to provide an internal combustion spark ignition engine adoptable for various alternate fuels viz. ethanol, methanol, gasohol, Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG) and suitable for single fuel / bi -fuel operation.

> Yet another object of this invention is to provide internal combustion spark ignition engine suitable for very high volume production.

> Yet another object of this invention is to provide internal combustion spark ignition engine with good NVH (Noise Vibration and Harshness) characteristics.

STATEMENT OF INVENTION

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine comprising of cylinder crankcase, cylinder head, crankshaft, flywheel assembly, balancer shaft, pistons, connecting rods, camshaft, valve train components, cylinder head cover, intake and exhaust manifolds, oil sump and engine management system, said cylinder crankcase is provided to act as a structural member to house said crankshaft; balancer shaft; pistons and connecting rods, said pistons are assembled in said cylinder crankcase and are connected to said crankshaft through connecting rods, said cylinder head is having cross flow type compact design with overhead camshaft and direct acting tappets, said cylinder head is assembled on said cylinder crankcase, said cylinder head cover is provided on top of said cylinder head, said intake and exhaust manifolds are provided on said cylinder head, said flywheel assembly is mounted on said crankshaft, said oil sump is provided at the bottom of said cylinder crankcase wherein said cylinder crankcase is having extended skirt to house said balancer shaft, said crankshaft is provided with 360 degree crank disposition and is supported on said cylinder crankcase through plurality of main bearings, said balancer shaft is provided with balancing means in such a way that the centre of gravity of said balancing means lies away from the axis of rotation of said balancer shaft, said balancer shaft is supported on said cylinder crankcase through plurality of bearings in such a way that the axis of rotation of said balancer shaft is parallel to said crankshaft axis, said engine management system is provided with hardware units and software to manage the overall operation of said engine.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said cylinder crankcase is provided with isolated blow-by passage and oil return passage, said blowby passage is further provided with reed valve for ensuring unidirectional flow of blowby gases required for positive crankcase ventilation.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said crankcase is having open deck feature, and is made with high pressure die casting and provided with "in situ" casted liners.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is having fuel injectors mounted on said cylinder head and are inserted inside intake ports.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is provided with either two or more valves per cylinder.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is either naturally aspirated or supercharged or turbocharged or rurbocharged and intercooled. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is provided with integrated oil pump and coolant pump which acts as a front cover of said cylinder crankcase.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is having mounting provisions for its accessories.

Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is having crankshaft with 180 Deg - 540 Deg crank disposition with an optional balancer shaft.

BRIEF DESCRIPTION OF INVENTION:

The novel Inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine in accordance with this invention basically comprises of cylinder crankcase, cylinder head, crankshaft, balancer shaft, camshaft, pistons, connecting rods, intake and exhaust manifolds, engine management system and valve train components. Wherein said cylinder crankcase acts as a structural member to house crankshaft, balancer shaft, pistons and connecting rods. Said cylinder crankcase is provided with open deck feature and extended skirt to house said balancer shaft. Said crankcase is also provided with "in situ" casted liners. Said cylinder head is having cross flow type compact design with overhead camshaft and direct acting tappets. Said cylinder head is also provided with reed valve to allow flow of blow-by gases only in one direction to ensure the positive crankcase ventilation. Said cylinder head is assembled on said cylinder crankcase. Said crankshaft is provided with 360 degree crank disposition and is supported on said cylinder crankcase through plurality of main bearings. Said balancer shaft is provided with balancing means in such a way that the centre of gravity of said balancing means lies away from the axis of rotation of said balancer shaft. Said balancer shaft is supported on said cylinder crankcase through plurality of bearings in such a way that the axis of rotation of said balancer shaft is parallel to said crankshaft axis. Said pistons are assembled in said cylinder crankcase and are connected to said crankshaft through connecting rods. Said intake and exhaust manifolds are provided on said cylinder head. Said engine management system is provided with hardware units and software to manage the overall operation of said engine.

Said engine is provided with coolant pump which is driven by said balancer shaft and is integrated with said cylinder crankcase front cover. Said engine is also provided with oil pump which is driven by said crankshaft and is also integrated with said cylinder crankcase front cover. Said engine is also provided with mounting provisions for its accessories such as for Alternator, A/c Compressor etc.

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 & left hand side of the engine,

Figure 3 shows an isometric view from the rear & right hand side of the engine,

Figure 4 shows front view of engine in vehicle mounted orientation,

Figure 5 shows section A-A marked in figure 4, Figure 6 shows section B-B marked in figure 5.

Referring to figures 1 to 6

The novel Inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine in accordance with this invention basically comprises of cylinder crankcase (1), cylinder head (2), crankshaft (3), balancer shaft (4), camshaft (5), pistons (7), connecting rods (8), intake and exhaust manifolds (11,12), valve train mechanisms (5A) and engine management system. Wherein said cylinder crankcase (1) acts as a structural member to house said crankshaft (3), balancer shaft (4), pistons (7) and connecting rods (8). Said cylinder crankcase is provided with open deck feature and extended skirt (IB) to house said balancer shaft. Said crankcase is also provided with "in situ" casted liners (1C). Said cylinder head (2) is having cross flow type compact design with overhead camshaft (5) and direct acting tappet mechanisms (5A). Said cylinder head is also provided with reed valve (41A) to allow flow of blow-by gases through passage (41) only in one direction to ensure the positive crankcase ventilation. Said passage (41) may also be provided with baffles to separate oil from blowby gases effectively. Said cylinder head (2) is assembled on said cylinder crankcase (1). Said crankshaft (3) is provided with 360 degree crank disposition and is supported on said cylinder crankcase (1) through plurality of main bearings. Said balancer shaft (4) is provided with balancing means (4A) in such a way that the centre of gravity of said balancing means (4A) lies away from the axis of rotation of said balancer shaft. Said balancer shaft (4) is supported on said cylinder crankcase (1) through plurality of bearings in such a way that the axis of rotation of said balancer shaft is parallel to said crankshaft axis. Said pistons (7) are assembled in said cylinder crankcase (1) and are connected to said crankshaft (3) through connecting rods (8). Said intake and exhaust manifolds (11, 12) are provided on said cylinder head (2). Said engine management system is provided with hardware units and software to manage the overall operation of said engine.

Front side of the said 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. Said coolant pump is driven by said balancer shaft (4). Said oil pump is driven by said crankshaft (3). Said engine is also provided with mounting provisions for its accessories such as for Alternator, A/c Compressor etc.

Now with reference to figure 1, wherein Cylinder Crankcase (1) is an Aluminium High Pressure Die casting (HPDC) provided with two bores in the "inline" configuration. The front side of said 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) is provided with a feature for oil separation. The high tension / ignition 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) encloses 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 mounting bracket (38). The alternator belt (21) and A/c Compressor belt (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 as and when required. The assembly (33) of flywheel and ring gear is mounted on said crankshaft (3), which facilitates starting as well as forms an interface for the transmission.

A - mounting arm (35) of engine made up of ductile iron / 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) is provided for checking oil level in the oil sump (13). The starter motor (30) is mounted on 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 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 or without fillet rolling / fillet hardening and which facilitates the mounting of the assembly (33) of flywheel and ring gear and various types of transmissions. The rear flange (IA) 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 integrated with crankshaft (3).

The alternator mounting bracket (39) made up of ductile iron / aluminium facilitates the 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 in orientation as 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. 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 availability of engine oil during various driving conditions. The single main oil gallery (ID) in the cylinder crankcase (1) directly supplies pressurized oil to crankshaft main journal bearings as well as to the balancer shaft journal bearings. It also supplies the pressurized oil to the oil gallery in the cylinder head (2). The low oil pressure switch (44) is located on the rear end of the oil gallery in cylinder head (2).

The illustrated crankshaft (3) is of 360 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 crankshaft (3) and the timing gear (19) is mounted on the front end of the camshaft (5). 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. The primary inertia forces are balanced by a balancer shaft. 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 provided in the blowby passage for ensuring 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. Only the big end of said connecting rod is provided with suitable thin wall bearing and the bush from the small end is eliminated.

The intake valves (9) and the exhaust valves (10) are actuated by the camshaft (5) through the direct acting tappets mechanisms (5A).

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. Half of the primary inertia force balance is achieved in the crankshaft (3) through the crank-webs (3A) and remaining half inertia force balance is achieved in the balancer shaft (4) through the counterweights (4A) provided.

Said novel inline two cylinder, four-stroke, reciprocating piston, internal combustion, spark ignition engine can also be provided with direct fuel injection (inside the combustion chamber) by suitable modifications in piston, cylinder head, engine management system etc. in place of Multi Point Fuel Injection. Said novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine can also be provided with air cooling system with necessary modifications.

This novel inline two cylinder Multi Point Fuel Injection four stroke reciprocating pistons internal combustion spark ignition engine consists of integration of following some of important key features:

360Degrees - 360 Degrees OR 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, the unbalanced primary inertia forces generated can be balanced by employing one primary balancer shaft driven at equal speed but in opposite direction by the crankshaft through gears. The unbalanced primary couple generated due to inertia force and centrifugal force induced by the counterweights on the primary balancer shaft can be isolated 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. 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 including hybrid vehicles and other transport / mobility applications, with focus on the 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 modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

Claims

1. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine comprising of cylinder crankcase, cylinder head, crankshaft, flywheel assembly, balancer shaft, pistons, connecting rods, camshaft, valve train components, cylinder head cover, intake and exhaust manifolds, oil sump and engine management system, said cylinder crankcase is provided to act as a structural member to house said crankshaft; balancer shaft; pistons and connecting rods, said pistons are assembled in said cylinder crankcase and are connected to said crankshaft through connecting rods, said cylinder head is having cross flow type compact design with overhead camshaft and direct acting tappets, said cylinder head is assembled on said cylinder crankcase, said cylinder head cover is provided on top of said cylinder head, said intake and exhaust manifolds are provided on said cylinder head, said flywheel assembly is mounted on said crankshaft, said oil sump is provided at the bottom of said cylinder crankcase wherein said cylinder crankcase is having extended skirt to house said balancer shaft, said crankshaft is provided with 360 degree crank disposition and is supported on said cylinder crankcase through plurality of main bearings, said balancer shaft is provided with balancing means in such a way that the centre of gravity of said balancing means lies away from the axis of rotation of said balancer shaft, said balancer shaft is supported on said cylinder crankcase through plurality of bearings in such a way that the axis of rotation of said balancer shaft is parallel to said crankshaft axis, said engine management system is provided with hardware units and software to manage the overall operation of said engine.

2. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claim 1 wherein said cylinder crankcase is provided with isolated blow- by passage and oil return passage, said blowby passage is further provided with reed valve for ensuring unidirectional flow of blowby gases required for positive crankcase ventilation.

3. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 and 2 wherein said crankcase is having open deck feature, and is made with high pressure die casting and provided with "in situ" casted liners.

4. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 to 3-wherein said engine is having fuel injectors mounted on said cylinder head and are inserted inside intake ports.

5. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 to 4 wherein said engine is provided with either two or more valves per cylinder.

6. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 to 5 wherein said engine is either naturally aspirated or supercharged or turbocharged or turbocharged and intercooled.

7. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 to 6 wherein said engine is provided with integrated oil pump and coolant pump which acts as a front cover of said cylinder crankcase.

8. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine as claimed in claims 1 to 7 wherein said engine is having mounting provisions for its accessories.

9. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, spark ignition engine wherein said engine is having crankshaft with 180 Deg - 540 Deg crank disposition with an optional balancer shaft.

10. Novel inline two cylinder, Multi Point Fuel Injection, four-stroke, reciprocating piston, internal combustion, and spark ignition engine substantially as herein described with reference to accompanying drawings.