WO2009116063A2

WO2009116063A2 - Cylinder head for two cylinder ic engine

Info

Publication number: WO2009116063A2
Application number: PCT/IN2009/000022
Authority: WO
Inventors: Narendra Kumar Jain; Hemant Ambadas Malekar; Kedar Digambar Gokhale; Sameer Madhukar Nagarkar
Original assignee: Tata Motors Limited
Priority date: 2008-01-08
Filing date: 2009-01-07
Publication date: 2009-09-24
Also published as: WO2009116063A3

Abstract

This invention relates to a Cylinder head for two cylinder IC engine comprising; said cylinder head configured to house a single overhead camshaft, bucket tappets; fuel injectors, fuel rail, cylinder head cover, intake manifold, exhaust manifold, cylinder head bolts and timing belt tensioner; said cylinder head is provided with separate passages for ventilation gases and oil return and at least one oil separating baffle plate is housed in the passages for ventilation, a one-way flow valve is provided in passages for ventilation at top face of said cylinder head to maintain negative crankcase pressure in the cylinder crankcase; fuel injectors are configured to mount directly on said cylinder head with cooling passages surrounding said injectors; said cylinder head bolts are provided at the top profile thereby rendering length of bolts.

Description

CYLINDER HEAD FOR TWO CYLINDER IC ENGINE

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.

PRIOR ART

1. JP 6229210 mentions about the cylinder head with SOHC valve train system for an internal combustion engine which can reduce the number of component parts and man hours for assembly while maintaining combustion efficiency, and which can enhance the support rigidity of a cam shaft and can make the valve system chamber compact. Drawbacks associated with said cited prior art are use of rocker arm which increases the cylinder head width, & valve train complexity, with higher cylinder head weight & difficulty in packaging.

2. DE 4007939 mentions about the cylinder head with rocker valve train wherein the lubricating oil return from a cylinder head to sump uses a collector along the cylinder head, to which is connected a return line to the sump. The oil removal takes place with the cylinder head housing attached pump. .

The said design provides for cylinder head control space. Drawback associated with cited prior art are use of external pump, complexity & no positive separation of oil return from blow-by gases.

OBJECTS OF THE INVENTION

The main object of this invention is to obviate the aforementioned drawbacks by providing an improved cylinder head for two cylinders IC engine.

The object of the invention is to have inline, two cylinder, low pressure die cast/ gravity die cast, aluminium cylinder head with following features:

- Suitable for inline, two cylinder application.

- Suitable for housing two valves per cylinder head with mechanical bucket tappet. - Capable of housing single overhead camshaft.

- Capable of housing two fuel injectors and fuel rail.

- Single main oil gallery supplying oil to three camshaft bearings.

- Dedicated blow-by / ventilation passages on front and rear sides.

- Capable of housing low oil pressure switch. - Having provision for mounting intake manifold with throttle body. - Having provision for mounting exhaust manifold.

- Capable of mounting timing belt tensioner.

Another object of the invention is 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.

Another object of the invention is 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.

Yet another object of the invention is 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.

Another object of the invention is 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.

Yet another object of the invention is to have cylinder head for two cylinder internal combustion engine with blow-by / ventilation gases circuit optimized for 0-360 firing order of pistons. Yet another object of the invention is to have cylinder head for an internal combustion engine with minimum usage of material, least cost, compact and light weight.

Yet another object of the invention is 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.

Yet another object of the invention is to have cylinder head for an internal combustion engine with rear end closed for reduced oil leakage.

BRIEF DESCRIPTION OF DRAWINGS

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.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

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 its 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 is capable of housing the oil separating baffle plate, if required, for further reduction in oil carry over in the 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 is 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, resulting in 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 to have proper cooling of combustion chamber, exhaust ports & spark plugs.

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.

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,

Now with reference to figures of one of the embodiment of the instant invention, Figure 1 shows Cylinder head mounting bolt hole (6) at the same height as exhaust manifold mounting face (1) to decrease the material usage and consequently reduce weight and increase fuel efficiency and 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) on one side of the cylinder head mounting.

Figure 2 shows Opening for Main coolant flow circuit in thermostat cover (13) just above the Interface for mounting thermostat valve & thermostat cover (7) at the lower part of the assembly, Boss for mounting coolant temperature sensor (8) adjacent to said thermostat valve and thermostat cover, Intake manifold mounting face (9) adjacent to said Boss for mounting coolant temperature sensor (8) distally to said thermostat valve and thermostat cover; Interface for mounting lifting hook rear (10), Interface for mounting dipstick bracket (11), and Front camshaft cap seal housing (12), at the upper part of the housing.

Figure 3 shows main oil gallery (14) above said Cylinder head mounting bolt hole (20) where Oil supply gallery from cylinder crankcase to main oil gallery (19) is situated below it and Interface for mounting fuel rail (15) is on frontal surface and Low oil pressure switch housing (18) is on side of said main oil gallery (14). Fuel injector housing (16) is substantially on the same surface as that of said Cylinder head mounting bolt hole (20). Bosses for mounting throttle body support bracket (17) is provided on the same side as that of Low oil pressure switch housing (18) on a lower horizontal plane.

Figure 4 shows Blow-by/ventilation gases opening for cylinder head cover (23) at the top surface of the housing and Camshaft housing which follows the contour of cam lobe for complete rotation of camshaft (22) and Spark plug housing (21) substantially at the same surface as that of said Cylinder head mounting bolt hole (20).

Figure 5 shows Front camshaft bearing (24) at one side of the arrangement and

Threaded hole for mounting reed plate in blow-by / ventilation gases circuit (31) at other side of the arrangement. Oil return passage (25) is proximally situated to said

Front camshaft bearing (24). Tappet bore (26), Valve guide bore (27), Spring seat housing (29) within the Cylinder head top profile with interface for mounting cylinder head cover, reed plate & camshaft caps (28) of the arrangement. , Oil groove for camshaft bearings (30) are provided in between two adjacent said spring seat housings ,.

Figure 6 shows Blow-by / ventilation gases passage opening to cylinder crankcase (32) at one end of the bottom side of the assembly and Oil return passage opening to cylinder crankcase (38) at the other side of the bottom side of the assembly and two arrangements of Squish type combustion chamber (35) having Intake valve seat insert housing (33), , Spark plug opening in combustion chamber (39), , , Exhaust valve seat insert housing (36). To cool the Squish type combustion chamber Coolant jacket entry holes (34), Coolant outlet for heater take off (37) are provided. .

Figure 7 indicates cross section showing Oil return passage (40) on one side and Blow-by / ventilation gases passage (44) on the other side; Exhaust port for first cylinder (41) being provided proximal to said Oil return passage (40) and Intake port for first cylinder(42) being provided distal to said Oil return passage (40). Coolant jacket (43) being provided between intake & exhaust ports. Oil drain passage (47) is provided between Valve guide bore for second cylinder (45) and Tappet bore for first cylinder (46). Figure 8 shows cross sectional view through intake port. It shows Coolant jacket around intake port (48), Intake port (49). Fuel injector housing (50) is provided at an angle above the intake port beneath the Main oil gallery (51). Valve spring seat housing (52), Contour of camshaft housing (53) is provided vertically above the intake port (49).

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) and 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 Threaded hole for camshaft cap mounting (60) at the top Coolant jacket around spark plug (59), , 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), below the Coolant temperature sensor mounting (65).

Figure 13 shows Housing for single acting thermostat valve (66) below the Coolant passage for main coolant flow circuit to radiator (67) and Housing for nipple for radiator coolant inlet hose (68) at one side of the coolant passage.

Important features of this invention are as discussed below:

The novel inline, two cylinder, low pressure die cast / gravity die cast cylinder head with two valves per cylinder, said cylinder head is provided to act as a structural member to house single overhead camshaft, direct acting bucket tappets, fuel injectors directly mounted on intake ports & fuel rail, cylinder head cover, intake manifold, exhaust manifold, timing belt tensioner and the said cylinder head is cross flow type (intake ports on one side & exhaust ports on opposite side) with compact design. There are separate passages for blow-by / ventilation gases & oil return to avoid mixing of the two for reducing the engine oil consumption. The reed valve(one way flow valve) is provided in blow-by circuit at the top face of cylinder head to maintain negative crankcase pressure in the cylinder crankcase which is required for regulation in gasoline engines. Provision is made in the cylinder head for housing the oil separating baffle plate in the blow-by passages if required, for further separating the oil from blow-by gases. The rear end of the said cylinder head is completely closed for reduction of oil / blow-by ventilation gases leakage to atmosphere and to reduce the machining & number of component & rejection at assembly line. The size of water core is optimized for low cost and 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 cylinder head bolts outside the top profile which results in their shorter length, with machined faces of the cylinder head designed for minimum machining setting for reduced machining costs and with provision for housing optimized low cost small size cylinder head cover. 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, with cooling passages surrounding the injectors optimized in such a way that the injectors are cooled & no vapor locks are formed in hot condition, and with proper injector spray targeting & reduced wall wetting to provide better emissions, better fuel economy & lower CO₂ emissions & greater consistency in performance. The cylinder head is provided with separate passages for blow-by / ventilation gases & oil return to avoid mixing of the two for reducing the engine oil consumption The reed valve is provided in blow-by circuit at the top face of cylinder head to maintain negative crankcase pressure in the cylinder crankcase which required for the regulation in gasoline engines. Oil separating baffle plate in the blow-by passages is provided in a preferred embodiment, for further reduction of blow-by gases.

The rear end of the said cylinder head is completely closed for reduction of oil / blow-by ventilation gases leakage to atmosphere and to reduce the machining & component costs & rejection at assembly line. The intake & exhaust port location, size & shape is optimized to get better torque, power, emissions & fuel economy. The 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 with reduced emissions, better fuel economy, low CO2 emissions & reduced knocking tendency. The size of water core is optimized for low cost and 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 oil cores in the cylinder head are optimized for proper oil supply to cam bearings, bucket tappet & return of oil back to oil sump and the oil cores shape is optimized so that no dead oil pockets are formed inside the cylinder head. The shape of the cylinder head is designed such a way that minimum material is used for the casting, with minimum possible wall thickness around coolant jacket, oil jacket, combustion chamber and camshaft housing thus providing the smallest possible size & weight while meeting all performance requirements. The novel inline, two cylinder, low pressure die cast / gravity die cast cylinder head ; with cylinder head bolts outside the top profile which results in their shorter length, with machined faces of the cylinder head designed for minimum machining setting for reduced machining costs and with provision for housing optimized low cost small size cylinder head cover.

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. A Cylinder head for two cylinder IC engine comprising: said cylinder head configured to house a single overhead camshaft, bucket tappets; fuel injectors, fuel rail, cylinder head cover, intake manifold, exhaust manifold, cylinder head bolts and timing belt tensioner; said cylinder head is provided with separate passages for ventilation gases and oil return and at least one oil separating baffle plate is housed in the passages for ventilation, a one-way flow valve is provided in passages for ventilation at top face of said cylinder head to maintain negative crankcase pressure in the cylinder crankcase ; fuel injectors are configured to mount directly on said cylinder head with cooling passages surrounding said injectors; said cylinder head bolts are provided at the top profile thereby rendering length of bolts shorter.

2. The Cylinder head for two cylinder IC engine as claimed in claim 1, wherein rear end of the said cylinder head is completely closed for reduction of oil and/or ventilation gases leakage to atmosphere.

3. The Cylinder head for two cylinder IC engine as claimed in claim 1, wherein intake and exhaust port location, size and shape is optimized to obtain better torque.

4. The Cylinder head for two cylinder IC engine as claimed in claims 1 to 4, wherein said cylinder head is adaptable for various alternate fuels.

5. The Cylinder head for two cylinder IC engine as claimed in claims 1 to 5 wherein wall thickness around coolant jacket, combustion chamber and cam shaft housing are decreased to reduce use of material in the cylinder head and to increase efficiency.

6. An internal combustion engine comprising a cylinder head as claimed in all or any one of the preceding claims.

7. A Cylinder head for two cylinder IC engine as hereinabove described with reference to the accompanying drawings.