WO2010035286A1

WO2010035286A1 - Integrated balancing and cooling system for ic engines

Info

Publication number: WO2010035286A1
Application number: PCT/IN2009/000529
Authority: WO
Inventors: Venugopalan Pattabiraman; Vinay Chandrakant Harne
Original assignee: Tvs Motor Company Limited
Priority date: 2008-09-29
Filing date: 2009-09-29
Publication date: 2010-04-01
Also published as: AP3835A; AP2011005641A0; WO2010035286A4

Abstract

An integrated balancing and cooling system (300) (IBCS) for an internal combustion (IC) engine is described herein. The IBCS (300) includes a shaft (130), a counter-weight (135) and an impeller (210). The shaft (130) is rotatably coupled to a crankshaft of the IC engine with a transmission ratio of 1:1. The counterweight is mounted on the shaft (130) to follow the motion of the shaft (130). In addition, the impeller (210) is axially mounted on the shaft (130) and is located in a coolant pump chamber of the IBCS (300). A direct mounting of the impeller (210) on the shaft (130) enables the impeller (210) to rotate at a speed of rotation of the crankshaft of the IC engine.

Description

INTEGRATED BALANCING AND COOLING SYSTEM FOR IC ENGINES TECHNICAL FIELD

The subject matter described herein, in general, relates to an internal combustion engine and in particular, relates to balancing and cooling system for internal combustion engines.

BACKGROUND

Internal combustion (IC) engines are used in vehicular, industrial, commercial and marine applications. The internal combustion engines can be classified as petrol engines and diesel engines. The usage of the petrol engines is more prevalent in vehicular applications like cars, scooters, and bikes than the diesel engines due to their compact size, light weight, smooth operation with high power output, and better throttle response. On the other hand, the diesel engines are largely used in heavy duty vehicles such as earth movers, dumpers, trucks, medium and light commercial load carriers, and more recently in utility vehicles and passenger cars. In industries, the diesel engines are used in generators, air compressors, and marine applications. As the diesel engines have higher fuel efficiency and better torque characteristics than their counterparts, their usage in light vehicles such as cars, scooters, motorcycles needs to be propagated more and on a larger scale.

As well known in the art, the diesel engine is a compression ignition type engine and thus requires significantly large and heavy moving components. During operation, a number of components inside the engine, such as crankshaft, pistons, and gears, function in tandem for reliable operation. As reciprocating motion of the piston is converted into rotary motion of the crankshaft, a large amount of vibration is caused by virtue of unbalanced forces that are caused as a result of reciprocation of the piston and rotation of the crankshaft, crankpin etc.

These unbalanced forces originate from center-line of a rotating crankshaft and are oriented along axis of the piston.

Such vibrations get transmitted to an operating machine or a vehicle associated with the engine, to which the engine supplies its rotary driving power. These type of vibrations can be annoying to a user who is handling or driving the vehicle/machine and may also shorten the life of components of the engine. Usually, a primary balancing system is employed in single cylinder engines for restricting the undesirable vibrations caused by the primary order unbalanced forces within tolerable limits.

In addition, the operation of gears in tandem with each other causes unwanted noise within a transmission assembly of the IC engine. The production of such noise is attributed to an unwanted but necessary characteristic exhibited by the gears, which is known as "backlash".

Furthermore, substantially large amount of heat that is generated inside the engine, particularly in diesel engines, on account of combustion of fuel in a fuel combustion chamber, is rejected to the coolant. Ih the absence of an effective cooling system, the heat rejected can cause temperature rise to go beyond the permissible heat tolerance limits of the IC engine material, thus subjecting the components inside the diesel engine assembly to thermal stress and degradation. A cooling system, such as an air cooling system or a liquid cooling system, is employed to curb the extent of temperature increase in IC engine components and operate at acceptable thermal limit for long durability. However, implementation of both the balancing and the cooling systems within the assembly of the diesel engine involves employment of additional shafts, counterweights, chain-pulley mechanisms etc. Such employment of additional components adds to the number of components, which in turn adds to the weight and size of the components within a diesel engine assembly. As a result, the manufacturing cost and the maintenance cost associated with the diesel engine rise considerably.

SUMMARY

The subject matter described herein is directed to an integrated balancing and cooling system for an internal combustion (IC) engine. The integrated balancing and cooling system includes a shaft that is rotatably coupled to a crankshaft of the IC engine. A counter- weight is mounted on the shaft and accordingly follows motion of the shaft. Likewise, an impeller is mounted on the shaft and thereby follows the motion of the shaft to pressurize a coolant liquid.

The integration of the balancing system and the cooling system eliminates the usage of a number of intermediate components like motion transmitting shafts, chain-pulley arrangement etc., for transmitting the motion from the crankshaft of the IC engine to the impeller. As a result, the overall weight and size of the IC engine is significantly reduced. Moreover^ a direct mounting of the impeller on the shaft reduces transmission losses caused by employment and operation of the aforesaid motion transmitting means. In addition, an improved regulation of the coolant liquid throughout the IC engine is achieved. These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF DRAWINGS

The above and other features, aspects, and advantages of the subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig. 1 illustrates a schematic representation of an exemplary liquid cooled internal combustion engine, according to an embodiment of the present subject matter.

Fig. 2 illustrates a sectional view of the internal combustion engine of Fig. 1, thereby depicting the integrated balancing and cooling system in accordance with the embodiment of the present subject matter.

Fig. 3a illustrates a sectional view of an exemplary integrated balancing and cooling system in the liquid cooled internal combustion engine, according to an embodiment of the present subject matter.

Fig. 3b illustrates an isometric view of the exemplary integrated balancing and cooling system of Fig. 3a according to the embodiment of the present subject matter.

DETAILED DESCRIPTION The subject matter described herein relates to integration of a balancing system and a cooling system in a liquid-cooled internal combustion engine. The balancing system of the IC engine includes a shaft, an integral gear and a counter-weight. The shaft is driven by the integral gear, which in turn is driven by a primary gear of the IC engine. The integral gear may also be referred as balancer gear. The primary gear is mounted on the crankshaft and meshes with the balancer gear with a transmission ratio of 1:1. In addition, the balancer gear is mounted on the shaft. Accordingly, the shaft is rotatably coupled to the crankshaft with a transmission ratio of 1 : 1 and thereby gets rotated at the speed of rotation of the crankshaft. In addition, the counter-weight is mounted on the shaft to follow the motion of the shaft. A simultaneous motion of the shaft and the counter-weight helps in reducing the vibrations caused by unbalanced forces that propagate along the axis of a piston of the IC engine.

Further, the cooling system that is integrated with the balancing system of the present IC engine includes an impeller located within a coolant pump chamber of the integrated balancing and cooling system. The impeller is directly mounted on an extreme end of the shaft and follows motion of the shaft. The impeller facilitates pressurizing and thereby pumping of a coolant liquid at a high velocity inside the coolant pump chamber. The high velocity flow of the coolant liquid enables effective circulation of the coolant liquid into different sections of the liquid cooled IC engine for cooling purposes.

Furthermore, the impeller is directly driven by the shaft at the speed of the crankshaft. This direct drive of the impeller by the shaft in the present system advantageously eradicates the usage of a plurality of additional motion transmitting components like pulley-chain arrangement, splined shafts, hollow shafts etc which are otherwise typically employed as a motion transmitting means between the crankshaft and the impeller. This leads to reduction in the overall weight and size of the IC engine as well as transmission losses caused by operation of the motion transmitting means.

The present integrated and balancing system may be used in various applications that employ usage of IC engines. Accordingly, the integrated balancing and cooling system of the present subject matter may be employed in an IC engine assembly of heavy vehicles like trucks, buses, trailers etc. Also, the integrated and balancing system may be employed in other vehicles like cars. hi addition, the present integrated balancing and cooling system may be employed in two wheeled vehicles like motorcycles, scooters, mopeds etc., to minimize vibratory forces and provide optimum cooling of the components of the IC engine assembly. Such optimum cooling of the components of the IC engine assembly in the two wheeled vehicles is facilitated by the provision of a liquid cooling mechanism of the present integrated balancing and cooling system. Fig. 1 illustrates a schematic representation of an liquid cooled internal combustion

(IC) engine 100 with an integrated balancing and cooling system. According to an embodiment of the present subject matter, the IC engine 100 includes a connecting rod 110, a crankshaft 115, a piston assembly (not shown in Fig. 1) and a primary gear 120, all aforesaid constituting a primary motion transmitting system of the IC engine 100. The connecting rod 110 of the primary motion transmitting system connects a piston (not shown in Fig 1) of the IC engine 100 with the crankshaft 115 through a needle roller bearing (not shown in Fig 1). The primary gear 120 is operably connected to the crankshaft 115 and rotates with the speed of rotation of the crankshaft 115.

The IC engine 100 further includes a balancer gear 125 which meshes with the primary gear 120 with a transmission ratio of 1:1. The balancer gear 125 is mounted on the balancer shaft 130. Accordingly, the shaft 130 is rotatably coupled to the crankshaft 115 with a transmission ratio of 1:1. In addition, a counter-weight 135 is mounted on the shaft 130 to follow motion of the shaft 130. In another embodiment, the counter-weight 135 and the balancer gear 125 are integral to the shaft 130. It may be inferred that the shaft 130, the balancer gear 125, and the counter-weight 135 constitute a balancing system of the IC engine

100.

Further, a crankcase housing 140 of the IC engine 100 supports all aforesaid components under the primary motion transmitting system and the balancing system.

As known in the existing art, the combustion of fuel inside the combustion chamber of the IC engine 100 provides reciprocating motion to a piston (not shown in Figure 1) located inside a cylinder (not shown in Figure 1) of the IC engine 100. The connecting rod 110 transfers the motion of the piston to the crankshaft 115 by way of conversion of the reciprocating motion of the piston into rotary motion of the crankshaft 115. The primary gear 120 acts as a motion transmitting means to facilitate transmission of the rotary motion of the crankshaft 115 to a drive-train system (not shown in Fig 1) and to various other components of the IC engine 100.

In the present embodiment, the primary gear 120 is in continuous mesh with the balancer gear 125 for transmitting a rotary motion. As the balancer gear 125 is mounted on one end of the shaft 130, the rotation of the primary gear 120 due to rotation of the crankshaft

115 results in the rotation of the shaft 130. Further, the counter-weight 135 having a considerable mass is mounted on the shaft 130 with appropriate orientation by using any mechanism known in the art. Such mass may be determined by computation of balancing factor for the IC engine 100. The mass is suitably distributed between the crankshaft 115 and the shaft 130 to achieve maximum balancing of the primary unbalance forces.

The mounting of the counter-weight weight 135 onto the shaft 130 facilitates rotation of the counter-weight weight 135 along with the rotation of the shaft 130. Accordingly, the rotation of the counter-weight 135 helps in reducing the vibrations caused by primary unbalance forces that lie along the axis of the piston of the IC engine 100. Fig. 2 illustrates a sectional view of the IC engine 100 of Fig. 1. As shown herein, the

IC engine 100 includes the crankshaft 115, the primary gear 120, and the shaft 130 supported in the crankcase-housing 140. The counter-weight 135, the balancer gear 125, and an impeller 210 are axially mounted on the shaft 130. The impeller 210 is directly mounted on the shaft 130 without any intermediate motion transmitting means. Accordingly, the rotation of the shaft 130 translates into rotation of the impeller 210.

Further, the balancer gear 125, the shaft 130 and the counter-weight 135 are enclosed in a clutch side chamber 215, which acts as an enclosed portion of the crankcase-housing 140. The clutch side chamber 215 includes a reservoir for storage of transmission oil that is used for lubrication of different components of the IC engine 100. In addition to the clutch side chamber 215, another enclosed chamber that forms another enclosed portion of the crankcase housing 140 is a coolant pump chamber 220.

The coolant pump chamber 220 surrounds the impeller 210 and a small portion of the shaft 130 preceding the impeller 210. In operation, the coolant pump chamber 220 receives a flow of a coolant liquid from a coolant liquid reservoir (not shown in Fig. 2) and pumps it to different sections within the IC engine 100 for cooling purposes. The aforesaid pumping action is facilitated by the rotation of the impeller 210. The rotating impeller 210 pressurizes the incoming coolant liquid from the coolant liquid reservoir and provides the pumping action to the coolant liquid. The rotation of the impeller 210 forces the coolant liquid to circulate through different components of the IC engine 100 like a cylinder block or a cylinder head, and thereby helps in cooling the component.

In the present embodiment of the subject matter described herein, the vane design of the impeller 210 is optimized to deliver desired coolant flow when the impeller 210 rotates at the speed of crankshaft 115. The speed of rotation of impeller 210 is determined based on a transmission ratio of 1 : 1 between the crankshaft 115 and the shaft 130. As the impeller 210 is directly mounted on the shaft 130, the impeller 210 gets directly driven from the shaft 130 and rotates at the speed of rotation of the crankshaft 115.

Fig. 3a and Fig. 3b illustrate a sectional view and an isometric view of an integrated balancing and cooling system (IBCS) 300, respectively, with respect to an embodiment of the subject matter described herein. The IBCS 300 includes a balancing system and a cooling system directly connected to each other. In one embodiment of the present subject matter, the balancing system of the IBCS 300 includes the balancer gear 125, a scissor gear 301, the shaft 130, the counter-weight 135, and a plurality of bearings 310-1 and 310-2. The cooling system of the IBCS 300 includes the impeller 210 present inside the coolant pump chamber 220. The shaft 130 of the IBCS 300 is firmly supported inside the crankcase housing 140 of the IC engine 100 with the help of the plurality of bearings 310-1 and 310-2. In an implementation, the shaft 130 is rotatably supported inside the housing 140 by employing the bearings 310-1 and 310-2. For sake of convenience, the bearings 310-1 and 310-2 hereinafter are collectively referred to as 310. As discussed previously, the shaft 130 rotates inside the crankcase housing 140 at the same angular velocity as that of the crankshaft 115. Accordingly, the rotation of counterweight 135 caused by the motion of the shaft 130 generates a force vector that lies into the plane of the aforementioned unbalanced forces. However, as the shaft 130 rotates in a phase that differs from the phase of rotation of the crankshaft 115 by 180 degrees, the direction of the generated force vector is linearly opposite to the direction of the unbalanced force. Accordingly, the unbalanced force is balanced or canceled by the generated force vector, hi addition, the shaft 130 acts as a motion transmitting means by facilitating rotation of the impeller 210 at a speed of rotation of the crankshaft 115. Further, the scissor gear 301 employed in the present IBCS 300 is a zero backlash gear and may be referred as a zero backlash gear 301. The scissor gear or zero backlash gear 301, in attachment with the balancer gear 125, helps in reducing the extent of unwanted noise that is generated by the operation of the balancer gear 125 in mesh with the primary gear 120. Li one implementation, the scissor gear 301 may be axially coupled to the balancer gear 125 by any elastic means 305 like a compressible spring. However, the scissor gear 301 is detachable and not integral to the balancer gear 125.

Specifically, the coupling of the scissor gear 301 with the balancer gear 125 results in formation of a combined gear. The combined gear so formed is positioned in a continuous mesh with the primary gear 120. The positioning of the combined gear reduces backlash that occurs by virtue of the continuous meshing of the balancer gear 125 and the primary gear 120 without the employment of the scissor gear 301.

The IBCS 300 further includes a radial oil sealing ring 315, a face water seal 320, and an air gap 325 with a drain hole. The air gap 325 is located between the radial oil sealing ring 315 and the face water seal 320. The coolant pump chamber 220 is separated from the clutch side chamber 215 to prevent seepage of transmission oil from the clutch side chamber 215 towards the coolant pump chamber 220. In addition, such separation prevents seepage of the coolant liquid from the coolant pump chamber 220 to the clutch side chamber 215.

Specifically, the radial oil sealing ring 315 is adapted to prevent the seepage of the transmission oil from the clutch side chamber 215 to the coolant pump chamber 220. The radial oil sealing ring 315 is located on an adjoining boundary of the clutch side chamber 215 and the coolant pump chamber 210 and is positioned within clutch side chamber 215. In addition, the face water seal 320 is located on the same adjoining boundary and positioned within the coolant pump chamber 220. The face water seal 320 prevents seepage of the coolant liquid from the coolant pump chamber 220 towards the clutch side chamber 215. In one implementation, the radial oil sealing ring 315 and the face water seal 320 are cylindrical in shape, immovably and circumferentially disposed on the shaft 130. In addition, the radial oil sealing ring 315 and the face water seal 320 are disposed on the shaft 130 in such a way that the air gap 325 is located between the two sealing rings 315 and 320. Such air gap 325 serves as a drain hole and facilitates disposal of leaking coolant liquid outside the IC engine 100.

The previously described versions of the subject matter and its equivalent thereof have many advantages, including those which are described below:

The IBCS 300 prevents employment of additional motion transmitting means, such as chain-pulley mechanisms, hollow shafts, splined shafts, camshafts etc which are needed in a group of two or more for connecting the cooling system with the crankshaft 115 of the IC engine 100.

Instead, the present IBCS 300 describes the shaft 130 as a motion transmitting means for the cooling system. This helps in reduction of size and weight of the IC engine 100. Due to the elimination of additional motion transmitting components, transmission losses associated with the operation of chain-pulley mechanisms, hollow shafts, splined shafts, camshafts etc. are reduced. Additionally, the shaft 130 of the present system 300 helps in canceling the vibrations caused by the primary order unbalanced forces.

Moreover, unwanted noise production by the operation of meshed gears is prevented by employment of the scissor gear 301.

Also, the direct drive of the impeller 210 by the shaft 130 enables efficient pumping of the coolant inside the IC engine 100.

In addition, the present IBCS 300 facilitates provision of a liquid cooling mechanism in two-wheeled vehicles like motorcycles, scooters etc. Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained.

Claims

IAVe claim:

1. An integrated balancing and cooling system (300) for an internal combustion (IC) engine (100), said system (300) comprising: a shaft (130); a counter-weight (135), wherein said counter-weight (135) is mounted on said shaft (130) and follows the motion of said shaft (130); characterized in that, an impeller (210) mounted on said shaft (130) to follow motion of said shaft (130) for pressurizing a coolant fluid.

2. The integrated balancing and cooling system (300) as claimed in claim 1, wherein said shaft (130) is rotatably coupled to a crankshaft (115) with a transmission ratio of 1:1.

3. The integrated balancing and cooling system (300) as claimed in claim 2, wherein said crankshaft (115) drives a primary gear (120) mounted on said crankshaft (115) and wherein said primary gear (120) meshes with a balancer gear (125) mounted on said shaft (130).

4. The integrated balancing and cooling system (300) as claimed in claim 3, wherein said balancer gear (125) is axially coupled to a scissor gear (301) by an elastic means (305) and wherein said scissor gear (301) meshes with said primary gear (115).

5. The integrated balancing and cooling system (300) as claimed in claim 1, wherein a pair of bearings (310) rotatably support said shaft (130) inside a crankcase housing

(140) of said IC engine (100).

6. The integrated balancing and cooling system (300) as claimed in claim 1, wherein a radial oil sealing ring (315) and a face water seal (320) are immovably and circumferentially disposed over said shaft (130) at an adjoining boundary of a clutch side chamber (215) and a coolant pump chamber (220).

7. The integrated balancing and cooling system (300) as claimed in claim 6, wherein said radial oil sealing ring (315) is disposed within said clutch side chamber (215) and said face water seal (320) is disposed within said coolant pump chamber (220).

8. The integrated balancing and cooling system (300) as claimed in claim 6, wherein said radial oil sealing ring (315) and said face water seal (320) are spaced apart with a drain hole (325).

9. An IC engine (100) comprising an integrated balancing and cooling system (300) as claimed in any of the preceding claims.

10. A two-wheeler comprising an IC engine assembly wherein said IC engine assembly comprises an integrated balancing and cooling system (300) as claimed in any of the preceding claims.