WO2002073016A1 - A low cost new compression ignition internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency - Google Patents

Abstract

Comprising crank mechanism (29) consisting reduced friction sliding and turning pairs wherein said crank mechanism is provided with at least one lighter mass better dynamic response crankshaft (15) with no/reduced counter weight (21) and/or flywheel (22) mass reducing harmful dynamic forces further lowering frictional force and mechanical loading, at least one air regulating mechanism having equal inlet and outlet port openings communicating with at least one reduced interference and plenum volume manifolds being provided in cylinder head and/or on cylinder, said openings being opened or closed by valves or piston with no/minimum stroke overlap timing events to eliminate harmful dynamic force, reduce pumping force and thereby increase gas force improving gas flow characteristics, at least one fuel regulating mechanism for faster injection of large quantity, shortening auto-ignition being facilitated by lower air compression pressure and fuel injection pressure due to increased air movements.

Description

TITLE OF INVENTION

A low cost new compression ignition internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency. TECHNICAL FIELD The present invention relates to a low cost new compression ignition (CI) internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency and in particular an improved CI internal combustion engine with improved engine cranking, air and fuel regulating mechanism resulting in a better compression-ignition combustion process, thereby making safe commercial utilization of low cost fuels & lubricants, and simplifying the said engine design which is capable of being used with all compression-ignition system fuel oils or gases economically and efficiently, thus resulting in obtaining higher torque and power densities, increased fuel economy, decreased exhaust pollution, and overall reduction in engine weight without compromising safety and reliability factors and hence lowering the cost of the said engine. BACKGROUND ART

It is observed that in any CI Internal Combustion engine by virtue of adopted conventional hydrodynamic lubricating mechanism, mechanical friction is high at low speed where as fluid friction is high at higher speed but overall friction force is low only at middle operating speed range of an engine. The harmful inertia forces decrease with the decrease in engine reciprocating and rotating masses, however, for reducing the mechanical and thermal loading of current engine there is a limitation. It is seen that both friction and inertia forces affect relative movement of moving masses. Now providing additional masses as counter weights currently, reduces the rotating inertia forces. An another additional rotating mass disc in the form of flywheel is also connected at one end of the crankshaft, which stores energy to carry the piston over compression stroke. In addition, crankshafts are too strengthened at main journals, crank webs and crank journals to withstand lateral & torsional vibrations caused by bending and torsional stresses created by gas loads and inertia forces. However, these additional rotating masses affect crankshaft relative movement due to increase in weight due to the said strengthening. It is also observed that due to mechanical stress and gas inertia effect considerations, valve lead and valve lag are provided in current engine valve timings, though with this improved performance there is a reduction of volumetric efficiency, expansion work, full load economy and emission control besides part load and idling operations also suffer. Increased valve overlap timings thus increase manifold interference promoting manifold clot, gas flow loss due to back pressure, back flow, pressure drop, and reduce gas pulsation effect based on which cylinder filling with fresh air charge and cylinder clearing of exhaust residuals depends. It is seen that there is also a limitation in decreasing manifold plenum volume for prompt and correct charge distribution to each cylinder which again this also affects the air movement, density and heat of compression factors which control compression- ignition and combustion process.

It is known that the liquid fuel regulation for the compression-ignition system are currently done with a either higher injection pressure mechanical or electronic fuel injection device, which not only make liquid fuel regulation system costlier but there is also an inherent problem in maintaining correct mixture strength more closer to appropriate fuel-air ratio for all climatic, load and speed operating conditions besides it give rise to difficulties in controlling exhaust pollutions.

Moreover, expensive modifications are required when alternate fuel bio-fuels or fuel gas such as compressed natural gas (CNG) is used and the same increases additional cost of regulation besides changes in compression ratio or injection timing of engines is necessary for optimizing performance.

In practice, it is observed that at present compression ratio of conventional CI internal combustion are kept higher enough not to create starting difficulties with subsequent inherent hydrocarbon emission, to increase thermal efficiency with compromised mechanical efficiency and to avoid combustion knock behaviour, which impose a limitation in controlling physical and chemical aspects of compression- ignition combustion of a liquid or gaseous fuel.

Moreover, in order to ensure engine maximum performance and control rate of combustion for various speed and load operating, advance injection static timings and centrifugal advance mechanisms are also incorporated in a conventional CI internal combustion engine. This increases possibility of mechanical and thermal loading more particularly at low speed-high load operating conditions. In addition, it is obvious that physical ignition delay of cetane rated fuels limits the quality of fuels to be used in a CI internal combustion engine. A co-pending PCT international publication no. WO/0040840 dated July 13,

2000 of the present applicant who is also the inventor, discloses a method of reducing mechanical and fluid friction at engine rubbing pairs by incorporating an improved lubricating system consists of forming a plurality of lubricating oil grooves at the interface cylindrical bearing surfaces of the moving contacting parts, which partly obviates disadvantages and draw back associated with conventional CI internal combustion engine, however, it is found having larger potential beyond disclosure and therefore, opens avenue for further reduction/elimination of inherent difficulties associated with the economical designing and efficient operation of CI internal combustion engine, which necessitates the filing of the present application for patent. Accordingly, an object of the present invention is to provide a low cost new

CI internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency, which is novel in its construction and obviates all disadvantages and drawbacks associated with the exiting CI internal combustion engine, which is simple in its construction, cheap in original costs and most important is its wide applications for automotive, locomotive, marine, industrial, agricultural and all other piston-type reciprocating current as well as under production CI internal combustion engine giving real performance benefits to the user.

Another object of the present invention is to provide a low cost new CI internal combustion engine, which facilitates safe commercial utilization of low cost fuels & lubricants, having higher torque and power densities, increased fuel economy, decreased exhaust pollution, and overall reduction in weight and hence lowering the cost of an engine.

A furthermore another object of the present invention is to provide a low cost new CI internal combustion engine having a novel slider-crank mechanism to increase relative motion of sliding and turning pairs by reducing reciprocating and rotating masses and thereby lowering harmful friction and inertia forces in order to improve gas load performance and crankshaft dynamic response.

Yet a further object of the present invention is to provide low cost new CI internal combustion engine having an improved air regulating mechanism with a novel gas exchange process, which increases overall work done by gas, eliminates ill- effect of inertia forces of moving masses and facilitates effective control of fundamental variables governing compression-ignition combustion process.

A still another object of the present invention is to provide low cost new CI internal combustion engine, which is having an improved cost effective liquid fuel regulating mechanism to proportionately supply liquid fuel with a higher fuel velocity relative to air to a definite limit demanded by compression-ignition system so that a better quality heterogeneous mixture is internally prepared at the earliest for reducing physical ignition delay of the fuel Yet a still object of the present invention is to provide low cost new CI internal combustion engine, which is having an improved combustion chamber resulting in an lower compression ratio, so as to reduce physical delay of fuel inorder to speed up diffusion combustion reaction and thereby minimizing combustion lag.

Another further object of the present invention is to provide low cost new CI internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency reducing static fuel injected timing with no centrifugal advance injection mechanisms for controlling increased rate of self sustaining chemical reaction and resultant gas expansion to cope up with corresponding fast enlarging cylinder volume achieved by increased crank dynamic response in order to reduce mechanical/thermal loading and explosive gas reactions eliminating power loss.

A still anothef object of the present invention is to provide low cost new CI internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency facilitating use of severe low cetane rating fuel due to relative increase ψ engine sensitivity by use of low cost fuels. A further object of the present invention is to provide low cost new CI internal combustion engine and method of operating said engine with increased mechanical and thermal efficiency facilitating use of low cost lubricant oil without certain additives making it cheaper in cost. DISCLOSURE OF INVENTION:

Keeping the above objective in mind, the present invention thus provides a low cost new CI internal combustion engine comprising cranking mechanism consisting of sliding and turning cylindrical rubbing pairs having a plurality of open or closed end circular and/or axial and/or helical lubricating oil grooves formed on the inner/outer contacting bearing surfaces for generating self controlled hydro- dynamic lubrication regime which reduce mechanical and fluid friction and increase relative motion at varying engine speed-load operating conditions, air regulating mechanism valves mechanically actuated by a valve control mechanism parts having rubbing pairs provided with a plurality of said lubricating oil grooves, a fuel regulating mechanism, a combustion chamber, a injection timing mechanism, characterized in that, the said crank mechanism is provided with atleast one lighter mass better dynamic response crankshaft mechanically connected to rotating and reciprocating engine parts reducing harmful friction forces resulting from the relative motion of said sliding and turning cylindrical rubbing pairs, thus lowering the resultant centrifugal/inertia disturbing forces and couples produced by the changing motions of rotating/reciprocating masses, a lighter mass counter weight if desired, an additional rotating mass if desired, carried on said crankshaft webs out of balance to oppose and neutralize the resultant disturbing forces and its couples, a lighter mass flywheel, another additional rotating masses is attached to the free end of crankshaft storing required additional energy during power stroke to propel engine during other strokes as a result of converting disturbing force into constructive or useful force; the said air regulating mechanism having an inlet and an outlet port openings in cylinder head and/or on cylinder which are opened/closed by valves or uncovered/covered by piston to control both admission of fresh air and expulsion of exhaust gas to and from cylinder, atleast one intake manifold communicating with inlet port openings to distribute fresh air to individual cylinders and atleast one exhaust manifold communicating with outlet port openings to channel out exhaust gas from individual cylinders into a central pipe, the said inlet port opening being reduced to the current outlet port opening size and equalizing said inlet and outlet ports opening areas so as to increase practical volumetric efficiency at all speeds and system operates with no/minimum overlap timing events effecting in reducing cylinder head, manifold size, plenum volume and weights; the said fuel regulating mechanism is provided with atleast one mechanical jerk injection pump consists of increased diameter and reduced height plunger having minimum activeland less than inlet port diameter providing more head clearance with reduced maximum fuel displacement volume from starting fuel quantity to full load enabling proper filling, faster injecting and cut-off of fuel, a pump camshaft having high lift cam coimnunicating with a lower contact stress roller and a lower friction tappet imparting faster pumping action to said plunger which is being twisted faster by a fuel control rod movement varying effective stroke, mechanically connecting said pump camshaft through lighter governor flyweights acting against a lower stiffness governor spring and a control lever movement enabling faster injection of larger quantity of accurately metered fuel before ignition for proper utilization of regulated air received from said air regulating mechanism reducing physical ignition delay; the said combustion chamber resulting lower compression ratio for proper combustion of regulated fuel-air received from said air and fuel regulating mechanism; and the said a injection timing mechanism with reduced fixed static injection timing and without centrifugal advance mechanism for controlling timing of proper ignition of heterogeneous combustible mixture obtained from said air and fuel regulating mechanism eliminating power loss. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature of this invention and to show how the same may be carried into effect, reference will now be made to the accompanying drawings in which: FIG 1 is a side view of the slider-crank mechanism of the present invention shows sectioned cylinder, piston and crankshaft, and eliminated counter weight and flywheel in phantom.

FIG 2A & 2B shows a side section view of crankshaft of the present invention and the prior art respectively. FIG 3 shows a side section view of camshaft of the present invention.

FIG 4 shows a side section view of a typical jerk pump-pipe nozzle system modified according to the present invention.

FIG 5 shows a side section view of a typical direct injection CI type combustion chamber modified according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please note that most of the elements of CI internal combustion engine are common with those of the prior art CI internal combustion engine so that further explanation for the elements common to both the invention and the prior art is thus not deemed necessary. In the co-pending PCT international publication referred earlier it is disclosed how to improve kinematics of motion or relative motion at engine bearings by implementing an improved lubricating mechanism consists of forming a combination of suitable open or close end circular, axial or spiral lubricating oil grooves, on the inner and/or outer cylindrical bearings contacting surfaces in engine sliding and turning pairs, for the reduction of mechanical and fluid frictions on account of development of effective self controlled hydrodynamic lubricating film with reduced contact area to improve relative motion in all operating conditions at bearing interface contributing for the overall improvement in the mechanical efficiency of an CI internal combustion engine. These enhanced relative sliding and turning motions reduce reaction force at engine rubbing pairs whereby increase useful force of cylinder gas pressure or gas load acting on the top of piston whereas minimize harmful inertia forces of reciprocating and rotating engine component masses, wherein kinetics of motions to control resultant inertia force and couples balancing and reduce vibrations in an engine are changed, which need to be modified and suitably optimized, which is described below by a novel method so that over all relative motion of moving masses is increased for a specific gas load by reducing weight of reciprocating and rotating engine parts.

Shown in Fig. 1 is an improved engine slider-crank mechanism 29 consists of one sliding pair with piston skirt 4 - cylinder liner 2 and three turning pairs with four interfaces piston boss 5 - piston pin 6, piston pin 6 - connecting rod small end bearing 7, connecting rod big end bearing 11 - crank journal 12 and main journal 14 - main bearing 13 in which a plurality of parallel circular cross-cutting with open end axial oil grooves (not shown) are formed on the out surface of the piston skirt 4, a pair of cross-cut helical grooves with open ends and a circular oil groove communicating with cross-cut points (not shown) are formed on the inner surface of piston boss 5 and on the inner surface of connecting rod small end bearing 7, circular grooves communicating with axial grooves and pressurized supply oil hole are formed on the inner surface of both connecting rod big end bearing 11 and main bearing 13. Briefed above is one of the many methods of forming oil grooves, which are described in the referred co-pending publication and hence not elaborated with figures, reducing friction force at rubbing pair and at the same time improving its relative motions at all engine speed-load operating conditions.

As a result of reducing both mechanical and fluid friction force at sliding and turning rubbing pairs of engine slider crank mechanism 29 increases both piston 1 stroking effect in cylinder liner 2 housing and crankshaft 15 turning effect with respect to main bearing 13 housing as both housings are mechanically connected to a common block or engine frame.

Now consider gas pressure 24 or gas load acting on the top of piston 1 which is resolved into two types of forces: tangential force 27 turning crankshaft 15 and piston side thrust force 25 on cylinder liner 2 walls. To these is added centrifugal force 26 produced by the rotation of crankshaft 15 with all rotating and reciprocating engine components attached to it.

It is well known that indicated work is the work done by the gas where as brake work is the done by the crankshaft. Now piston side thrust force 25 or piston inertia load which switches sides as the piston passes through Top Dead Center (TDC) and Bottom Dead Center (BDC), and near TDC the friction force changes sign have been minimized because of development effective lubricating mechanism in piston-cylinder liner interface 3 even when piston 1 rests at either dead centers. Piston side slap or inertia force fluctuation is also reduced between each piston strokes whereby lowers piston rings (not shown) inertia loading and helps in minimizing accumulation of forces in piston 1 as well as piston rings, which also contributes for effective sealing action at piston-cylinder liner interface 3 and in addition, improve relative sliding motion enhancing piston 1 pumping effect with reduced effort during expansion, exhaust, suction or compression periods.

During expansion, thus an enhanced gas load 24 component is transmitted to connecting rod small end bearing 7 via piston boss 5 and piston pin 6, which constitutes a turning pair at the small end of connecting rod 20. These piston pin bearings on the piston pin 6 oscillates back and forth without completing a revolution, however said open end oil grooves provided at piston boss 5 - piston pin 6 and piston pin 6 - connecting rod small end bearing 7 receives oil via helical oil groove open ends and distributes to entire bearing length so even with oscillating motion effective hydro dynamic lubrication regime with sufficient oil film thickness is formed as a result reduce inertia force on piston 1, piston pin 6 and connecting rod small end 7 and enhance turning effort whereas minimize accumulation and fluctuation of forces in the components at this turning pair.

Similarly said oil grooves provided at connecting rod big end bearing 11, which oscillates in addition to crank journal 12 rotation, develops oil film of sufficient strength enhancing tangential force 27 component whereas reducing centrifugal force 26 component. In addition reduce inertia load, minimize fluctuation as well as accumulation of forces at this turning pair. The above description hold good for the last turning pair comprising crankshaft main journal 14, which rotates and main bearing 13 which is stationary and hence development of sufficient thickness oil film with said oil grooves counter peak gas pressure 24 by properly regulating this useful force to produce more work at crankshaft 15 drive end as the harmful inertia forces of moving parts are being reduced.

In addition, reducing or elimination of destructive heating at engine rubbing pairs on account of minimizing mechanical and fluid friction assists in maintaining operating viscosity of lubricating oil as well as working clearance at rubbing pair interface whereby contribute for the generation of effective oil film of sufficient strength at various speed-load engine operating conditions so that reaction load of minimized fluctuating inertia forces caused by reciprocating mass on account of piston uneven movement acting on engine bearings are effectively reduced as it is countered by oil film pressure at improved sliding and turning pairs. Hence the deviation between maximum bearing pressure and mean bearing pressure is considerably reduced even during maximum gas load fluctuation.

Due to obliquity of connecting rod 20 inertia forces are greater at TDC crank position than at BDC position, which necessarily results in an inbalance of forces that cannot be balanced simply by attaching counter weight 21 on the opposite side of the crank journal 12. As a result, both primary and secondary forces act in the same direction at TDC whereas at BDC the secondary force opposes the primary force. The secondary forces at TDC and BDC therefore point in the same direction towards TDC and are referred to as being positive.

The overall magnitude of inertia forces are perfectly countered and eliminated by directing this force to impart useful pumping work to the motive fluid or working gas as this is possible now due to reduction in friction force and modifying timing of gas pumping and exchange process, which is an another object of the present invention and is described in detail after slider-crank mechanism.

Now the magnitude of resultant forces of inertia of the reciprocating weight consists of piston 1, piston rings, piston pin 6, and weight of the upper end of the connecting rod 20 along with forces of inertia of rotating weight assumed to be concentrated at crank radius 19 which will produce a centrifugal force 26 equivalent to that of the entire crank structure, plus the weight of the lower end of connecting rod 20, are not only thus considerably reduced and in turn accumulation of forces in reciprocating and rotating mass are also minimized or eliminated. The resultant couples expected to be formed by the resultant inertia forces and supposed to be acting at various distances from the middle of crankshaft 15 are minimized. In addition, enhancement of engine slider-crank mechanism 29 overall relative movement, piston 1 pumping effect and crankshaft 15 turning effect or relative rotational speed are increased. Hence providing additional rotating mass as counter weights 21, placed opposite this cranks to take care of unbalanced couples and has for its chief object a more uniform loading and wear of main bearing 13, need to be minimized or eliminated which further improves effectiveness of slider-crank mechanism 29 as this additional mass otherwise accumulates centrifugal force 26 which resists its relative movement and thus acts as a frictional force.

Similarly flywheel 22, an additional rotating mass fastened to crankshaft 15 one end, solely to store kinetic energy during the power stroke and return it during the other strokes and also to help to start engine as well as to make the rotation of the crankshaft more or less uniform, need to be minimized or eliminated, as piston 1 pumping effect is enhanced whereas pumping effort is reduced. This still improves the effectiveness of slider-crank mechanism 29 as described above and thus reduce pump friction load, which interferes with the prompt transmission of gas pressure 24 or gas load from piston 1 to the driven shaft.

The reduction of counter weight 21 mass in a conventional crankshaft 15 is done in such a way that crankshaft 15 center of gravity coincides with its center line even after reduction, which can be tested by supporting its ends on two horizontal knife edges so that the shaft will be stable at any position on the cranks with no tendency to roll confirming that it is statically balanced.

The reduction of flywheel 22 mass is performed taking into account the weight of clutch cover assembly also, if provided to connect drive train, in such a way its weight is reduced to the barest minimum and in case, if it acts as a mounting surface for clutch cover assembly, a smaller size flywheel made of lighter weight material such as aluminum can very well be used along with proportionately smaller clutch cover assembly as the torsional stresses from torsional vibration are considerably reduced even at critical speeds, and at the same time taking care that the engine idling speed should not be affected. The relative side movements of revolving and reciprocating components pounding from side to side, that is bombardment of one component against another, in their respective clearances are minimized because of formation of effective thickness oil film. This avoids critical speed rumble and resonant torsional vibrations. Having reduced additional rotating masses another potential area is crankshaft mass as strong pulsating gas and inertia forces which give rise to torsional and bending stress are reduced. Current practice is to enlarge main journal radius 17b shown in Fig. 2B, by providing adjacent journal 12b with a certain amount of lateral overlap 31b, through this improves lateral rigidity of crankshaft 15b, the additional rotating mass provided by relatively increasing main journal radius 17b above crank journal radius 18b to design short crank throws without changing connecting rod length 28, interfere engine slider-crank mechanism 29 effective relative motion with respect to engine frame because it increases surface rubbing velocity between main bearing 13 and main journal 14. By virtue of combustion modeling in CI internal combustion engines, the instantaneous peak gas pressure is maximum when slider- crank mechanism 29 sliding and turning pairs are almost in line with cylinder axis and hence relative effectiveness of main journal 14b turning effect with respect to crank journal 12b turning effect is of immense importance therefore, according to the present invention, the additional mass from the journal overlap region of main journal 14b is removed to eliminate overlap in such a way that main journal radius 17b and crank radius journal 18b are atleast equal, which will not alter the crank throw or engine displacement volume, besides provide flexibility to crankshaft webs 9b.

An improved crankshaft 15 modified according to the present invention is shown clearly in Fig. 2A. Thus, because of reduction in cranking effort due to lowering reaction force at rubbing pairs and increase in cranking effect, a larger proportion of useful gas pressure 24 is converted into tangential force 27 which in turn increase crankshaft 15 torque and power output capabilities as the harmful inertia forces of reciprocating and rotating masses are minimized which lowers bearing loads and improve the relative motion of the component parts, avoid setting up of accumulation of forces or mechanical loading that tend to make engine shake and rock due to vibrations, which ensure perfect balancing with reduced counter weight 21 mass. In addition, influence of the periodic combustion impulses causing torsional and lateral oscillation of crankshaft 15, which initiate vibration of engine components due to the elastic deformation of the component parts are minimized. Because of reduction of reaction force at engine bearings, the embodiment according to the present invention, crankshaft 15 wherein dynamic balance has been built into the shaft without or with a relatively lighter counter balance 21 mass, torsional vibrations are reduced without or with a relatively lighter flywheel 22 mass, lateral stiffness and cranking effect enhanced with a relatively lighter main journal 14 mass having no j oumal overlap.

Thus an overall reduction of harmful friction force and dynamic force due to additional mass enable a relatively lower gas load to perform the same work at the output shaft, which indicates a reduced displacement volume is sufficient to do a particular operation. In two-stroke CI internal combustion engine with only piston-controlled port plurality of lubricating oil grooves, as described earlier, is formed on piston skirt area but not communicating with port areas.

Another object of the present invention is to improve gas exchange process with a novel timing of events having no/reduced overlap which coincide with theoretical timing operations, and more particularly, an improved gas exchange process to improve motive or working fluid movement by reducing scavenging and pumping loads so that increased mass flow rate of spent gas expelled out of cylinder to minimize residual fractions and increased mass flow rate of fresh air charge pulled in the cylinder to maximize practical volumetric efficiency inorder to maintain effective fresh air charge density to take care of ignition and combustion parameters. Valve controlled ports influence gas movements in an engine with suitable effective flow area and valve opening and closing timings and/or piston controlled ports with suitable port area timings.

Cams 36 and 37 constructed on camshaft 35, which is an embodiment of the present invention shown Fig. 3 actuate valves (not shown) via valve gear mechanism, which consists of rubbing pairs with plurality of suitable lubricating oil grooves formed, as indicated earlier and hence not described here, at either inner or outer surface of each cylindrical contacting pair to increase relative motion, reduce inertia force, mechanical loading and vibrations in the valve-gear mechanism. This increases the rapidity in which said valves are opened or closed and hence the opening lead or closing lag period provided in degrees of Crank Angle (C A) in the valve timing of current engine are not required. Moreover, said valves or piston actual movement with respect crank angle will be more closer to theoretically predicated movement because of reduction of disturbing inertia forces, which change gas inertia effect as well as gas flow characteristics of modified engine according to present invention.

Thus it becomes possible to optimize valve/port area timings with the object of minimizing open periods, during when the gas flow exchange process takes place and maximizing closed period, when the compression, heat addition and expansion processes take place and in addition stroke overlap periods are either eliminated or reduced which eliminate or reduce manifold gas interference and viscous friction where as improve all strokes performance.

Camshaft 35 consists of exhaust cam 36 so constructed inorder to open the exhaust valve exactly at BDC, which eliminates overlap of exhaust stroke with expansion stroke and exactly closes at TDC 38 comprising a total exhaust valve opening period of 180° CA. Similarly inlet cam 37 opens the inlet valve at TDC 38, which eliminates inlet and exhaust valve overlap period around TDC 38, which are usually provided in a current engine for scavenging purpose, and closes it exactly at BDC, which eliminates overlap with compression period comprising a total inlet valve opening period of 180 CA. As started earlier, the overlap if provided in three stroke events during valve open period to account for lag in mechanical movement and gas inertia effects ultimately interfere with consistency in gas movements and gas load 24 performance. Therefore, cams 36 and 37 actuate valves according to ideal valve timings of 180° CA for each stroke, enhance gas movement, fresh charge mass flow rate increase, enhancement in expansion work, improvement in compression efficiency where as reduce manifold interference in each cylinder and also between cylinders in multi- cylinder engines.

Hence, cam base circle can be increased to construct more uniform opening/closing ramps and flanks, which further reduce valve inertia force and vibrations.

Cam lift 39 needs to be minimized in order to reduce steepness of cam caused by shortening the opening period. Fortunately medium to low lift cam effectively operate poppet valve by maintaining a greater discharge coefficient, as more gas jet will fill the gap. Moreover, it is noticed if the intake port opening size is reduced to the current outlet port opening size, making both intake and outlet port openings equal, the practical volumetric efficiency is found consistently high for various load speed engine operating conditions. This is due to improved gas pulse effect and subsequent mass flow with minimum flow lag. Apart from reducing over all gas viscous friction, the other advantages are reduction of scavenge work based on gas pressure differential of intake and. exhaust systems, which influences short circuiting as well as back flow depending on engine operating conditions, enhancement of consistency in effective volumetric efficiency to take care of density and temperature factors of combustion parameters with minimized exhaust gas recirculation (EGR) because of generation of improved pulse effect and gas motion inside cylinder and in manifolds as the piston is functioning as a perfect vacuum pump which assists in the design of simpler fuel regulating mechanism to maintain more preferable fuel according to new engine demand, and also provides a method to effectively control exhaust pollutants. Instead of using camshaft to actuate valves, electro-magnetic or other device can be used separately or with a combination to operate specified valve timings. Automatically, the extra time provided for closed period facilitates for the proper completion of compression and expansion strokes.

In the case of piston controlled ports of two stroke CI internal combustion engines, relative height of scavenge and exhaust ports are reduced at the upper portion from BDC where as keeping the width of ports same so that overlap period is reduced. Such a reduction in overlap period is also possible in case of uniflow scavenging of two-stroke CI internal combustion engine where camshaft controlled exhaust valve is used as a combination.

As a result of eliminating/minimizing gas interference and viscous friction in both inlet and exhaust manifolds, plenum volume of manifolds could be reduced, which may be done by reducing plenum area with fixed length for induction manifolds where as both plenum area and length be reduced for constructing exhaust manifolds, wherein such manifolds became another embodiments of the present invention, which enhance gas relative movement with respect to particular engine ^' speed facilitating better mixture preparation for heterogeneous process.

There is a characteristic change in the formation of cylinder depression caused by effectively expanding cylinder volume during open valve period coincide with the start of induction piston stroke. As a result, the instantaneous cylinder pressure at filling is more closely follow atmospheric pressure because of reduction in flow lag which enables prompt and proper cylinder filling at different engine speeds as the build up of effective stagnation pressure in the intake manifold/port volume above inlet valve space during closed periods assists filling process as the speed increases, even though available time for filling proportionately decreases.

Hence improvement in pressure differential across intake valve with respect to speed change provides a method to determine total plenum volume and tract length requirement of intake manifold/port for optimization of an engine according to present invention, taking into account minimum/maximum velocity of gas.

With a similar method, the exhaust manifolds are also need to be optimized so that the exhaust gas inside the cylinder volume are promptly and perfectly driven out by the out flowing pressure wave, caused by the pressure differential across the exhaust valve during open period when the piston is just ready to assist the scavenge and exhaustion process so that exhaust gas flow lag is also minimized. The disadvantages associated with minimizing exhaust gas residuals are thus reduced.

As a result of improvements made in slider-crank mechanism and air regulating mechanism, it is desirable to burn maximum fuel with air at the moment when just piston starts descending or at the commencement of power stroke. This becomes possible as the increased rate of chemical reaction and consequent higher rate of expansion of cylinder gas are promptly sensed by piston and instantly delivered to the crankshaft for doing external work without any accumulation of forces in the engine. Since enlarging cylinder volume including un-swept volume, which is provided in the combustion chamber based on adopted compression ratio accommodates the intensity of increased rate of reaction by virtue of decreased disturbance to piston movement. Therefore, by increasing un-swept volume by lowering compression ratio, it is further possible to make the engine more capable of handling high rate of expansion of gas by increased rate of chemical reaction, which results in faster combustion and thereby eliminate particulate emissions whereas increase power out put.

One main effect of reducing the engine compression ratio is that it increases the cylinder clearance volume, which result in an increase of the cylinder volumetric efficiency since more fresh charge will be drawn into the cylinder per stroke and at the same time, there will be a lowering of the cylinder's residual exhaust gases, which are more consistency maintained by the new timing events described earlier.

Now the effective compression of fresh air charge starts from BDC onwards and at relatively higher rate because of increase in relative motion of piston with respect to cylinder, which results in lesser time for heat transfer and subsequently any engine will reach the desired speed in a shorter time, convection heat loss to combustion chamber, valves, cylinder and piston reduces, which minimize heat loss to the coolant, and in turn this heat energy is available as heat of compression in the reactants and heat for expansion in the products as well as assists in the formation of equilibrium products during combustion. As the fresh air charge is compressed to a larger un-swept volume because of relatively lower compression ratio, which results in lower squish with reduced reverse squish mass and heat loss of compressed fresh air charge through piston-rings, piston-ring to cylinder-wall friction are all reduced.

It is therefore another object of the present invention to decrease compression ratio of the CI internal combustion engine in which the rate of pressure raise is higher due to increase in chemical reactions by virtue of nature of fuel, mixture formation and resultant combustion process i.e formation of many precursors as ignition points in the heterogeneous prepared mixture which accounts for reduction in flame prorogation time and completion of proper combustion. This reduces chemical ignition delay of cetane fuel. Lowering of compression ratio further increases mechanical efficiency of modified engine of the present invention and also minimizes heat and mass loss due to lower compression pressure, increase compression end temperature. Due to increase in relative crankshaft speed as the time available for heat and mass transfer is further reduced.

Such a reduction in compression ratio is not possible in a conventional CI internal combustion engine as compression end temperature or heat of compression of fresh air charge will not be sufficient to evaporate and ignite fuel quickly which may result in starting problem as well as increase unburnt hydrocarbon emission. It need to be appreciated that starting difficulty associated with CI internal combustion engine can be eliminated even in indirect injection engines with lower compression ratio modified engine of present invention because of reduced break away torque requirement, engine can rotate faster on account of reduction in friction force as well as reduction in rotating masses.

Therefore, the overall increase in heat of compression, swirl ratio, turbulence characteristic and resultant global and local temperature increase of fresh air charge mass well above to readily evaporate fuel, intimately mix with air and cause prompt compression ignition and subsequent shorter burn time of a cetane fuel by enlarging the interface between fuel and oxygen, which results in more air utilization.

In addition, a retarded injection advance timing could be used to limit high cylinder pressure and temperature so that possibility of negative work done by the piston is reduced. The resultant increase in air movement which is further enhanced by lowered compression ratio because of lesser density of the fresh air charge influences injected fuel characteristics for which fuel regulation mechanism need to be optimized, which is the an another object of the present invention. The main characteristics change of any injection fuel regulating mechanism needed are elimination of extra fuel supply mechanism for cold start, reduced static injection advance with no centrifugal advance mechanism and fast injecting maximum quantity of required fuel before ignition occurs by increasing rate of injection. The required change in fuel injection characteristics can even be achieved by modifying a conventional mechanical jerk pump system. Shown in Fig. 4 is a common in-line jerk pump-pipe-nozzle system, having one pumping element 80 per cylinder but combined with camshaft 70 in one housing. The output of the fuel is controlled by spilling the surplus fuel from pumping element 80 by helix 82, constructed on the head of pumping plunger 65 so that minimum height 71 is less than inlet port 81 diameter. This is done by reducing plunger 65 height and increasing its diameter in order to maintain same effective displacement volume with a shorter vertical up and down movement of plunger 65, which increases head clearance eliminating plunger 65 head to bump against delivery valve seat 73 whereas reduce injection lag because during filling period when plunger 65 occupies relatively a lower position from inlet port 81, more time is available for proper barrel filling even during raising camshaft speed. In addition, it provides a means to cut off fuel during deceleration period by repositioning of helix 82 relative to spill port 72 so that effective delivery becomes nil soon after idling position even before vertical slot 75 is in line with ports 81 and 72 whereas prompt control rod 79 movement, instantly supply fuel for acceleration as desired.

Stroking movement of plunger is controlled by symmetrical shape high lift cam 69 in order to increase cam rate and plunger velocity, which lower injection lag caused by control rod 79 opening. Plurality of circular and axial lubricant oil grooves 63 and 64 provided on the outer of the tappet 68 and/or on the inner surface of tappet barrel (not shown) reduce contacts stress in cam-roller interface 74. Moreover, nozzle 78 injection pressure can be lowered because of lower engine compression pressure, which further reduce cam and roller surface stress, nozzle valve closing velocity and the seat stress where as increase the ability of pump to inject even a relatively minimum quantity of fuel with stability and also offers better flexibility in the control of mis-match to avoid dribble and secondary injections.

The characteristics change in engine's cylinders to react faster to different fuel delivery inputs, lower flywheel 22 energy absorption and faster release effect created by the total reduced rotating inertia of the crankshaft 15 assembly, for effective speed regulation a lighter mass flyweight 77 is provided to instantly sense changes in engine speed and respond rapidly by accurately altering the fuel delivery by means of the control rod 79 opening. Tilting accelerator lever 67 anti-clockwise increases engine speed, this stretches a relatively low tension governor spring 66 and a lower retraction force of the extended spring acts against movement caused by lighter flyweight 77 centrifugal force as a result control rod 79 moves control-rack faster towards maximum fuel delivery direction 84, until the fast opposing flyweight 77 centrifugal thrust balances the governor spring 66 tension. Thus, this variable speed governor 62 response is improved to the level of enhancement in engine sensitivity.

Due to reduction in engine friction and pump load even at cold starting, the starting fuel delivery position can be made conveniently to coincide with maximum fuel delivery position and there by eliminates excess fuel regulating provision required for cold starting. With the same cranking effort, engine turns faster with a relatively improved air-fuel movement and the same compressed red hot air supplies heat to reduced starting quantity fuel, which is injected with more stability for proper mixing, evaporation and faster burning. After injection caused by excess fuel is eliminated. Wall wetting and unburnt hydrocarbon carbon emission are also avoided as flexibility exists in the designing of combustion chamber, which are recessed in the piston head of a direct injection engine, with larger un-swept volume by suitably selecting chamber aspect ratio in accordance with changed spray penetration characteristics. The un-swept volume of a divided combustion chamber indirect injection engine can be enlarged by increasing pre-chamber volume or throat passage so that spray impingement to the wall is eliminated and in addition, indirect injection engine can be started without any cold starting air, such as heater plug, due to reduction in heat and friction pumping losses.

For idling, thus a reduced fuel quantity is only needed because of reduction in engine internal load, thereby control rod 79 occupies a lower opening position, which is nearer to fuel cut-off position by helix 82 with respect to spill port 72. Now inorder to assist this fuel cut-off operation, provision should be given in governor mechanism 62 in order to move flyweights 77 more outwardly as shown in position 76 so that during sudden deceleration conditions when the engine load is suddenly removed governor's ability to counteract the rising engine speed by promptly moving control rod 79 towards the cut-off no-load direction. As the engine speed reduces and falls to idling speed automatically, idling quantity fuel is injected with stability, as described earlier, inhibiting missing as the control rod 79 is again promptly moved to the required idling position. At idling speed, even though engine warms up from cold, the decrease in frictional and pumping losses are lower as it is already minimized so that for a given control rod 79 opening the extra energy now available to raise the idle speed is minimum and hence, even with a small speed drop it is possible to stabilize speed fluctuations contributing for smooth operation of engine. Suitable torque control device can also be designed based on changed engine volumetric efficiency curve and easily accommodated. During transient acceleration condition, acceleration control lever 67 has only to be tilted anti-clockwise a comparatively small amount to tension low stiffness governor spring 66 promptly to oppose lighter mass flyweight 77 centrifugal force thrust, so that control rod 79 moves faster to the required load fuel delivery position. Meanwhile, due to improved combustion characteristics injected fuel completely burns eliminating particulate emissions and in addition, increase engine speed faster, which results in increased centrifugal force thrust at flyweight 77, thereby move control rod 79 to reduce fuel delivery position.

More flexibility exists in the design of the combustion chamber as overlapping of valve period is eliminated necessity of providing valve pockets in piston crown is avoided and in addition, as the relative expansion and contraction of engine components are reduced on account of lowering mechanical and thermal loading a minimum bump clearance can be provided between piston crown and cylinder head, whereby minimize trapped fresh air charge in squish region by increasing compression squish and reduce reverse squish in direct injection contributing for enhancement in mixture preparation and combustion process. Fast burn combustion chambers of current indirect injection engines can be suitably modified to reduce pumping and heat losses.

Shown in Fig. 5 is a typical direct injection combustion chamber 90 modified according to the present invention by converting a high aspect ratio chamber 91 to low aspect ratio chamber 92 for optimization of changed spray penetration. In case of indirect injection engine, pre-combustion chamber and/or throat or passage can be enlarged and in particular, taking care combustion chamber design and injection characteristics must be compatible to be free of jet impingement on the cylinder walls or piston for a clear exhaust performance.

It has thus now become very clear that the practical difficulties encountered, such as lowering of compression ratio, reducing bump clearance, avoiding valve pockets and reverse squish, increasing of swirl and turbulences and reducing of heat and mass loss for improving heat of compression, which interfere with the better method of designing a suitable combustion chamber for conventional CI internal combustion engine are eliminated in the modified combustion chamber of the present CI internal combustion engines, which results in a further reduction of physical ignition delay or in other word, shortens auto-ignition of a cetane fuel.

Favourable conditions exist for cool combustion process as developed indicated mean effective pressure is lower whereas brake mean effective pressure (BMEP) or available fuel heat to do useful work is higher because initial sign of gas expansion pressure rises above the normal compressive pressure for a given most effective CA movement occur at a faster rate. In order to further reduce the time lag associated with combustion process, which is not only caused by mixture strength but also by constituents of fuels composition or in other words, quality of fuel influence combustion process and thermal loading. Further, it is also evident as the compression ratio is increased for maximizing thermal efficiency by compromising mechanical efficiency, the requirement of higher quality fuel is increased.

The activation energy and the heat of adsorption are the two important quantities, which control the reaction rate. Changes in density, temperature factors at the end of compression process with raising engine speed are also influenced by compression ratio, heat and mass loss of fresh charge wherein increase ignition and combustion lags as speed increase for which injection advance mechanisms are conventionally introduced. Now in engines according to the present invention even when it is operated with conventional fuels, there is a characteristics change in said controlling parameters as a result ignition and combustion lags are reduced for a practical conventionally rated cetane fuel and hence intensity of advance from fixed static timing need to be minimized. In addition, the necessity of an advance injection timing control mechanism are avoided as the combustion controlling parameters are more consistently maintained even with changing speed as described earlier.

Accordingly, lowering fuel's cetane number requirement to match reduced tendency to detonate and knock enable higher knock-limited mean effective pressure to be generated in the engine cylinder to achieve a faster combustion process.

Now, the engine has become more tolerant for increased rate of reaction. Which in turn governed by two fundamental factors - heat liberation and its dissipation, upon which the design of 'compression - ignition' combustion process in CI internal combustion engine are based. The quality of fuel to assist the particular nature of combustion process are currently determined by the extent of exacting the suitable fuel with conflicting ignition and combustion nature fuel in order to limit explosive auto-ignition and its attendant knock or combustion noise.

Cetane fuels used in current engines demand some very exacting specifications, more particularly to meet stringent exhaust emissions norms in order to control air pollution from the combustion of fossil fuels in CI internal combustion engines. The exacting process influences cost factor of a fuel and more the exacting required costlier the fuel becomes. The boiling point and fuel molecular structure reflects the conflicting nature and hence a good gasoline will make a poor diesel engine fuel and vice versa.

Now, when a lower cetane rating fuel with slightly lower boiling point and less spontaneous ignition fuel fraction, is used in a modified CI internal combustion engine, as a result of reducing associated physical delay, cold start ability is improved. By virtue of promptly injecting maximum fuel quantity required for a particular operation before ignition as explained earlier in fuel regulation mechanism provide sufficient time for less ignition quality fuel fraction to seek out more oxygen from fresh air during this period by the time being getting heated up and assist in increasing the rate of reaction in order to select a suitably retarded timing without power loss.

When a common paraffin series gases, methane, ethane, and propane are used as CI internal combustion fuels, either separately or as constituents of natural gas in a modified engine in which the compression ratio is already dropped to a convenient lower level (12 to 10:1) and the same will be more suitable for best operation of fuel gas. This minimizes problem of load de-rating of engine and hence best suited for dual fuel applications.

Conventional practice of mandatory checking the suitability of fuel gas constituents composition and also specifying a limit of 20% by volume of hydrogen H₂ for dual fuel engines can be relaxed as more flexibility exists in the present CI engine to advance or retard the static pilot fuel injection timing to control the increased rate of reaction with reduced thermal loading and optimize combustion process for increasing operational efficiency of all CI engines with any compression- ignition system fuel gas or oil when used in the improved engine according to the present invention and hence found suitable for all practical applications. INDUSTRIAL APPLICABILITY

This low cost new CI internal combustion engine technology and method of operating said engine with increased mechanical and thermal efficiency finds wide applications for automotive, locomotive, marine, industrial, agricultural, aeronautical fields and all other piston-type reciprocating current as well as production CI internal combustion engine giving real performance benefits to the user. Thus, current engine, when implemented with the above-described modification found operates well below its designed load factor with resultant extreme durability. Moreover, combustion characteristics are changed due to relative change in gas movements. In order to optimize engine efficiency, in such a situation, different methods are described below, which can be applied to even current or production CI internal combustion engines.

For example in the case of current road vehicles, due to increase in torque or power densities, extra power is bound to be always in the reserve as it could not be effectively utilized due to restriction in maximum speed operation being limited by road conditions or traffic rules. So new transmission with longer final drive ratios with two overdrive facilities could be easily designed according to improved engine torque characteristics and fitted in modified current vehicles. Engine operates mostly in lower revolution per minute. This will further improve fuel economy and enhance emissions control. In order to modify production CI internal combustion engines for optimization of design factors, displacement volume have to be minimized by either reduction of piston stroke or crank radius and/or cylinder bore to the required level so that a smaller engine could be constructed to produce same power, which could not be achieved by conventional engine design practice as bmep or mean piston speed is already optimized.

Crankshaft having reduced diameter main journal and crank journal of equal size with no journal overlap and reduced crank radius is advantages as it reduces mean piston speed for a particular engine design whereas reducing cylinder bore in term of over square, square or under square engine contribute for the enhancement of slider-crank mechanism effectiveness. Overall mass of reciprocating and rotating parts are thus further reduced contributing for cost factors.

The present invention will find wide industrial application not only among diesel engine builders but its user as well and everyone will be benefited by implementing this new CI technology in their respective fields. It is well known that currently diesel engine parts are reinforced with added material resulting in increased dynamic forces inaddition to gas loading and higher stress that arise from the diesel combustion process. As a result friction losses are larger in diesel engines especially at higher engine speeds and this inevitably increase specific fuel consumption.

Now, the extent of scope and potential of the present invention to penetrate diesel engine market is very high as it fulfills the requirement of all diesel engine builders which cannot be achieved by conventional engine design practice because no compromise need be done in optimizing any one of the important factors which are specifically described below.

In automotive applications, lower power to weight ratio to achieve maximum speed, reduced first cost penalty, more consistency in fuel economy with lesser dependency on driving cycle, ability to meet stringent emission regulation norms, good vehicle drivability since increased torque for acceleration or hill climbing is instantly available without changing gear are the salient features which increase its penetration in the passenger world-wide diesel car market.

The main demands relating to bus and truck engines such as low cost, correct performance reliability, long service life, low fuel and oil consumption, ease of servicing, low exhaust and noise emissions and above all ease of manufacture by minimizing extra work on product development for providing best possible total economy for production are simultaneously met which will contribute a great deal for the development of current diesel engine in this field. Diesel engines used in locomotives applications are expected to produce high power output for quick running, improved specific fuel consumption to reduce operation cost, reduced noise and gaseous emissions and should compete well with electrified trains besides engine increased durability and reliability to resist thermal low cycle fatigue and mechanical high cycle fatigue operating conditions to fulfill engine builders as well as railway administration are simultaneously met by the present invention and due to extreme versatility of modified engines, as described above potential market also exists in stationary high speed and rail-traction applications as it is also expected to meet both continuous and intermittent service in climatic conditions which range from arctic to tropical. The requirement of stationary lower speed engines to operate at maximum continuous crankshaft speeds, more preferably compact and small in size besides it should operate economically on gaseous as dual fuel engines as well as in low quantity residual bunker fuel oils are successfully met and therefore the present invention will also find wide application in marine propulsion and auxiliary purposes engines.

Thus more flexibility exists for improving current engines to optimize desired characteristics for specific applications without sacrificing other beneficial factors and thereby the present invention will also find wider potential in ship propulsion engine and also in air-cooled engines used for commercial and special vehicles, and agricultural machinery.

Now it will evident that with the modifications and new methods described, the CI internal combustion engine of the present invention will suit ideal requirements of all diesel engine builders as well as get customer preference.

In addition, it will induce a revolutionary change in oil refineries and among lubricant oil manufacturers for healthy competition.

Claims

CLAIMS :

1. A low cost new CI internal combustion engine comprising cranking mechanism (29) consisting of sliding and turning cylindrical rubbing pairs having a plurality of open or close end circular and/or axial and/or helical lubricating oil grooves formed on the inner/outer contacting bearing surfaces for generating self controlled hydro-dynamic lubrication regime which reduce mechanical and fluid friction and increase relative motion at varying engine speed-load operating conditions, air regulating mechanism valves mechanically actuated by a valve control mechanism parts having rubbing pairs provided with a plurality of said lubricating oil grooves, a fuel regulating mechanism, a combustion chamber (90), a injection timing mechanism, characterized in that, the said crank mechanism (29) is provided with atleast one lighter mass better dynamic response crankshaft (15) mechanically connected to rotating and reciprocating engine parts reducing harmful friction forces resulting from the relative motion of said sliding and turning cylindrical rubbing pairs, thus lowering the resultant centrifugal/inertia disturbing forces and couples produced by the changing motions of rotating/reciprocating masses, a lighter mass counter weight (21) if desired, an additional rotating mass if desired, carried on said crankshaft webs (9) out of balance to oppose and neutralize the resultant disturbing forces and its couples, a lighter mass flywheel (22), another additional rotating masses is attached to the free end of said crankshaft (15) storing required additional energy during power stroke to propel engine during other strokes as a result of converting disturbing force into constructive or useful force; the said air regulating mechanism having an inlet and an outlet port openings in cylinder head and/or on cylinder which are .opened/closed by valves or uncovered/covered by piston to control both admission of fresh air and expulsion of exhaust gas to and from cylinder, atleast one intake manifold communicating with inlet port openings to distribute fresh air to individual cylinders and atleast one exhaust manifold communicating with outlet port openings to channel out exhaust gas from individual cylinders into a central pipe, the said inlet port opening being reduced to the current outlet port opening size and equalizing said inlet and outlet ports opening areas so as to increase practical volumetric efficiency at all speeds and system operates with no/minimum overlap timing events effecting in reducing cylinder head, manifold size, plenum volume and weights; the said fuel regulating mechanism is provided with atleast one mechanical jerk injection pump (61) consists of increased diameter and reduced height plunger (65) having minimum activeland (71) less than inlet port (81) diameter providing more head clearance with reduced maximum fuel displacement volume from starting fuel quantity to full load enabling proper filling, faster injecting and cut-off of fuel, a pump camshaft (70) having high lift cam (69) communicating with a lower contact stress roller (74) and a lower friction tappet (68) imparting faster pumping action to said plunger (65) which is being twisted faster by a fuel control rod (79) movement varying effective stroke, mechanically connecting said pump camshaft (70) through lighter governor flyweights (77) acting against a lower stiffness governor spring (66) and a control lever (67) movement enabling faster injection of larger quantity of accurately metered fuel before ignition for proper utilization of regulated air received from said air regulating mechanism reducing physical ignition delay; the said combustion chamber (90) resulting lower compression ratio for proper combustion of regulated fuel-air received from said air and fuel regulating mechanism; and the said a injection timing mechanism with reduced fixed static injection timing and without centrifugal advance mechanism for controlling timing of proper ignition of heterogeneous combustible mixture obtained from said air and fuel regulating mechanism eliminating power loss.

2. The CI internal combustion engine as claimed in claim 1, wherein said crankshaft (15) includes reduction of main journal (14), crank journal (12) and crank web (9) masses eliminating said journals overlap improving sliding pair to increase said crankshaft (15) relative rotational speed.

3. The CI internal combustion engine as claimed in claims 1 or 2, wherein said crank mechanism includes reduction of all moving and non-moving engine parts by minimizing cylinder bore (8) and/or crank radius (19) or stroke in order to lower engine displacement volume on account of increased work done by gas per unit displacement volume.

4. The CI internal combustion engine as claimed in any one of claims 1 to 3, wherein said air regulating mechanism includes opening and closing of valve control ports being actuated hydraulically and/or electro-magnetically and/or piston control ports by said valve/port area and timing of stroke events.

5. The CI internal combustion engine as claimed in any one of claims 1 to 4, wherein said fuel regulating injection pump includes mechanical or electronic distributor or the like that fuel injection pumps with lower injection pressure.

6. Method of operating CI internal combustion with increased mechanical and thermal efficiency by combustion process wherein in a fresh air charge is compressed to lower compression ratio is said combustion chamber (90) resulting compression end temperature more than ignition point of fuel, mixture ignited faster by said reduced fixed static injection timing due to increased rate self sustained cool combustion and thereby reducing mechanical/gas/thermal loading and increasing mechanical/thermal efficiency.

7. Method of operating CI internal combustion with increased mechanical and thermal efficiency as claimed in claim 6, wherein said engine is designed by reducing overall engine weight and size due to lowered working stress level in engine components and thereby lowering said cost and increasing mechanical/thermal efficiency.

8. Method of operating CI internal combustion with increased mechanical and thermal efficiency as claimed in claim 6 or 7, wherein said engine, fuel is designed with poor quality fuels due to self sustained knock noise limited gas pressure rise resulting in cool combustion and thereby said fuel cost and increasing mechanical/thermal efficiency.

9. Method of operating CI internal combustion with increased mechanical and thermal efficiency by as claimed in any one of claims 6 to 8 wherein said engine, lubricant is designed with poor quality oils due to lowered operating temperature of oil and thereby lowering said lubricant cost and increasing mechanical thermal efficiency.