Title of Invention: Improved Thrust Vectoring Ignition Chamber Engine with Multi Purpose Multi H-Slot Scotch- Yoke Actuator

Field of Invention

[01] This patent is related to internal combustion engine using scotch yoke actuator. More particularly, this invention is related to improved arrangements to operate scotch yoke actuator in a thrust vectoring ignition chamber engine and also improved model of scotch yoke actuator and its operating mechanism.

Background of Invention

[02] Thrust vectoring ignition chamber described in PCT application PCT/IN2019/050544 for my Indian patent 201821027867 providing high compression ratio (without increasing the size of ignition chamber resulting in judicious use of rotatory force created by fuel) by two phase compression mechanism is shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 and Fig. 6.

[03] In my aforementioned patent thrust vectoring ignition chamber engine comprise (among other components) fuel supply system (FSS), which in turn comprise fuel delivery and ignition mechanism (FDI). Fuel delivery and ignition mechanism (FDI), whose function is suction, compression and transfer the compressed air-fuel mixture into the ignition chamber and further compress the transferred air- fuel mixture in the ignition chamber, comprises Scotch- Yoke operation mechanism (SYM) and a bilaterally operated multi-purpose Scotch- Yoke actuator (SYA).

[04] Scotch-Yoke actuator (SYA) is a bilaterally operated multipurpose double action front dwell scotch yoke actuator which facilitates two phase compression of air-fuel mixture as described above. Scotch-Yoke actuator (SYA) by virtue of its special features circumvents the need to use larger size ignition chamber for providing high compression ratio resulting in judicious use of rotatory force created by fuel and also decrease the traversal distance of yoke slot.

[05] Engines like Bourke’s engine use conventional Scotch yoke, which is operated via a single pin crank. This causes sideward thrust on the yoke slot. This issue has been addressed by inventor in uspto 4075898. We have addressed this problem in a different way. [06] Scotch yoke, described in Indian patent 201821027867, (due to requirement to be used in thrust vectoring ignition chamber engine) is bilaterally operated in a complementary bidirectional way. Scotch yoke mechanism has one yoke slot partitioned mid way to engage two pins on its left side and right side respectively. Two pins PI and P2 are always at equal distance from midpoint of yoke slot on opposite sides and therefore downward sideward thrust applied by pin on the upper part of the yoke slot is cancelled out by upward sideward thrust applied by pin on the upper part of the yoke slot. Issue of sideward thrust carries more significance in case of double action scotch yoke in which yoke arm is on both sides of the of yoke slot.

Disadvantages in the prior art

[07] Bilateral operation on the yoke slot, used in my Indian patent 201821027867 as described hereinabove, may cause torsional twisting action on the yoke slot.

[08] One of the drawbacks of one slot scotch yoke is friction caused on bounding plates of yoke slot, an issue which has been addressed by many inventors including the patent uspto 4559838.

[09] One of the drawbacks of one slot scotch yoke is that it may not be suitable for high torque application. This is insufficient use of the scotch yoke mechanism.

[10] Engine described in the aforementioned patent has two constraints. First constraint is that front piston chamber needs to be of length equal to that of compression chamber (located at rearward end of the engine). Length of compression chamber for given volume V and radius r is V/(pi*r ³ ). Second constraint is that rotation space of crank needs to lie beyond the front piston chamber. One of the cylinder of the ignition chamber needs to have rearward extension of length atleast equal to the length of the front piston chamber so that the cam gear can mesh with cam follower gear operating the crank. If we reduce the length of rearward extension of internal cylinder of ignition chamber we will need to have cam follower gear of larger radius in order to be able to mesh with cam gear which in turn would require cam gear to be larger radius (as radius of cam gear needs to be double of that of cam follower gear). Thus we do not gain any efficiency more rotatory force will be spent to rotate the cam gear and cam follower gear. Also this arrangement will forbid the possibility of allowing multiple slots for the scotch yoke mechanism as the cam follower gear for the subsequent slots need to have same radius.

Summary of Invention [11] In order to overcome the disadvantages mentioned above, relevant component of thrust vectoring ignition chamber engine, that is fuel delivery and ignition mechanism, have been appropriately improved.

[12] More particularly, in this invention, Scotch- Yoke operation mechanism and Scotch- Yoke actuator have been appropriately modified to make the engine more fuel efficient, appropriate for high torque application and incurring less wear and tear resulting in improved life time.

[13] In one embodiment we substitute bilaterally operated bipartitioned slot with quad-laterally operated H-slot (quad-partitioned slot) in scotch yoke actuator in order to overcome drawbacks mentioned in paragraphs [07] to [08]

[14] In one embodiment we introduce multi-slot feature into the scotch yoke mechanism in order to overcome drawbacks mentioned in paragraphs [08] to [09] Multiple yoke slots facilitate the application of force on larger area and therefore less friction on the bounding plates of the yoke slot and lesser torsional force on the yoke slot. Multiple slots functions as reinforcement mechanism to support high torque application, to reduce sideward thrust.

[15] Yoke slots of the multi-slot scotch yoke are stacked in parallel along yoke rod with bounding plate of one slot facing the bounding plate of subsequent slot. In the resulting quad- laterally operated multi slot scotch yoke actuator we have retained bidirectional movement of pins on opposite sides and have preferred bidirectional movement of pins on subslots on same side. That is, pins on the subslots on opposite sides of a yoke slot are on the opposite sides at equal distance midpoint of the yoke slot.

[16] In two of the four models we allow coherent directional movement of pins in subslots of subsequent yoke slots by mounting inter-slot transmission gear between consecutive cam follower gears and crank gears.

[17] In the second embodiment, in order to overcome drawback mention in paragraph [10], a transmission gear is mounted between the cam gear and first set of cam follower gears and each set of cam follower gears is meshingly engaged, directly or via idler gears, with subsequent set cam follower gears.

[18] Transmission gear will allow shorter rearward extension of internal cylinder of ignition chamber by allowing accommodation of front piston chamber in the scotch yoke operation chamber. Transmission gear will also allow the radius of cam follower gear to be close to that half of radius and hence radius of cam gear close to radius of internal cylinder of ignition chamber. Shorter length of internal cylinder of ignition chamber and smaller radius of cam gear will allow judicious utilization of rotatory force generated by fuel.

[19] Additionally, quad-lateral crank operation mechanism facilitates more teeth contact with cam gear mounted on ignition chamber cylinder.

Brief Description of Drawings

[20] Fig. 1 to Fig.6 Thrust vectoring ignition chamber engine using bilaterally operated single slot scotch yoke as described in my Indian patent 201821027867.

[21] Fig. 7 to Fig. 14 Improved thrust vectoring ignition chamber engine using quad-laterally operated multi H-slot scotch yoke actuator according to the first model in this invention.

[22] Fig. 7 Front view of thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the first model in this invention.

[23] Fig. 8 Left side view of rear portion of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the first model in this invention.

[24] Fig. 9 Right side view of rear portion of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the first model in this invention.

[25] Fig. 10 Front view of quad-laterally operated front dwell Multi- Slot- Scotch- Yoke actuator (MSYA), according to the first model in this invention.

[26] Fig. 11 Rear view of quad-laterally operated front dwell Multi- Slot- Scotch- Yoke actuator (MSYA), according to the first model in this invention.

[27] Fig. 12 Partial view of quad-laterally operated front dwell Multi-Slot-Scotch-Yoke actuator (MSYA), exposing four sub-slots of first H-slot (FYS) and second H-slot (SYS).

[28] Fig. 13 Arrangement of crank gear and its pin of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the first model in this invention.

[29] Fig. 14 Intermediate yoke rod support (IYRS) and Inter-Slot Reinforcement Mechanism (ISRM) for additional support mechanism for multiple slots. [30] Fig. 15 to Fig. 20 Improved thrust vectoring ignition chamber engine using quad-laterally operated multi slot scotch yoke actuator according to the second model in this invention.

[31] Fig. 15 Front view of improved thrust vectoring ignition chamber engine showing Multi- Slot Scotch Yoke Operation Mechanism (MSYM) according to the second model in this invention.

[32] Fig. 16 Front view of rear portion of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the second model in this invention.

[33] Fig. 17 Rear view of rear portion of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the second model in this invention.

[34] Fig. 18 Front view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the second model in this invention.

[35] Fig. 19 Rear view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the second model in this invention.

[36] Fig. 20 Arrangement of crank gear and its pin of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the second model in this invention.

[37] Fig. 21 and Fig. 24 Improved thrust vectoring ignition chamber engine using quad-laterally operated multi slot scotch yoke actuator according to the third model in this invention.

[38] Fig. 21 Front view of rear part of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the third model in this invention.

[39] Fig. 22 Front view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the third model in this invention.

[40] Fig. 23 Rear view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the third model in this invention.

[41] Fig. 24 Arrangement of crank gear and its pin of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the third model in this invention. [42] Fig. 25 to Fig. 28 Improved thrust vectoring ignition chamber engine using quad-laterally operated multi slot scotch yoke actuator according to the fourth model in this invention.

[43] Fig. 25 Front view of rear portion of improved thrust vectoring ignition chamber engine showing Multi-Slot Scotch Yoke Operation Mechanism (MSYM) according to the fourth model in this invention.

[44] Fig. 26 Front view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the fourth model in this invention.

[45] Fig. 27 Rear view of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the fourth model in this invention.

[46] Fig. 28 Arrangement of crank gear and its pin of quad-laterally operated Multi- Slot- Scotch- Yoke actuator (MSYA), according to the fourth model in this invention.

[47] Fig. 29 Schematic diagrams of left side view of operation between crank gears of Multi- Slot- Scotch- Yoke actuator (MSYA) and flywheel gear (FWG) and cam follower gears of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to first model in this invention. Solid dot inside a circle or ellipse represent pin of the corresponding crank gear.

[48] Fig. 30 Schematic diagrams of right side view of operation between crank gears of Multi- Slot- Scotch- Yoke actuator (MSYA) and flywheel gear (FWG) and cam follower gears of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to first model in this invention.

[49] Fig. 31 Schematic diagrams of left side view of operation between crank gears of Multi- Slot- Scotch- Yoke actuator (MSYA) and flywheel gear (FWG) and cam follower gears of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to second model in this invention.

[50] Fig. 32 Schematic diagrams of right side view of operation between crank gears of Multi- Slot- Scotch- Yoke actuator (MSYA) and flywheel gear (FWG) and cam follower gears of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to second model in this invention.

[51] Fig. 33 Schematic diagrams of operation between first quad-lateral crank operation mechanism (FQCM) and second quad-lateral crank operation mechanism (SQCM) (causing operation between first quad-lateral crank-pin set (FQCP) and second quad-lateral crank-pin set (SQCP), of Multi- Slot- Scotch- Yoke actuator (MSYA)) of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to third model in this invention.

[52] Fig. 34 Schematic diagrams of operation between first quad-lateral crank operation mechanism (FQCM) and second quad-lateral crank operation mechanism (SQCM) (causing operation between first quad-lateral crank-pin set (FQCP) and second quad-lateral crank-pin set (SQCP), of Multi- Slot- Scotch- Yoke actuator (MSYA)) of Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to fourth model in this invention.

Description of Embodiments

[53] Referring to Fig. 7 to Fig. 34, embodiments of improvements in the thrust vectoring ignition chamber engine described in my Indian patent 201821027867, according to the present invention will be described in detail below.

[54] Thrust vectoring ignition chamber engine according to the aforementioned patent have been shown in Fig. 1 to Fig. 6 (by reproducing from my aforementioned patent application).

[55] Comparing Fig. 1 to Fig. 6 reproduced from my aforementioned patent application for the engine, with Fig. 7 to Fig. 34 that describe the improved engine according to this invention, it may be noted that some of the components and its parts are same and therefore their labels are same. Parts which are different in this invention have been labeled with labels which are very closely similar for easier understanding of the improvements.

[56] In the prior art thrust vectoring ignition chamber engine comprise (among other

components) Fuel supply system (FSS), which in turn comprise fuel delivery and ignition mechanism (FDI). Fuel delivery and ignition mechanism (FDI), comprises a bilaterally operated Scotch-Yoke actuator (SYA) which is bilaterally operates Scotch-Yoke operation mechanism (SYM). In this invention Fuel delivery and ignition mechanism (FDI), is improved to comprise a quad-laterally operated Multi-Slot Scotch-Yoke actuator (MSYA) which is quad- laterally operated by Multi-Slot Scotch-Yoke operation mechanism (MSYM). Multi-Slot Scotch-Yoke actuator (MSYA) have more than one slots and in this patent application we have it to have two slots for convenience. Two yoke slots (instead of one yoke slots) stacked in parallel along yoke slot (CR) with bounding plate of one slot facing the bounding plate of subsequent slot. Each yoke slot has four sub-slots each on one of the four sides that are, left, right, upper and bottom side. [57] Improvements in fuel supply system, (FSS), is four different models, namely first model, second model, third model and fourth model, wherein each model differ from others in the way crank pins corresponding to a yoke slot are oriented with respect to each other and accordingly crank gears for the slot mesh or not mesh with adjacent crank gears;

crank gear corresponding to a yoke slot transmit rotation to crank gear corresponding to adjacent yoke slot by directly meshing or via an idler gear;

scotch yoke operation mechanism is configured corresponding to the configuration of crank- pin gear set.

[58] According to the first model, Multi- Slot- Scotch- Yoke actuator (MSYA), a multi-purpose quad-laterally operated double action front dwell multi slot scotch-yoke mechanism is shown in Fig. 10, Fig. 11, Fig. 12, Fig. 13 and Fig. 14 to consist of two yoke slots, namely first yoke slot (FYS), second yoke slot (SYS), a connecting rod (CR), two quad-lateral crank-pin set, namely first quad-lateral crank-pin set (FQCP), second quad-lateral crank-pin set (SQCP), inter-slot transmission mechanism (ISTM), front yoke rod support (YRSl), and rear yoke rod support (YRS2), intermediate yoke rod support (IYRS), Inter-Slot Reinforcement Mechanism (ISRM), front piston plate (PLT1), rear piston plate (PLT2), fuel pressure valve (FPV) and compressor valve (CVLV) wherein

first yoke slot (FYS), and second yoke slot (SYS), are yoke slots with front end dwell located such that slot opens towards left crank wheel, right crank wheel, upper crank wheel, and bottom crank wheel;

first yoke slot (FYS), and second yoke slot (SYS), are consecutively arranged that is, rear bounding plate of first yoke slot (FYS), parallely faces the front bounding plate of second yoke slot (SYS);

first yoke slot (FYS) has four subslots, two of which, namely first left yoke slot (FLYS), first right yoke slot (FRYS) are obtained by vertically partitioning a vertical slot along the mid part, and other two , namely, first upper yoke slot (FUYS), first bottom yoke slot (FBYS) are obtained by adjoining horizontally oriented front dwell slots on the upper and lower sides of the vertical slot;

second yoke slot (SYS) has four sub-slots, two of which, namely second left yoke slot (SLYS), second right yoke slot (SRYS) are obtained by vertically partitioned along the mid part, and other two , namely, second upper yoke slot (SUYS), second bottom yoke slot (SBYS) are obtained by adjoining horizontally oriented front dwell slots on the upper and lower sides of the vertical slots; connecting rod, (CR), which functions as continuous yoke slot, is a horizontal rod, with a longitudinal coaxial cylindrical hole, passing through all the slots, first yoke slot (FYS), second yoke slot (SYS), and attached to them;

front piston plate (PLT1) and rear piston plate (PLT2), circular disks with holes at their centers, are attached coaxially to the front and rear end, respectively, of connecting rod; front piston plate (PLT1) of radius equal to inner radius of front piston chamber (FPC) and is housed coaxially inside the latter;

rear piston plate (PLT2) of radius equal to inner radius of air compression chamber (ACC) and is housed coaxially inside the latter;

fuel pressure valve (FPV) and compressor valve (CVLV) are pressure valves, opening along front side, mounted coaxially to the centers of front piston plate (PLT1) and rear piston plate (PLT2) respectively, so that fuel under pressure can enter through rear end of compressor valve (CVLV) pass through cylindrical hole in the connecting rod (CR) and exit from the front end of fuel pressure valve (FPV);

first quad-lateral crank-pin set (FQCP), which quad-laterally operates first yoke slot, comprises first left yoke crank gear (FYCG1), first right yoke crank gear (FYCG2), first upper yoke crank gear (FYCG3) and first bottom yoke crank gear (FYCG4), first left inner bearing (FB5), first right inner bearing (FB6), first upper inner bearing (FB7), first bottom inner bearing (FB8), first left yoke pin (FP1), first right yoke pin (FP2);, first upper yoke pin (FP3), and first bottom yoke pin (FP4);

second quad-lateral crank-pin set (SQCP), which quad-laterally operates second yoke slot, comprises second left yoke crank gear (SYCG1), second right yoke crank gear (SYCG2), second upper yoke crank gear (SYCG3) and second bottom yoke crank gear (SYCG4), second left inner bearing (SB5), second right inner bearing (SB6), second upper inner bearing (SB7), second bottom inner bearing (SB8), second left yoke pin (SP1), second right yoke pin (SP2), second upper yoke pin (SP3), and second bottom yoke pin (SP4); each crank gear of a quad-lateral crank-pin set is a spur gear journalled on corresponding side (left, right, upper or bottom) of inner wall of Scotch- Yoke operation chamber (SOC) facing a yoke slot with its center along the midpoint of corresponding yoke slot via an inner ball bearing (which are annular thrust ball bearings) and engaged with corresponding sub- slot of corresponding yoke slot via corresponding yoke pin;

each pin of a quad-lateral crank-pin set is a cylindrical peg projecting outward from the periphery of the face of a crank gear to engage with corresponding yoke sub slots (for example, first left yoke pin (FP1) projects outward from the periphery of the face of first left yoke crank gear (FYCG1) to engage with first left yoke slot (FLYS));

crank gears corresponding to a yoke slot are assembled such that the corresponding left yoke pin and right yoke pin are on the opposite sides on the midpoint of the corresponding yoke slot with equal distance from the said midpoint and corresponding upper yoke pin and bottom yoke pin are on the opposite sides on the midpoint of the corresponding yoke slot with equal distance from the said midpoint;

left crank gear and right crank gear do not mesh with upper and bottom crank gear;

inter-slot transmission mechanism (ISTM), consists of four spur gears, namely left inter-slot gear (ISG1), right inter-slot gear (ISG2), upper inter-slot gear (ISG3) and bottom inter-slot gear (ISG4), journalled on the inner side of left, right, upper and bottom wall, respectively, of scotch-yoke operation chamber (SOC), between the corresponding first and second crank gears and function as idler gear;

front yoke rod support, (YRSl) and rear yoke rod support (YRS2) are vertical rods, located inside Scotch- Yoke operation chamber (SOC), on front side of traversal space of front yoke slot and rear side of traversal space of rear yoke slot, respectively;

intermediate yoke rod support (IYRS), as shown in Fig. 12 and Fig. 14, is a horizontally oriented H-shaped truss of appropriated thickness, located inside Scotch- Yoke operation chamber (SOC), empty space between the traversal space of consecutive yoke slots;

Inter-Slot Reinforcement Mechanism (ISRM), as shown in Fig. 12 and Fig. 14, consists of four straight horizontal rods each of which connects oppositely facing bounding plates of consecutive yoke slots near one of the four corners of said plates and passes through holes in horizontal arms of intermediate yoke rod support (IYRS);

all yoke rod supports, has a hole through which connecting rod (CR) (that is, continuous yoke rod) passes through.

[59] According to the first model, Multi- Slot- Scotch- Yoke operation mechanism (MSYM), as shown in Fig. 7, Fig. 8 and Fig. 9, consists of a cam gear (CMG), Ignition-to-Scotch

transmission mechanism (ItS), two quad-lateral crank operation mechanism, namely, first quad- lateral crank operation mechanism (FQCM) and second quad-lateral crank operation mechanism (SQCM), inter-cam transmission mechanism (ICTM), wherein

cam gear (CMG) is a circular annular crown gear with its tooth projecting rearward (that is, towards Scotch- Yoke operation chamber) is coaxially mounted on the rearward extension of the inner annular cylinder of the ignition chamber; first quad-lateral crank operation mechanism (FQCM) operates first quad-lateral crank-pin set (FQCP) and comprises first left cam follower gear (FCF1), first right cam follower gear (FCF2), first upper cam follower gear (FCF3) and first bottom cam follower gear (FCF4), first left cam axis (FCA1), first right cam axis (FCA2), first upper cam axis (FCA3), first bottom cam axis (FCA4), four ball bearings, namely, first left outer bearing (FBI), first right outer bearing (FB2), first upper outer bearing (FB3), first bottom outer bearing (FB4); second quad-lateral crank operation mechanism (SQCM) operates second quad-lateral crank-pin set (SQCP) and comprises second left cam follower gear (SCF1), second right cam follower gear (SCF2), second upper cam follower gear (SCF3), second bottom cam follower gear (SCF4), second left cam axis (SCA1), second right cam axis (SCA2), second upper cam axis (SCA3), second bottom cam axis (SCA4), four ball bearings, namely, second left outer bearing (SB1), second right outer bearing (SB2), second upper outer bearing (SB3), second bottom outer bearing (SB4);

left cam follower gear, right cam follower gear, upper cam follower gear and bottom cam follower gear are spur gears coaxial to crank gears corresponding to yoke slot, with radius equal to half the radius of cam gear (CMG) coaxially journalled on outer side the left, right, upper and bottom wall, respectively, of Scotch- Yoke operation chamber (SOC) via corresponding ball bearings, that is, left outer bearing, right outer bearing, upper outer bearing and bottom outer bearing, respectively;

left cam axis, right cam axis, upper cam axis and bottom cam axis are straight rods attached at one end to the center of left cam follower gear, right cam follower gear, upper cam follower gear and bottom cam follower gear respectively and extends inside the Scotch- Yoke Operation Chamber (SOC) from latter’s left, right, upper and bottom wall, respectively, to connect to the center of corresponding crank gear;

Ignition-to- Scotch transmission mechanism (ItS) consists of four sub-mechanism, namely, left Ignition-to-Scotch transmission mechanism (ItS 1), right Ignition-to-Scotch

transmission mechanism (ItS2), upper Ignition-to-Scotch transmission mechanism (ItS3), bottom Ignition-to-Scotch transmission mechanism (ItS4) each of which transmit rotation of cam gear (CMG) (mounted on ignition cylinder) to first left cam follower gear (FCMF1) and first right cam follower gear (FCMF2), first upper cam follower gear (FCMF3), first bottom cam follower gear (FCMF4), respectively, as idler gear, which in turn are connected to first crank gears via respective cam axis;

left Ignition-to-Scotch transmission mechanism (ItS 1) right Ignition-to-Scotch transmission mechanism (ItS2), upper Ignition-to-Scotch transmission mechanism (ItS3) and bottom Ignition-to- Scotch transmission mechanism (ItS4), are gear trains of one (or more according to length of Ignition Chamber (IC)) spur gear(s) journalled to the outer side of left, right, upper and bottom wall, respectively, of Scotch- Yoke operation chamber (SOC) and meshingly engages (towards the front side of engine) with cam gear (CMG),

(functioning as its pinion gear) and meshingly engages (towards the rear side of engine) with the first left cam follower gear (FCMF1), first right cam follower gear (FCMF2), first upper cam follower gear (FCMF3) and first bottom cam follower gear (FCMF4), respectively;

left Ignition-to-Scotch transmission mechanism (ItSl) right Ignition-to- Scotch transmission mechanism (ItS2), upper Ignition-to-Scotch transmission mechanism (ItS3) and bottom Ignition-to-Scotch transmission mechanism (ItS4), are gear trains of same number of gears and are of equal lengths;

inter-cam transmission mechanism (ICTM), consists of four spur gears, namely left inter cam gear (ICG1), right inter-cam gear (ICG2), upper inter-cam gear (ICG3) and bottom inter-cam gear (ICG4), journalled on the outer side of left, right, upper and bottom wall, respectively, of scotch-yoke operation chamber (SOC), between the corresponding first and second cam follower gears and function as idler gear.

[60] Second model of scotch yoke mechanism and corresponding scotch yoke operation mechanism, as shown in Fig. 15 to Fig. 20, is a variation of the first model with the variation being

left and right crank gears of each crank-pin set are meshingly engaged with upper and bottom crank gears;

Ignition-to-Scotch transmission mechanism (ItS) is modified to rotate the first left, right, upper and bottom cam follower gears in consonance with two modification being

a) left Ignition-to-Scotch transmission mechanism (ItS 1), and right Ignition-to-Scotch transmission mechanism (ItS2), are gear trains of same number of gears but one gear more than that of upper Ignition-to-Scotch transmission gear (ItS3), (or bottom Ignition- to-Scotch transmission gear (ItS4));

b) radii of spur gears of left Ignition-to-Scotch transmission mechanism (ItS 1), and right Ignition-to-Scotch transmission mechanism (ItS2), are appropriately smaller than that of upper Ignition-to-Scotch transmission gear (ItS3), bottom Ignition-to-Scotch

transmission gear (ItS4) , such that all the gear trains of Ignition-to-Scotch transmission mechanism (ItS) are of equal lengths. [61] Third model, as shown in Fig. 21 to Fig. 24, and fourth model, as shown in Fig. 25 to Fig. 28, of scotch yoke mechanism and corresponding scotch yoke operation mechanism are variations of first and second model, respectively, with the variation being

interslot gears are removed and consecutive crank gears on each side are meshingly engaged and pins of consecutive crank gears are oppositely oriented with respect to each other; inter-cam transmission mechanism (ICTM), is removed and consecutive cam follower gears on each side are meshingly engaged with each other.

[62] In second and fourth model, upper and bottom crank gears may be crown gear with teeth extending in the vertical direction according to the depth of upper and bottom yoke sub-slots. The said crank gear teeth appropriately extend sideways to meshingly engage with neighboring gears.

[63] Note that important difference between scotch yoke described in my aforementioned Indian patent and scotch yoke according this invention is that crank bases are replaced by crank gears. Also note that the parts - connecting rod, (CR), front piston plate (PLT1), rear piston plate (PLT2), fuel pressure valve (FPV) and compressor valve (CVLV) - are same and have been redescribed in order to keep the explanation self contained.

[64] Note that important difference between scotch yoke operation mechanism described in my aforementioned Indian patent and scotch yoke operation mechanism according this invention is that in addition to Cam follower gears on left and right side we have two more cam follower gears on upper and bottom side and also transmission gears between cam gear and cam follower gears are included.

[65] Schematic diagrams in Fig. 29 to Fig. 34 illustrates operation of crank gears of Multi-Slot- Scotch-Yoke actuator (MSYA) by cam gear (CMG) and Multi- Slot- Scotch- Yoke operation mechanism (MSYM) according to first model, second model, third model and fourth model in this invention. Ellipses and circles represent the cam follower gears (and crank gears), Ignition- to-Scotch (ItS) transmission gears and cam gear (CMG) with ellipses represent the gears mounted on upper and bottom side of scotch-yoke-operation chamber (SOC) and circles represent gears mounted on left and right side of scotch-yoke-operation chamber (SOC). Solid portions represent the side facing the reader and dotted portions represent the side away from the reader. Each of the big dots represents pin of corresponding crank gear being operated. Arrow on the circles and ellipses represent the direction of rotation of gears. All the schematic diagrams describe the operation of scotch yoke actuator for movement of scotch yoke towards the cam gear represented by straight arrow.

Scotch-yoke operation (first model)

[66] As shown in Fig. 29 and Fig. 30, according to first model, in each quad-lateral crank-pin set left crank gear and right crank gear rotates in clockwise direction and anti-clockwise direction, respectively, with respect to axis pointing towards left direction. Upper crank gear and bottom crank gear rotates in clockwise direction and anti-clockwise direction, respectively, with respect to axis pointing upward direction. During the time duration yoke rod (CR) moves from rear to front direction, represented by straight arrow, left yoke pin moves towards midpoint from lower most point in the left sub-slot, right yoke pin moves towards midpoint from upper most point in the right sub-slot, upper yoke pin moves towards midpoint from left most point in the upper sub-slot, bottom yoke pin moves towards midpoint from right most point in the bottom sub-slot. We can see that torsional twist action on yoke slot caused by left and right yoke pins is mitigated by upper and bottom yoke pins. Sideward thrust of left yoke pin is mitigated by opposite thrust caused by right yoke pin.

Scotch-yoke operation (second model)

[67] Second model is a variation of first model in which left and right crank gears can mate with upper and bottom crank gears. In each quad-lateral crank-pin set, as shown in Fig. 31 and Fig. 32, left crank gear and right crank gear rotates in clockwise direction and anti-clockwise direction, respectively, with respect to axis pointing towards left direction and upper crank gear and bottom crank gear rotates in anti-clockwise direction and clockwise direction, respectively, with respect to axis pointing upward direction. During the time duration yoke rod (CR) moves from rear to front direction, represented by straight arrow, left yoke pin moves towards midpoint from lower most point in the left sub-slot, right yoke pin moves towards midpoint from upper most point in the right sub-slot, upper yoke pin moves towards midpoint from right most point in the upper sub-slot, bottom yoke pin moves towards midpoint from left most point in the bottom sub-slot. Sideward thrust of left yoke pin is mitigated by opposite thrust caused by right yoke pin.

Scotch-yoke operation (third model and fourth model)

[68] Third model, as shown in Fig. 24 and Fig. 33 in conjunction with Fig. 29 and Fig. 30, and fourth model, as shown in Fig. 27 and Fig. 34 in conjunction with Fig. 31 and Fig. 32, are a variation of first model and second model, respectively, in which crank gears of two crank-pin set on each side Scotch- Yoke operation chamber mate. Mating crank gears of two crank-pin set rotates in opposite direction. Therefore, pins of mating crank gears are configured to be in the opposite phase. Thus the first left yoke pin and second right yoke pin are in same phase, first right yoke pin and second left yoke pin are in same phase, first upper yoke pin and second bottom yoke pin are in same phase and first bottom yoke pins and second upper yoke pin are in same phase. Movement of pins of coupled crank gears is represented by circular arrow.

Torsional twist action and sideward thrust of a crank gear is additionally mitigated by that of mating crank gear.