WO2018051339A1

WO2018051339A1 - Method and aparatus for dynamically controlling engine combustion chamber's volume

Info

Publication number: WO2018051339A1
Application number: PCT/IL2017/051033
Authority: WO
Inventors: Eran Ofek
Original assignee: Eran Ofek
Priority date: 2016-09-13
Filing date: 2017-09-13
Publication date: 2018-03-22

Abstract

A variable stroke engine comprises: (a) an engine main body; (b) at least one piston slidably received in a cylinder; (c) a crankshaft mechanism rotatably supported by the engine main body; the crankshaft mechanism comprising a crankpin base and a crankpin pulley rotatable relative to the crankpin base; and (e) an output shaft extending substantially with the crankshaft and rotatable by the crankshaft. The engine comprises a crankpin pulley positioning means rotatably interconnecting the output shaft and the crankpin pulley. The crankpin pulley positioning means comprising a phase shifting mechanism driven by the output shaft and shifting a rotating torque provided by the output shaft when the rotating torque is transmitted to the crankpin pulley. Said phase shifting mechanism controls a lateral distance of the crankpin from rotation center thereof which determines the output shaft's motion.

Description

METHOD AND APARATUS FOR DYNAMICALLY CONTROLLING ENGINE COMBUSTION CHAMBER'S VOLUME

ABSTRACT

FIELD OF THE INVENTION

The present invention relates to a variable stroke engine, and, more specifically, to an engine provided with a crankshaft assembly affecting engine combustion chamber's volume by controlling its piston's stroke length.

BACKGROUND OF THE INVENTION

Most automobiles employ internal combustion engines as the source of mechanical power. Such a vehicle is typically equipped with an engine that is large enough to meed desired perfomance criteria such as maximum acceleration and hill climing capability. On the other hand, only a fraction of the engine is needed for highways cruising. To meet various load requirements, it is necessary to incorporate some kind of engine load control mechanism. Most internal combusion engines employ the crank-and-lider mechanism with a constan stroke length as the engine mechanism.load control is achieved bu throttling the inlet. Throttling, however, introduces pumping losses. It becomes clear that engine efficiency can be improved igf the throttling can be eliminated or reduced.

US 4887560 discloses a crankshaft carried crankpin carrying an eccentric interposed between the crankpin and the slider of a yoke type engine. The eccentric carries a gear to permit rotatable adjustment to be imparted to the eccentric about the crankpin axis. Positioning of the eccentric includes the use of a gear train. A gear set in the gear train has displaceable gears carried by a carrier responsive to engine control means. The movable gear set serves to accelerate or decelerate the rotational speed of a pair of shaft mounted driven gears to momentarily alter their rotational speed so as to in turn rotate the eccentric mounted gear to reorientate the eccentric to the crankpin. Such relocating of the eccentric serves to alter the piston stroke between high and low compression ranges.

Analysis of the abovementioned patent document indicates that asymmetry of the forces applied to control levers implies use of powerful actuator in order to vary the stroke distance. Thus, there is a long-felt and unmet need to provide a variable stroke engine with easy control of stroke distance which does not need a powerful actuator.

SUMMARY OF THE INVENTION

It is hence one object of the invention to disclose a variable stroke engine comprising: (a) an engine main body; (b) at least one piston slidably received in a cylinder; (c) a crankshaft rotatably supported by the engine main body; the crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to the crankpin base; and (d) an output shaft extending substantially in parallel with the crankshaft and rotatable by the crankshaft. It is a core purpose of the invention to provide the engine comprising a crankpin pulley positioning means rotatably interconnecting the output shaft and the crankpin pulley. The crankpin pulley positioning means comprising a phase shifting mechanism driven by the output shaft and shifting a rotating torque provided by the output shaft when the rotating torque is transmitted to the crankpin pulley. Another object of the invention is to disclose the phase shifting mechanism comprising a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around the common rotation axis such that the rotating torque transmittable from the first bevel cogwheel to the second cogwheel is phase-shifted with angular displacement of the third bevel cogwheel around the common rotation axis.

A further object of the invention is to disclose the phase shifting mechanism comprises an inverting cogwheel train providing the crankpin pulley with the rotating torque of opposite to the output shaft.

A further object of the invention is to disclose the cylinder displaceable relative the engine main body such that to provide effective compressive ration within the cylinder.

A further object of the invention is to disclose the valve train comprising a compensating wheel configured to keep an effective belt tension with cylinder displacement.

A further object of the invention is to disclose the phase shifting mechanism comprising a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along the axis; the belt is strained between the rollers and intercouples the output shaft and the crankpin pulley; the frame is linearly displaceable along the axis such that the rotating torque transmittable from the output shaft to the crankpin pulley is phase-shifted with linear displacement of the frame.

A further object of the invention is to disclose the phase shifting mechanism comprising: (a) a servomechanism configured for controlling an engine stroke volume; (b) a servomechanism configured for controlling said phase shifting mechanism; and (c) a control unit configured for optimizing engine operation according driver's behavior and road conditions by means transmitting actuating signals to said servomechanisms.

A further object of the invention is to disclose a crankpin slidably displaceable along a slide rail disposed on the crankpin base.

A further object of the invention is to disclose the variable stroke engine comprising a sensing mechanism configured for sensing a load applied to said engine and optimize engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position.

A further object of the invention is to disclose the mechanism selected from the group consisting of a spring-based mechanism, a pneumatic mechanism, a hydraulic

mechanism, a gear-based mechanism and any combination thereof.

A further object of the invention is to disclose the variable stroke engine comprising a manually controlled mechanism configured for varying said engine capacity.

A further object of the invention is to disclose a method of varying a stroke in a combustion engine. The aforesaid method comprises the steps of: (a) providing a variable stroke engine comprising: (i) an engine main body; (ii) at least one piston slidably received in a cylinder; (iii) a valve train; (iv) a crankshaft rotatably supported by the engine main body; the crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to the crankpin base; (v) an output shaft extending substantially in parallel with the crankshaft and rotatable by the crankshaft; the engine comprises a crankpin pulley positioning means rotatably interconnecting the output shaft and the crankpin pulley; the crankpin pulley positioning means comprising a phase shifting mechanism driven by the output shaft and shifting a rotating torque provided by the output shaft when the rotating torque is transmitted to the crankpin pulley; (b) starting the variable stroke engine; (c) translating rotating torque provided by the output shaft to the crankpin pulley; (d) varying the phase shift between the output shaft to the crankpin pulley.

A further object of the invention is to disclose the step of varying the phase shift performed by the phase shifting mechanism comprising a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around the common rotation axis such that the rotating torque transmittable from the first bevel cogwheel to the second cogwheel is phase-shifted with angular displacement of the third bevel cogwheel around the common rotation axis. A further object of the invention is to disclose the step of varying the phase shift comprising an inverting the rotating torque of the output shaft and transmitting an opposite torque to the crankpin pulley.

A further object of the invention is to disclose the method comprising a step of displacing the cylinder displaceable relative the engine main body such that to provide effective compressive ration within the cylinder.

A further object of the invention is to disclose the method comprising a step of maintaining an effective belt tension the valve train in the valve train with cylinder displacement by a compensating wheel.

A further object of the invention is to disclose the step of varying the phase shift performed by the phase shifting mechanism comprising a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along the axis; the belt is strained between the rollers and intercouples the output shaft and the crankpin pulley; the frame is linearly displaceable along the axis such that the rotating torque transmittable from the output shaft to the crankpin pulley is phase-shifted with linear displacement of the frame.

A further object of the invention is to disclose the step of varying said phase shift performed by said phase shifting mechanism comprising: (a) a servomechanism configured for controlling an engine stroke volume; (b) a servomechanism configured for controlling said phase shifting mechanism; and (c) a control unit configured for optimizing engine operation according driver's behavior and road conditions by means transmitting actuating signals to said servomechanisms.

A further object of the invention is to disclose the step of varying the phase shift comprising slidably displacing a crankpin along a slide rail disposed on the crankpin base.

A further object of the invention is to disclose the step of varying said phase shift comprising a step of sensing a load applied to said engine and optimizing engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position. A further object of the invention is to disclose the mechanism selected from the group consisting of a spring-based mechanism, a pneumatic mechanism, a hydraulic

mechanism, a gear-based mechanism and any combination thereof.

A further object of the invention is to disclose the step of varying engine capacity performed manually.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments is adapted to now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which

Figs la and lb show crankpin pulley in positions corresponding to minimal and maximal stroke distances;

Figs 2 and 3 are isometric schematic views of a first embodiment of a phase-shifting mechanism;

Figs 4 and 5 are isometric schematic views of a variable stroke engine;

Figs 6a and 6b are isometric schematic views of a second embodiment of a phase-shifting mechanism;

Figs 7a and 7b are isometric schematic views of a third embodiment of a phase-shifting mechanism;

Fig. 8 is an isometric schematic view of a second embodiment of a crankpin mechanism; Fig. 9 is a schematic view of a fourth embodiment of a phase-shifting mechanism;

Fig. 10 is an isometric schematic view of a third embodiment of a crankpin mechanism; Fig. 11 is a schematic view of a hydraulic mechanism for controlling a piston stroke; and

Fig. 12 is an isometric schematic view of a fourth embodiment of a crankpin mechanism. DETAILED DESCRIPTION OF THE INVENTION

The following description is provided, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, are adapted to remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a variable stroke engine and a method of varying a stroke in a combustion engine.

The term "belt" hereinafter refers to any loop-like flexible mechanical linkage configured for transfer rotational motion from one body to another. The term "chain" is in the scope of the present definition.

Reference is now made to Figs la and lb, illustrating positions of crankpin pulley corresponding to maximum and minimum stroke lengths, respectively. Crankpin pulley 20 is rotatably emplaced at crankpin base 30. The position of crankpin pulley 20 is controlled by cogwheel 40 kinematically coupled to output shaft (not shown) as specified below. It is known in the art that stroke length defines compression degree in the cylinder and, ultimately, output power. Thus, varying the stroke length provides an additional freedom degree in controlling output engine power.

Reference is now made to Figs 2 and 3, presenting phase- shifting mechanism 10 transmitting a rotating torque from crankpin base 30 to cogwheel 40 controlling the position of crankpin pulley 20. During an expansion stroke of piston 120, piston rod 125 applies a force directed downward to crankpin 24 of crankpin pulley 20 and turns crankpin base 30. Abovementioned crankpin base 30 is coupled to cogwheel 50 which transmits the rotating torque to three -bevel cogwheel assembly 76 including two bevel cogwheels 60 and 80 having a common rotation axis and cogwheel 70 interconnecting cogwheels 60 and 80. Cogwheel 70 is rotatable around the abovementioned common rotation axis. Angular displacement of cogwheel 70 varies a phase shift between cogwheels 60 and 80. Then, a train of cogwheels 90, 100 and 110 transmits the rotating torque to cogwheel 30 controlling position of crankpin pulley 30.

Reference is now made to Fig. 4, presenting variable stroke engine 200. Pistons 120 are received by cylinders 127. Inlet and outlet of fuel-air mixture is controlled by valves 180 driven by camshafts 185. Engine block 170 is displaceable relative crank case 175 (shown partially). Engine block 170 ascends with increase in stroke length and descends with opposite change by displacing means 160. Output shaft 130 transmits the rotating torque to valve train via belt 150. Synchronizing shaft 140 controls the position of other crankpin pulleys of the engine 200.

Reference is now to Fig. 5, presenting a tightening device 152. Cogwheel 151 connected to output shaft 130 transmits the rotating torque to cogwheel 153 connected to camshaft 185. Cogwheel 159 is a follower of cogwheel 153. Tension of belt 150 is changed with displacement of engine block 170 relative crank case 175. Means 153 (shown

schematically) compensates changes in tension of belt 150 when engine block 170 is displaced.

Reference is now made to Figs 6a and 6b, presenting an alternative embodiment 210 of the phase-shifting mechanism. Similar to Figs 2 and 3, mechanism 210 kinematically interconnects wheel 260 sitting on output shaft 265 and wheel 250 sitting on

synchronizing shaft 255 connected to cogwheel 40. Mechanism 210 includes frame 220 frame having a longitudinal axis carrying rollers 230. Belt 240 is strained between rollers 230. Linear displacement of frame 220 shifts belt 240 resulting in change in a distance between wheels 250 and 260 along belt 240. The aforesaid distance defines difference in rotation phase between wheels 250 and 260. Figs 6a and 6b show utmost positions of frame 220 corresponding maximum and minimum in the provided stroke length.

Reference is now made to Figs 7a and 7b, presenting an alternative embodiment 270 of the phase-shifting mechanism. Frame 280 carries four rollers 230. Similar to embodiment 210, mechanism 270 interconnects wheel 260 sitting on output shaft 265 and wheel 250 sitting on synchronizing shaft 255 connected to cogwheel 40.

Reference is made to Fig. 8, presenting a second embodiment of crankpin mechanism. Specifically, crankpin 24 sits on slider 290 driven by cogwheel 40 coupled to slider 290 in a rack-and-pinion manner. Rods 300 function as a guide rail. Linear displacement of slider 290 results in change in the stoke length.

Reference is now made to Figs 9 and 10, presenting a third embodiment of crankpin mechanism. Specifically, crankpin 330 and a slider 325 are rigidly interconnected member 320. Aforesaid member 320 is slidably movable within guiding passage 340 mechanically secured to crankpin base 30. Spiral rail 310 is mechanically secured to crankpin pulley 40. Slider 325 located at a terminal of member 320 is slidable along spiral rail 310. Position of crankpin 330 is defined by an angle of crankpin pulley 40 relative to crankpin base 30.

Reference is now to Fig. 11 , presenting a hydraulic mechanism for controlling a piston stroke. The aforesaid mechanism comprises hydraulic cylinder 360 in which slidably movable piston 350 ascending or descending cylinders 127 (not shown). Numeral 390 refers to a tank accommodating a hydraulic fluid. Volume 400 of the hydraulic fluid within hydraulic cylinder 360 is controlled a phase shift between rotation of lobe pump 370 gear pump 380. Phase lag in rotation of gear pump 380 relative to lobe pump 370 results in increase in volume 400 of the hydraulic fluid within hydraulic cylinder 360. Consequently, piston 350 and cylinders 127 ascend. Phase advance in rotation of gear pump 380 relative to lobe pump 370 leads to decrease in volume 400 of the hydraulic fluid and downward movement of piston 350 and cylinders 127.

Reference is now to Fig. 12, presenting a fourth embodiment of a crankpin mechanism. The discriminating technical feature is the following: crankpin 24 is secured to slider 290 guided by member 300. Slider 290 and crankpin pulley 40 are interconnected by means of a rack and pinion mechanism.

According to one embodiment, crankpin pulley 40 is rotatable by an electrical mechanism (such as, for a non-limiting example, be a servo, linear motor, spiral cogwheel driver motor etc.), not shown. The crankpin 330 (Fig. 9) is kept locked in a desired position along a slide rail in accordance to the size of the said phase shift. The crankpin is positioned closer to the center of rotation and therefor drive a shorter stroke length to the pistons or be positioned further away from the center of rotation and therefore drive a longer stroke length to the pistons. According to the present invention, a variable stroke engine comprises: (a) an engine main body; (b) at least one piston slidably received in a cylinder;; (c) a crankshaft rotatably supported by the engine main body; the crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to the crankpin base; and (d) an output shaft extending substantially in parallel with the crankshaft and rotatable by the crankshaft.

It is a core feature of the invention to provide the engine comprising a crankpin pulley positioning means rotatably interconnecting the output shaft and the crankpin pulley. The crankpin pulley positioning means comprising a phase shifting mechanism driven by the output shaft and shifting a rotating torque provided by the output shaft when the rotating torque is transmitted to the crankpin pulley.

According to one embodiment of the present invention, the phase shifting mechanism comprises a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around the common rotation axis such that the rotating torque transmittable from the first bevel cogwheel to the second cogwheel is phase- shifted with angular displacement of the third bevel cogwheel around the common rotation axis.

According to another embodiment of the present invention, the phase shifting mechanism comprises an inverting cogwheel train providing the crankpin pulley with the rotating torque of opposite to the output shaft.

According to a further embodiment of the present invention, the cylinder is displaceable relative the engine main body such that to provide effective compressive ration within the cylinder.

According to a further embodiment of the present invention, the valve train comprises a compensating wheel configured to keep an effective belt tension with cylinder displacement.

According to a further embodiment of the present invention, the phase shifting mechanism comprises a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along the axis; the belt is strained between the rollers and intercouples the output shaft and the crankpin pulley; the frame is linearly displaceable along the axis such that the rotating torque transmittable from the output shaft to the crankpin pulley is phase-shifted with linear displacement of the frame.

According to a further embodiment of the present invention, the phase shifting mechanism comprises: (a) a servomechanism configured for controlling an engine stroke volume; (b) a servomechanism configured for controlling said phase shifting mechanism; and (c) a control unit configured for optimizing engine operation according driver's behavior and road conditions by means transmitting actuating signals to said servomechanisms.

According to a further embodiment of the present invention, a crankpin is slidably displaceable along a slide rail disposed on the crankpin base.

According to a further embodiment of the present invention, the variable stroke engine comprises a sensing mechanism configured for sensing a load applied to said engine and optimize engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position.

According to a further embodiment of the present invention, the mechanism is selected from the group consisting of a spring-based mechanism, a pneumatic mechanism, a hydraulic mechanism, a gear-based mechanism and any combination thereof.

According to a further embodiment of the present invention, the variable stroke engine comprises a manually controlled mechanism configured for varying said engine capacity.

According to a further embodiment of the present invention, a method of varying a stroke in a combustion engine is disclosed. The aforesaid method comprises the steps of: (a) providing a variable stroke engine comprising: (i) an engine main body; (ii) at least one piston slidably received in a cylinder; (iii) a crankshaft rotatably supported by the engine main body; the crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to the crankpin base; (v) an output shaft extending substantially in parallel with the crankshaft and rotatable by the crankshaft; the engine comprises a crankpin pulley positioning means rotatably interconnecting the output shaft and the crankpin pulley; the crankpin pulley positioning means comprising a phase shifting mechanism driven by the output shaft and shifting a rotating torque provided by the output shaft when the rotating torque is transmitted to the crankpin pulley; (b) starting the variable stroke engine; (c) translating rotating torque provided by the output shaft to the crankpin pulley; (d) varying the phase shift between the output shaft to the crankpin pulley.

According to a further embodiment of the present invention, the step of varying the phase shift is performed by the phase shifting mechanism comprising a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around the common rotation axis such that the rotating torque transmittable from the first bevel cogwheel to the second cogwheel is phase-shifted with angular displacement of the third bevel cogwheel around the common rotation axis.

According to a further embodiment of the present invention, the step of varying the phase shift comprises an inverting the rotating torque of the output shaft and transmitting an opposite torque to the crankpin pulley.

According to a further embodiment of the present invention, the method comprises a step of displacing the cylinder displaceable relative the engine main body such that to provide effective compressive ration within the cylinder.

According to a further embodiment of the present invention, the step of varying said phase shift is performed by said phase shifting mechanism comprising: (a) a servomechanism configured for controlling an engine stroke volume; (b) a servomechanism configured for controlling said phase shifting mechanism; and (c) a control unit configured for optimizing engine operation according driver's behavior and road conditions by means transmitting actuating signals to said servomechanisms.

According to a further embodiment of the present invention, the method comprises a step of maintaining an effective belt tension the valve train in the valve train with cylinder displacement by a compensating wheel.

According to a further embodiment of the present invention, the step of varying the phase shift is performed by the phase shifting mechanism comprising a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along the axis; the belt is strained between the rollers and intercouples the output shaft and the crankpin pulley; the frame is linearly displaceable along the axis such that the rotating torque transmittable from the output shaft to the crankpin pulley is phase-shifted with linear displacement of the frame.

According to a further embodiment of the present invention, the step of varying the phase shift comprises slidably displacing a crankpin along a slide rail disposed on the crankpin base.

According to a further embodiment of the present invention, a step of varying the phase shift comprises rotating spiral slide rail capable of moving the crankpin along a straight slide rail disposed of the crankpin base. The rotating spiral is controlled by the phase shifting in a way that the crankpin is kept locked in its desired position along a slide rail in accordance to the size of the said phase shift. The crankpin is positioned closer to the center of rotation and therefor drive a shorter stroke length to the pistons or be positioned further away from the center of rotation and therefore drive a longer stroke length to the pistons.

According to a further embodiment of the present invention, a step of varying the phase shift comprises a mechanical piston (with, as a non-limiting example, internal rod, cogwheels, tooth-bar, air, water, oil etc.) capable of moving the crankpin along a straight slide rail disposed of the crankpin base. The mechanical piston is controlled by the phase shifting size in a way that the crankpin is kept locked in its desired position along a slide rail in accordance to the size of the said phase shift. The crankpin is positioned closer to the center of rotation and therefor drive a shorter stroke length to the pistons or be positioned further away from the center of rotation and therefore drive a longer stroke length to the pistons.

According to a further embodiment of the present invention, a step of varying the phase shift comprises an electrical mechanism capable of moving the crankpin along a straight slide rail disposed of the crankpin base. The electrical mechanism (such as, for a non- limiting example, be a servo, linear motor, spiral cogwheel driver motor etc.) is controlled by the said phase shifting size in a way that the crankpin is kept locked in its desired position along a slide rail in accordance to the size of the said phase shift. The crankpin is positioned closer to the center of rotation and therefor drive a shorter stroke length to the pistons or be positioned further away from the center of rotation and therefore drive a longer stroke length to the pistons.

According to a further embodiment of the present invention, the step of varying said phase shift comprises a step of sensing a load applied to said engine and optimizing engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position.

According to a further embodiment of the present invention, the step of varying engine capacity is performed manually.

Table. Potential embodiments of the present invention

Category A: Category B: Category C: Category D:

Phase Shift Control Crank Pin Control Cylinder Height Control Phase Shift Selection

(our blue conic cogwheel (our green crankpin base (our black belt) (how to select the volume) now) cogwheel now)

1. A belt in a structure 1. Rotating eccentric 1. A belt transmission 1. Calculated by engine' s to allow changing the length base that allows the sensing with tension controlling efficiency considerations and of the belt that is running of the exact orientation of the structure to keep constant belt controlled electronically between the crankpin pulley crankshaft pulley and then length between the crankshaft

and the crankshaft pulley positioning the crankpin pulley and the valve train

drivers pulley in the desired relative pulley.

orientation.

2. Chain in a structure 2. Tooth-bar Slider 2. A chain transmission 2. Mechanical selection to allow changing the length base that is mounted to the with tension controlling by a tension sensing of the belt that is running crankshaft pulley and then structure to keep constant mechanism connected between between the crankpin pulley sliding along a rail to chain length between the the vehicle traction mechanism and the crankshaft pulley reposition the crankpin in crankshaft pulley and the (as a non-limiting example: drivers accordance to the phase shift valve train pulley. wheels, chain tractor drive, between the crankshaft pulley propeller etc.) and the engine's and the crankpin pulley output pulley (directly or indirectly). In that case, as the tension is higher, meaning that more power is required, so the engine will increase its volume accordingly.

3. A cogwheel 3. Tooth-bar Slider 3. A cogwheel 3. A mechanism (as a structure, comprising of at base that is mounted to the structure transmission to non-limiting example: spring least one set of conic crankpin pulley and then compensate for the change in based, pneumatic, hydraulic, cogwheels that allows the sliding along a rail to distance between the gear based etc.) controlled by creation of a phase shift reposition the crankpin in crankshaft main pulley and the resistance (force, torque) of between the crankshaft pulley accordance to the phase shift the valve train pulley to keep the drive shaft to rotate as a and the crankpin pulley between the crankshaft pulley constant phase between the result for the engine's drive.

and the crankpin pulley crankshaft pulley and the This mechanism translates said valve train pulley. resistance level into a control in the phase-shift- control mechanism

4. An electric 4. Spiral slide rail 4. A mechanism 4. A mechanism allowing transmission capable of pushing a crankpin that slides designed to copy the a manual selection of engine copying the exact orientation along a straight slide rail in disposition of the phase- shift- volume

of the crankshaft pulley to the the crankshaft pulley control mechanism into the

crankpin pulley and create a translated change in distance

phase shift when required. between the crankshaft pulley

and the valve train pulley Category A: Category B: Category C: Category D:

5. A fluid based 5. A fluid based 5. A fluid based 5. Calculated volume of transmission that can create a transmission that can translate mechanism (as a non-limiting engine volume while taking phase shift by copying the a phase shift between two example: cylinder & piston, into consideration at least one exact motion of the input side rotating pulleys into a linear pneumatic, hydraulic) that of the following factors: engine to the output side of it, and eccentric disposition of the can translate the disposition min/max volume available, create phase shift by changing crankpin over one of the of the phase-shift-control gasoline level in the tank, slope the balance of the fluids pulleys center of rotation mechanism into the translated of climbing or descending, between at least two change in distance between optimal engine RPM per chambers the crankshaft pulley and the relevant factors, speed, wind valve train pulley resistance, vehicle weight, etc.

6. Or any combination 6. Or any combination 6. Or any combination 6. Or any combination thereof thereof thereof thereof

Claims

Claims:

1. A variable stroke engine comprising:

a. an engine main body, comprising of at least one cylinder;

b. at least one piston slidably received in said cylinder;

c. a crankshaft rotatably supported by said engine main body; said crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to said crankpin base;

d. an output shaft extending in parallel with the crankshaft and rotatable by said crankshaft;

wherein said engine comprises a crankpin pulley positioning means rotatably interconnecting said output shaft and said crankpin pulley; said crankpin pulley positioning means comprising a phase shifting mechanism driven by said output shaft and shifting a rotating torque provided by said output shaft when said rotating torque is transmitted to said crankpin pulley.

2. The variable stroke engine according to claim 1, wherein said phase shifting mechanism comprises a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around said common rotation axis such that said rotating torque transmittable from said first bevel cogwheel to said second cogwheel is phase-shifted with angular displacement of said third bevel cogwheel around said common rotation axis.

3. The variable stroke engine according to claim 1, wherein said cylinder is displaceable relative said engine main body such that to provide effective compressive ration within said cylinder.

4. The variable stroke engine according to claim 1, wherein a timing belt is provided with a compensating wheel configured to keep an effective belt tension with cylinder displacement.

5. The variable stroke engine according to claim 1, wherein said phase shifting mechanism comprises a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along said axis; said belt is strained between said rollers and rotatably intercouples said output shaft and said crankpin pulley; said frame is linearly displaceable along said axis such that said rotating torque transmittable from said output shaft to said crankpin pulley is phase-shifted with linear displacement of said frame.

6. The variable stroke engine according to claim 1, wherein said phase shifting mechanism comprises:

a. a servomechanism configured for controlling an engine stroke volume; b. a servomechanism configured for controlling said phase shifting mechanism; and

c. a control unit configured for optimizing engine operation according driver's behavior and road conditions by means transmitting actuating signals to said servomechanisms.

7. The variable stroke engine according to claim 1, wherein a crankpin is slidably displaceable along a slide rail disposed on said crankpin base.

8. The variable stroke engine according to claim 7, wherein said slide rails is spiral.

9. The variable stroke engine according to claim 1, comprising a sensing mechanism configured for sensing a load applied to said engine and optimize engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position.

10. The variable stroke engine according to claim 9, wherein said mechanism is

selected from the group consisting of a spring-based mechanism, a pneumatic mechanism, a hydraulic mechanism, a gear-based mechanism and any

combination thereof.

11. The variable stroke engine according to claim 1 , comprising a manually controlled mechanism configured for varying said engine capacity.

12. A method of varying a stroke in a combustion engine; said method comprising the steps of:

a. providing a variable stroke engine comprising:

i. an engine main body, comprising of at least one cylinder;

ii. at least one piston slidably received in said cylinder; iii. a crankshaft rotatably supported by said engine main body; said crankshaft comprising a crankpin base and a crankpin pulley rotatable relative to said crankpin base;

iv. an output shaft extending substantially in parallel with the crankshaft and rotatable by said crankshaft;

wherein said engine comprises a crankpin pulley positioning means rotatably interconnecting said output shaft and said crankpin pulley; said crankpin pulley positioning means comprising a phase shifting mechanism driven by said output shaft and shifting a rotating torque provided by said output shaft when said rotating torque is transmitted to said crankpin pulley;

b. starting said variable stroke engine;

c. translating rotating torque provided by said output shaft to said crankpin pulley;

d. varying engine capacity by means of varying said phase shift between said output shaft to said crankpin pulley to control the piston stroke length.

13. The method according to claim 12, wherein said step of varying said phase shift is performed by said phase shifting mechanism comprising a three-cogwheel bevel train comprising first and second utmost bevel cogwheels having a common rotation axis and intercoupled by means of a third bevel cogwheel mounted rotatably around said common rotation axis such that said rotating torque transmittable from said first bevel cogwheel to said second cogwheel is phase- shifted with angular displacement of said third bevel cogwheel around said common rotation axis.

14. The method according to claim 12, wherein said step of varying said phase shift is said phase shifting mechanism comprising:

15. The method according to claim 12, wherein said step of varying said phase shift comprises an inverting said rotating torque of said output shaft and transmitting an opposite torque to said crankpin pulley.

16. The method according to claim 12 comprising a step of displacing said cylinder displaceable relative said engine main body such that to provide effective compressive ration within said cylinder.

17. The method according to claim 12 comprising a step of maintaining an effective belt tension said valve train in said valve train with cylinder displacement by a compensating wheel.

18. The method according to claim 12, wherein said step of varying said phase shift is performed by said phase shifting mechanism comprising a belt, a frame having a longitudinal axis and carrying at least two rollers disposed along said axis; said belt is strained between said rollers and intercouples said output shaft and said crankpin pulley; said frame is linearly displaceable along said axis such that said rotating torque transmittable from said output shaft to said crankpin pulley is phase-shifted with linear displacement of said frame.

19. The method according to claim 10, wherein said step of varying said phase shift comprises slidably displacing a crankpin along a slide rail disposed on said crankpin base.

20. The method according to claim 10, wherein said step of varying said phase shift comprises slidably displacing a crankpin along a spiral rail.

21. The method according to claim 10, wherein said step of varying said phase shift comprising a step of sensing a load applied to said engine and optimizing engine capacity according to said applied load defined at least one of the following: position of said at least one cylinder and crankpin position.

22. The method according to claim 21, wherein said mechanism is selected from the group consisting of a spring-based mechanism, a pneumatic mechanism, a hydraulic mechanism, a gear-based mechanism and any combination thereof.

23. The method according to claim 21, wherein said step of varying engine capacity is performed manually.