2. Geometric & Kinematic Models for An I.C. Engine P M V Subbarao Professor Mechanical Engineering Department Creation of Infrastructure to Facilitate Thermodynamic Actions…..

3. Kinematics of Conventional I.C. Engine

4. Kinematics of Unconventional Piston Movement

6. Variable Piston Motion Kinematics

7. Free Piston Engine with Opposed Pistons

8. Free Piston Gas Generator

9. Free-Piston Engine With Linear Generator

10. p- v diagram for Free Piston Engine

11. The Dilemma of the Classical Engine Kinematics 1. High efficiency requires high expansion ratio 2. High power density requires low compression ratio BUT UNFORTUNATELY Expansion ratio = Compression ratio

12. How can we change a “ BUT UNFORTUNATELY = “ into an “ AND FORTUNATELY ≠ ” ?

13. The Unreasonable Bias A I R Combustion Products Ignition Intake Stroke FUEL Fuel/Air Mixture Compression Stroke Power Stroke Exhaust Stroke

14. A General Physician to A Team of Specialists Why not add an additional degree of freedom? Three times... “There is no reason to not try it!” Why not allow different cylinders to concentrate on different tasks? Why not add an additional engine stroke? Why not add an additional engine stroke?

15. In 2000, a new engine is born...

16. The software design...

17. The hardware manufacturing...

18. The New p-v Diagram

19. Six Stroke Engine Velozeta Six-stroke engine German Charge pump Crower six stroke engine Griffin six stroke engine Velozeta six-stroke engine Bajulaz six stroke engine

20. Kinematics of Conventional I.C. Engine

21. Engine Cylinder Geometry

22. Bore/Stroke Ratio Bore – to –Stroke Ratio

23. Geometry of Cylinder : A Primary Signature An engine is described as a square engine when it has equal bore and stroke dimensions, giving a bore/stroke value of exactly 1. By custom, engines that have a bore/stroke ratio of between 0.95 and 1.04 can be considered "square". An engine is described as under-square or long-stroke if its cylinders have a smaller bore than its stroke - giving a ratio value of less than 1. At a given engine speed, a longer stroke increases engine friction and increases stress on the crankshaft.

24. The smaller bore also reduces the area available for valves in the cylinder head, requiring them to be smaller or fewer in number. These factors favor lower engine speeds, under-square engines are most often tuned to develop peak torque at relatively low speeds. An under-square engine will typically be more compact in the directions perpendicular to piston travel but larger in the direction parallel to piston travel. An engine is described as over-square or short-stroke if its cylinders have a greater bore diameter than its stroke length, giving a bore/stroke ratio greater than 1.

25. An over-square engine allows for more and larger valves in the head of the cylinder, lower friction and lower crank stress. Due to the increased piston- and head surface area, the heat loss increases as the bore/stroke-ratio is increased excessively. These characteristics favor higher engine speeds, over- square engines are often tuned to develop peak torque at a relatively high speed. The reduced stroke length allows for a shorter cylinder and sometimes a shorter connecting rod, generally making over-square engines less tall but wider than under-square engines of similar engine displacement.