Internal Combustion Engines

1. Internal Combustion Engines

2. Engine • “A machine for converting energy into mechanical force and motion.”

3. Heat Engine An engine which uses heat to convert the chemical energy of a fuel into mechanical force and motion

4. Two general categories based on design. External combustion engine Internal combustion engine

5. Engine Size • Largest: • The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1,820 liters) and produces 7,780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 liters) for the fourteen cylinder version.

6. Engine Size--cont. • Smallest: • Not much bigger than a stack of pennies, the "mini engine" is the first engine of its size to deliver power on a continuous basis. • Currently will produce 2.5 watts of electricity (0.00335 hp). • Uses 1/2 fluid ounce of fuel per hour

7. Engines are further classified by ignition, number of strokes, cylinder design/orientation and cooling system.

8. Ignition • Spark ignition Compression ignition

9. Number of Strokes • Four stroke Two stroke

10. Cylinder Design-cont. Three common cylinder configuration in multiple cylinder engines: V Horizontally opposed In-line

11. When fuel is oxidized (burned) heat is produced. • Only approximately 30% of the energy released is converted into useful work. • The remaining (70%) must be removed from the engine to prevent the parts from melting.

12. Excess heat is removed by: • Cooling system • Exhaust system • Lubrication system • Radiation

13. Additional heat is also generated by friction between the moving parts. • This heat must also be removed.

14. Energy Conversion Principle • “All internal combustion engines exhibit and convert different forms of energy.” • “Energy is the resource that provides the capacity to do work”. • The two forms of energy used in engines are potential and kinetic.

15. Potential Energy • “Stored energy a body has due to its position, chemical state, or condition.”

16. Examples of Potential Energy A compressed spring has potential energy due to its mechanical condition. • Fuels have potential energy based on their chemical state. Water behind a dam has potential energy due to difference in elevation.

17. Kinetic Energy

18. A speeding automobile • Flywheel Water falling over a dam.

19. Force • In engines the amount of force exerted on the top of a piston is determined by the cylinder pressure during the combustion process.

20. Torque • “A force acting on the perpendicular radial distance from a point of rotation.” To (lb-ft) = Force x Radius

21. Lever • “A lever is a simple machine that consists of a rigid bar”, which pivots on a fulcrum with both resistance and effort applied. Applied force Resultant force

22. Power is the rate of doing work

23. 1 Hp = 33,000 ft-lb/min A unit of power developed by James Watt to provide a basis for comparing the amount of power produced by horses and other engines. Horsepower