1. Transportation Technology Engine Terms C. Stemmler 4 Engine Terms

2. Engine Terms ?The following terms are commonly found in automotive literature, e.g., repair manuals, advertising ?all of these terms relate to the internal combustion engine.

3. Engine Terms--continued TDC ?Top Dead Centre Cylinder Piston ?is the farthest point of upward travel, of the piston, in the cylinder.

4. Engine Terms--continued BDC ?Bottom Dead Centre ?is the lowest point of downward travel, of the piston, in the cylinder.

5. Engine Terms--continued Bore ?Inside diameter of the cylinder ?measured in inches or millimetres.

6. Engine Terms--continued Stroke ?The distance traveled by the piston as it moves from TDC to BDC (or top to bottom)

7. Engine Terms--continued Piston Displacement (PD) ?The volume that the piston displaces as it travels from TDC to BDC

8. Engine Terms--continued Total Displacement X (times) PD # of Cylinders =

9. Engine Terms--continued Total Displacement ?displacement of all the pistons added together ?each cylinder will have exactly the same displacement ?Units: CID or cubic inches, 351 ?cc 5000cc ?L5.0 liter

10. Engine Terms--continued Total Displacement  To calculate:  TD =  (1/2 of bore 2 ) X stroke

11. Engine Terms--continued Torque ?Turning or twisting force-- imparted on the driveline by the engine.

12. Engine Terms--continued Horsepower ?Gross No accessories (fan, alternator, etc.) connected to the engine during testing. ?NetAccessories connected to the engine during testing. ?Brake Actual horsepower develop by the engine when measured at the crankshaft.

13. Engine Terms--continued Volumetric Efficiency ?Ratio between the amount of fuel/air that enters the cylinder (on intake stroke) and the amount required to fill the cylinder. ?Turbo-chargers, after-coolers, headers, ram-air, and super-chargers increase efficiency.