top dead center


Also found in: Acronyms.

top dead center

[¦täp ′ded ′sen·tər]
(mechanical engineering)
The dead-center position of an engine piston and its crankshaft arm when at the top or outer end of its stroke.

top dead center (TDC)

top dead center (TDC)click for a larger image
top dead center (TDC)click for a larger image
Topographical map
The position of the piston within the cylinder when the piston has reached its farthest uppermost (closest to the cylinder head and valves) position.
References in periodicals archive ?
This value describes the distance between blip start and the firing top dead center of the working cycle in which the blip occurs.
The type M durometer produced curves which were more peaked, with the hardness values rapidly decreasing on either side of top dead center (figure 4).
Two signals are provided: a top dead center indicating the zero degree position of the crankshaft and a pulse per degree signal.
Turn the engine so the piston is at top dead center (all the way up in the cylinder) and secure the output shaft so it cannot turn.
I have resisted the temptation to put in wildcat wells, instead opting for the measured approach where we now have real, top dead center discovery wells, on structure, with proven source rock and reservoir potential giving us the best chance of success in this high risk, high reward, frontier basin play.
A magneto-based ignition system always fires the spark plugs at the same point--usually 25 degrees before top dead center--with the idea that the combustion event will reach maximum pressure by the time the piston reaches about 11 to 17 degrees past top dead center.
I found that when I duplicated their original torque I invariably "over timed", meaning the extensions went too far and actually passed top dead center.
The 4-cycle, 4-cylinder engine of early Farmalls was set at the factory to provide current to the spark plug from 8 to 4 degrees before top dead center.
The diesel fuel is delivered just prior to top dead center, followed by the main fuel quantity of natural gas.
Chief among them: A unique disc-valve design that handles both the inlet and outlet valves of the compression cylinder, allowing trapped gases to be removed from the cylinder, which improves volumetric efficiency, while spark plug firing has been configured to occur after top dead center for improved thermal performance.