Look up top dead center in Wiktionary, the free dictionary.

Top dead centre (TDC) in a piston engine, is the position of a piston in which it is farthest from the crankshaft. The position closest to the crankshaft is known as bottom dead centre (BDC). Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ... Components of a typical, four stroke cycle, DOHC piston engine. ... For the use of the term in optics, see piston (optics). ... Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black) Continental engine marine crankshafts, 1942 Components of a typical, four stroke cycle, DOHC piston engine. ...

Internal combustion engine

Top dead center is the datum point from which engine timing measurements are made. For example, ignition system timing is normally specified as degrees before top dead centre (BTDC) although a very few small and fast-burning engines, require a spark just after top dead centre (ATDC), such as the Nissan MA engine with hemispherical combustion chambers, or hydrogen engines. Timing refers to how events are spaced in time. ... The ignition system of an internal-combustion engine is an important part of the overall engine system that provides for the timely burning of the fuel mixture within the engine. ... The MA is a all aluminium straight-4 SOHC 0. ... A combustion chamber is part of an engine in which fuel is burned. ... Sequel, a fuel cell-powered vehicle from General Motors A hydrogen vehicle is a personal transportation vehicle, such as an automobile, that uses hydrogen as its on-board fuel for motive power, or another vehicle, such as an aircraft, that use hydrogen in a similar fashion. ...

Top dead center for cylinder one is often marked on the crankshaft pulley, the flywheel or dynamic balancer or both, with adjacent timing marks showing the recommended ignition timing settings as decided during engine development. These timing marks can be used to set the ignition timing either statically by hand or dynamically using a timing light, by rotating the distributor in its seat. Spoked flywheel Flywheel from stationary engine. ... Timing mark on pulley at 6° before TDC. A timing mark is a mark used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel, being the largest radius rotating at crankshaft speed and therefore the place where... A timing light is a stroboscope used to dynamically set the ignition timing of an Otto cycle or similar internal combustion engine. ... Distributor cap. ...

In a multi-cylinder engine, pistons may reach top dead center simultaneously or at different times depending on the engine configuration. For example: Engine configuration is an engineering term for the layout of the major components of an internal combustion engine. ...

• In the V-twin configuration, the two pistons reach TDC at different times, equal to the angular displacement between the cylinders.
• In the boxer twin configuration, two opposing pistons reach TDC simultaneously, which is also called 0° displacement.
• In the straight-4 configuration, the two end pistons (pistons 1 and 4) reach TDC simultaneously, as do the two centre pistons (pistons 2 and 3), but these two pairs reach TDC with an angular displacement of 180°. Similar patterns are found in almost all straight engines with even numbers of cylinders, with the two end pistons and two middle pistons moving together (not necessarily 180° out of phase however) and the intermediate pistons moving in pairs in mirror-image around the centre of the engine.
• In the flatplane V8 and many larger V engines, the piston motion within each bank is similar to that of a straight engine, however in the crossplane V8 and all V10 engines the motion is far more complex.

The concept of top dead center is also extended to pistonless rotary engines, and means the point in the cycle in which the volume of a combustion chamber is smallest. This typically occurs several times per rotor revolution; In the Wankel engine for example it occurs three times for every one revolution of the rotor. Honda 90° transversely mounted V-twin A V-twin is a two cylinder internal combustion engine where the cylinders are arranged in a V configuration. ... Rotation of a rigid object P about a fixed object about a fixed axis O. Angular displacement of a body is the angle in radians (degrees, revolutions) through which a point or line has been rotated in a specified sense about a specified axis. ... A 1967 BMW R50/2 logitudinally mounted flat-twin engine, with tank removed. ... The straight-4 or inline-4 is an internal combustion engine with four cylinders aligned in one row. ... Usually found in 4 and 6 cylinder configurations, the straight engine (often designed as inline engine) is an internal-combustion engine with all cylinders aligned in one row, with no or only minimal offset. ... The Liberty V8 aircraft engine clearly shows the configuration, although modern automotive versions use a 90 degree block angle. ... A V engine is a common configuration for an internal combustion engine. ... The crossplane or cross-plane is a crankshaft design for V8 engines with a 90° angle between the cylinder banks. ... A V10 engine is a V engine with 10 cylinders in two banks of five. ... A pistonless rotary engine is an internal combustion engine that does not use pistons in the way a reciprocating engine does, but instead uses one or more rotors, sometimes called rotary pistons. ... Wankel Engine in Deutsches Museum Munich, Germany The Wankel rotary engine is a type of internal combustion engine, invented by German engineer Felix Wankel, which uses a rotor instead of reciprocating pistons. ...

Steam engine

As steam engines are commonly horizontal, the relevant terms are front dead centre and back dead centre rather than "top" and "bottom". // The term steam engine may also refer to an entire railroad steam locomotive. ... In astronomy, geography, geometry and related sciences and contexts, a plane is said to be horizontal at a given point if it is locally perpendicular to the gradient of the gravity field, i. ...

If a single-cylinder steam engine stops in either of the dead centre positions it must be moved off the dead centre before it will re-start. In small engines this is done by turning the flywheel by hand. In large engines the flywheel is moved with a lever or "turning bar". Both operations must be done with care to avoid the operator becoming entangled in the machinery. Spoked flywheel Flywheel from stationary engine. ...

Steam locomotives normally have two cylinders with the cranks set at right angles so one piston will always be off the dead centre and no starting assistance is required. One of the last mainline steam locomotives built in the UK: British Railways Standard Class 9F 2-10-0 no. ... Steam locomotive cylinders may be arranged in several different ways. ... A crank is a bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it; also used to change circular into reciprocating motion, or reciprocating into circular motion. ... This article is about angles in geometry. ... For the use of the term in optics, see piston (optics). ...

Other machines

This term is also used in the realm of production equipment. A mechanical punch press employs a crankshaft similar to that found in an engine. In the punch press the crankshaft drives a ram which when it is farthest away from the platen of the press is considered to be in the position of top dead center.

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