IOE engine

Inlet over Exhaust ( IOE, English for " inlet over outlet " ) is a type of valve control in internal combustion engines.

Technology and Definition

Unlike poppet valve engines, in which only the exhaust valve is controlled, both of the valves are controlled by a camshaft in the IOE engine. The inlet valve is " hanging up" (opens down) and is bumper and rocker arm, the exhaust valve " standing among them" ( open up), is moved directly by the camshaft.

This mixed form of pages and kopfgesteuertem engine is called a " change control " or " unchecked ". The SV valve control is called "bottom -driven", refers to the OHV / OHC - control as a " top -driven".


In the early days of motor vehicles IOE was a common type of valve assembly. Manufacturer of IOE motorcycle engines were, for example, MAG, FN, Harley -Davidson (1911-1929), Indian Four, Moto Guzzi single cylinder, Nimbus, NSU. Because of the unfavorable shaped combustion chamber and the limited compression IOE engines are no longer produced today. The about these engines often built bag cylinder has the advantage of not requiring cylinder head gasket, but has disadvantages of a technically complex production casting and a rugged and fuel- poor combustion chamber shape.

The British car manufacturer Rolls- Royce ( Silver Dawn, Silver Wraith, Silver Cloud ) and Rover (P3, P4) used IOE engines until the mid 1960s.