Semi Diesel

Designating an internal combustion engine of a type resembling the Diesel engine in using as fuel heavy oil which is injected in a spray just before the end of the compression stroke and is fired without electrical ignition The fuel is sprayed into an iron box called a hot bulb or hot pot opening into the combustion chamber and heated for ignition by a blast lamp until the engine is running when it is ordinarily kept red hot by the heat of combustion