The modern Diesel engine incorporates the features of direct (airless) injection and compression-ignition. Both ideas were patented by Akroyd Stuart and Charles Richard Binney in May 1890.[6] Another patent was taken out on 8 October 1890, detailing the working of a complete engine—essentially that of a diesel engine—where air and fuel are introduced separately. The difference between the Akroyd engine and the modern Diesel engine was the requirement to supply extra heat to the cylinder to start the engine from cold. By 1892, Akroyd Stuart had produced an updated version of the engine that no longer required the additional heat source, a year before Diesel's engine.