UAV engine exhaust gas temperature control

摘要

For an unmanned aerial vehicle (UAV) engine, an exhaust gas temperature control method is provided during operation of the UAV engine to protect exhaust components, particularly lightweight aluminium components, from overheating or melting. The engine is operated with a leaner than stoichiometric air-fuel ratio during low or part engine load conditions. Transition to a richer than stoichiometric air-fuel ratio is made as engine load or engine speed, or both engine load and engine speed, increase(s). At sufficiently low engine loads, the air-fuel ratio can be maintained in a lean ratio region. As demand on the engine causes engine speed and load to increase, the amount of excess air available reduces. The ability to operate lean is reduced and the exhaust gas temperature increases as the mixture becomes richer. In order to obtain the demand power, and keep exhaust temperature below an exhaust gas temperature limit, the air-fuel ratio is transitioned to a richer than stoichiometric region. As engine load and speed demand decreases, the air-fuel ratio can be transitioned back to a leaner region.

主权项

1. A method of controlling exhaust gas temperature of an exhaust system of an unmanned aerial vehicle (UAV) engine during operation, the UAV engine having an engine management system for controlling the operation of the UAV engine, the method including the engine management system controlling the engine to operate with a leaner than stoichiometric air-fuel ratio during low or part engine load conditions, and controlling the exhaust gas temperature to be no higher than a threshold exhaust gas temperature by transitioning the air-fuel ratio to a richer than stoichiometric air-fuel ratio based on a measured, demanded or required increase in engine load or engine speed, or both engine load and engine speed.