Zibani, Ishmael; Marumo, Rapelang; Chuma, Joseph; Ngebani, Ibo; Tsamaase, Kelebaone
(Elsevier, 2018-01)
Engine efficiency could be increased if valve timing could change with engine revolutions per minute. Poppet valves are fitted with strong springs which return them to their rest positions after being pushed down by cam ...