The cam has been an integral part of the IC engine from its invention. The cam controls the â€œbreathing channelsâ€ of the IC engines, that is, the valves through which the fuel air mixture (in SI engines) or air (in CI engines) is supplied and exhaust driven out.Â
Besieged by demands for better fuel economy, more power, and less pollution, motor engineers around the world are pursuing a radical â€œcamlessâ€ design that promises to deliver the internal â€“ combustion engineâ€™s biggest efficiency improvement in years. The aim of all this effort is liberation from a constraint that has handcuffed performance since the birth of the internal-combustion engine more than a century ago. Camless engine technology is soon to be a reality for commercial vehicles. In the camless valve train, the valve motion is controlled directly by a valve actuator â€“ thereâ€™s no camshaft or connecting mechanisms .Precise electrohydraulic camless valve train controls the valve operations, opening, closing etc. The seminar looks at the working of the electrohydraulic camless engine, its general features and benefits over conventional engines. The engines powering todayâ€™s vehicles, whether they burn gasoline or diesel fuel, rely on a system of valves to admit fuel and air to the cylinders and let exhaust gases escape after combustion. Rotating steel camshafts with precision-machined egg-shaped lobes, or cams, are the hard-tooled â€œbrainsâ€ of the system. They push open the valves at the proper time and guide their closure, typically through an arrangement of pushrods, rocker arms, and other hardware. Stiff springs return the valves to their closed position. In an overhead-camshaft engine, a chain or belt driven by the crankshaft turns one or two camshafts located atop the cylinder head.Â
A single overhead camshaft (SOHC) design uses one camshaft to move rockers that open both inlet and exhaust valves. The double overhead camshaft (DOHC), or twin-cam, setup does away with the rockers and devotes one camshaft to the inlet valves and the other to the exhaust valves.