Search Results

Two heavy duty turbocharged and aftercooled diesel engines have been converted to spark ignition (SI) for natural gas fuelling. One engine features two valves per cylinder, high primary swirl and a compact combustion chamber. The other engine has four valves per cylinder and a more open combustion chamber shape. Both engines were characterized on a dynamometer and subsequently put into service where one of the engines has been monitored extensively. When a diesel engine is converted to SI operation, there is an involved process which must be carried out to insure reliable and efficient operation. Many aspects of the conversion process are limited by the original configuration of the diesel engine. Some of these aspects, such as combustion chamber shape, are shown to be important to the optimization of an SI converted engine and are highlighted in the comparison of these two engines.