System for fueling an internal combustion engine with low and high pressure gaseous fuel

摘要

A hybrid gaseous fueling system having a low pressure supply and a high pressure supply is disclosed. This system provides the advantages of fueling with a low pressure charge during steady state operation and also provides a way to more rapidly smooth engine transients resulting from changes in engine operating characteristics such as speed or load by modulating high pressure fueling of the engine. Furthermore, air/fuel ratio control may be readily integrated into this system. In addition, start-up of the engine is performed using more fuel from the high pressure supply than the low pressure supply up to a predetermined level of engine operation. At that level and beyond, low pressure fueling is greater than high pressure fueling.