| 摘要 |
PURPOSE:To improve response of the titled device to an abrupt change in an engine load, by arranging such that a modified gas flow ratio and an excess air ratio may be predetermined in their maximum levels in accordance with a capability of a modifier to modify gas properties, in an engine adapted to use both liquid fuels and modified gases. CONSTITUTION:Supplied to an engine 4 is an air passing through an air valve 28, a modified gas flowing via a gas valve 25 out of a modifier (not shown) and a liquid fuel passing through an injection valve 27. A controller 29 adapted to input signals indicative of operating conditions computes required levels of gas- fuel ratio (a flow ratio of modified gas to a total fuel rate) and an excess air ratio from a magnitude of accelerator operation and an engine speed, while at the same time computing maximum limit levels of gas-fuel ratio and the excess air ratio utilizing signals outputted from a gas pressure sensor 33 and a modified catalyst temperature sensor 32. Smaller ones of these required and maximum limit levels are selected to control each supplying valve, and thereby making it possible to control the excess air ratio in a stable state even when an abrupt change takes place in an engine load as experienced in burning a poorly modified gas. |
