| 摘要 |
<p>A system for mixing fumigation fuel with the intake air in a compression ignition engine includes a variable area venturi in an engine intake air duct to draw controlled amounts of a pre-mixed fumigation fuel/air mixture into the main air stream in proportion to the amount of suction created downstream of the variable area venturi by the engine air flow. The variable area venturi creates a pressure depression proportional to the engine air flow motivating the fumigation fuel/air mixture to flow into the engine along with the main air stream at a rate related to the engine load and speed. The variable area venturi includes a housing having a downstream branch connected to a conventional demand-type mixer which is supplied with the fumigation fuel via a demand-type regulator, and air through a filter from the atmosphere. The variable area venturi is formed by a spring-loaded, normally closed flapper valve which variably opens in response to air drawn through the housing by the engine. The variable area venturi thus created provides a proportional control of the fumigation fuel introduced into the main air stream over a wide range of engine operating conditions with relatively small pressure drops.</p> |
