The present invention relates to the art of internal combustion engines and, more particularly, to a method and apparatus for generating and delivering gaseous fuel vapor to the air induction passage of an internal combustion engine.
Many efforts have been made heretofore to provide apparatus and systems for generating gaseous vapor from a liquid fuel such as gasoline and operating an internal combustion engine with such gaseous vapor. The greatest advantage of a gaseous vapor operating engine would of course be fuel economy which is becoming progressively more important in light of present day petroleum fuel shortages. Generally, gaseous fuel vapor generating systems include a source of liquid fuel such as gasoline which is heated to produce gaseous vapor which is then delivered to the air induction passage of an internal combustion engine for mixture with air and combustion of the mixture in the cylinders of the engine to achieve operation thereof.
To the best of my knowledge, the systems and apparatus heretofore provided have not been commercially acceptable for a number of reasons including safety, reliability and/or efficiency of operation, and the size and/or complexity and production costs. More particularly in this respect, certain systems heretofore devised have been dual systems relying on liquid fuel for starting an engine and gaseous vapor for operating the engine after starting. Such a system is structurally complex and expensive to produce because of the dual nature thereof and, additionally, is less economical and efficient than desired because of the use of liquid fuel. Moreover, any burning of liquid fuel is undesirable from the standpoint of pollution. Systems have also been devised to operate internal combustion engines using gaseous vapor alone, but these systems require a waiting period during which sufficient fuel vapor is generated to start and operate the engine. Such initial vapor generation requires a source of heat separate from the internal combustion engine for heating the liquid gasoline, such a source being an electrical resistance heater for example from the vehicle battery. Accordingly, in addition to the time delay in connection with starting the engine, there is a danger associated with the use of such external heating means. Moreover, systems relying on exhaust line temperatures of the engine for heating the liquid fuel after the engine is started are likewise dangerous because of the spark content in exhaust gases. Still further, the systems heretofore provided have included electrically operated control valves, pumps and the like, again creating potential hazards with respect to spark ignition of the highly volatile fuel vapor. Furthermore, such component parts and the electrical circuitry therefore are expensive and the component parts do not lend to a compact unitary arrangement thereof but, rather, require excessive space for installation as well as physical separation from one another in mounting.