Rochester Ramjet: Difference between revisions
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Revision as of 18:58, 3 June 2018
The Rochester Ramjet is a automotive fuel injection system developed by the Rochester Products Division of General Motors and first offered as a high-performance option on the Corvette and GM passenger cars in 1957. It was discontinued partway through 1965 in favor of the Chevrolet Big Block as a performance option.[1][2]
History
In the early 1950s, fuel injection was the topic of a significant amount of research by the auto industry in the US and internationally. Ed Cole, who had become the chief engineer of Chevrolet in 1952, pushed for Chevrolet to be the first GM brand to offer a fuel injection option on a production car. Much of the development of the Ramjet was done by engineer John Dolza, with supporting effort from Zora Arkus-Duntov. Dynamometer-based tests of a 265 cid small block engine running with fuel injection were performed as early as 1955.[3]
Between 1957 and 1965, the Ramjet was offered as the top performance option on the Corvette. When it was first introduced, it passed the threshold of one horsepower per cubic inch of engine displacement and this fact was used in marketing material.[2]
Technical details
The Ramjet is a continuous-flow port-injection system. Unlike later fuel injection systems that used electronics, this one is based on purely mechanical principles. The two main sub-assemblies of the system are the air meter and fuel meter. The air meter measures airflow into the engine and manages thermostatic warmup enrichment, fuel shutoff on overrun, and idle settings. These measurements are sent via pressure and vacuum signals to the fuel meter, which contains the high-pressure fuel pump and controls delivery of fuel to the injector nozzles.[4]
There are three easily identifiable revisions of the Ramjet, each spanning three years of the system's nine year production life. The first of these (1957-1959) are identified by the "finned top" sand cast plenum, followed by the "flat top" plenum (1960-1962), and finally the die-cast plenum (1963-1965). All versions of the system required a special distributor that provided a cable drive to the high-pressure fuel pump.[3]
References
- ^ Mueller, Mike (2011). The Complete Book of Corvette: Every Model Since 1953. Motorbooks / MBI Publishing Co. ISBN 978-0-7603-4140-7.
- ^ a b Corvette 50th Anniversary. Publications International, Ltd. ISBN 978-0-7853-7987-4.
- ^ a b Kayser, Kenneth (2007). The History of GM's Ramjet Fuel Injection on the Chevrolet V-8 and its Corvette Racing Pedigree. The Tachometer Press. ISBN 978-0984205004.
- ^ Dolza, John; Kehoe, E. A.; Stoltman, Donald; Arkus-Duntov, Zora (1957-01-15). The General Motors Fuel Injection System. Detroit, Michigan: Society of Automotive Engineers. pp. 739–757.