Automotive Exhaust Hydrocarbon Reduction During Deceleration by … Induction System Devices 580039
EARLY in 1955 the Automobile Manufacturers Association created the Induction system Task Group to build, test, and evaluate devices for the reduction of unburned hydrocarbon emission from vehicles by induction system methods. This paper is a progress report of the work performed to mid-1957 by the group.
Two types of devices are described: those which stop the flow of fuel from the carburetor during the deceleration cycle and those which maintain burnable mixtures during deceleration. However, the effectiveness of such devices is limited. Los Angeles traffic survey data have indicated that the hydrocarbon emission during deceleration is considerably less than reported by early investigators and that relatively low speed decelerations predominate in traffic.
In addition, the wide variety of carburetors and engine installations in use today make it unlikely that any one device is entirely suitable for universal adaptation. The Induction System Task Group found that the principle of the vacuum limiting type of device appears to be the best approach to this requirement.