Steady-State and Transient A/F Control Requirements for Cold Operation of a 1.6 Liter Engine with Single-Point Fuel Injection

An engine dynamometer test facility-capable of controlling temperatures from 0°F to 150°F was used to investigate A/F control characteristics of a 1.6 liter engine with single point fuel injection. Two types of tests were run. In the first, the effect of induction system temperature on manifold wall wetting and transient A/F control was determined. In the second, a cold start procedure was developed to determine the effect of engine temperature on the percent of fuel which burns by observing exhaust A/F during steady state operation while the engine warms up. It was found that transient A/F control problems due to manifold wall wetting are much greater than steady state problems associated with incomplete fuel burning.