Quick-Heat Intake Manifolds for Reducing Cold Engine Emissions

This report presents some design parameters and development experience on quick-heat intake manifolds for evaporating the fuel. These can achieve good fuel evaporation soon after a cold start. Used in conjunction with a fast-opening choke, such a quick-heat intake manifold helps reduce carbon monoxide (CO) emissions. This is especially effective on cars with catalytic converters, since CO caused by cold enrichment is produced at a time when the catalyst is not yet hot and effective.

The sensitivity of one design of quick-heat intake manifold to fuel volatility characteristics is included. A variety of ways to correlate drivability with the ASTM distillation characteristics of the fuel are evaluated.