Water Injection in IC - SI Engines to Control Detonation and to Reduce Pollutant Emissions

In this paper the effects of water injection in the intake pipe of a single-cylinder standard CFR engine are investigated from an experimental viewpoint. Research was carried out at AGIP Petroli and ISAB ERG Refineries of Priolo Gargallo (SR).

Tests were performed according to ASTM Research and Motor Method. Water was supplied by a continuous and pulsed injection system. The engine was fed with low Octane Number (O.N.) base gasoline (cheap products, intermediate of refinery processes). The water to fuel mass flow rate ratio was varied in the range 0 to 2.

Measurements of O.N. have shown that water injection virtually increases the water/fuel mixture O.N. and that it is possible to obtain a correct run feeding the engine with a low octane number fuel. The pollutant emissions measurements confirm the effectiveness of water injection in reducing the engine environmental impact.

In conclusion results have shown that water injection really represents a way to avoid detonation and to control NO_x formation in SI engines.