Water injection in directly injected turbocharged spark ignition engines

The paper explores the use of water injection in a turbocharged, direct injection, spark ignition engines fuelled with ethanol where port injection of water numerically prove to be effective in increasing the charge efficiency, reducing the tendency to knock, and controlling the temperature of gases to turbine. With injection of water in selected operating conditions, the engine may run higher compression ratios and boost pressures and closer to maximum brake torque spark advances for improved top power output and peak efficiency as well as better part load efficiencies. The paper suggests the introduction of this old technique now used in aftermarket kits possibly evolved to direct water injection in the design stage of novel turbocharged engines.

► Water injection may help further improve turbocharged spark ignited engines.
► Water injection reduces the temperature of gases to turbine.
► Water injection reduces the tendency to knock.
► Water injection reduces the heat losses.
► If directly rather than port injected, water may better enhance fuel conversion efficiency.