TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred System: The liquid contained in the second source is a fuel on which the engine can be operated without the fuel from the first source. The compression ratio is greater than 11. The fuel management system uses a microprocessor and the knock detector to minimize the use of the liquid that is directly injected from the second source. The spark retard is changed so as to reduce consumption of the liquid from the second source. The spark retard is changed as a function of the amount of liquid from the second source that has been consumed. The liquid from the second source is directly injected so as to provide a non-uniform distribution of the liquid in the cylinder with a greater concentration near the walls of the cylinder, where liquid from the second source to gasoline ratio is sufficiently high so as to prevent knock and resulting in the liquid from the second source to gasoline ratio is reduced as compared to a situation using a uniform distribution. The mixture of alcohol and another liquid is directly injected into the engine from the second source and where this mixture has variable characteristics. An ethanol-water mixture is directly injected into the engine from the second source. The methanol-water mixture is directly injected into the engine from the second source. The liquid that is directly injected into the engine is mixed with a lubricant. The manifold pressure is at least 2 bar. Preferred Engine: In the turbocharged spark ignition engine different ethanol/gasoline ratios are used. The engine is also operated on gasoline alone. The engine is operated without knock with sotichiometric fuel/air mixture at a manifold pressure of at least 2 bar. The maniold pressure is at least 2.5 bar. The turbocharged spark ignition engine further includes cooled EGR and port fuel injection of fuel. The ratio of fuel that is port fuel injected to fuel that is direct injected varies over a drive cycle. The spark retard is varied when the ethanol/gasoline ratio in the engine is changed. The manifold pressure is at least 2 bar. The maximum manifold pressure provided by turbocharging is changed when the ethanol/gasoline ratio in the engine is changed.