Unthrottled lean mixture gasoline engine

Abstract

A gasoline internal combustion engine is operated at all times with a full charge of air and is thus unthrottled. At low power levels for such an engine, the ratio of gasoline to air is too lean for normal combustion; therefore, special arrangements are provided by this invention for ensuring combustion. These special arrangements, which may be used together, singly, or in any combination, include (1) the formation of droplets of gasoline within the cylinder, with each gasoline droplet having around it a zone that is within the combustible range, and the provision of a spark that will ingite the combustible zone around at least a few droplets and will then propagate to other droplets; (2) the provision of a series of compartments separated by partitions at the top of a cylinder and supplying a combustible charge and ignition to a variable number of the compartments, depending on the power desired; (3) the use of either or other similar ignition-enhancing material to cause combustion despite a very lean mixture. Another feature of the invention improves the efficiency of the above provisions by maintaining the walls of the cylinder cool by employing porous walls and air at high pressure filtering through the walls into the piston chamber.