Method and fuel injection system for fuel supply to a mixture-compressing internal combustion engine having externally supplied ignition

A method for supplying fuel to a mixture-compressing internal combustion engine having an air intake tube and externally supplied ignition by means of a fuel injection system having metering valve means disposed in a fuel supply line for metering a quantity of fuel at a specific proportion to the quantity of air aspirated by said engine, the metering being effected at a pressure difference which is constant yet can be varied in accordance with operating characteristics of the engine, a movable valve element of a regulating valve disposed downstream of each of said metering valve means for regulating the pressure difference at each of said metering valve means, a control pressure line which communicates with said fuel supply line and is limited at one end by a control throttle means and at the other end by a return-flow throttle means and leads to a return-flow line, and having individual injection-valve means, comprising the steps of:

• injecting the metered fuel ahead of each cylinder of said engine;
• and
• further injecting fuel into the air-intake tube of said engine by means of a supplementary injection valve means in accordance with engine operating characteristics, whereby the pressure in said control pressure line is reduced by means of the supplementary injection valve means, and the pressure difference at said metering valve means is increased to thereby increase the metered fuel quantity transmitted by means of said individual injection valve means.

A fuel injection system for supplying fuel to a mixture-compressing internal combustion engine having an air intake tube and externally supplied ignition comprising:

• metering valve means disposed in a fuel supply line for metering a quantity of fuel at a specific proportion to the quantity of air aspirated by said engine,
• a movable valve element of a regulating valve means disposed downstream of each of said metering valves for regulating the pressure difference at each of said metering valve means,
• a control pressure line communicating with said fuel supply line,
• a control throttle means at one end of said control pressure line,
• a return-flow throttle means at the other end of said control pressure line,
• individual injection valve means positioned ahead of each cylinder of said engine and connected to said fuel supply line by means of said regulating valve means, and
• a supplementary injection valve means connected to said control pressure line, whereby fuel can be additionally injected into the air-intake tube of said engine in accordance with engine operating characteristics.