Fuel injection system for self-igniting internal combustion engines

In a fuel injection system for an internal combustion engine, including a suction tube through which air for engine combustion is drawn, an exhaust gas line through which engine exhaust gas flows, an exhaust gas recycle line, a control mechanism including a throttle flap member mounted in any one of said suction tube, exhaust gas line and recycle line, with the recycle line extending between and being connected to the suction tube and the exhaust gas line to thereby establish a flow path for a recycled portion of the exhaust gas flow through the exhaust gas line into the suction tube, with the connection of the recycle line to the suction tube being downstream of the location of the throttle flap member in the suction tube, and with the connection of the recycle line to the exhaust gas line being upstream of the location of the throttle flap member in the exhaust gas line, said throttle flap member controlling the pressure drop between the exhaust gas line and the suction tube for determining the flow rate of the recycled portion of the exhaust gas, fuel injection means, and regulating means for regulating the quantity of fuel injected by the fuel injection means, said regulating means including an air measuring member mounted within the suction tube and comparison means connected to the air measuring member, the throttle flap member and the fuel injection means, wherein the fuel quantity delivered by said fuel injection means is arbitrarily variable, with said injection quantity serving as a control parameter which is detected by said comparison means and transmitted to the throttle flap for adjusting the quantity of air and recycled portion of the exhaust gas drawn into the engine.

In a fuel injection system for an internal combustion engine, including a suction tube through which air for engine combustion is drawn, an exhaust gas line through which engine exhaust gas flows, an exhaust gas recycle line, a control mechanism including a throttle flap member mounted in any one of said suction tube, exhaust gas line and recycle line, with the recycle line extending between and being connected to the suction tube and the exhaust gas line to thereby establish a flow path for a recycled portion of the exhaust gas flow through the exhaust gas line into the suction tube, with the connection of the recycle line to the suction tube being downstream of the location of the throttle flap member in the suction tube, and with the connection of the recycle line to the exhaust gas line being upstream of the location of the throttle flap member in the exhaust gas line, said throttle flap member controlling the pressure in its respective tube or line for determining the flow rate of the recycled portion of the exhaust gas, and regulating means including an air measuring member mounted within the suction tube and a fuel injection apparatus for regulating the quantity of fuel injected by the system, wherein the fuel quantity delivered by said fuel injection apparatus is arbitrarily variable, with said injection quantity serving as a control parameter for said regulating means, said fuel injection apparatus including:

• a. an injection pump;
• b. a fuel measuring member for said injection pump;
• c. a servo-motor;
• d. two fixed opening throttle members;
• e. means defining a first variable throttle slit;
• f. means defining a second variable throttle slit;
• and
• g. a hydraulic bridge circuit with means for detecting a parameter characteristic of the fuel injection quantity and a parameter characteristic of the fresh-air quantity, and with means for comparing said parameters, wherein:
• i. one diagonal branch of said bridge circuit serves as a fuel delivery and drainage line and the other diagonal branch is connected with said servo-motor and said throttle flap member;
• ii. said throttle members are disposed in different ones of said bridge arms so that they can be in hydraulic communication with said first and second throttle slits;
• iii. said first throttle slit is variably set by said furl measuring member and said second throttle slit is variably set by said air measuring member;
• and
• iv. the bridge circuit changes the setting of the throttle flap member and correspondingly the fresh-air flow and the flow of recycled exhaust gas whenever a deviation from a nominal set value occurs, said setting change continuing until the nominal set value is reached.