Fuel supply system for internal combustion engines
AssigneeRobert Bosch GmbH
InventorsJohannes Brettschneider, Valerio Bianchi, Osvaldo Bejerman, Lorenz Bundesen, Hans Zeller
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Abstract
A fuel supply system for internal combustion engines includes a fuel reservoir adjacent the induction manifold from which fuel is aspirated depending on pressure differences in two separate regions of the manifold. An electric controller reacts to engine rpm and exhaust gas composition signals to actuate electromagnetic valves in the air conduits leading from the manifold to the fuel reservoir. Various valve opening schedules can be performed depending on the desired fuel mixture.
Claims18
A fuel supply system for an internal combustion engine, said engine including an induction manifold and an exhaust manifold, comprising:
- a fuel reservoir connected by at least two separate conduits with different respective regions of said induction manifold;
- electromagnetic valve means disposed in each of said conduits for controlling the air pressure in said reservoir;
- an electric controller for actuating said electromagnetic valve means in mutually opposed phase relationship;
- and
- an oxygen sensor disposed in said exhaust manifold for generating a signal for said controller and wherein said controller includes means for generating a set-point signal, means for comparing said set-point signal with the signal from said oxygen sensor and means for opening one of the electromagnetic valves in said conduit leading to a region of relatively lower pressure in said induction manifold when said signal from said oxygen sensor is higher than said set-point signal and for opening the other of said electromagnetic valves in said conduit leading to a region of relatively higher pressure in said induction manifold when said signal from said oxygen sensor is lower than said set-point signal, and wherein said electric controller is connected to be triggered by the ignition pulses of the engine to open said electromagnetic valves for a constant period of time.
A method for controlling the fuel supply of an internal combustion engine, said engine including an induction manifold, an exhaust manifold, and a fuel reservoir connected by at least two separate conduits with different respective regions of said induction manifold, comprising the steps of:
- providing an electromagnetic valve in each of said conduits and providing a controller for actuating said electromagnetic valves;
- actuating said electromagnetic valves in mutually opposed phase relationship;
- providing an exhaust gas oxygen sensor for generating a control signal for said controller
- adjusting the basic setting of said controller to deliver a rich fuel-air mixture;
- generating a set-point voltage;
- comparing the signal from said oxygen sensor with said set-point signal;
- energizing a first one of said electromagnetic valves which opens a conduit to a region of said manifold at relatively lower pressure whenever said oxygen sensor signal is greater than said set-point signal and energizing a second of said electromagnetic valves which opens a conduit to a region of said manifold at relatively higher pressure whenever said oxygen sensor signal is smaller than said set-point signal;
- keeping constant the opening times of said first and second electromagnetic valves;
- and
- triggering the opening cycles for said valves with pulses derived from the ignition pulses of said internal combustion engine.
Dependencies are inferred from the claim text.