Apparatus repetitively controlling the composition of exhaust emissions from internal combustion engines, in predetermined intervals
AssigneeRobert Bosch GmbH
InventorsJosef Wahl, Peter Jurgen Schmidt, Richard Zechnall
Life of this patent
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Abstract
Certain intervals are determined in which output signals from an exhaust gas sensing device are sensed, and then applied to a control circuit, to control the fuel supply system (carburetor, or fuel injection system) in such a direction that a predetermined ratio of fuel and air is being supplied to the engine to provide exhaust gases of predetermined composition. The intervals are determined by a logic circuit which has applied thereto engine operating parameters such as operating time of the engine after having been started, engine speed, engine power condition (idling, or supplying power), engine temperature, or the like.
Claims17
Apparatus to control the composition of exhaust gases from an internal combustion engine subject to operating parameters including engine temperature, engine power, engine speed, and ignition switch operation,
- said apparatus having an exhaust gas sensor (15), a fuel-air mixture and balance means (17, 18, 19, 20) adjusting the relative proportion of fuel and air supplied to the engine;
- and means (11, 12, 13, 14) sensing at least one of said operating parameters;
- said apparatus comprising
- a first timing circuit (23) generating and operating time signal having a limited time duration with respect to the operating time of the engine after starting of the engine and subsequent to the engine having been stopped;
- a first logic circuit (22) connected to at least one of said operating parameters and having its output connected to and controlling said first timing circuit (23) to start a timing interval of said limited time duration upon energization by said logic circuit (22);
- a second timing circuit (22, 40);
- a second logic circuit (29) connecting the output of said first timing circuit (23) to the second timing circuit (32, 40):
- and gating means (33) enabled by the output of said second timing circuit connecting the output signal from the exhaust sensor (15) to said balance means (17, 18, 19, 20).
System to control the composition of exhaust gases from an internal combustion engine subject to operating parameters including engine temperature, engine power, engine speed, ignition switch operation,
- said system including
- an exhaust gas sensor (15) providing an exhaust output signal representative of composition of the exhaust gases;
- a fuel-air mixing and balancing means (17, 18, 19, 20) adjusting the relative proportion of fuel and air applied to the engine;
- means (11, 12, 13, 14) sensing at least one of said operating parameters and providing an indication signal of the respectively sensed parameter when said parameter has reached a predetermined value;
- a timing interval timing circuit (32) controlling generation of a time signal having a limited time duration with respect to operating time of the engine after starting of the engine subsequent to the engine having seen stopped and enabled to start said timing interval when the respective sensing means provides said indication signal;
- and an operating control means (17, 18, 19, 20) connected to and controlled by the timing interval time circuit (32) and acting on and adjusting the fuel-air mixing and balance means to adjust the relative proportion of fuel and air in dependence on said exhaust output signal and to change, if required, said relative proportion only upon presence of the indication signal and said timing signal.
System according to claim 25 further comprising an additional timing circuit (23) connected to said engine temperature sensor (11) and said engine power condition operation sensor (12) and determining a further timing interval, said further timing circuit (23) being interposed in the connection of said respective sensors and the operating control means to enable the operating control means only if said sensors sense persistance of conditions of the other predetermined value for a time duration of said further time interval.
Dependencies are inferred from the claim text.