Method and apparatus repetitively controlling the composition of exhaust emissions from internal combustion engines, in predetermined intervals

• US 3,919,983 A
• Filed: 09/12/1973
• Issued: 11/18/1975
• Est. Priority Date: 09/14/1972
• Status: Expired due to Term

• Current Assignee: Josef Wahl, Peter Jurgen Schmidt, Richard Zechnall
• Original Assignee: Josef Wahl, Peter Jurgen Schmidt, Richard Zechnall
• Inventors: Wahl, Josef, Schmidt, Peter Jurgen, Zechnall, Richard
• Primary Examiner(s): Myhre, Charles J.
• Assistant Examiner(s): Devinsky, Paul
• Application Number:
  US05/396,477
• Time in Patent Office: 797 Days
• Field of Search: 123/32EA,32AE,119E,124,119R 60/285,276
• US Class Current: 123/680
• CPC Class Codes: F02D 2250/14 Timing of measurement, e.g. synchronisation of measurements to the engine cycle
• CPC Class Codes: F02D 2700/09 Other ways of controlling
• CPC Class Codes: F02D 41/1474 by detecting the commutation time of the sensor
• CPC Class Codes: F02D 41/2454 Learning of the air-fuel ratio control
• CPC Class Codes: F02D 9/00 Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits

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.

Claims

1. Method of controlling the composition of the exhaust gases from internal cOmbustion engines, including the step of controlling the relative proportion ( lambda ) of air and fuel being applied to the engine;

sensing operating parameters of the engine, comprising at least one of;

operating time of the engine upon starting, after having been stopped;

engine speed;

engine operation under idling, or power supplying condition;

engine temperature;

sensing composition of the exhaust gases and providing an exhaust output signal representative thereof;

sensing if a predetermined operating condition of the engine prevails for a predetermined time limit;

comparing the exhaust sensed signal with a reference if said operating conditions persisted beyond said predetermined time limit;

generating a timing signal; and

controlling said relative proportion ( lambda ) of air and fuel in accordance with sensed composition, as represented by the exhaust signal, during said timing signal.

2. Method according to claim 1 wherein an exhaust sensing element (15) is provided, further comprising the step of exposing said sensing element to the exhaust gases for a time period which is short with respect to the operating time of the combustion engine.

3. Method according to claim 2 wherein said exposing step is controlled by occurrence of said sensing signal.

4. Method according to claim 1 wherein an exhaust sensing element is provided, further comprising the step of continually exposing said sensing element (15) to the exhaust gases.

5. Method according to claim 1 wherein step of sensing an operating parameter of the engine comprises sensing that the engine is operating under idling conditions, has reached a predetermined temperature level, has a speed within a predetermined range, and that these conditions pertain for the first time upon repeated operation of the engine after it had been stopped.

6. Method of controlling the composition of the exhaust gases from internal combustion engines, including the step of controlling the relative proportion ( lambda ) of air and fuel being applied to the engine;

generating an operating 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 been stopped;

sensing operating parameters of the engine, comprising at least one of;

engine speed;

engine operation under idling, or power supplying condition;

engine temperature;

providing an indication signal of at least one of said operating parameters having reached a predetermined value;

sensing composition of the exhaust gases and providing an exhaust output signal representative thereof; and

controlling the relative proportion of air and fuel in dependence on said exhaust output signal upon conjunction of occurrence of said timing signal and said indication signal, to change, if required, said relative proportion, and only during concurrent presence of the indication signal and said timing signal.

7. Method according to claim 6, wherein an exhaust sensing element (15) is provided, further comprising the step of intermittently exposing said sensing element to the exhaust gases for a time period which is short with respect to the operating time of the combustion engine.

8. Method according to claim 7 wherein the time period of said exposing step is controlled by occurrence of said indication signal.

9. Method according to claim 6, wherein an exhaust sensing element is provided, further comprising the step of continually exposing said sensing element (15) to the exhaust gases.

10. Method according to claim 6, wherein the step of sensing operating parameters of the engine comprises sensing that the engine is operating under idling conditions, has reached a predetermined temperature level, has a speed within a predetermined range, and that these conditions pertain for the first time upon repeated operation of the engine after it had been stopped.