Control of exhaust gas recycling into combustion engine - inhibits feedback when engine speed is too low for starting, or too high for clean combustion

摘要

A portion of the exhaust is returned via a feedback pipe (5) contg. a flow restriction (4) to the inlet manifold (2). The feedback valve (6) is operated by an electrical controller (7) whose excitation circuit (8) includes a switch (11) opened at about 1200 rev/min for starting, and closed again to inhibit the feedback at about 3200 rev/min. Another switch (12) in series opens when atmos. pressure falls to 910 mbar (corresp. to an altitude of 900 m above sea level) to inhibit feedback. ADVANTAGE - Emission of smoke or soot at starting is avoided at low cost with use of well-tried components.