DISPOSITIF DE COMMANDE EN FREQUENCE, NOTAMMENT POUR LA REDUCTION DE LA POLLUTION PROVOQUEE PAR LES MOTEURS A ESSENCE

摘要

1319982 Spray carburettors; regulating ignition timing REGIE NATIONALE DES USINES RENAULT AND AUTOMOBILES PEUGEOT 18 Sept 1970 [23 Sept 1969] 44699/70 Heading F1B A device for reducing atmospheric pollution during overrun of a vehicle engine comprises an A.C. generator 4, Fig. 1, driven from the vehicle transmission and connected via a transistor 8 to a diode pump 9-13 which is connected via an emitter follower 15 to an electronic switch comprising transistors 18, 19, 20 with positive feedback via a resistor 31 and an emitter follower output to the winding 29 of an electromagnetic valve 43, Fig. 3. At speeds above idling speed, the frequency of the output of generator 4 is high enough to reduce the output voltage of the diode pump to a value at which it triggers the electronic switch to its non-conductive state, thereby de-energizing the winding 29 to move the valve 43 from a position in which a diaphragm chamber 41 is vented to atmosphere via an orifice 45 to a position in which the diaphragm chamber is subjected, via a pipe 44, to the vacuum in the induction manifold of the engine 37. The diaphragm then acts on the throttle valve 40 to increase its minimum opening beyond the idling opening to ensure good combustion during overrun. When the manual control 49 of a choke or enrichment device is operated, a contact 48 energizes the winding 47 of an electromagnetic valve 46 to disconnect the vacuum chamber 50 of the distributor 39 from the vacuum pipe 52 and connect it instead to the induction manifold via the pipe 44, to provide a vacuum advance of the ignition even when the accelerator pedal is released. Alternatively, the vacuum chamber 50 may be vented to atmosphere by an electromagnetic valve energized in parallel with an electromagnetic valve 34 controlling the automatic transmission in accordance with the output of the generator 4.