| 摘要 |
1514098 Control of carburetter throttle valves NISSAN MOTOR CO Ltd 5 Feb 1976 [10 Feb 1975] 04614/76 Headings F1B and F1H A carburetter for an I.C. engine is electronically controlled in use in response to the composition of exhaust gases from the engine entering a three way catalytic converter and includes a throttle valve 24, with which one or both of mechanisms 44 and 46 co-operate to prevent or relieve vacuum downstream thereof during deceleration. When the throttle valve 24 is closed, a projection 32 on a lever 30 rigid with the throttle valve engages an arm 42 whose leftward movement as shown in Fig. 1 is damped by a dashpot mechanism 44 having an orifice 62 in parallel with a check-valve 66. If the vacuum downstream of the throttle valve 24 exceeds a predetermined value, a diaphragm 96 opens a valve 101 so that vacuum acts by way of a diaphragm 72 to move the arm 42 to the right and thereby slightly open the throttle valve 24. Subsequent opening of the throttle valve 24 by the engine operator causes a fall in the vacuum downstream thereof so that valve 101 closes and the pressure acting on diaphragm 72 is increased to atmospheric by means of air-flow through a passage 106, thus returning arm 42 to its normal operating position. The exhaust gas condition is sensed, e.g. by an oxygen sensor 40, upstream of three-way catalytic converter 38 and a signal is fed to a computing means 34 which issues signals to a valve means 33 to control the fuel flow-rate to the carburetter to ensure that it delivers a stoichiometric mixture.
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