Abstract: A fuel vapor storage canister includes a vapor inlet for introducing vapor into the canister and a bed of adsorbant material in fluid communication with the inlet for adsorbing vapor within the canister. A vapor purge tube is in fluid communication with the bed for purging fuel vapor from the bed. A thermoelectric cooler/heater selectively cools the inlet tube to promote condensation of vapors therein and selectively and alternatively heats the bed to promote purging of vapors from the bed and the remainder of the canister.

Abstract: A pressure transducer of the manometer type comprises two interconnected columns of liquid with means for applying differential pressure across the columns. The liquid is a magnetic liquid and a magnetic field is impressed on the columns to attract the liquid by magnetic force to a reference position. The applied differential pressure acts counter to the magnetic force to shift the columns so that their difference in lengths reflects the pressure. By using capacitor plates to define the walls for the liquid columns and a magnetic liquid which is a dielectric, the capacitance between the plates is a function of the column lengths and therefore is a function of the applied differential pressure.

Abstract: A closed loop fuel control system for an internal combustion engine having a catalytic converter in its exhaust system and a pair of zirconia sensors for generating respective signals indicative of the air-fuel ratio in the gases upstream and downstream of the catalytic converter. These sensors are used in the control system to control the rate of flow of fuel or air to the engine in response to the sensor signals to maintain a constant stoichiometric air-fuel ratio in the exhaust system for maximum catalytic converter efficiency in simultaneous oxidation and reduction. A circuit is described for imposing the output of the zirconia sensor upstream from the catalytic converter across the zirconia sensor downstream of the catalytic converter until the zirconia sensor downstream of the catalytic converter reaches its operating temperature.