Abstract: An evaporative control system for conventional or hybrid vehicles includes a fuel tank for storing a volatile fuel and an engine having an air induction system. A primary canister contains a first volume of a first adsorbent material, a vapor inlet coupled to the fuel tank, a purge outlet coupled to the air induction system, and a vent/air inlet. A secondary canister is coupled to the vent/air inlet and contains a second volume of a second adsorbent material that is different than the first adsorbent material. The first and second adsorbent materials adsorb fuel vapors when the engine is not running to reduce breakthrough and desorb fuel vapors when the engine is running. The second adsorbent material adsorbs butanes and pentanes at low concentrations. The second adsorbent material includes activated carbon derived from a coconut shell and a heater.

Abstract: An engine fuel system includes liquid fuel delivery for normal engine operation and fuel vapor generation for use in cold starting on fuel vapor alone. A fuel vapor generator, preferably in a vehicle fuel tank, includes a fuel vapor collector connected in a return line between a pressure regulator and an in-tank fuel pump. A charging portion includes a pump for conducting fuel vapor from the collector to the cold start canister and a return line to provide circulation of the vapor into the canister. A vapor delivery portion includes a delivery line between the cold start canister and an air inlet of an associated engine. An air inlet line delivers air to the canister during cold starting. A subsystem is formed by the fuel vapor generator connected in a circuit with the in-tank fuel pump and the pressure regulator return fuel line.

Abstract: A method and apparatus for galvanically measuring vapor pressure of a volatile liquid is described. Vapor pressure of the volatile liquid is derived by galvanically detecting the reduction in oxygen partial pressure in air that is caused by evaporation of the volatile liquid into that air. In one example, an automotive engine/fuel EVAP system is described in which fuel vapor pressure exiting an EVAP canister is measured during purging. The measurement is used to compensate the primary fuel supply to better control overall air/fuel ratio to the engine during purging. In another example, a galvanic oxygen meter is used to identify the type of volatile liquid, including the RVP of engine fuel.

Abstract: An evaporative control system for conventional or hybrid vehicles includes a fuel tank for storing a volatile fuel and an engine having an air induction system. A primary canister contains a first volume of a first adsorbent material, a vapor inlet coupled to the fuel tank, a purge outlet coupled to the air induction system, and a vent/air inlet. A secondary canister is coupled to the vent/air inlet and contains a second volume of a second adsorbent material that is different than the first adsorbent material. The first and second adsorbent materials adsorb fuel vapors when the engine is not running to reduce breakthrough and desorb fuel vapors when the engine is running. The second adsorbent material adsorbs butanes and pentanes at low concentrations. The second adsorbent material includes activated carbon derived from a coconut shell and a heater.

Abstract: A gasoline vapor storage canister is employed to temporarily store hydrocarbon vapors vented from the gas tank in an automotive vehicle using an engine or fuel cell motive means which is fuelled at least in part from an on-board-the-vehicle, partial oxidation (POx) reactor for converting gasoline to a hydrogen-containing POx fuel. During cold start situations, gasoline vapor is purged from the storage canister to supply a stream of combustible fuel/air mixture to the POx reactor for ignition and heat up of the catalytic reactor to its operating temperature.

Abstract: A gasoline vapor storage canister is employed to temporarily store hydrocarbon vapors vented from the gas tank in an automotive vehicle using an engine or fuel cell motive means which is fuelled at least in part from an on-board-the-vehicle, partial oxidation (POx) reactor for converting gasoline to a hydrogen-containing POx fuel. During cold start situations, gasoline vapor is purged from the storage canister to supply a stream of combustible fuel/air mixture to the POx reactor for ignition and heat up of the catalytic reactor to its operating temperature.

Abstract: The engine or powertrain control module of a vehicle remains electrically powered after the engine is stopped and is used to assess whether there is a leak in the evaporative emissions control system. Fuel tank temperature and pressure data, as well as fuel level data, is analyzed over a brief period of time by module and, if ambient conditions are suitable, the vent on the fuel adsorption canister is closed by signal from the module. The system is thus sealed and the module then analyzes the system pressure changes over a second brief period as the fuel cools by heat loss to detect the vacuum that will occur if the system has no leak.

Abstract: The effectiveness against vapor breakthrough of an adsorbent material (e.g., activated carbon granules) containing canister in an evaporative fuel emission control system is greatly increased by employing a relatively small secondary volume of adsorbent downstream of the vapor vent of the primary adsorbent volume and heating the secondary volume just prior to commencing the flow of purge air back through the two adsorbent volumes to remove adsorbed fuel and carry the purged fuel to the induction system of an associated engine. The secondary volume is heated to a temperature enabling complete purging of hydrocarbons from it and, thus, to greatly increase the capacity of that volume to prevent fuel vapor breakthrough during the subsequent engine-off fuel vapor storage cycle. The secondary volume may be contained in a common canister with the primary volume or in a secondary canister.

Abstract: A fuel vapor storage and recovery apparatus including a fuel vapor storage canister having an atmospheric vent port, a control valve for opening and closing the atmospheric vent port, a fuel vapor adsorbent material in the vapor storage canister, a vapor/purge conduit between the vapor storage canister and a fuel tank, and a heater operative to heat the vapor adsorbent material. With the atmospheric vent port open, a fuel vapor/air mixture is expelled from the fuel tank into the vapor storage canister. A fuel vapor fraction of the fuel vapor/air mixture adsorbs in the pores of the adsorbent material while an air fraction of the mixture escapes through the atmospheric vent port. When the control valve closes the atmospheric vent port, the heater heats the body of adsorbent material to a purge temperature above an ambient temperature in the fuel tank. At the purge temperature, the adsorbed fuel desorbs and fills the storage canister with large volume of hot gaseous vapor.

Abstract: A canister purge control strategy in which canister purge operation is adjusted when operating conditions normally identified as leading to purge system deterioration are present, such as high humidity operating conditions and operating conditions in which the fuel vapor canister is substantially fully purged. High humidity conditions, as are present during rainy conditions or inside a vehicle car wash, are detected by monitoring hardware normally available on the vehicle, such as a wiper switch state and a transmission gear state. Canister purging is adjusted or deactivated as a function of wiper switch state and transmission gear state to prevent moisture from entering the fuel vapor canister and reducing the capacity of the fuel adsorbing material. A substantially fully purged fuel vapor canister is detected by estimating a level of fuel vapor contained in the canister as a function of a change in injector pulse width under closed-loop control before and after canister purge is enabled.

Abstract: Automotive internal combustion engine control and diagnostics responsive to an up-to-date on-board estimate of fuel reid vapor pressure (RVP). An on-board fuel vapor recovery system traps fuel vapors released from a fueling system and is controlled to release the vapors to the engine for consumption therein, along with an injected fuel charge under closed-loop engine air/fuel ratio control. The change in the injected fuel charge required to maintain, under closed-loop control conditions, a target air/fuel ratio in the presence and in the absence of the released fuel vapors is applied along with fuel temperature information to estimate RVP, and the RVP estimate is applied under coldstart operating conditions to adjust engine fueling to account for corresponding changes in the vaporization characteristic of the fuel and is applied, when determined to be relatively high, to indicate potential false positives in fuel vapor recovery system diagnostics.