Evaporative and Refueling Emission Control

All gasoline powered vehicles and equipment create exhaust and evaporative and refueling emissions. Unlike exhaust emissions, which occur only when the engine is operating, evaporative emissions (evap emissions) occur all the time. Controlling evap emissions to PZEV levels is as challenging as controlling exhaust emissions. It becomes even more important in the case of plug-in hybrid electric vehicles (PHEV) and extended range electric vehicles (EREV) which generate evaporative fuel vapors, but have no place to burn/consume the vapors when the engine does not operate for extended periods of time. Constantly changing evaporative regulations including new test procedures for accommodating future EREVs and PHEVs vehicle evap systems, new test fuels to reflect changing commercial gasolines, identifying and controlling new sources of fuel vapor emissions, etc., require that individuals working in this area have a solid understanding of both regulatory and system design issues for evap emissions control.

This comprehensive seminar introduces the participants to the principles of gasoline evaporative fuel vapor generation (diurnal, hot soak, running loss, and refueling) from the vehicle fuel tank, fuel vapor storage in activated carbon canisters, and fuel vapor desorption and consumption in engine combustion. The seminar begins with an analysis of gasoline and gasoline/ethanol blends and estimation of their vapor pressures and vapor generation. In-depth analysis of various vapor generations as a function of fuel properties (ethanol content, Reid Vapor Pressure, etc.) and ambient conditions will be presented. Activated carbon canister design, OBD II leak detection, hydrocarbon permeation, and CARB and EPA evaporative test procedures will also be covered. Participants will have the opportunity to apply the knowledge gained by designing a sample evaporative and refueling emissions control system in class.

Participants are asked to bring a calculator for use in classroom exercises.

What Will You Learn

By attending the seminar, you will be able to:
  • Identify various sources of evaporative fuel vapor emissions
  • Predict the effects of ethanol on evaporative emissions
  • Estimate diurnal and refueling vapor generation
  • Analyze the differences in the test procedures: U.S., Europe, and Asia
  • Explain activated carbon canister operation: loading, purging, vapor redistribution, and back-purge
  • Identify potential solutions to induction hydrocarbon emissions
  • Estimate the effect of altitude on evaporative emissions

Is This Course For You

This course is designed for engineers in all fields related to the design and development of evaporative and refueling emission control systems including platform fuel system design engineers for fuel tanks, onboard refueling vapor recovery systems, evaporative emission control canisters, fuel vapor lines, vapor purge lines, purge and vent valves, etc. Air induction system design engineers dealing with induction hydrocarbon adsorbers, powertrain fuel delivery design engineers responsible for canister purge vapors, powertrain calibration engineers responsible for evaporative canister purge and evaporative emission diagnostics, and environmental engineers who deal with state and federal emission regulations, will all find the seminar valuable.

Materials Provided

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Course Requirements

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  • Introduction
    • Evaporative and refueling emission control system
    • Why and how to control fuel vapor emissions
  • Fuel and Fuel Vapor Pressure
    • Hydrocarbon fuels
    • Oxygenated fuels and non-ideal solutions
    • Estimation of vapor pressures of ideal (hydrocarbon fuels) and non-ideal solutions (oxygenated fuels)
    • Flexible Fuel Vehicles (FFV) and fuel commingling
    • Vapor pressure and boiling point estimation
  • Fuel Vapor Generation
    • Diurnal, hot-soak, running loss
    • Refueling - liquid seal and mechanical seal, hot tank/cold dispensed fuel, cold tank/hot dispensed fuel, RVP, air entrainment and vapor recirculation, etc.
    • Effect of altitude on vapor generation and fuel boiling in running loss test
    • Effect of oxygenates on fuel vapor generation and fuel boiling in running loss test
  • Carbon Canisters
    • Adsorbents and isotherms
    • Activated carbons
    • Adsorption/desorption phenomena
    • Canister vapor loading, purging, redistribution, and back-purge
    • Canister design
  • Evaporative and Refueling Emission Control System Design
    • Test procedures - EPA & CARB 3-day test, EPA-ORVR, EPA & CARB 2-day test, ECE and other global EVAP test procedures, etc.
    • Canister sizing - determine optimum size
    • Purge air volume requirement
  • Miscellaneous Evaporative Emission Control Topics
    • Hybrid and plug-in hybrid evaporative emission control
    • Pressurized/sealed and bladder fuel tank for evaporative emission control
    • Evap OBD II leak detection
    • Permeation losses - effects of materials, temperature, fuel composition, etc.