Evaporative Emissions due to EVAP System Malfunctions Sam R. Reddy, Ph.D.,P.E. Evaporative Emissions Consulting, Inc. www.EvapConsulting.com On behalf of Stoneridge, Inc. November 6th, 2012 Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Evaporative Emission Control System Purge Vapor (air+HC) to Engine Normally Closed Purge Control Solenoid Gasoline Activated Carbon Canister Diurnal vapors expelled from the fuel tank consists of HC + Air Evap canister traps HCs; Air escapes into the atmosphere During engine operation, the canister is purged/cleaned/regenerated and the vapors are consumed in engine combustion Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Malfunctioning Purge System No canister purge Electrical problems Stuck closed purge valve Plugged/blocked/broken purge line Gasoline No active purging of Evap canister Passive purging of canister results in 65% diurnal vapor back purge into the fuel tank * 35% of diurnal vapor escapes into the atmosphere * * EPA Report EPA420-R-08-014, “Feasibility of Evaporative Emission Control,” September 2008 . Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Passive Purging of EVAP canister (No canister purge due to Purge Malfunction) 35% vapor loss 35oC Gasoline 65% vapor adsorbed 20oC Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Passive Purging of EVAP canister (Cont’d) (No canister purge due to Purge Malfunction) Air 35oC Gasoline 65% vapor passively purged During tank cool down 20oC Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Large Leaks in EVAP System Leaks in the EVAP system > 1 mm dia leaks Loose or missing fuel cap Plugged/blocked/broken vapor line Gasoline 100% of diurnal vapor escapes into atmosphere Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Diurnal Vapor Generation in Two Representative Cities* Average Vehicle fuel tank: 50 L (57.5 L total volume); 40% fuel level ** * For comparison, Euro5 EVAP diurnal vapor generation from 50 L tank is 20.5 grams/day ** S. R. Reddy, “Prediction of Fuel Vapor Generation from a Vehicle Fuel Tank as a Function of Fuel RVP and Temperature,” SAE Paper 892089. Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Vehicle Diurnal Vapor Generation in two Representative Cities (50 L fuel tank; 40% fuel level) Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Vehicle Diurnal Vapor Generation in two Representative Cities (50 L fuel tank; 40% fuel level) Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Malfunctioning Purge System (35% diurnal vapor escapes into the atmosphere) No canister purge Electrical problems Stuck closed purge valve Plugged/blocked/broken purge line Gasoline Average summer diurnal vapor generation 11.1 g/summer day Avg vapor loss into the atmosphere 0.35*11.1 = 3.9 g/summer day Avg vapor loss into the atmosphere 0.35*7.2 = 2.5 g/avg day Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Large Leaks in EVAP System (100% diurnal vapor escapes into the atmosphere) Leaks in the EVAP system > 1 mm dia leaks Loose or missing fuel cap Plugged/blocked/broken vapor line Gasoline Average diurnal vapor generation 11.1 g/summer day Avg vapor loss into the atmosphere 11.1 g/summer day Avg vapor loss into the atmosphere 7.2 g/avg day Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

All EVAP System Malfunctions (Assume 50% purge malfunctions; 50% large leaks) Gasoline Avg malfunction vapor loss into the atmosphere (11.1+3.9)/2 = 7.5 g/summer day Avg malfunction vapor loss into the atmosphere (7.2+2.5)/2 = 4.9 g/avg day Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc. Estimation of Evaporative Emission Inventory due to EVAP Malfunctions - Summer 250,000,000 vehicles in Europe; 60% petrol vehicles 150,000,000 petrol vehicles 1% EVAP malfunctions (7.5 g/day)*(1,500,000) = 11,250,000 g/day or 11,250 kg/day 10% EVAP malfunctions (7.5 g/day)*(15,000,000) = 112,500,000 g/day or 112,500 kg/day Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc. Estimation of Evaporative Emission Inventory due to EVAP Malfunctions – All Year 250,000,000 vehicles in Europe; 60% petrol vehicles 150,000,000 petrol vehicles 1% EVAP malfunctions (4.9 g/day)*(365 days/yr)*(150,000,000/100) 2.7 kt/yr or 3,832,500 liters of petrol/yr 10% EVAP malfunctions (4.9 g/day)*(365 days/yr)*(150,000,000/10) 27 kt/yr or 38,325,000 liters of petrol/yr Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Estimated Evaporative Emission Inventory due to EVAP Malfunctions Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc. Solution A simple low cost OBD leak detection system including canister vent solenoid valve can capture EVAP malfunctions and prevent HC emissions into the atmosphere: 13.5 kt HC emissions per year or 19 million liter petrol loss (Conservative estimate because running loss emissions are not included) Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.

What about Running Loss ? Running loss vapors are consumed in engine combustion; however, Purge malfunctions causes running loss emissions through the canister EVAP system leaks can cause running loss vapor emissions into the atmosphere Estimation of running loss as % increase in diurnal: Two trips per day: AM and PM Ignore the effect of AM trip because it is partially accounted in diurnal vapor generation PM trip will increase the tank fuel temperature by about 3⁰C Re-calculate tank vapor generations by incrementing the peak tank temperature by 3⁰C Tank vapor generation will increase by 40% EVAP Emissions inventory and fuel loss estimation will increase by up to 30% (assuming running loss occurrence 5 days per week) Sam R. Reddy, PhD PE Evaporative Emissions Consulting, Inc.