Diesel Exhaust Aftertreatment Systems for Gasoline Engine Instructors Curt Ward
Introductions Professor: Joliet Junior College Visiting Instructor: Southern Illinois University Author: Pearson Education ASE Master Certified Technician Over 25 years Industry Experience
Topics to be Covered Diesel exhaust system maintenance Description and operation of the diesel exhaust aftertreatment components Case studies Aftermarket Reprogramming Diesel Emission Testing
What I hear We don’t test diesels in our area! Why should I teach this? Because: New diesel powered cars and light duty trucks are one of the fastest growing segments in the industry. – Example: United States light duty diesel vehicle sales up 25% in 2015
Exhaust System (aftertreatment) A good or bad thing?
Exhaust System Maintenance! Diesel Fuel Diesel Exhaust Fluid Diesel Motor Oil Diesel Engine Maintenance Habits Customer Driving Habits
Ultra-Low Sulfur Fuel Required for use in 2007 and later engines Maximum 15 ppm sulfur content Allows use of exhaust after-treatment systems Phased in starting September 2006 Feds require labels at the pump
Diesel Fuel Conditioning
Can I use BioDiesel? 2012 Volkswagen TDI 2012 Ford F250
Diesel Exhaust Fluid (DEF) What is it What is its purpose Maintenance issues
DEF Concerns 36 Month Shelf Life DEF “Creeping” – Crystallize Freezes at 12 degrees (F) Storage Tank Heater Failures DEF Quality
Diesel Motor Oil Low Ash Motor Oil Assists in reduction of PM emissions API CJ-4 oils meet low ash specs (CK-4 coming in December 2016) Required to meet manufacturers warranty requirements
Diesel Engine Maintenance Fuel/Water Filters Air Filter Oil and Oil Service Engine Coolant *Coolant and Oil Consumption are creating exhaust after treatment failures*
Customer Driving Habits Cause – Short trip driving – Long idle time – Poor Maintenance Effect – Fuel mileage – Oil Life – Life of Particulate Filter – MIL On
Aftertreatment Components Diesel Oxidation Catalyst Selective Catalyst Reduction NOx Adsorber Catalyst Diesel Particulate Filter (DPF) DPF Pressure Sensor Exhaust Gas Temperature Sensors O 2 and NOx Sensors
Diesel Oxidation Catalyst (DOC) Reduce Carbon Monoxide by up to 85% Reduce Hydrocarbons by up to 60% Convert Nitrogen Monoxide (NO) into Nitrogen Dioxide (NO 2 ) Reduces Particulate Matter by up to 20%
DOC Flow Through Design Platinum Washcoat Similar functions of a catalytic converter Generates heat to be used by DPF during Regeneration May be combined with DPF in one housing
Selective Catalyst Reduction (SCR) Diesel Exhaust Fluid (ammonia) with the catalyst reduces Oxides of Nitrogen into the natural elements of Nitrogen and water
NOx Adsorber Catalyst Reduce NOx emissions Adsorbers are incorporated into the washcoat Does not use DEF NOx held during lean operation Reduced to Nitrogen during rich operation Similar to NOx bed of gasoline converter 1.Diesel Oxidation Catalyst #1 2.Oxygen Sensor Bung 3.Exhaust Temperature Sensors 4.NOx Adsorber Catalyst 5.Diesel Particulate Filter
Particulate Filter (DPF) Wall-flow design Filters, stores, burns particulate matter PM oxidized into CO 2 at 600 degrees F Ash residue will remain in DPF Will require service eventually
DPF Pressure Sensor Differential Pressure Sensor Monitors DPF for restrictions Used to determine if a Regeneration is required Similar to System used to Monitor EGR
Exhaust Gas Temperature Sensors Monitors temperatures of DPF/ DOC/ SCR Most likely a PTC (positive temperature coefficient) Sensor 3 or More Used Prevents overheating of DPF during a regeneration event
NOx Sensors Typically part of a Smart Module Used to verify DEF for Quality PCM Calculates DEF based on Feedback Can be used for EGR Calculations
O 2 Sensors Wide Band – Similar to Gasoline Engines Not Used for Fuel Calculations Used for EGR Calculations
DPF Regeneration Passive – Vehicle driven under load to perform regeneration Active – Additional fuel added for regeneration Manual – Available to technician on some models
OBDII for Diesels 2007 Model Year & Newer Many Monitors are the same as gasoline models New to Diesel Include: – Crankcase ventilation – DPF – EGR Cooler – Glow Plug
Lots of TSBs on Model Year Vehicles Check Before you Begin Diagnosis – Updated Sensors – Module Reprogramming – Cleaning of Systems
Case Study # Ford Truck, 6.4L Engine 10,456 Miles MIL On and Lacks Power on Acceleration Code P2463 Particulate Filter – Soot Accumulation Perform Manual DPF Regeneration & Clear Code Concern caused by extended idle
Case Study # Ford Truck 6.7L with 19,852 Miles No Power, MIL and Maintenance Lights On Code P204F – Reductant System Performance Found Diesel Exhaust Fluid Reservoir empty Filled Reservoir with proper fluid & cleared code Cause: Failure to heed warning lamps
Aftermarket Programmers Primary use to increase torque and horsepower Typically change fuel delivery May have a negative effect on aftertreatment system May cause emissions failure at test lane
Diesel Emission Testing Growing number of states testing Select areas of testing within these states Testing typically classified by vehicle weight (GVWR) Processes include visual inspection, smoke opacity, and OBDII Many of the same exemptions as gasoline powered vehicles
Coming Attractions! Light Vehicle Diesel Engines New Text from Pearson Education Authors: James Halderman and Curt Ward
May You Enjoy Safe Travels I hope to see you at a conference in the future Thanks for attending Don’t forget to thank our hosts
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