E – Exhaust G – Gas R – Recirculation EGR Cooler
The ABC’s OfExhaust Gas Recirculation (EGR) OVERVIEW In general, the higher the engine temperature, the more efficient the engine. Which results in: 1) Good Performance 2) Good Fuel Economy
When peak temperatures are high enough for long enough periods of time, the nitrogen and oxygen in the air combine to form new compounds, primarily NO and NO2. These are normally referred to collectively as “NOx – Nitrogen Oxide” The ABC’s OfExhaust Gas Recirculation (EGR)
The ABC’s OfExhaust Gas Recirculation (EGR) • Too much NOx in the atmosphere contributes to the production of smog. • In October of 2002, new NOx standards required the diesel engine industry to introduce additional technology to meet the new standards. • EGR COOLER
How Can NOx Be Reduced? • Since high cylinder temperatures cause NOx, NOx can be reduced by lowering cylinder temperatures. Charge air coolers are already commonly used for this reason. • Reducing the amount of oxygen in the cylinder, inhibits the combustion process
How Can NOx Be Reduced? • The best way to reduce NOx is to limit the amount of oxygen in the cylinder. Which results in lower cylinder temperatures. • This is done by recirculation of exhaust gas (EGR) into the cylinder. • This technique lowers cylinder temperature, reducing NOx, But it also reduces fuel economy and performance, and creates excess soot.
The ABC’s OfExhaust Gas Recirculation (EGR) • When EGR is required, the engine’s electronic controls open the EGR valve. • Turbocharger & EGR Valve (1) 1
Exhaust Gas Recirculation (EGR) • The exhaust gases flow through this pipe to the EGR cooler. (2) 2
The ABC’s OfExhaust Gas Recirculation (EGR) • The exhaust gases are cooled by water from the engine cooling system. (3) 3
The ABC’s OfExhaust Gas Recirculation (EGR) • The cooled exhaust gases then flow through the EGR transfer pipe into the intake manifold. (4) • Which then lowers the cylinder temperature • Results in lower NOx production. 4 4 Intake Manifold
Regeneration SystemWhat is its job ? • The system's job is to capture and burn off (regenerate) the particulate matter (soot) in the engine exhaust gas . • It does this using a Diesel Oxidation Catalyst (DOC) and a Diesel Particulate Filter (DPF). By monitoring exhaust gas temperature and system back pressure, Detroit Diesel Electronic Control determines when and how additional help is needed to ensure complete regeneration of the soot captured in the DPF.
Types of Regeneration • There are two types of Regeneration ? • Active • Stationary.
Types of Regeneration • Active Regeneration • During normal driving the Intake Throttle is electronically actuated to help increase the After treatment System temperature while the unit is running. • The Dosing Valve injects a mist of diesel fuel into the exhaust system to further increase the After treatment System temperature until satisfactory regeneration is complete.
Types of Regeneration 2. Stationary Regeneration • Depending on engine duty or application, the Detroit Diesel Electronic Control (DDEC) may notify the driver that stationary regeneration is necessary. • After the driver begins the manual activation of the regeneration process, the RPM’s go up to 1650 (High Idle is 1400 RPM’s) • Regeneration take about 20-30 minutes.
Manual Regeneration Switches Regen Request Regen Inhibit
Regeneration Manual Switch Position Hold Regen Request Switch up for 5 – 10 sec. Regen Switch UP
Regeneration Location Regeneration Valve
References • Detroit Diesel Engine Manual • www.detroitdiesel.com • Firefighter Chris Adams Station 13C