Question

In which type of injection mode the exhaust gas temperature for the regeneration of the particulate filter is increased?

(a) Pilot injection mode

(b) Retarded post ignition mode

(c) Main injection

(d) Double pre injection

The question was asked at a job interview.

My doubt is from Modern Common Rail Fuel Injection System in division Diesel Engine Fuel Supply System of Automotive Engine Design

Answer 1

The correct option is (b) Retarded post ignition mode

The explanation is: After the main injection phase, after which post-injection spurt of fuel is added, which reduces soot emissions. Finally, after upto 180 degrees of the crankshaft, a retarded post ignition occurs, which acts as a reducing agent for NOx and increases the exhaust gas temperature for the regeneration of the particulate filter.