LEC Emissions Control Systems 3

Question 1

Which federal regulation establishes the primary emissions standards for in-use locomotive engines in the United States?

Accepted Answer

40 CFR Part 1033

Answer

40 CFR Part 1033 contains EPA's emissions standards specifically for locomotives and locomotive engines, covering both new and in-use engines.

Question 2

What effect does exhaust gas recirculation (EGR) have on combustion temperature?

Accepted Answer

It lowers peak combustion temperature to reduce NOx formation

Answer

EGR dilutes the intake charge with inert exhaust gases, lowering peak combustion temperatures and thereby reducing NOx formation.

Question 3

A locomotive engineer observes visible black smoke during a throttle notch increase. Which emissions issue does this most likely indicate?

Accepted Answer

Rich fuel mixture causing incomplete combustion

Answer

Black smoke indicates incomplete combustion of diesel fuel, often caused by a rich fuel-air mixture, a clogged air filter, or injector problems.

Question 4

Under EPA regulations, how often must in-use locomotives undergo emissions testing?

Accepted Answer

Only at major overhaul

Answer

Under 40 CFR Part 1033, locomotives are subject to emissions testing at the time of remanufacture or major overhaul, not at routine annual inspections.

Question 5

What is the role of an oxidation catalyst in an after-treatment system when the exhaust temperature is below its light-off temperature?

Accepted Answer

Its conversion efficiency is significantly reduced

Answer

Catalytic converters require minimum light-off temperatures (typically 200–300°C) to activate; below this threshold, conversion efficiency drops sharply.

(LEC) Locomotive Engineer Certification Practice Test

(LEC) Locomotive Engineer Certification Practice Test

LEC Emissions Control Systems 3