Week 2 Emissions Practice Test

Technician A says Diesel Emissions were established in the 1970's. Technician B says todays Diesels must comply with regulations to reduce emissions.

• Tech A

• Tech B

• Both Techs

• Neither Tech

Modern diesel engines emit...

• Much more emissions than gasoline engines

• Close to zero emissions

• Low emissions but with reduced power

• Low emissions but with reduced fuel economy

Which standards are the set used for Off-Road diesel engines?

• Tier

• CARB

• EURO

• HD-OBD

Answer explanation

Tier, which goes 1-4, are the standards that both the US and Europe use for off road diesel engines. CARB is for cars on the road and only applies to the US. Euro is for road going vehicles in Europe. HD-OBD is the Heavy duty diesel on board diagnostics, which isn't a regulation, but rather a way to scan a vehicle for emissions and other diagnostic trouble codes.

Tech A says Diesel and Gasoline engines both have Evaporative Emissions Controls. Tech B says Modern Diesels Emit close to Zero emissions. Which Tech is correct?

• Tech A

• Tech B

• Both Tech

• Neither Tech

Answer explanation

Diesels do not require an Evap Control system. Diesel has very little vapors that come

off of it, while gasoline has a lot more. These vapors (VOC's) mix with compounds in the air to create smog.

Thanks to regulations on emissions, on and off road diesel engine emissions have been reduced by...

• 5%

• 17%

• 20%

• 29%

Tech A says Volatile organic compounds (VOC's) mix with chemicals in the atmosphere to create Ozone. Tech B says Diesel and Gasoline engines create the same amount of VOC's. Which one is correct?

• Tech A

• Tech B

• Both Techs

• Neither Tech

Answer explanation

Diesels create less than a tenth of the VOC's a gasoline engine creates. This is because of the flashpoint of diesel and gasoline. Gas is -49f while Diesel is 140f. This means for Diesel to produce VOC's it would need to be heated to over 140 degrees Fahrenheit.

Technician A says that black smoke from the exhaust of a diesel engine is evidence of particulate emission. Technician B says that black smoke is just soot which will harmlessly fall to the ground. Who is correct?

• Tech A

• Tech B

• Both Techs

• Neither Tech

Answer explanation

Visual emissions from the tail pipe that are either Solid or Liquid are called Particulate Matter. Unburnt fuel droplets and soot are both visible and physical, so they fall under particulate matter. They are not harmless and cause pollution and have been linked to increased risks of certain types of cancer.

Technician A says that creating clean diesel engines has resulted in diesels using more fuel and less power output compared to older engines. Technician B says that even the latest engine technology has not allowed diesels to operate as cleanly as spark ignited gasoline engines. Who is correct?

• Tech A

• Tech B

• Both Tech A and B

• Neither Tech A or B

Tech A says refining Diesel fuel from oil naturally adds sulfur to it. Tech B says burning fuel with sulfur in it can contribute to sulfate emissions and pollution like acid rain. Which Tech is correct?

• Tech A

• Tech B

• Both Techs

• Neither Tech

Answer explanation

Since sulfur finds its way into diesel fuel most road going trucks have to use Ultra low sulfur diesel fuel to help circumvent sulfate emissions.

Fuels are classified as Hydrocarbons because they...

• Create Hydrocarbons as part of the combustion process

• Form Hydrocarbons when injected at high pressure

• Because they are liquid carbons

• Because they are mostly made of Hydrogen and Carbon.