Question

Technician A says that before electronic engine controls were used, most manufacturers used mechanical systems to control engine emissions. Technician B says that one of the first steps taken to reduce diesel engine emissions was to reduce the sulfer content in the diesel fuel. Who is correct?

a) Technician A only
b) Technician B only
c) Both A and B
d) Neither A nor B

Answer 1

Both Technician A and Technician B are correct (option c); mechanical systems were initially used to control engine emissions, and one of the early steps to reduce diesel emissions was to reduce the sulfur content in diesel fuel.

Step-by-step explanation:

The question addresses the measures taken by manufacturers to control engine emissions in both gasoline and diesel engines before and after the advent of electronic engine controls. Technician A is correct in stating that mechanical systems were previously used to control engine emissions before the introduction of electronic engine controls. This approach included measures such as command-and-control regulations that required the installation of certain equipment to reduce pollution.

Over time, the internal combustion engine has transitioned to a highly sophisticated computer-controlled system that pairs well with advances in fuel formulation, such as the removal of tetraethyllead from gasoline and adjustments to reduce volatile and unsaturated hydrocarbons.

Technician B is also correct in stating that one of the earlier steps to reduce diesel engine emissions included lowering the sulfur content in diesel fuel. Reductions in sulfur levels in diesel fuel help in the overall reduction of hydrocarbon and nitrogen oxide emissions when paired with technologies such as catalytic converters and diesel particulate filters.

Therefore, the correct option in the final answer to the question of who is correct between Technician A and Technician B is c) Both A and B.