AMT 242 Chapter 1

Which of the following examples will achieve the greatest annual fuel savings for a diesel-powered vehicle traveling distances of 12,000 miles (20,000 km)? a. Increasing fuel economy 45% from 40 to 60 mpg b. Increasing fuel economy 30% from 35 to 50 mpg c. Increasing fuel economy 25% from 30 to 40 mpg d. Increasing fuel economy -20% from 16 to 19 mpg

-20% from 16 to 19 mpg

Which of the following diesel engine combustion chambers requires a glow plug to start? a. Direct injection b. Indirect injection c. Hemispheric chamber d. Turbulence chamber

Indirect injection

Prolonged ignition delay in a diesel engine will more likely produce which one of the following? a. An engine knocking sound b. Blue smoke c. White smoke d. Lower peak cylinder pressures

a. An engine knocking sound

The rate at which combustion occurs when additional fuel is added to a cylinder changes in which of the following ways? a. Combustion time is shortened. b. Combustion time is lengthened. c. Combustion time remains the same.

a. Combustion time is shortened.

Which combustion chamber design produces the best fuel economy in a diesel engine? a. Direct injection b. Indirect injection c. Swirl chamber d. Wedge chamber

a. Direct injection

Which type of fuel nozzle is used in a direct-injection combustion chamber? a. Multiorifice nozzle b. Pintle type nozzle c. Closed nozzle d. Open nozzle

a. Multiorifice nozzle

Which combustion chamber design has traditionally operated with the least amount of noise? a. Direct injection b. Indirect injection c. Two-stroke d. Penta chamber

b. Indirect injection

Which diesel engine combustion chamber design will produce the fastest coolant warm-up times? a. Direct injection b. Indirect injection c. Two-stroke d. Hemispheric chamber

b. Indirect injection

Pilot injection accomplishes which of the following? a. Better fuel economy b. Lower combustion chamber noise c. Longer ignition delay d. Precise injection timing

b. Lower combustion chamber noise

The term ignition delay in a diesel engine is best described by which of the following? a. The time required to raise the fuel pressure high enough to overcome compression pressure in a cylinder b. The time lag from initial injection to actual ignition c. The time require to heat up a glow plug d. The time require for vaporized fuel to atomize

b. The time lag from initial injection to actual ignition

What is the average compression ratio of an on-highway diesel engine? a. 23:1 b. 20:1 c. 16:1 d. 10:1 e. 8:1

c. 16:1

At which of the following compression ratios does the efficiency of an engine begin to diminish with increasing compression? a. 12:1 b. 16:1 c. 23: 1 d. 25:1

c. 23:1

A centrally located fuel injector in a diesel engine is most likely to have which of the following number of valves? a. 2 valves per cylinder b. 3 valves per cylinder c. 4 valves per cylinder d. any number of valves

c. 4 valves per cylinder

Which of the following factors does not account for diesels longevity and durability? a. Slower engine speeds b. Lubricating properties of fuel c. Higher compression ratios d. Fuel injection at the end of compression stroke

c. Higher compression ratios

How does fuel consumption change as vehicle weight increases? a. Fuel consumption increases proportionally the same in both gasoline and diesel engines. b. Fuel consumption by diesel engines increase more than in gasoline engines. c. Fuel consumption by diesel decreases while gasoline engine increase. d. Fuel consumption by diesels does not rise as much as gasoline engines.

d. Fuel consumption by diesels does not rise as much as gasoline engines.