Deck 19: Producing Power: Valve Timing, Power and Torque Measurement

Question 1

Technician A says thermal efficiency is the ratio of how effectively an engine converts a fuel's heat energy into usable work. Technician B says the thermal energy of gasoline is about 50,000 BTUs per pound. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Answer 1

A

Question 2

What are the two types of hydraulic phasers?

Answer 2

The two types of hydraulic phasers are: oil pressure actuated (OPA) cam torque actuated (CTA)

Question 3

What term refers to the intake and exhaust valves being equally open at TDC?

A) neutral LCA
B) advanced cam
C) retarded cam
D) split overlap

Answer 3

D

Question 4

Technician A says changes in cam timing are made to improve high-performance operation. Technician B says the computer advances the cam and high rpm and low load. Who is right?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 5

List three methods of adjusting cam phasing.

Question 6

Power produced at the crankshaft with only the alternator and water pump drawing power is called _____.

A) gross horsepower
B) indicated horsepower
C) brake horsepower
D) raw horsepower

Question 7

The camshaft is the determining factor in how efficiently the engine pumps air while operating at various speeds.

Question 8

Variable timing of the exhaust lobe is used to control torque.

Question 9

What is a pumping loss?

Question 10

What is the formula for mechanical efficiency?

Question 11

Some aftermarket camshaft sprockets for OHC engines are adjustable.

Question 12

Technician A says the effective compression ratio is determined by the point at which the intake valve closes. Technician B says effective compression ratio and static compression ratio are synonymous terms. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 13

Technician A says excessive valve lift causes piston-to-valve interference. Technician B says high valve overlap can lead to clearance problems between the valves and pistons. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 14

What are three types of variable valve timing?

Question 15

All of the below are factors in camshaft performance EXCEPT _____.

A) duration
B) rate of lift
C) overlap
D) valve size

Question 16

What term refers to how fast motion is produced against a resistance?

A) force
B) power
C) torque
D) inertia

Question 17

What value is determined by multiplying the lobe lift by the rocker arm ratio?

A) total valve lift
B) gross valve lift
C) net valve lift
D) rate of lift

Question 18

Net horsepower is the power lost through friction in the driveline and due to wind resistance, vehicle weight, tires, and weather.

Question 19

Technician A says running a dynamometer test is noisy. Technician B says carbon monoxide (CO) is a major concern when using an engine dynamometer. Who is correct?

A) Technician A
B) Technician B
C) Both technicians
D) Neither technician

Question 20

Compression ratio affects the amount of power an engine can produce by increasing the thermal efficiency of the engine.