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

Which engine can achieve higher crankshaft rpm, one with a short stroke or one with a longer stroke?

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

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

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

What would be the valve lift with a 1.5:1 rocker arm ratio and 0.300" of lobe lift?

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?

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

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?

Technician A says that the rpm range of the engine is controlled by the point where the intake valve closes. Technician B says that closing the intake valve later in the compression stroke lowers the effective compression ratio. Who is right?

To improve idle quality on longer duration cams, _____ lobe centers are used.

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?

The timing of the camshaft events is listed in camshaft/crankshaft (choose one) degrees.

What are three types of variable valve timing?

High rpm power is improved by _____ cam timing.

When inertia from exhaust gas exiting the cylinder sucks out even more exhaust, this is called ___________.

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

What is a pumping loss?

Technician A says that it is normal for the piston to remain stationary at TDC for a few degrees of crankshaft rotation. Technician B says that if the intake valve is open more at TDC than the exhaust valve, the cam is retarded. Who is right?

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

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