The major cause of trouble in a mechanical-hydraulic governor is contamination of the hydraulic fluid by ______.
A. dirt
B. fuel oil
C. governor cooling water
D. fuel oil tar(焦油)
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Cooling of engines is achieved by circulating a cooling liquid around internal ______within the engine.
A. air
B. passages
C. pipes
D. means
In a diesel engine, when refitting piston rings you should______. I. check the ring gap at
A. I only
B. II only
C. both I and II
D. neither I nor II
Fuel has been injected but ignition fails. The possible cause may be ______.
A. slightly leaky exhaust valve
B. increased scavenging air temperature
C. engine cylinders not scavenged sufficiently
D. too much water in the fuel oil
During the valve overlap period, the exhaust pressure of a turbocharged four-stroke/cycle
A. effective cylinder scavenging and cooling
B. constant pressure from the turbochargers
C. cooler operation of the exhaust system
D. effective constant pressure for turbocharger operation