Diesel engine piston ring blow-by is usually caused by excessive ring clearance at the ring（）

A . seal the space between the piston and liner B . transmit heat from the piston to the cylinder liner C . reduce the amount of combustion gas blow-by D . all of the above

A . high lube oil viscosity B . increased lube oil consumption C . low lube oil temperatures D . high firing pressure

A . top of the ring groove B . cylinder liner oil film C . bottom of the ring groove D . back of the ring groove

A . Ⅰ only B . Ⅱ only C . both Ⅰ and Ⅱ D . neither Ⅰ nor Ⅱ

A . Ⅰ only B . Ⅱ only C . either Ⅰ or Ⅱ D . neither Ⅰ or Ⅱ

A . Low compression pressure and high exhaust temperature B . Low firing pressure and high exhaust temperature C . Low compression pressure and low exhaust temperature D . Low firing pressure and low exhaust temperature

A . In a two-stroke/cycle engine, the rings run hotter, requiring the end gap to be greater B . Some provision must be made in a two-stroke/cycle engine to keep the rings from binding in the ports C . No gap is required to exist between the ends of the ring when cold in a two-stroke/cycle engine, but a small gap is required in a four-stoke/cycle engine D . The gaps should be staggered on either side of a piston in a two-stroke/cycle engine, while staggering is not necessary in a four-stroke/cycle engine

A . chromium-plate against wear B . anti-corrosion treated C . white metal lined against wear D . flame hardened against wear

A . Low viscosity index B . Low carbon forming tendencies C . High film strength D . High non-corrosive qualitie

A . radiated through the engine block B . transferred to water cooled cylinder walls C . conducted through the piston crown D . transferred to escaping exhaust gase

A . prevent any lubricant from reaching B . prevent excessive lubrication from reaching the combustion space C . Provide metal-to-metal contact to seal the cylinder against blow-by D . assure a positive means of scraping carbon accumulation from the cylinder

A . Ⅰ only B . Ⅱ only C . both Ⅰ and Ⅱ D . neither Ⅰnor Ⅱ

A . Ⅰonly B . Ⅱ only C . both Ⅰ and Ⅱ D . neither Ⅰ nor Ⅱ

A . provide a reservoir for cylinder lubrication B . pump oil into the combustion space for cylinder cooling C . prevent excessive lubricating oil consumption D . allow hydraulic oil film formation on the cylinder

A . (1) only is correct B . (2) only is correct C . both (1) and (2) are correct D . neither (1) or (2) axe correct

A . excessive lube oil consumption B . lower than normal lube oil temperature C . higher than normal exhaust back pressure D . excessive crankshaft end play

A . residual carbon deposits B . lube oil viscosity breakdown C . uneven heat expansion of the rings D . uneven heat expansion of the pisto

A . diametrical tension B . gap clearance C . radial thickness D . face thickne

A . Control the amount of lube oil burned in the combustion chamber B . Transmit heat from the piston to the cylinder liner C . Prevent damage to ring groove inserts by acting as a heat dam D . Dissipate combustion chamber gas pressure by channeling it through the ring ga

A . excessive piston to liner clearance B . excessive dirt beneath the piston crown that reduces heat transfer C . faulty nozzle spray D . all of the above

A . compression stroke B . suction stroke C . expansion stroke D . exhaust stroke

A . jam in the most worn part of the cylinder when the rings expand B . break in the most worn part of the cylinder when the rings expand C . wear eccentrically on the side opposite the end gap D . overheat and jam at the top center on the combustion stroke

A . excessive ring action B . excessive ring temperature C . improper ring rotation D . excessive ring face wear

A . insufficient lubrication B . improper piston cooling C . blow-by D . overload operatio