单选题The pressure of pilot air is usually （） than that of starting air.AhigherBlowerClowDhigh
单选题
The pressure of pilot air is usually （） than that of starting air.
A
higher
B
lower
C
low
D
high
参考解析
解析：
暂无解析
相关考题：
Forces other than damaging winds are also at work inside tornadoes (龙卷风) . Sometimes,as the wind passes a house, the walls and ceiling burst apart as if a bomb had gone off inside. This explosion is caused by the low air pressure at the center of a tornado.The pressure at the center of a tornado is usually 13 pounds per square inch. However,inside the house the air pressure is normal, about 15 pounds per square inch.The difference of 2 pounds per square inch between the inside and outside pressure may not seem like much. But suppose a tornado passes over a small building that measures 20 by 10 by feet. On each square inch of the building, there is 2 pounds of pressure from the insidethat is not balanced by air pressure outside the building. On the ceiling, that adds up to an unbalanced pressure of 57600 pounds. The pressure of the four walls adds up to 172800 pounds.If windows are open in the building, some of the inside air will rush out through them.This will balance the pressure inside and outside the building.But if the windows are shut tightly, the huge inside pressure may cause the building to burst.Unfortunately, heavy rain often occurs in the storms that later produce tornadoes,so people often shut their windows. This may cause far worse damage later.21、 What did the paragraph before this passage most probably discuss?A、 Measuring rainfall from a stormB、 The kinds of damage caused by explosionsC、 The powerful winds of tornadoes22、 Which of the following is the main topic of the passage?A、 How tornadoes can be preventedB、 When tornadoes usually occurC、 Why tornadoes cause so much damage23、 Tornadoes can destroy buildings because the()A、 force of a tornado increases the air pressure in a buildingB、 air pressure inside a tornado is less than the air pressure inside a buildingC、 air pressure at the center of a tornado is over 172000 pounds24、 What is the difference per square inch between the air pressure inside a building and the air pressure inside a tornado?A、 2 poundsB、 13 poundsC、 15 pounds25、 What would happen if the windows are shut tightly in the stormy weather?A、 Tornadoes may be formedB、 The house may be apartC、 There may not be any pressure inside the building
When using a fuel with a higher than normal sulfur content in an auxiliary four stroke diesel engine, you mayA.maintain higher than normal jacket water temperatureB.change the lube oil more frequently than normalC.maintain a higher air-box temperature than normalD.maintain a higher air-box pressure than normal
_______is usually driven by the engine camshaft and supplies pilot air to the cylinder air start valve.A.An air receiverB.An operating valveC.An automatic valveD.An air distributor
The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually______.A.greater than the average exhaust manifold pressureB.less than the average exhaust manifold pressureC.greater at the turbine wheel than at the impellerD.greater at reduced engine speed
A low in a marine weather report is an air pressure system the pressure at the center of which is ______.A.the highest over the areaB.the lowest over the areaC.higher than 1013 HPAD.lower than 1013 HPA
In international air cargo transportation， Specific Commodity Rates are usually lower than General Cargo Rates.
单选题A marine diesel engine is started by（）Asupplying high pressure oil into a hydraulic motorBsupplying high temperature air into the cylinderCsupplying high pressure air into the cylinderDelectrical igniting
单选题A more sophisticated pressure reducing valve incorporates a pilot valve which controls the fluid above the valve operating piston in response to downstream pressureThe bold and italic word “which” means （）.Aa pressure reducing valveBa pilot valveCan operating pistonDdownstream pressure
单选题Which of the following statements is true concerning the overall efficiency of air compressors?（）AHigh pressure compressors are more efficient than low pressure compressorsBMechanical efficiency divided by compressor efficiency will equal the overall efficiency of the compressor unitCTwo stage compressors are generally more efficient than single stage compressorsDThe volumetric efficiency is decreased in multistage compressors
单选题On small, low pressure, air compressors, the cylinders are usually lubricated by the （）.Asplash methodBmechanical force feed lubricatorsCdetached sump methodDinternal cooling passages in the crankshafts and connecting rods
单选题An air mass is termed warm if（）.Ait is above 70°FBthe ground over which it moves is cooler than the airCit originated in a high pressure areaDit originated in a low pressure area
单选题The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually（）Agreater than the average exhaust manifold pressureBless than the average exhaust manifold pressureCgreater at the turbine wheel than at the impellerDgreater at reduced engine speed
单选题In the starting system, the automatic valve is controlled by（）, and the cylinder start valves are controlled by（）Apilot air；pilot airBhandle；solenoidChandle；pilot air coming through the distributorDsolenoid；pilot air coming through the distributor
单选题Each cylinder has one starting valve which is usually opened by air pressure and closed by （）Anuts and boltsBnew jointsCspring forceDsealing rings
单选题An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.Aoil foaming in the compressorBhigher than normal suction and discharge pressures with a higher box temperatureChigher than normal discharge pressure with a normal box temperatureDthe compressor to run continuously
单选题（） is usually driven by the engine camshaft and supplies pilot air to the cylinder air start valve.AAn air receiverBAn operating valveCAn automatic valveDAn air distributor
单选题Low pressure air is usually taken through （） or pressure regulators to a low pressure reservoir supplying a ring main through driers.Aglobe valvesBbutterfly valvesCgate valvesDreducing valves
单选题Cyclones that have warm sectors usually move（）.AwesterlyBparallel to the isobars in the warm sectorCtoward the nearest high pressure areaDfaster than the accompanying cold front
单选题（） supplies pilot air to control the cylinder air start valves.AAn air compressorBAn indicator cockCAn air distributorDA safety valve
判断题In international air cargo transportation， Specific Commodity Rates are usually lower than General Cargo Rates.A对B错
单选题Which of the following statements concerning frontal movements is TRUE（）.AThe temperature rises after a cold front passesBThe barometric pressure rises when a warm front passesCA cold front generally passes faster than a warm frontDA warm front usually has more violent weather associated with it than a cold front
单选题A crew member reports that the high-pressure alarm light of a low-pressure CO2 fixed fire extinguishing system is illuminated. The most probable cause of this condition would be that（）.Aan air leak has developed in the tankBthe tank cooling system has malfunctionedCthe pilot cylinder discharge valve is leakingDan excessive amount of insulation has been installed on the tank and piping
单选题The process of supplying a diesel engine cylinder with air at a pressure greater than atmospheric is called（）.Aengine displacementBsuper-aspiratingCair injectionDsupercharging
单选题The pilot of the plane which flies faster than sound travels does not hear the thunderclaps because______.Athe sound of plane engine travels slower than the planeBthe frequency of the sound altersCthe passage does not mention itDthe pressure decreased when the plane flies in the air
单选题When one cylinder has a lower compression pressure and higher exhaust gas temperature than any of the other engine cylinders, which of the conditions listed will indicated?（）AAdvanced ignitionBClogged air intakeCLeaky exhaust valveDHigh exhaust pressure
单选题Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.Aleaky discharge valves on the LP cylinderBleaky discharge valves on the HP cylinderCinsufficient intercooler coolingDlow ambient air pressure
单选题When using a fuel with a higher than normal sulfur content in an auxiliary diesel engine, you should（）Amaintain higher than normal jacket water temperatureBchange the lube oil more frequently than normalCmaintain a higher air-box temperature than normalDmaintain a higher air-box pressure than normal