题目
A large fraction of the heat input to the main engine and auxiliary engines is wasted as a latent heat in the exhaust gases.Smaller but significant fractions are lost via cooling of the jacket water，lube oil，and inlet air.For example，the fractions of heat input of a two-stroke main engine might be 35% to exhaust gases，15% to jacket water，5%to lube oil and 5% to all kinds of coolers.The diesel engine exhaust gas temperature is at least 600℃ at full load，so it is feasible to extract part of its heat.With the installation of the turbochargers on main engines，much waste heat in the exhaust has been used to drive the turbochargers，which increase the inlet density，resulting in a great increase of engine output.The exhaust gases from the turbochargers are still at a high temperature，and it is possible to make further use of the high temperature gases to produce usable steam.For this purpose，exhaust gas boilers have been widely used and waste heat systems have been formed on board. （1）According to the passage，about ____ of the total heat input of a two-stroke main engine is discharged to the exhaust gases.A.one quarterB.one-thirdC.halfD.two-thirds（2）According to the passages，the diesel engine exhaust gas temperature is at least ____ at full load.A.600℃B.400℃C.315℃D.200℃（3）With the installation of the turbocharger on main engine，a great increase of engine output result s from ____ .A.decreased exhaust gas temperatureB.increased inlet air densityC.increased exhaust gas temperatureD.decreased inlet air density（4）In the next paragraph of the passage，which of the following statements may probably be described？ ____ A.n auxiliary boiler.B.A fresh water generator.C.A waste heat boiler.D.A turbocharger.
A large fraction of the heat input to the main engine and auxiliary engines is wasted as a latent heat in the exhaust gases.Smaller but significant fractions are lost via cooling of the jacket water，lube oil，and inlet air.For example，the fractions of heat input of a two-stroke main engine might be 35% to exhaust gases，15% to jacket water，5%to lube oil and 5% to all kinds of coolers.The diesel engine exhaust gas temperature is at least 600℃ at full load，so it is feasible to extract part of its heat.With the installation of the turbochargers on main engines，much waste heat in the exhaust has been used to drive the turbochargers，which increase the inlet density，resulting in a great increase of engine output.The exhaust gases from the turbochargers are still at a high temperature，and it is possible to make further use of the high temperature gases to produce usable steam.For this purpose，exhaust gas boilers have been widely used and waste heat systems have been formed on board.
（1）According to the passage，about ____ of the total heat input of a two-stroke main engine is discharged to the exhaust gases.
A.one quarter
B.one-third
C.half
D.two-thirds
（2）According to the passages，the diesel engine exhaust gas temperature is at least ____ at full load.
A.600℃
B.400℃
C.315℃
D.200℃
（3）With the installation of the turbocharger on main engine，a great increase of engine output result s from ____ .
A.decreased exhaust gas temperature
B.increased inlet air density
C.increased exhaust gas temperature
D.decreased inlet air density
（4）In the next paragraph of the passage，which of the following statements may probably be described？ ____
A.n auxiliary boiler.
B.A fresh water generator.
C.A waste heat boiler.
D.A turbocharger.
（1）According to the passage，about ____ of the total heat input of a two-stroke main engine is discharged to the exhaust gases.
A.one quarter
B.one-third
C.half
D.two-thirds
（2）According to the passages，the diesel engine exhaust gas temperature is at least ____ at full load.
A.600℃
B.400℃
C.315℃
D.200℃
（3）With the installation of the turbocharger on main engine，a great increase of engine output result s from ____ .
A.decreased exhaust gas temperature
B.increased inlet air density
C.increased exhaust gas temperature
D.decreased inlet air density
（4）In the next paragraph of the passage，which of the following statements may probably be described？ ____
A.n auxiliary boiler.
B.A fresh water generator.
C.A waste heat boiler.
D.A turbocharger.
题目解答
答案
（1）细节理解题。根据第三句For example，the fractions of heat input of a two-stroke main engine might be 35% to exhaust gases，15% to jacket water，5%to lube oil and 5% to all kinds of coolers.（例如，一台两冲程主机的热能输入中，35%流失到排气中，15%流失到水套，5%流失到润滑油，5%流失到各种冷却器。） 可知，一台两冲程主机的热能输入中，35%流失到排气中，也就是说，大约有三分之一的热量会被排放到废气中。故选B。
（2）细节理解题。根据第四句The diesel engine exhaust gas temperature is at least 600℃ at full load，so it is feasible to extract part of its heat.（柴油机排气温度在全负荷时至少为600℃，因此可以提取部分热能。）可知，柴油机全负荷时排气温度至少600℃。故选A。
（3）细节理解题。根据第五句With the installation of the turbochargers on main engines，much waste heat in the exhaust has been used to drive the turbochargers，which increase the inlet density，resulting in a great increase of engine output. （安装了主机涡轮增压器后，排气中的大部分废热被用来驱动涡轮增压器，增加进气密度，从而大幅提高了发动机输出功率。）可知，在主机上安装涡轮增压器后，发动机的输出功率大大提高是因为增加入口空气密度。故选B。
（4）推理判断题。根据最后一句For this purpose，exhaust gas boilers have been widely used and waste heat systems have been formed on board.（为此，排气锅炉被广泛应用，船舶上形成了废热系统。）由此可以推断，接下来可能会写排气锅炉。故选C。
（2）细节理解题。根据第四句The diesel engine exhaust gas temperature is at least 600℃ at full load，so it is feasible to extract part of its heat.（柴油机排气温度在全负荷时至少为600℃，因此可以提取部分热能。）可知，柴油机全负荷时排气温度至少600℃。故选A。
（3）细节理解题。根据第五句With the installation of the turbochargers on main engines，much waste heat in the exhaust has been used to drive the turbochargers，which increase the inlet density，resulting in a great increase of engine output. （安装了主机涡轮增压器后，排气中的大部分废热被用来驱动涡轮增压器，增加进气密度，从而大幅提高了发动机输出功率。）可知，在主机上安装涡轮增压器后，发动机的输出功率大大提高是因为增加入口空气密度。故选B。
（4）推理判断题。根据最后一句For this purpose，exhaust gas boilers have been widely used and waste heat systems have been formed on board.（为此，排气锅炉被广泛应用，船舶上形成了废热系统。）由此可以推断，接下来可能会写排气锅炉。故选C。