求高手翻译，有用，非高手别来

Question

Older, naturally aspirated diesel engines can use only about 70-80 percent of the fuel employed by a gasoline engine with the same swept volume and still avoid black smoke
In diesel engines, the utilization factor (the ability to have smoke-free combustion) varies with the combustion system. For example, the diesel engine featuring a precombusiton chamber system, or indirect injection (IDI), has a utilization value of about 80 percent. The earlier naturally aspirated direct-injection system has a value of about 70-80 percent. The turbocharged direct-injection (DI) system has values of approximately 50-70 percent
The utilization percentage of light-duty diesel engines with direct injection has been improved upon greatly with recent designs. This is the result of advanced combustion chamber technology and electronic controls along with the need to limit tailpipe emissions.
An IDI system sprays the fuel into a small precombustion chamber where the ignition occurs and then spreads out into the main combustion chamber. In contrast, a DI engine has no prechamber. Due to the differences in pressure rise, combustion chamber shape, and burn speed with an IDI versus a DI design, the combustion sound becomes unique. To a trained diesel enthusiast, each combustion chamber will produce a unique noise
Interestingly, the latest version of the GM Duramax has a slightly lower compression ratio to limit the noise generation of this already extremely quiet engine
The compression ratio of a diesel engine is usually indicative of the combustion chamber design. Due to an increased surface-to-volume ratio and its inherent negative impact on thermal efficiency, an IDI design will employ a higher static compression ratio of usually 20:1 or more. In contrast, a DI diesel has less combustion chamber surface volume, so a compression ratio of approximately 15:1 to 17:1 is sufficient. In addition, an IDI application would depend more on forced induction to clean up the exhaust over a DI engine.
Since any Otto cycle engine's output is dependent on the amount of air the pistons can pump, high rpm are required to produce horsepower. The higher the rpm, the greater the potential for horsepower. This is due, in part, to the definition of horsepower being work over time
The quicker the engine can do the work, the more horsepower it has. A naturally aspirated diesel is limited in power per cubic inch simply because the burn rate of diesel fuel is very slow when compared to gasoline. Thus, by nature of the chemical composition of the fuel, the diesel engine is slow to rev and has limited maximum rpm. For this reason, the diesel engine responds favorably to forced induction through turbocharging or supercharging
（and an extremely rich ratio is very inefficient. The mixture is supplied to the gasoline engine by a carburetor or fuel injectors in the manifold and is well mixed and nearly homogeneous.）

Answer 1

相比之下，同样活塞排量的旧式自吸气柴油机所用的燃油量只是汽油机的70%到80%，并且还能够避免黑烟产生。

就柴油机来说，它的利用效率（也就是“无烟燃烧性能”）会根据燃烧系统的不同而有所变化。例如，柴油机都有一个特色，就是它的预燃室系统或是说间接喷射功能（IDI），利用率都可达80%左右；而早期的自吸式柴油机，这种利用率多在70%—80%之间。而对于有直喷式涡轮增压系统（DI）的内燃机，这种利用率只有大约50%—70%。

采用最新设计的轻型直喷式柴油机在很多方面都得到了很大的改进，而这种改进，是先进的燃烧室技术和电控技术的应用以及人们对尾气排放限制的需求而产生的必然结果。

间接喷射系统会把燃油喷入一个小型的预燃室，小预燃室内产生点火，然后火苗会进入到大预燃室内。而相反，直喷式发动机却没有预燃室。由于间接喷射式发动机和直喷式发动机在增压速度、燃烧室形状、以及燃烧速度方面存在差异，间接喷射式发动机的响声很特别，尤其是对一个专业的柴油机爱好者来说，间接喷射式发动机每个燃烧室的响声都是不一样的。

通用公司出的Duramax型柴油机运行的时候，可以说是异常地“安静”，而有趣的是， 在Duramax系列的最新版本中，他们又采用了更低的压缩比，来“限制”柴油机运行时产生的噪音。

柴油机的压缩比通常都会体现它的燃烧室设计。由于表面积体积比的增加以及在热效率方面固有的负面影响，间接喷射型柴油机通常采用更高的静态压缩比，这个比值一般为20:1，甚至更高。相反，直喷型柴油机的表面积体积比通常要小一些，这样，直喷型的静态压缩比达到15:1或者17:1就足够了。此外，相比直喷型，间接型喷射柴油机在汽车尾气的净化方面，对强制增压进气系统的依赖性要更高。

任何四冲程柴油机的输出功率都是由活塞的吸气量决定的，这就需要更高的转速产生马力；转速越高，产生的马力就越大。从某种成都上说，这是由于人们对于“马力”定义的理解，而产生了这种认识。

发动机产生动力的时间越快，它的马力就越大，而自吸式柴油每立方英寸燃油的功率是有限的。原因很简单，相比于汽油发动机，柴油的燃烧率要慢得多。受燃料化学成分自然特性所限，柴油机的转速要慢，而最大转速也很有限。由于这些原因，多数柴油机用涡轮增压或强制进气装置。

（如果采用过大的表面积体积比值，效率反而特别的差；混合燃料可以用在汽油机上，汽油机在进气歧管处有一个化油器或燃油喷射器装置，混合燃料会被充分混合，几达均匀。）

（我不是高手，但希望能帮到你）

Answer 2

用翻译器追问

汗，翻译器翻译的一点都不通顺