The old motor roars back
老马达焕新姿
Aug 14th 2008
From The Economist print edition
The internal combustion engine is more than 100 years old, but it still has a future
一百多年历史的内燃机仍有好前景
Alamy
SMALL cars sometimes struggle to climb steep hills. But a converted Chevrolet Lacetti has something special to help it along. Instead of having to keep changing down and revving harder to ascend a winding Alpine-type test track, the engine can cruise almost to the summit in top gear. This is because the car benefits from one of the developments that in these more economical and greener times promises to give the petrol engine a new lease of life.
小型车有时在爬陡坡时会显得相当吃力。不过一辆改装过的雪佛兰Lacetti已经解决了这个问题。在一个陡峭的测试车道上，不用低档高转速，它一样轻松自如，甚至在最高档位下它的发动机仍然能够进入巅峰状态。这是因为这辆车受益于一项改良技术，在节能环保兼顾的前提下，给了汽油发动机以新生。
Old technologies have a habit of fighting back when new ones come along. This is not surprising because they often have an enormous amount of design, engineering and production knowledge invested in them―especially so in the case of car engines. So new hybrid systems, fuel cells and electric motors will be chasing a moving target. The internal combustion engine will be getting better too.
老技术总习惯于在新技术诞生的威胁下给以有力回击。这不令人惊讶，因为老东西常常有强大的后盾，包括大量的设计储备、工程技术已经生产知识，统统可以投入到改进中来――这一点在汽车发动机领域尤其明显。所以，新混合动力系统、燃料电池以及电动马达将面对一个并非一成不变的对手。内燃机也将变得更好。
The Lacetti is just one example. It gets its extra oomph from a supercharger forcing more air into the combustion chambers of its engine. This is an old idea that used to speed up 1920s racing cars, like "blower" Bentleys. But their engines tended not to last very long. With stronger engines, superchargers have been staging a comeback in big cars. The one in the Lacetti is different: it is a dual-speed supercharger that provides its highest boost at low speeds. This gives the car a huge 40% increase in torque, or pulling power.
Lacetti只是其中一例。它的出色表现来自一个增压器，它推送更多的空气进入内燃机的燃烧室。这是一项古老的创意，早在上世纪20年代就被用来给宾利"风箱"这样的赛车提速。不过这类发动机改良趋势并没有延续很久。增压器后来仅被使用在一些大型车的高功率马达上面。Lacetti上面使用的有一些不同：它是一个双速增压器，即便在低速下也可以高频率运转。这能够提升车辆的扭力（或推力）高达40%。
The car was fitted with the device by its developer, Antonov Automotive Technologies, a British company. The supercharger is purely mechanical and uses planetary gears to change speed. Antonov reckons that it could be used to reduce the size of a car's engine by up to 50%―so it would use less fuel and produce fewer CO2 emissions, but still provide good performance.
这部车配备的增压装置的研发者，是一家叫安东诺夫汽车技术的英国公司。这个增压器完全采用机械技术运转，并通过一组行星齿轮来实现变速。安东诺夫估计这个装置能够把汽车引擎的尺寸缩小达50%――在提供良好性能的前提下，能够减少燃料消耗和二氧化碳排放。
Car engines (racing cars aside) have long been a compromise between efficiency, power and durability. Greater flexibility has come with fuel injectors, which can metre fuel more precisely than carburettors, and variable-valve control, which can optimise the opening and closing of inlet and exhaust valves to produce more power when accelerating or greater economy when dawdling around town. The same systems are also used in some big and thirsty V8 and V6 engines to shut down a few cylinders when driving slowly.
汽车引擎（不包括赛车）一直以来都在效能、功率和使用寿命之间采取着折中的方案。重要改进来自于电喷系统，它能比化油器更精确地控制燃料的喷射；以及可变气门系统，它能够优化发动机的进气和排起阀门的开启，让车子在加速时更有力而在低速运行时更省油。同样的系统也用在像V8以及V6等大型喝油引擎上，实现在低速行驶的时候，部分气缸关闭，以节约燃料。
Now engineers are taking these developments much further. The e-Valve system developed by Valeo, a French automotive supplier, uses electromagnetic controls to open and shut valves instead of pushrods operated by a camshaft. As each valve can be operated independent of any other, all sorts of tricks become possible, including shutting down cylinders and switching temporarily from the traditional four-stroke Otto cycle (as developed by Nicolaus Otto, a German engineer in 1876) to a type of Atkinson cycle (an ultra-lean system invented as a rival in 1882 by James Atkinson, a British engineer, but which suffered from a lack of power). The Toyota Prius already uses a form of Atkinson cycle for the petrol engine that operates alongside an electric motor in its hybrid system.
如今，工程师们在类似的改进方面走得更远。一个法国的汽车配件商Valeo开发出一种称作e-阀的系统。它使用电磁控制气门的开关，而非传统的曲轴连杆。它可以独立控制单个气门的开阖，不与其他的联动。这就使得很多操作成为可能，包括关闭气缸，以及从一个四冲程的Otto模式（德国工程师Nicolaus Otto于1876年改进）临时切换到Atkinson工作模式（英国工程师James Atkinson于1882年作为Otto模式竞争者发明，一种稀油系统，最大缺点是动力不足）。丰田普锐斯的混合动力系统中已经使用了一种Atkinson模式的发动机与电力引擎协同工作。
Valeo reckons that on average their e-Valve system can cut fuel consumption and CO2 emissions in a car by up to 20%. It could also be used to make three- and two-cylinder engines that run efficiently and smoothly. These tiny engines could power small cars directly, combine with electric motors in hybrids or work as "get-you-home" engines or range-extending generators in plug-in electric cars.
Valeo估计平均下来，他们的e-阀系统可以减少高达20%油耗和二氧化碳排放量。它同样可以应用到3缸和2缸的发动机上面，确保它们高效而平稳地运行。这些微型引擎可以直接驱动小型车，也可以和电动马达一道，使用在混合动力系统中，或者与类似"带你回家"引擎或内置发电机一起用到电动汽车上面。
Fiat is investing heavily in smaller engines with its new valve-control system, Multiair. This uses hydraulics and electronics to optimise valve settings. When combined with a turbocharger (a supercharger driven by exhaust gases), Fiat engineers talk of producing a "downsized" two-cylinder engine that performs like a bigger four-cylinder one, but with fuel savings of some 20%. Fiat is expected to start using Multiair engines in its cars in a year or so.
菲亚特在开发一款Multiair的小型发动机上投入巨资，它有一个全新的阀门控制系统。它使用液压和电子技术优化气门调整。和涡轮系统（一种尾气驱动的增压器）协同工作，按菲亚特工程师的说法，一个小尺寸的两缸发动机可以提供和大一号四缸发动机同样的性能，而且节油大约20%。菲亚特预计大约一年内开始把Multiair发动机装配到它的汽车上。
Using a combination of variable valve-control, fuel injection and turbocharging, Daimler is developing an entirely new type of engine. It can switch between operating as a petrol engine, with agility and power, to operating as a diesel, with economy and torque. The DiesOtto engine, as Daimler has called it, starts as a petrol engine with spark plugs igniting the mixture of fuel and air in its cylinders, and remains as a petrol engine when high performance is needed. But at low and medium speeds the engine switches into diesel mode, in which the fuel is ignited by compression and heat alone. A 1.8-litre four-cylinder test version of DiesOtto fitted to a prototype Mercedes S-class saloon produced plenty of power, but also returned an average fuel consumption of 5.3 litres per 100km (equivalent in America to 44.4mpg)―extremely good for a such a big car. The vehicle's emissions were also lower.
结合应用可变气门，喷油系统以及涡轮技术，戴姆勒正在开发一种新型引擎。它可以在汽油机模式和柴油机模式之间切换，结合了汽油机的灵敏和高性能，以及柴油机的经济和高扭力的双重优点。戴姆勒称作DiesOtto的发动机，启动时是一款使用火花塞点火引燃气缸内汽油与空气混合气体的汽油发动机，并在要求高性能的场合保持汽油发动机模式。然而，当车辆行驶在中低速时，发动机则切换到柴油模式，这时燃料依靠压缩热能点燃工作。一台1.8升的DiesOtto发动机装配在了一部梅赛德斯奔驰S系轿车原型车上面，在提供足够动力的同时，油耗仅百公里5.3升（相当于每加仑44.4英里）――对于这样一辆大型轿车来说，这个成绩非常不错。同时车辆的排放也低很多。
In a similar vein, Ricardo, another British automotive-engineering company, has been working with a group of partners on an engine that can switch from four-stroke to two-stroke running. Two-stroke engines can provide very high levels of torque. Ricardo reckons such an engine could not only improve fuel economy by 27% over a traditional engine but also greatly reduce its size and complexity. And because small engines take up less space in a car, that means there will be more room for occupants, inviting more innovative designs.
出于类似的努力，另一家英国汽车工程公司Ricardo，也在和一群合作者开发一种可以在四冲程和二冲程工作模式之间切换的发动机。二冲程发动机能提供相当高水平的扭力。Ricardo估计这样一款发动机不仅可以做到比传统发动机节油27%，而且可以大大减少发动机的尺寸和复杂度。加上小引擎占用的空间更小，意味着乘用空间会变得更大，使更多的创新设计成为可能。
By putting all these technologies together, small cars capable of breaking the 100mpg barrier will become possible. Getting more than 80mpg from some small diesel-powered cars is already feasible―with a very light foot on the accelerator. Indeed, according to Edmunds.com, an automotive-information service, when you count the overall costs of owning a car, only one hybrid in America, the Honda Civic Hybrid, gets into the top ten of the least expensive vehicles to run, with fuel prices at $5 a gallon. It may be old hat, but the internal combustion engine still has a lot of mileage in it.
把所有这些技术结合起来，一辆小车打破每加仑100英里有望成为可能。一些小型柴油车已经创造了超过每加仑80英里的行驶记录――通过轻踩油门。现实是，按照汽车信息服务网站Edmunds.com的统计，如果用总成本来衡量一辆汽车的话，仅有美国销售的一辆混合动力车，本田思域混合动力，按每加仑5美元的价格计算，进入了最具性价比汽车前十名。尽管显得有点老气横秋，但内燃机的前景依旧光明。
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