现代柴油机的应用已经非常普遍了。据权威数字，2006年德国交付的347万辆的新车中，有154万辆是柴油车，与上年相比，柴油车交付数量增加了7.7%。但是，为应对未来不断提高的排放法规，柴油机必须大幅降低自身排放。可控燃烧是非常有效的降低NOX和CO2排放的措施，BERU提供的的带气缸压力传感器的电热塞就是实现可控燃烧的核心部件。

程碑式的技术

排放是决定柴油机能否继续前进的重要因素。举例来说，2009年开始，欧Ⅴ标准开始执行，将柴油机NOX的排放限制在180mg/km。2014年开始，欧Ⅵ标准将开始执行，对应的NOX的排放则是80mg/km。在美国市场，也有类似的越来越严格的排放限制。

这些极高要求的排放标准只能通过技术手段来实现，这一技术方向是使得未经后处理的排放能降到尽可能低，因为NOX后处理装置的转换能力是有限的。对于柴油机部分负荷的运行，优化的燃烧技术可以控制NOX的形成，但优化的燃烧过程必须要实现“闭循环燃烧控制”。

奔驰汽车发动机开发部门负责人Dr. Leopold Mikulic确认了气缸压力传感器的核心作用并指出，为了能建立更精确的闭循环燃烧控制，BERU的带气缸压力传感器的电热塞具有及其重要的意义。无论是柴油机或是汽油机，能探测气缸内工作压力的传感器是能实现更高效更低排放燃烧的核心部件。

实现更低的排放标准

在BERU和AVL双方合作开发的基于气缸压力的燃烧控制中，显示了BERU气缸压力传感器电热塞的巨大应用潜力。在采用了BERU的气缸压力传感器电热塞和AVL CYPRESS控制系统的演示车辆上，在未用后处理的情况下，能够实现比将要实施的欧Ⅵ标准NOX限值更低的排放。但这还不是气缸压力传感器电热塞所能提供的全部，由于可精确地采集气缸的压力，所以能够实现更高的峰值压力，使标准的燃烧过程达到极限而不引起任何问题。这在新一代的小型化高强度的发动机上体现更为明显。而最终的结果是：实现更高的发动机性能，更高的效率。气缸压力传感器电热塞还能补偿各气缸间的燃烧延迟，气缸的平衡从而得变得可行。特别是对于美国市场的宽十六烷值的柴油来说，长期稳定的排放也会随着PSG的应用而得到保证（类似中国的柴油油品）

更多技术优势

BERU的气缸压力传感器电热塞的优势明显：

1. 可实现对于不同燃油质量和喷嘴老化的补偿；

2. 在发动机全寿命周期内能够保证最优的排放控制；

3.可节省NOX后处理装置和空气质量测量装置的成本；

4. 可减少发动机相关的振动和噪声问题；

5. 可使后处理装置小型化和最优化。

有关该产品更多详情请参观E5-E022展台。

To Achieve Optimum Combustion

The diesel is more popular than ever. To maintain this status a reduction in untreated engine emissions is already compulsory due to drastic exhaust limits planned for the future. As a key component of controlled combustion, the BERU PSG is helping to reduce NOX and CO2 emissions.

The future of the diesel has only just begun. Among the 3.47 million brand-new cars delivered in Germany in 2006, 1.54 million vehicles had a diesel engine under the bonnet according to Federal Motor Transport Authority (KBA) statistics. Increase compared with the previous year: 7.7 percent. In 2006, the diesel share of all new vehicles amounted to 44.2 percent. When it came to new registrations of CI engines in 2006, France reached around 1.43 million vehicles (diesel share: 71.4 percent). France is followed by Italy with 1.36 million new diesel cars (diesel share: 58.2 percent) and Spain with 1.02 million vehicles (diesel share: 68.2 percent). The trend is continuing on an upward path everywhere. In the USA, experts are likewise predicting enormous potential  for CI engines. The current study of a leading American market research organization is forecasting a US market share of around 12 percent for diesel drives in cars and light trucks by 2015; worldwide it is then projected to be just under 25 percent.

Milestone in combustion technology

In order for the diesel to increase its popularity still further, today and in the future it must comply with the strictest emissions guidelines. Take the example of Europe: from 2009 Euro 5 limits will apply, reducing the discharge of nitric oxides in diesels to 180 mg/km. From 2014, under Euro 6, only 80mg/km will be permitted by law. In the USA the challenges for engine developers are likewise growing, with the tightening of BIN 8 to BIN 5. Instead of 200 milligrams of nitric oxides per mile, only 70 milligrams will then be allowed.

“These demanding limits can only be achieved technically if the untreated emissions of the diesel engines are already as low as possible”, explains Dipl.-Ing. Hans Houben, Development Director of Ludwigsburg company BERU AG. “Because the realistic conversion level of a nitric oxide after-treatment system is limited”. For the partial load area, according to Houben, alternative combustion methods present themselves. They avoid the area of thermal nitric oxide formation, but are no longer controllable on an “open loop” basis.

“In order to be able to build a closed loop control system and thereby control the combustion processes in the engine even more precisely, the BERU PSG intelligent pressure sensor glow plug is of outstanding importance”. Dr. Leopold Mikulic, Head of Car Engine Development at Mercedes, confirms the key role of cylinder pressure sensors in the trade magazine Automotive Engineer: “Sensors for measuring cylinder pressure are key components in highly efficient and low-emission combustion systems, irrespective of whether they are for diesels or petrol-driven cars”. To this end, the multiple award-winning PSG, featuring the particularly robust heating rod of the BERU ISS diesel instant start system combined with a piezo-resistive sensor, determines the pressure in the combustion chamber which changes rapidly on a cyclical basis and relays it continuously to the engine’s electronics control system.

Euro 6 with no expensive NOX after-treatment

One of the proofs of the enormous potential possessed by the BERU pressure sensor glow plug comes in the form of a cooperation agreement covering applications of cylinder pressure-based combustion control, between BERU AG and Grazer AVL, the world’s largest independent organization for the development of drive systems with combustion engines. Houben: “Using the BERU PSG and the AVL CYPRESS control system in demonstration vehicles, it was possible to achieve low emission combustion design with untreated NOX emissions which are still below the Euro 6 limit currently being discussed”.

For BERU’s Head of Development, the possibilities of the PSG are therefore by no means exhausted. “Thanks to the exact recording of cylinder pressure using the PSG, higher peak pressures can be achieved and thus standard combustion processes can be taken to their limits without causing problems, especially in the new generation of downsizing engines“. Result: higher engine performance, higher efficiency. Houben sees a further benefit of the PSG in the compensation of different ignition delays: “Each cylinder is unique. Thanks to the data provided by the PSG, ignition can be optimized based on cylinder selection. Cylinder balancing is technically feasible, the engine runs like clockwork, cold start and cold running quality is again improved. Particularly also for US applications with a broader dispersion of the cetane number of the fuel, stable long-term emissions control is therefore finally representable”.

Further major innovation potential offered by the BERU PSG:

● effective compensation of different grades of fuel and injector ageing,

● optimum emissions control over the entire service life of the engine,

● possible savings on cost-intensive NOX sensors and air mass measuring devices,

● reduction in engine-dependent vibration and acoustic problems (noise, vibration, harshness, NVH),

● optimum control of torque,

●minimisation and optimisation of exhaust after-treatment.