【作者】

Christoph Kendlbacher

【摘要】

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。Large Diesel Engines which fulfill the EPA tier4 final emissions have just entered the market. The EPA deterioration factor tests and the field validation are positively completed and the ramp up is ongoing. Robustness, reliability and durability statistics are currently not available. Field inspections will support the learnings. They will set the targets for further evolutionary improvements on the EPA Tier 4 engines to ensure mature systems. The current publications show following solutions on the market. CRS > 1800 bar +SCR and CRS 2200 bar + EGR and DOC. Due to further combustion optimization we will also see CRS 1600 bar + SCR + DOC in future. All solutions lead to significant cost increase compared to EPA Tier 2 engines. EGR and SCR costs, as well as cooling- and packaging requirements made the application of Tier 4 solutions very complex and cost intensive. Although learning on the EPA Tier 4 systems is not completed already new emission limits are under discussion. A proposal for EU Stage 5 has been published. It shows further significant reductions on PM and NOx emissions. This paper is trying to give an outlook on the requirements for the injection system and the exhaust after treatment. What emissions can be achieved with a 2200 bar CRS on a large high speed engine and is this sufficient to fulfill upcoming emission legislation? The injection system is described and its performance at the emission relevant load points is documented and brought into relation to the emission and fuel consumption results. The injection rate, the spray performance and the spray velocity at the spray hole exit is analyzed in detail. The investigations include engine measurements with a one and two stage turbo charger like setting on a high end single cylinder high speed large engine. Based on the experience of heavy duty on and off highway engines a prediction on the requirements for the injection system and the exhaust after treatment for a high speed LE engine can be given to fulfill future emission legislations. Current EU Stage 4 and EPA Tier 4 heavy duty off highway applications (<560 kW) fulfill already today the emissions limits which are close to future LE (>560 kW) EU Stage 5 limits. EU Stage 4 with 0,4 g/kWh NOx and 0,025 g/kWh PM. EPA Tier 4 with 0,4 g/kWh NOx and 0,02 g/kWh PM. Current on highway emission legislations are on a comparable level, but with additional PM limitation and already applied in service conformity testing. Existing heavy duty solutions and existing LE engine results enable the prediction on possible technologies to fulfill LE EU Stage 5emissions. Solutions which prevent further increase of costs, packaging and complexity are beneficial. Robustness,durability and reliability requirements must be fulfilled with all solutions.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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