【作者】

Marko Pueschel,Bert Buchholz,Christian Fink

【摘要】

论文已在中国上海举行的第27届CIMAC大会上发表。论文的版权归CIMAC所有。 With introduction of IMO Tier ll in 2016 the marine diesel engine technology faces a radical change. The lMO Tier ll requires nitric oxide(NOx) reductions of 75 % compared to the current level(IMOTier l1). In connection with the stringent NOx reductions massive sulfur oxide(SOx) reductions will be introduced stepwise ti 2015. In light of this, the potential of exhaust gas recirculation (EGR) to fulfill the IMO Tier lll NOx limits at medium-speed marine diesel engines is systematically analyzed. The targetsaredefined by a NO, emissions level of 2 g/kWh, invisible smoke and minimum fuel consumption penalty.The analyses are carried out at a six-cylinder mediumspeed test engine with 1,000 kW output @ 1000 rpm.The research engine is equipped with a cooled EGR system,a common-rail injection system and a programmable engine control unit. The CR injectors are solenoid-operated and allow multiple injections. Systematic variations of EGR rate, injection pressure andinjection timing were carried out and the results regarding combustion process, NO, and soot emissions as well as fuel consumption are presented. The results show, that significant EGR rates are necessary, to obtain NO,-reduction rates as required for IMO Tier lll compliance. These high EGR rates result in un-wanted and unacceptable soot emission levels even at increased injection pressures. To reduce these soot emissions, post-injection strategies were analyzed at the medium-speed test engine. Post-injection proved to be an efficient soot reduction measure in on-road diesel engine. The effect of different post-injections on the soot emissions is shown. Based on the results the soot emission reduction potential of post-injections at marine medium-speed diesel engines is outlined and the requirements for a successful implementation of post-injection strategies are discussed. The application of post-injections requires detailed information on the dynamic behavior of the common-railsystem and especially on the CR-injectors applied. Due to this, the dynamics of the CR injectors in case of post-injections were established at an injection rate analyzer and the findings are discussed. The functionality of the CR injectors at the test engine is monitored by measurements of the current feed signal and the injection pressure at the injector inlet. Finally, the preconditions for a successful application of EGR at medium-speed ma-rine diesel engines are summarized. The use of EGR not only challenges the injection(rail pressure, postinjections), charging and the cooling system(EGR, charge air) but also the engine control system.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

2

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