Optimizing Common Rail-Injection by Optical Diagnostics in a Transparent Production Type Diesel Engine

International Journal of Engine Research

Zhao

2012

The final, definitive version of this paper has been published in International Journal of Engine Research, Vol 15 Issue 1, September 2012, ppublished by SAGE Publishing, All rights reserved.In order to meet the ever more stringent emission standards, significant efforts have been devoted to the research and development of internal combustion engines. The requirements for more efficient and responsive diesel engines have led to the introduction and implementation of multiple injection strategies. However, the effects of such injection modes on the hydraulic systems, such as the high-pressure pipes and fuel injectors, must be thoroughly examined and compensated for since the combustion and the formation of pollutants in direct-injection engines are directly influenced by the spatial and temporal distribution of the injected fuel within the combustion chamber. This study investigated the hydraulic effects of two-stage fuel injection on diesel combustion and emissions. The fuel-injection system was characterised for all the tested strategies through the measurement of the fuel-injection rate and quantity. In particular, the interaction between the two injection events was identified. The effects of two-stage injection, dwell angle and the interactions between two consecutive injection events on the combustion process and the emissions were investigated in a high-speed direct-injection single-cylinder optical diesel engine using heat-release analysis and high-speed fuel spray and combustion visualisation techniques. The results indicated that the two-stage injection strategy has the potential for simultaneous reduction of nitrogen oxide, soot and unburned hydrocarbon emissions. The results suggested that an optimum fuel quantity in the first injection exists, 0???30%, with which simultaneous reduction of nitrogen oxide, soot and unburned hydrocarbon emissions can be achieved with the added benefits of improved engine performance, fuel economy and combustion noise. However, higher soot emissions were produced, mainly due to the interaction between the two consecutive fuel-injection events whereby the fuel sprays during the second injection were injected into burning regions, as well as reduced soot oxidation due to the continuation of the combustion into the expansion stroke

Section: Introductionmentioning

confidence: 99%

Experimental investigation of hydraulic effects of two-stage fuel injection on fuel-injection systems and diesel combustion in a high-speed optical common-rail diesel engine

International Journal of Engine Research

Zhao

2012

“…Koyanagi et al [9] investigated the effects of engine design and operating parameters, in particular injector stability, spray symmetry, nozzle geometry, injection rate, pilot injection and swirl, in a lightduty single-cylinder optical diesel engine with similar production-type combustion chamber geometry. The authors reported that the pilot-main strategy was characterised by a complete premixed combustion of the fuel injected during the pilot injection, 10% of the total injected fuel quantity in this case.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation into the effects of two-stage injection on fuel injection quantity, combustion and emissions in a high-speed optical common rail diesel engine

Attar

et al. 2013

Fuel

“…The results showed that NOx emission was reduced with the latter injection system in comparison to a conventional injection system, though soot emission was higher, particularly at low loads. Koyanagi et al [4] also used an optical engine equipped with a common rail fuel injection system. They compared the effect of fuel injection rate using a conventional solenoid injector and a piezoelectric injector.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of effects of dwell angle on fuel injection and diesel combustion in a high-speed optical CR diesel engine

Proceedings of the Institution of Mechanical Engineers, Part D:

Zhao

2012

The final, definitive version of this paper has been published in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Vol 227 (2), August 2012, published by SAGE Publishing, All rights reserved.In order to meet the ever-more stringent emission standards, significant efforts have been devoted to the research and development of cleaner internal combustion engines. Diesel combustion and the formation of pollutants are directly influenced by the spatial and temporal distribution of the fuel injected. This study investigated the effects of dwell angle of split injection on diesel combustion and emissions in a high-speed common rail direct injection optical diesel engine. The fuel injection system was characterized through the measurement of the fuel injection rate and quantity for the tested strategies on a fuel injection test rig. In particular, the interaction between the two injection events was identified. Effects of the split injection dwell angle and the interactions of the two consecutive injection events on diesel combustion and exhaust emissions were then investigated in the single cylinder optical engine using heat release analysis and optical diagnostic techniques. The fuel injection process was illuminated by a high repetition copper vapour laser and recorded synchronously by a high speed video camera. The combustion temperature and soot distribution during the combustion process were measured by a recently developed high speed two-colour system. The results indicated that this injection mode has the potential to improve fuel economy and engine performance while substantially reducing the combustion noise, provided that the injection timings are appropriately selected