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Technical Paper

HCCI Combustion of Natural Gas and Hydrogen Enriched Natural Gas Combustion Control by Early Direct Injection of Diesel Oil and RME

Natural gas and hydrogen enriched natural gas has been tested as fuels together with diesel oil and RME in a single cylinder Scania research engine. The gas was introduced as port injection while the diesel was introduced as early direct injection. Because the gas was premixed with air before combustion and the diesel was injected early in the compression stroke, the engine ran close to HCCI mode. However, a more precise description of the combustion would be PPC (Partially Premixed Combustion) as the diesel oil was not expected to be totally premixed. The experiments revealed that the combustion phasing could successfully be controlled by the amount of diesel oil injected for loads between 3.5 and 7.5 bar IMEPg at 1200 rpm. For a given combustion phasing, the hydrogen was not found to influence the required amount of diesel noticeable. However, a large difference between the RME and diesel oil could be seen by the necessity to inject more RME to obtain the same combustion phasing.
Technical Paper

Ignition and Combustion Characterization of Hydrogen/Methane Mixtures by Visualization in a Rapid Compression Machine (RCM)

Experiments has been carried out on a hydraulically actuated rapid compression machine (RCM) under engine like condition using both pure methane and methane with 5 and 30 vol% hydrogen addition with a wide range of excess air ratios (1.0–2.2) for spark ignition (SI) mode. The RCM has a variable compression ratio, charge air preheating and control of cylinder block temperature, allowing both spark ignition and compression ignition without any modifications other than adjustments of the control system. Cylinder pressure and volume recordings were performed. The ignition and early combustion was visualized by a schlieren optical system and a high speed video camera at a rate of 10 000 frames per second. Flame size, and hence the apparent flame propagation velocity is found from the schlieren images, but the images are also used to investigate flame morphology for the different gas mixtures and excess air ratios studied.
Technical Paper

Influence of Ethanol Blend Addition on Compression Ignition Engine Performance and Emissions Operated with Diesel and Jatropha Methyl Ester

The world is looking for an alternate fuel to replace the existing petroleum based products due to the depletion of natural resources and it has been projected for future unavailability and fluctuation of oil price in an international market. The EU directive targets 20% of all fuel should be from bio-fuels by 2020. There is a need to improve performance and emission levels in Compression Ignition (CI) or Spark Ignition (SI) engines to comply with stricter automotive norms and regulations due to the global warming issues. This research work is influenced by these factors and is expected to motivate the governing bodies to implement directives with higher bio fuel blends. In this context, a four stroke, single cylinder naturally aspirated (NA) direct injection (DI) diesel engine with 8 BHP @ 1500 rpm coupled with water cooled eddy current dynamometer was used for the experiments.
Technical Paper

Study of Particulate Matter-, NOx- and Hydrocarbon Emissions from a Diesel Engine Fueled with Diesel Oil and Biodiesel with Fumigation of Hydrogen, Methane and Propane

To investigate possibilities for reduction of particulate matter emission from diesel engines, experiments with hydrogen, methane and propane mixed to the inlet air were performed in a Euro 2 Scania diesel engine. The base fuels were marine gas oil (MGO, a diesel oil quality) and biodiesel (80 vol% rape seed methyl ester and 20 vol% soy bean methyl ester). Up to 40 % of the fuel energy was replaced by gas at three different load conditions. The emission of particulate matter (PM) was evaluated through particle mass measurements as well as filter smoke number (FSN) unit. The biodiesel resulted in higher PM emissions at low load, but considerably lower PM emissions at high load compared to MGO. The FSN was much lower for biodiesel than for MGO at all loads. Fumigation was not found to be exclusively advantageous with respect to PM emission.