Load Variation Effects on Combustion Regimes in A Hydrogen-Diesel Dual Fuel Engine

AbstractThis work presents an experimental study about the impacts of the use of hydrogen as a partial substitution in a direct injection diesel engine. Hydrogen gas was fumigated into the intake manifold of a single cylinder diesel engine to mix with fresh air before entering the combustion chamber of the engine at constant speed with load variation. The homogeneous charges of air-hydrogen mixture were then ignited in the chamber by the main diesel injected. The added hydrogen amounts generated the hydrogen-to-diesel ratios. These affect combustion pressure, heat release rate, and combustion variation in the three regimes investigated, i.e. ignition delay, premixed combustion phase, and mixing-controlled combustion phase as well as the heat release in each combustion phase due to the different hydrogen-to-diesel ratios. The obtained results have shown the reductions in diesel and total fuel consumptions, including exhaust gas emissions when adding hydrogen. These lead the thermal efficiencies to be higher when adding hydrogen. The benefits of this research will be appropriately used in the improvement and development of hydrogen-diesel dual fuel engine and its fuel strategy management in the near future

Reformed Exhaust Gas Recirculation Products of Rapeseed-based Biodiesel: A Chemical Equilibrium Simulation

AbstractThis paper simulates the products from an exhaust gas fuel reforming of rapeseed methyl ester (RME) in comparison with ultra-low sulphur diesel (ULSD). Both types of fuel were also correspondingly used as reformer fuels. In all cases, the reactor inlet temperature was kept constant at 300°C which represents exhaust gas temperature at low load engine condition and is comparable to the actual average exhaust gas temperature. The gas hourly space velocity (GHSV) was set-up at 30,000 h-1 and 45,000 h-1 whereas the latter is a half of typical value for automotive three-way catalytic converters. Different fuel flow rates between 25 and 55 ml×h-1 were tested. The reforming products and temperatures were calculated using an equilibrium model. The results have shown that different engine and reforming fuels affect the produced reformed gasses. Reforming of RME produced less hydrogen compared to the ULSD reforming. The results from simulation were compared with those from experiment at the same condition. At the higher GHSV, an offset between the measured experimental results and the predicted results from the equilibrium model has been found for all conditions tested. For the lower GHSV, the equilibrium model enables a good prediction in reforming yields of hydrogen

The Investigation of CNG Dual-Biodiesel fuel Approach to Address the Performance - Emission Assisted Multipurpose Diesel Engine

AbstractDiesel engines can operate on a variety of the different fuels such as diesel fuel derived from crude oil, natural gas and biodiesel. Nowadays, the price of compress natural gas (CNG) and biodiesel is cheaper than diesel fuel since it is a potential advantage to use a combined CNG and biodiesel for multipurpose diesel engine. The aims of this work were to investigate the efficiency and emission from the multipurpose diesel engine. In the experiments, the fuel used in a combustion chamber was diesel, biodiesel derived from waste cooking oil (B100) and combined B100 and CNG. Effect of the various ratios of CNG (10, 20 and 30%), engine load (25, 50 and 75%) and exhaust gas recirculation (EGR: 0, 10 and 20%) were also investigated. Based on these experiments, the brake thermal efficiency decreased with an increase in CNG ratio. However, the brake thermal efficiency increased with an increase in the engine load. When the CNG ratio in a combustion chamber increased, the hydrocarbon concentration and Smoke number (SN) increased whereas the nitrogen oxide decreased. In term of exhaust gas recirculation (EGR), the use of EGR was not significant effect to brake thermal efficiency for various fuels. However, the increasing of EGR and CNG ratio led to an increase in hydrocarbon, carbon monoxide and Bosch smoke number. It should be noted that the nitrogen oxide decreased with an increase in EGR and CNG ratio

Effect of Injection Timing on the Engine Performance and Exhaust Emissions of a Dual-Fuel Compression Ignition Engine

AbstractThe investigation of available alternative fuel to meet high efficiency and more stringent emission controls for compression ignition engine is very challenge. Di-Methyl Ether (DME) is a very interesting fuel of choice in the evolution of alternative fuel due to the physical and chemical properties that matches with conventional diesel fuel. DME combustion also emits overall low emissions especially, particulate matter (PM). The aims of this study was to demonstrate and evaluate the feasibility of the engine performance improvement with lower fuel consumption by optimising the injection timing. The experimentation was conducted on different injection timing (e.g. 15.5°, 13.5° and 17.5° BTDC (before top dead center)). The retard injection timing (13.5° CAD) at high engine load with EGR addition was able to improve engine performances and reduced the level of NOX emissions however this can be  effect on higher black smoke. Therefore, the optimisation of injection timing for dual fuel (DME additions together with diesel engine) engine is required for different operating conditions

Design and Development of Electronic Fuel Injection Control System Program for Single Cylinder Diesel Engine

This research aimed to evaluate mainly on engine-out emission of a single cylinder diesel engine on two conditions of fuel injection system: mechanically and electronically controlled fuel injection system. The research engine was modified to have changeable fuel injection system. The in-house built PECU was capable of producing 3 consecutive injection pulses. Fuel pressure was adjusted between 500 bar to 1100 bar. Engine with electronically controlled fuel injection system produced less NOx than original engine approximately 50%. However, as the result of higher injection pressure HC and CO were increased due to fuel impingement on combustion chamber

Nano-particle Characteristic Emitted from Gasoline Direct Injection Engine Equipped with Non-Thermal Plasma Device

The impact of non-thermal plasma (NTP) on particulate matter (PM) removal, nitrogen oxide (NOx) reduction, and hydrocarbon species in exhaust gases from gasoline direct injection (GDI) engines using gasoline E20 fuel and a mean effective pressure (IMEP) of 6 bar. The experiments were conducted with an exhaust gas flow rate of 20 L/min, applying high voltage in the range of 0 to 10 kV (2 kV per step) at a frequency of 500 Hz. The results show that NTP reduces PM concentrations, particularly in the nucleation mode (10 nm particles). Maximum PM removal of approximately 83% However, with experimental results, compared to 0 kV, the production of particulate matter Aitken mode increased up to 19 times for a voltage increase of 10 kV, and NOx removal has been at a maximum of about 9.5%, with an energy density of 5 J/L at 10 kV. The effects of NTP on hydrocarbon species such as ethylene, propylene, acetylene, 1.3 butadiene, methane, and ethane have been slightly affected by increased high voltages

Diesel exhaust-gas reforming for H2 addition to an aftertreatment unit

This is the post-print version of the final paper published in Chemical Engineering Journal. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2008 Elsevier B.V.The work described in this paper has been undertaken as part of the design of an integrated system comprising a diesel engine, an exhaust-gas fuel reformer and a NOx aftertreatment unit. The exhaust-gas reformer is used to provide hydrogen-rich reformate to the NOx aftertreatment unit, containing a hydrocarbon-SCR catalyst, in order to improve its NOx reduction activity at low exhaust-gas temperatures. The reformer configuration and operating parameters have been examined in order to optimise the performance of the hydrocarbon-SCR catalyst, which is promoted by the presence of H2 but inhibited by CO. The length of the catalyst bed inside the reformer is a key factor in determining the extent to which the water-gas shift reaction can contribute to the reforming process, and therefore strongly influences the proportions of CO and H2 in the reformate. However, it is also necessary for the reactant ratios at the reformer inlet to be controlled in response to changes in the engine operating conditions. In practice, this means that the rate of fuel addition to the reformer needs to be optimised for different exhaust gas compositions and space velocities

Performance, combustion and emissions of a diesel engine operated with reformed EGR. Comparison of diesel and GTL fuelling

This is the post-print version of the final paper published in Fuel. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2008 Elsevier B.V.In this work, the effects of a standard ultra-low sulphur diesel (ULSD) fuel and a new, ultra-clean synthetic GTL (gas-to-liquid) fuel on the performance, combustion and emissions of a single-cylinder, direct injection, diesel engine were studied under different operating conditions with addition of simulated reformer product gas, referred to as reformed EGR (REGR). For this purpose various levels of REGR of two different compositions were tested. Tests with standard EGR were also carried out for comparison. Experiments were performed at four steady state operating conditions and the brake thermal efficiency, combustion process and engine emission data are presented and discussed. In general, GTL fuel resulted in a higher brake thermal efficiency compared to ULSD but the differences depended on the engine condition and EGR/REGR level and composition. The combustion pattern was significantly modified when the REGR level was increased. Although the extent of the effects of REGR on emissions depended on the engine load, it can be generally concluded that an optimal combination of GTL and REGR significantly improved both NOx and smoke emissions. In some cases, NOx and smoke emission reductions of 75% and 60%, respectively, were achieved compared to operation with ULSD without REGR. This offers a great potential for engine manufacturers to meet the requirements of future emission regulations.Shell Global Solutions UK, the Government of Castilla-La Mancha (Spain) and the Royal Thai Government