Experiments on the influence of intake conditions on local instantaneous heat flux in reciprocating internal combustion engines

[EN] The present study tries to be a contribution for the development of more precise theoretical models for predicting the dissipation of heat through the combustion chamber walls of reciprocating (internal combustion) IC engines. A fast response thermocouple was embedded in the combustion chamber of a single cylinder engine to measure instantaneous wall temperatures. The heat flux was obtained by solving the one-dimensional transient energy equation with transient boundary conditions using the Fast Fourier Transform. The engine was tested under different operating conditions to evaluate the sensitivity of the measurement procedure to variations of three relevant combustion parameters: injection pressure, air temperature and oxygen concentration at the intake. The local heat flux obtained was compared with other relevant parameters that characterize the thermal behaviour of engines, showing, in most of the cases, correlation among them. The results showed that the instantaneous heat flux through the walls and hence the local wall temperatures are strongly affected by the ignition delay and the start of combustion. © 2010 Elsevier Ltd.Desantes, J.; Torregrosa, AJ.; Broatch, A.; Olmeda González, PC. (2011). Experiments on the influence of intake conditions on local instantaneous heat flux in reciprocating internal combustion engines. Energy. 36(1):60-69. doi:10.1016/j.energy.2010.11.011S606936

Characteristics of LPG-diesel dual fuelled engine operated with rapeseed methyl ester and gas-to-liquid diesel fuels

AbstractA Liquefied Petroleum Gas (LPG)-diesel dual fuelled combustion experimental study was carried out to understand the impact of the properties of the direct injection diesel fuels, such as rapeseed methyl ester (RME) and gas-to-liquid (GTL), on combustion characteristics, engine performance and emissions. The experimental results showed that up to 60% of liquid fuel replacement by LPG was reached while keeping engine combustion variability within the acceptable range and obtaining clear benefits in the soot-NOx trade-off. However, the amount of LPG was limited by adverse effects in engine thermal efficiency, HC and CO emissions. LPG–RME showed a good alternative to LPG-diesel dual fuelling, as better engine combustion variability, HC, CO and soot behaviour was obtained when compared to the other liquid fuels, mainly due to its fuel oxygen content. On the other hand, NOx emissions were the highest, but these can be balanced by the application of EGR. LPG–GTL dual fuelling resulted in the highest NOx emissions benefit over a wide range of engine operating conditions. The high cetane number and the absence of aromatic of GTL are the main parameters for the more favourable soot-NOx trade-off compared to LPG–ULSD (ultra low sulphur diesel) dual fuelling

Effects of EGR rate on performance and emissions of a diesel power generator fueled by B7

This paper analyses the impacts of the application of an exhaust gas recirculation (EGR) system on the performance and emissions of a stationary, direct-injection diesel engine operating with diesel oil containing 7% biodiesel (B7). Experiments were carried out in a 49-kW diesel power generator with the adapted EGR system, and engine performance and emissions were evaluated for different load and EGR settings. The results were compared with the engine operating with its original configuration without the EGR system, and revealed a reduction of peak cylinder pressure and fuel conversion efficiency, mainly at high engine loads. The use of EGR caused opposite effects on carbon dioxide (CO2), carbon monoxide (CO) and total hydrocarbons (THC) emissions, depending on load and EGR rate, showing an increase in most situations. The application of EGR consistently reduced oxides of nitrogen (NOX) emissions, reaching a maximum reduction close to 30%. In general, the use of EGR increased CO2, CO and THC emissions at high loads. The use of 7.5% EGR was found to be at an adequate rate to simultaneously reduce CO, THC and NOX emissions at low and moderate loads, without major penalties on CO2 emissions and engine performance

NOx and PM emissions reduction on an automotive HSDI Diesel engine with water-in-diesel emulsion and EGR: an experimental study

National audienc

Experimental study of an automotive Diesel engine efficiency when 4 running under stoichiometric conditions

National audienceIf run under stoichiometric air-fuel ratio a Diesel engine could use a simple three way catalyst for NOx after-treatment instead of complex and expensive devices. This concept of Stoichiometric Diesel Combustion (SDC) has been experimentally tested on a modern automotive Diesel engine. Injection strategy (injection pressure, phasing, with or without pilot, multi-injection) and intake strategy (exhaust gas recirculation rate, swirl level) have been studied, for three operating points. It appears that, for the best strategies, brake thermal efficiency drops between 5 and 10% as compared with conventional lean Diesel. For each operating point, this drop is analysed with energy balance charts, and combustion rate of heat release. In particular the evolutions of combustion efficiency and gross indicated thermal efficiency are studied and it appears that there are some trades-offs between these two parameters. The evolution of particulate emissions and exhaust temperature are also described and commented. Finally, these results are used to propose some hardware modifications to improve SDC engine efficienc

Experimental study of Inlet Manifold Water Injection on a Common Rail HSDI automobile Diesel Engine, compared to EGR with respect to PM and NOx Emissions and Specific Fuel Consumption,

International audienc

Experimental study of intake conditions and injection strategies influence on PM emissions and engine efficiency for stoichiometric Diesel combustion

National audienc

Influence of EGR unequal distribution from cylinder to cylinder on NOx-PM trade-off of a HSDI automotive Diesel engine

National audienc

Simulation study of a ship's engine behaviour running with a periodically immersed exhaust

International audienc