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Technical Paper

Innovative Ultra-low NOx Controlled Auto-Ignition Combustion Process for Gasoline Engines: the 4-SPACE Project

2000-06-19
2000-01-1837
The purpose of the 4-SPACE (4-Stroke Powered gasoline Auto-ignition Controlled combustion Engine) industrial research project is to research and develop an innovative controlled auto-ignition combustion process for lean burn automotive gasoline 4-stroke engines application. The engine concepts to be developed could have the potential to replace the existing stoichiometric / 3-way catalyst automotive spark ignition 4-stroke engines by offering the potential to meet the most stringent EURO 4 emissions limits in the year 2005 without requiring DeNOx catalyst technology. A reduction of fuel consumption and therefore of corresponding CO2 emissions of 15 to 20% in average urban conditions of use, is expected for the « 4-SPACE » lean burn 4-stroke engine with additional reduction of CO emissions.
Technical Paper

Direct In-cylinder CO2 Measurements of Residual Gas in a GDI Engine for Model Validation and HCCI Combustion Development

2013-04-08
2013-01-1654
An accurate prediction of residual burned gas within the combustion chamber is important to quantify for development of modern engines, especially so for those with internally recycled burned gases and HCCI operations. A wall-guided GDI engine has been fitted with an in-cylinder sampling probe attached to a fast response NDIR analyser to measure in-situ the cycle-by-cycle trapped residual gas. The results have been compared with a model which predicts the trapped residual gas fraction based on heat release rate calculated from the cylinder pressure data and other factors. The inlet and exhaust valve timings were varied to produce a range of Residual Gas Fraction (RGF) conditions and the results were compared between the actual measured CO2 values and those predicted by the model, which shows that the RGF value derived from the exhaust gas temperature and pressure measurement at EVC is consistently overestimated by 5% over those based on the CO2 concentrations.
Technical Paper

Combustion and Emission Characteristics of a HCCI Engine Fuelled with Different n-Butanol-Gasoline Blends

2014-10-13
2014-01-2668
Biobutanol, i.e. n-butanol, as a second generation bio-derived alternative fuel of internal combustion engines, can facilitate the energy diversification in transportation and reduce carbon dioxide (CO2) emissions from engines and vehicles. However, the majority of research was conducted on spark-ignition engines fuelled with n-butanol and its blend with gasoline. A few investigations were focused on the combustion and exhaust emission characteristics of homogeneous charge compression ignition (HCCI) engines fuelled with n-butanol-gasoline blends. In this study, experiments were conducted in a single cylinder four stroke port fuel injection HCCI engine with fully variable valve lift and timing mechanisms on both the intake and exhaust valves. HCCI combustion was achieved by employing the negative valve overlap (NVO) strategy while being fueled with gasoline (Bu0), n-butanol (Bu100) and their blends containing 30% n-butanol by volume (Bu30).
Technical Paper

The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Disesel Engine Emissions - Part 4: Effects of Carbon Dioxide and Water Vapour

1997-05-01
971660
This paper deals with the effects on diesel engine combustion and emissions of carbon dioxide and water vapour the two main constituents of EGR. It concludes the work covered in Parts 1, 2, and 3 of this series of papers. A comparison is presented of the different effects that each of these constituents has on combustion and emissions. The comparison showed that the dilution effect was the most significant one. Furthermore, the dilution effect for carbon dioxide is higher than that for water vapour because EGR has roughly twice as much carbon dioxide than water vapour. On the other hand, the water vapour had a higher thermal effect in comparison to that of carbon dioxide due to the higher specific heat capacity of water vapour. The chemical effect of carbon dioxide was, generally, higher than that of water vapour.
Technical Paper

The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Diesel Engine Emissions - Part 2: Effects of Carbon Dioxide

1996-05-01
961167
This is the second of a series of papers on how exhaust gas recirculation (EGR) affects diesel engine combustion and emissions. It concentrates on the effects of carbon dioxide (CO2) which is a principal constituent of EGR. Results are presented from a number of tests during which the nitrogen or oxygen in the engine inlet air was progressively replaced by CO2 and/or inert gases, whilst the engine speed, fuelling rate, injection timing, inlet charge total mass rate and inlet charge temperature were kept constant. In one set of tests, some of the nitrogen in the inlet air was progressively replaced by a carefully controlled mixture of CO2 and argon. This ensured that the added gas mixture had equal specific heat capacity to that of the nitrogen being replaced. Thus, the effects of dissociated CO2 on combustion and emissions could be isolated and quantified (chemical effect).
Technical Paper

The Dilution, Chemical, and Thermal Effects of Exhaust Gas Recirculation on Diesel Engine Emissions - Part 1: Effect of Reducing Inlet Charge Oxygen

1996-05-01
961165
This is a first of a series of papers describing how the replacement of some of the inlet air with EGR modifies the diesel combustion process and thereby affects the exhaust emissions. This paper deals with only the reduction of oxygen in the inlet charge to the engine (dilution effect). The oxygen in the inlet charge to a direct injection diesel engine was progressively replaced by inert gases, whilst the engine speed, fuelling rate, injection timing, total mass and the specific heat capacity of the inlet charge were kept constant. The use of inert gases for oxygen replacement, rather than carbon dioxide (CO2) or water vapour normally found in EGR, ensured that the effects on combustion of dissociation of these species were excluded. In addition, the effects of oxygen replacement on ignition delay were isolated and quantified.
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