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Technical Paper

A Study of the Effects of 30% Biodiesel Fuel on Soot Loading and Regeneration of a Catalytic DPF

2007-07-23
2007-01-2023
Biofuels are a renewable energy source. When used as extenders for transportation fuels, biofuels contribute to the global reduction of Green House Gas and CO2 emissions from the transport sector and to security and independence of energy supply. On a “Well to Wheel” basis they are much more CO2 efficient than conventional fossil fuels. All vehicles currently in circulation in Europe are capable of using 5 % biodiesel. The introduction of higher percentages biodiesel needs new specific standards and vehicle tests validation. The development of vehicles compatible with 30% biodiesel blends in diesel fuel includes the validation of each part of both engine and fuel vehicle systems to guarantee normal operation for the entire life of the vehicle.
Technical Paper

A Validated Numerical Simulation of Diesel Injector Flow Using a VOF Method

2000-10-16
2000-01-2932
Progress in Diesel spray modelling highly depends on a better knowledge of the instantaneous injection velocity and of the hydraulic section at the exit of each injection hole. Additionally a better identification of the mechanisms which cause fragmentation is needed. This necessitates to begin with a precise computation of the two-phase flow which arises due to the presence of cavitation within the injectors. For that aim, a VOF type interface tracking method has been developed and improved (Segment Lagrangian VOF method) which allows to describe numerically the onset and development of cavitation within Diesel injectors. Furthermore, experiments have been performed for validation purpose, on transparent one-hole injectors for high pressure injection conditions. Two different entrance geometries (straight and rounded) and various upstream and downstream pressure levels have been considered.
Technical Paper

Advanced Onboard Fuel Processor for PEM Fuel Cell Vehicles

2006-04-03
2006-01-0216
To reduce greenhouse gas emissions such as CO2, automakers are actively pursuing alternative propulsion systems. Improvements to current engine technology are being investigated along with new power plant technologies. Fuel Cell Vehicles offer an exciting option by producing electric power through a reaction that combines hydrogen and oxygen to make water. However, hydrogen storage onboard vehicles and construction of an expensive hydrogen distribution and fueling infrastructure remain as challenges today. In addition, greenhouse gas emissions from the production of hydrogen must be considered since most hydrogen is currently produced from non-renewable sources. While these issues are being worked on, Renault has chosen to pursue a fuel cell vehicle with a fuel processor that converts gasoline and other liquid fuels to hydrogen onboard the vehicle.
Technical Paper

Advances of Durability of Ceramic Converter Systems

1996-10-01
962372
Governing bodies world-wide are setting increasingly tighter emission standards to help improve air quality. US and Californian LEV/ULEV standards are pace setting, European Stage II legislation has just become effective. In Brazil, the upcoming 1997 standards are also demanding for tighter emission control. The monolithic ceramic honeycomb catalytic converter -for more than the past 20 years- has been a reliable key element in the automotive emission control systems. In order to help meet tightened emission regulation as well to satisfy even more stringent durability requirement, an advanced thinwall ceramic Celcor XT has been developed for increased geometric surface area and reduced backpressure. The product properties as well as FTP and ECE emission and durability test results are being described in this paper. Converter system durability is also determined by robust canning and mounting systems. A durable mounting concept, especially for preconverters, is being described.
Technical Paper

Air Quality and Odors Evaluation for Passengers Compartment

1995-02-01
950016
The paper presents the VALEO and RENAULT approach to study odor problems for passengers compartment. The first part describes the method chosen to form a panel, and the second part presents a vehicle application.
Technical Paper

An Investigation into the Influence of LPG (Autogas) Composition on the Exhaust Emissions and Fuel Consumption of 3 Bi-Fuelled Renault Vehicles

1996-05-01
961170
Studies using a bi-fuelled (autogas/gasoline) Renault Laguna vehicle meeting °the 1996 European exhaust emission legislation has demonstrated that over the European test cycle at 25°C the LPG operated vehicle provides substantial benefits of reduced emissions compared to unleaded reference gasoline. At lower test temperatures (i.e. 5°C) even larger reduction in emissions have been observed. Lower CO (up to 95% at -5°C and 65% at 25°C), HC (90% at -5°C and 40% at 25°C) emissions and lower ozone HC reactivity have been observed and could all offer significant environmental air-quality benefits for LPG. Various autogas mixtures have been tested including 70/30, 30/70 and 49/30/21 (% mass propane / butane / propene). Results show that NOx emissions for this vehicle appear dependent on autogas composition. The two gas mixtures containing only 30% butane gave about 50% more NOx at +25°C than the 70% butane autogas mixture.
Technical Paper

Analysis of the Emission Conversion Performance of Gasoline Particulate Filters Over Lifetime

2019-09-09
2019-24-0156
Gasoline particulate filters (GPF) recently entered the market, and are already regarded a state-of-the-art solution for gasoline exhaust aftertreatment systems to enable EU6d-TEMP fulfilment and beyond. Especially for coated GPF applications, the prognosis of the emission conversion performance over lifetime poses an ambitious challenge, which significantly influences future catalyst diagnosis calibrations. The paper presents key-findings for the different GPF application variants. In the first part, experimental GPF ash loading results are presented. Ash accumulates as thin wall layers and short plugs, but does not penetrate into the wall. However, it suppresses deep bed filtration of soot, initially decreasing the soot-loaded backpressure. For the emission calibration, the non-linear backpressure development complicates the soot load monitoring, eventually leading to compromises between high safety against soot overloading and a low number of active regenerations.
Technical Paper

Comparison between the exhaust particles mass determined by the European regulatory gravimetric method and the mass estimated by ELPI

2005-05-11
2005-01-2147
Electrical Low Pressure Impactor (ELPI) is often employed to measure the particle number and size distribution of internal combustion engines exhaust gas. If appropriate values of particle density are available, the particle mass can be estimated by this method. Exhaust particles of three Euro3 passenger cars (one gasoline operating under stoichiometric conditions, one Diesel and one Diesel equipped with Diesel Particulate Filter) are measured using the current European regulations (gravimetric method on the are New European Driving Cycle) and estimated by ELPI particle number and size distribution. Different values for particle density are used to estimate the particle mass using all ELPI stages or only some of them. The results show that the particle mass estimated by ELPI is well correlated with the mass determined by filters for PM emissions higher than 0.025 g/km. This correlation is not very good at lower emissions.
Journal Article

Computational Fluid Dynamics Calculations of Turbocharger's Bearing Losses

2010-05-05
2010-01-1537
Fuel consumption in internal combustion engines and their associated CO2 emissions have become one of the major issues facing car manufacturers everyday for various reasons: the Kyoto protocol, the upcoming European regulation concerning CO2 emissions requiring emissions of less than 130g CO2/km before 2012, and customer demand. One of the most efficient solutions to reduce fuel consumption is to downsize the engine and increase its specific power and torque by using turbochargers. The engine and the turbocharger have to be chosen carefully and be finely tuned. It is essential to understand and characterise the turbocharger's behaviour precisely and on its whole operating range, especially at low engine speeds. The characteristics at low speed are not provided by manufacturers of turbochargers because compressor maps cannot be achieve on usual test bench.
Journal Article

Control-Oriented Modeling of a LNT-SCR Diesel After-Treatment Architecture

2011-04-12
2011-01-1307
Lean NOx trap (LNT) and Selective Catalytic Reduction catalysts (SCR) are two leading candidates for diesel NOx after-treatment. Each technology exhibits good properties to reduce efficiently diesel NOx emissions in order to match the forthcoming EURO 6 standards. NOx reduction in LNT is made through a two-step process. In normal (lean) mode, diesel engine exhausts NOx is stored into the NOx trap; then when necessary the engine runs rich during limited time to treat the stored NOx. This operating mode has the benefit of using onboard fuel as NOx reducer. But NOx trap solution is restrained by limited active temperature windows. On the other hand, NH₃-SCR catalysts operate in a wider range of temperature and do not contain precious metals. However, NH₃-SCR systems traditionally use urea-water solution as reducing agent, requiring thus additional infrastructure to supply the vehicles with enough reducer. These pros and cons are quite restrictive in classical LNT or NH₃-SCR architecture.
Technical Paper

Corporate Responsibility: Example of Local Environment Public-Private Partnership Project

2003-11-18
2003-01-3708
This paper presents the Clean Air Project for Rio de Janeiro jointly managed by Renault and the City of Rio de Janeiro. This project is one of the results of a regional initiative of the World Bank which aimed to develop local public-private actions in order to improve air quality in major metropolitan regions of Latin America. In that case, the partnership will result in the installation of a model, adapted to the local needs and the use of this model to test scenarios, quantifying the impact in terms of emissions. This partnership represents a new kind of long-lasting relationship between the private sector, aware of its social responsibility and local authorities which tend to foster the development of technical capacity to strengthen their role and awareness in that field and open new possibilities for environment investments. This paper presents this case study from the management and technical standpoint underlining the principal benefits of such a partnership.
Technical Paper

DPF Regeneration-Concept to Avoid Uncontrolled Regeneration During Idle

2004-10-26
2004-01-2657
Significant particulate emission reductions of diesel engines can be achieved using diesel particulate filters (DPFs). Ceramic wall flow filters with a PM efficiency of >90% have proven to be effective components in emission control. The challenge for the application lies with the development and adaptation of a reliable regeneration strategy. The main focus is emission efficiency over the legally required durability periods, as well as over the useful vehicle life. It will be shown, that new DPF systems are characterized by a high degree of integration with the engine management system, to allow for initiation of the regeneration and its control for optimum DPF protection. Using selected cases, the optimum combination and tuning will be demonstrated for successful regenerations, taking into account DPF properties.
Technical Paper

Design Parameters and Product Characteristics for Automotive Converter

1997-12-31
973049
Catalytic converter substrates for automobile emission control have to operate under the hostile conditions of the automotive exhaust. This paper will first discuss the mechanical and physical properties to ensure durable mechanical function of the catalytic substrate and converter system. High temperature mechanical and thermal shock substrate requirements and properties will be discussed. The functionality of a catalytic converter is significantly influenced by the catalytic coating. At the same time, substrate characteristics as will be shown, also effect converter functional parameters like back pressure, light-off and conversion efficiency. The importance of the substrate parameters cell shape, cell density and substrate mass and their effect on thermohydraulic parameters like heat- and mass transfer factors for various cell structures and substrates will be presented.
Journal Article

Development and Validation of a New Zero-Dimensional Semi-Physical NOx Emission Model for a D.I. Diesel Engine Using Simulated Combustion Process

2015-04-14
2015-01-1746
Reducing NOx tailpipe emissions is one of the major challenges when developing automotive Diesel engines which must simultaneously face stricter emission norms and reduce their fuel consumption/CO2 emission. In fact, the engine control system has to manage at the same time the multiple advanced combustion technologies such as high EGR rates, new injection strategies, complex after-treatment devices and sophisticated turbocharging systems implemented in recent diesel engines. In order to limit both the cost and duration of engine control system development, a virtual engine simulator has been developed in the last few years. The platform of this simulator is based on a 0D/1D approach, chosen for its low computational time. The existing simulation tools lead to satisfactory results concerning the combustion phase as well as the air supply system. In this context, the current paper describes the development of a new NOx emission model which is coupled with the combustion model.
Technical Paper

Development of an Improved Gravimetric Method for the Mass Measurement of Diesel Exhaust Gas Particles

2005-05-11
2005-01-2145
The Particulate Measurement Programme (PMP) works on the identification of a method to replace or complete the existing particle mass (PM) measurement method. The French PMP subgroup, composed by IFP, PSA Peugeot-Citroën, Renault and UTAC, proposes an improved gravimetric method for the measurement of emitted particles, and conducted an inter-laboratory test to evaluate its performances. The technical programme is based on tests carried out on a Euro3 Diesel passenger car (PC), tested on the New European Driving Cycle (NEDC). To achieve low particulate matter (PM) emissions, the EGR is disconnected and a paraffinic fuel is used. The regulated pollutants are also measured. It is shown that the multiple filter weighing and a 0.1 μg balance instead of a 1 μg one are not necessary, as the first weighing and the 1 μg balance performances are satisfactory for type-approval purposes.
Technical Paper

Development of an Onboard Fuel Processor for PEM Fuel Cell Vehicles

2004-03-08
2004-01-1473
Reduction of pollutants and greenhouse gas emissions is one of the main objectives of car manufacturers and innovative solutions have to be considered to achieve this goal. Electric vehicles, and in particular Fuel Cell Electric Vehicles, appear to be a promising alternative. Renault is therefore investigating the technical and economic viability of a Fuel Cell Electric Vehicle (FCEV). A basic question of this study is the choice of the fuel that will be used for this kind of vehicle. Liquid fuels such as gasoline, diesel, naphtha, and gas-to-liquid can be a bridge for the introduction of fuel cell technologies while hydrogen infrastructure and storage are investigated. Therefore, multi-fuel Fuel Processor Systems that can convert liquid fuels to hydrogen while meeting automotive constraints are desired. Renault and Nuvera have joined forces to tackle this issue in a 3-year program where the objective is to develop and to integrate a Fuel Processor System (FPS) on a vehicle.
Technical Paper

DuraTrap® AT Particulate Filter for Passenger Car Applications with EU5/BS5 Emissions Legislation

2011-01-19
2011-26-0037
Upcoming EU5 and expected emissions legislation BS5 in India in combination with efforts to optimize the overall fuel economy has created new challenges in the development of aftertreatment systems for passenger cars equipped with diesel engines. Since EU5 and BS5 emissions legislation will strongly be focused on the reduction of particulate matter it is likely that all vehicle applications will need aftertreatment systems with diesel particulate filters. High filtration efficiency combined with a high resistance to thermo-mechanical stress is a strong requirement for diesel particulate filters to meet EU5 and BS5 emission legislation. Besides those requirements the backpressure of particulate filters has to be considered since backpressure is also related to fuel economy and therefore CO₂ emissions.
Technical Paper

Effect of Flow Distribution on Emissions Performance of Catalytic Converters

1998-02-23
980936
The emissions performance of catalytic converters under different conditions of flow distribution was investigated. Computational Fluid Dynamics methods were utilised to model the maldistribution effects of different inlet cones. The effects of maldistribution on ageing, light-off and conversion were investigated using steady state tests on an engine bench. Emission testing was also conducted on a vehicle throughout ECE and EUDC test cycles. Maldistribution was found to have a significant effect on the efficiency of the catalyst during the early stages of the ECE cycle for both fresh and aged catalysts. The effects were less significant over later stages of the ECE cycle and throughout the EUDC except NOx where maldistribution did have an effect on the conversion at higher flow rates during the later stages of the test.
Journal Article

Effects of Methane/Hydrogen Blends On Engine Operation: Experimental And Numerical Investigation of Different Combustion Modes

2010-10-25
2010-01-2165
The introduction of alternative fuels is crucial to limit greenhouse gases. CNG is regarded as one of the most promising clean fuels given its worldwide availability, its low price and its intrinsic properties (high knocking resistance, low carbon content...). One way to optimize dedicated natural gas engines is to improve the CNG slow burning velocity compared to gasoline fuel and allow lean burn combustion mode. Besides optimization of the combustion chamber design, hydrogen addition to CNG is a promising solution to boost the combustion thanks to its fast burning rate, its wide flammability limits and its low quenching gap. This paper presents an investigation of different methane/hydrogen blends between 0% and 40 vol. % hydrogen ratio for three different combustion modes: stoichiometric, lean-burn and stoichiometric with EGR.
Technical Paper

Energy Management of a High Efficiency Hybrid Electric Automatic Transmission

2010-04-12
2010-01-1311
The energy management of a hybrid vehicle defines the vehicle power flow that minimizes fuel consumption and exhaust emissions. In a combined hybrid the complex architecture requires a multi-input control from the energy management. A classic optimal control obtained with dynamic programming shows that thanks to the high efficiency hybrid electric variable transmission, energy losses come mainly from the internal combustion engine. This paper therefore proposes a sub-optimal control based on the maximization of the engine efficiency that avoids multi-input control. This strategy achieves two aims: enhanced performances in terms of fuel economy and a reduction of computational time.
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