R.P. Roethlisberger

R.P. Roethlisberger
La Haute Ecole d'Ingénierie et de Gestion du Canton de Vaud | HEIG-VD · Institut of Thermal Engineering

PhD

About

17
Publications
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232
Citations

Publications

Publications (17)
Conference Paper
Full-text available
Today, the energy content of wood chips is determined based on metering of heat delivered by the boiler. Consequently, the wood chip supplier can only bill for the useful heat that the consumer is able to produce with his boiler. The goal of this project was to develop a system able to determine the energy content of wood chips at the time of deliv...
Conference Paper
Full-text available
In order to reduce pollutant emissions, a commercial wood log stove with staged combustion was fitted with an exhaust gas after treatment device based on a metal-based oxidation catalyst coated with platinum and palladium followed by a sintered metal particle filter (both used on diesel internal combustion engines) and a regulated exhaust gas fan f...
Article
Full-text available
La cogénération se définit comme un système très efficace qui produit simultanément de l’électricité (ou de la puissance mécanique) et de la chaleur à partir d’un seul combustible (“combined heat and power”, CHP en anglais). En d’autres termes, l’utilisateur génère à la fois de la puissance et une chaleur exploitable dans nombre de procédés industr...
Article
A DeNO x demonstration system for a diesel engine used in construction machineries and mobile cranes was setup. In preliminary experiments various extruded and coated SCR catalysts were evaluated with and without oxidizing pre-catalyst. The data from stationary tests with two selected catalysts were used to establish various model-based control alg...
Article
DeNOx system comprising a single, highly active SCR catalyst with a catalyst volume of about twice the swept volume of the engine was set up and evaluated at Liebherr Machines Bulle SA in Switzerland. Various control algorithms have been tested with this system. A novel NOx sensor became available for these experiments being used to measure NOx and...
Article
Bei Liebherr Machines Bulle SA wurde ein DeNOx-System für die Entstickung von Dieselmotor-Abgasen mit einen einzigen hochaktiven SCR-Katalysator aufgebaut, dessen Volumen dem doppelten Hubvolumen des Dieselmotors entspricht. An diesem System wurden verschiedene Steuer- und Regelalgorithmen für die Harnstoffdosierung erprobt. Erstmals stand für dies...
Article
Full-text available
The effects and the consequences of transferring the ignition point of the conventional combustion chamber into a small unscavenged prechamber were evaluted through a numerical simulation based on the CFD-code KIVA- 3V. The prechamber flow characteristics at the location of the gap between the spark plug electrodes and in the crank angle period whe...
Article
Full-text available
The operation of the small size cogeneration gas engine (6 cylinders, 122mm bore, 142mm stroke) modified for unscavenged prechamber ignition was experimentally investigated. The objective was to evaluate the potential to reduce the exhaust gas emissions, particulary the CO emissions, below the Swiss limits (NOx and CO emissions: 250 and 650 mg/m3N,...
Article
Full-text available
Gaseous fuels produced, for example, by waste or agricultural by-products fermentation (biogas) can be burned in-situ by cogeneration systems like spark-ignition internal combustion engines. However, the more and more stringent legislation for exhaust gas emissions requires improvement of the combustion process particularly when catalytic after tre...
Article
Full-text available
In a first paper (part I), prechamber ignition in cogeneration natural gas engines has been shown to significantly intensify and accelerate the combustion process, offering a further potential to reduce the exhaust gas emissions while keeping efficiency at a high level. This second part discusses the influence of the engine operating parameters (sp...
Article
Full-text available
The operation of a cogeneration internal combustion engine with unscavenged prechamber ignition was investigated. The objective was to evaluate the potential to reduce the exhaust gas emissions, particularly the CO emissions, without exhaust gas after treatment. The investigation was carried out on a small size gas engine (150kW) and required the d...
Article
Full-text available
Gaseous fuels produced, for example, by waste or agricultural by-products fermentation (biogas) can be burned in-situ by cogeneration systems like spark-ignition internal combustion engines. However, the more and more stringent legislation for exhaust gas emissions requires improvement of the combustion process particularly when catalytic after tre...
Article
Full-text available
The operation of a cogeneration internal combustion engine with unscavenged prechamber ignition was investigated. The objective was to evaluate the potential to reduce the exhaust gas emissions, particularly the CO emissions, below the Swiss limits (NOx and CO emissions: 250 and 650 mg/m3N, 5% O2 , respectively), without exhaust gas after treatment...
Article
Full-text available
In order to determine the origin of the CO emissions from a cogeneration spark ignition engine fuelled with a lean natural gas-air mixture, the influence of several combustion chamber parameters have been measured in detail. In an attempt to interpret the experimental results, the engine process was simulated to dissociate the contribution of the b...
Article
Full-text available
A medium size diesel engine converted to natural gas operation on the Otto principle has been studied under stoichiometric and lean burn operation in order to evaluate the potential to reduce the NOX exhaust gas emissions below the stringent limit prescribed by the Swiss Federal Clean Air Act - 250 mg/mN3, 5 % O2 (at normal (N) conditions, 5 % resi...
Article
Full-text available
The Swiss limit for NOx exhaust gas emissions from decentralised electrical power and heat cogeneration units using stationary I.C. engines operating on natural gas, despite a recent increase from 80 to 250 mg/mN3 (5% O2), remains the most severe in force in the world. The only technology currently able to meet this limit - the use of a stoichiomet...
Article
Full-text available
In the frame of the decentralised electrical power and heat cogeneration with stationary I. C. engines operating on natural gas, the Swiss limit for exhaust gas emissions, with 80 mg/mN3 (5% O2), is the most severe in force on an international level. On the other hand, the only technology able to meet this requirement, with the use of a stoechiomet...

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