Your Selections

Schmidt, Stephan
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Simulation Analysis of the Scavenging Process of a Uniflow and Loop Scavenging Concept

Institute of Internal Combustion Engines and Thermodynamics,-Stefan Sturm, Michael Lang, Stephan Schmidt
  • Technical Paper
  • 2019-32-0549
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
The two-stroke engine, as a today unconventional concept in automotive applications, has a great potential for a relaunch in the fast-growing market of Plugin Hybrid Electric Vehicle (PHEV) or Range Extender Electric Vehicle (REX) [2, 3, 4, 8, 9]. An efficient scavenging to remove the in-cylinder burnt gases and to fill the cylinder with fresh charge, performed at the same time is one of the major challenges, as losses of fresh air and fuel towards the exhaust line should be avoided when operating a lambda = 1 concept necessary for a 3-way catalyst aftertreatment system.A prior study [1] of different gas exchange designs for two-stroke engines concludes that two possible concepts cover this purpose. In this paper, 3D-CFD simulation is used to compare these two different scavenging concepts, a uniflow and a loop scavenging type with control elements for the gas exchange process. As boundary conditions, it is assumed that both concept types have nearly the same displacement, are used with an external scavenging blower and have a lubrication system like a conventional oil sump…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Ion Current Comparison in Small, Fast Running Gasoline Engines for Non-Automotive Applications

ANDREAS STIHL AG & Co. KG-Martin Arenz
Graz University of Technology-Riccardo Basso, Gabriel Gruber, Pascal Piecha, Hans-Juergen Schacht, Stephan Schmidt
Published 2018-10-30 by SAE International in United States
Small engines for non-automotive applications include 2-stroke and 4-stroke gasoline engine concepts which have a reduced number of sensors due to cost and packaging constraints. In order to cope with future emission regulations, more sophisticated engine control and monitoring becomes mandatory. Therefore, a cost-effective way has to be found to gain maximum information from the existing sensors and actuators. Due to an increasing bio-fuel share in the market, the detection of bio-fuel content is necessary to guarantee a stable combustion by adapting the injection and ignition control strategy.Meaningful information about the combustion can be retrieved from combustion chamber ion current measurements. This paper proposes a general overview of combustion process monitoring in different engine concepts by measuring the ion current during combustion. Actually, the ion current measurement technique is not yet established in the automotive sector due to the presence of other more accurate and less signal analysis intense sensors as the oxygen and knock sensor. But in small non-automotive applications the ion current could be beneficial for a dynamic control of the engine, due…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Influence of Ethanol and 2-Butanol Blended Fuels on Combustion and Emissions in a Small Displacement Two Stroke Engine

Andreas Stihl AG & Co. KG-Tilman Seidel
Graz University of Technology-Stephan Jandl, Stephan Schmidt, Pascal Piecha, Hans-Juergen Schacht
Published 2018-10-30 by SAE International in United States
Small displacement two-stroke engines are cheap and low-maintenance propulsion systems and commonly used in scooters, recreation vehicles and handheld power-tools. The restriction by emission legislation and the increasing environmental awareness of end users as well as decreasing energy resources cause a rethinking in the development of propulsion systems and fuels in these fields. Despite recent improvements of electric powertrains, two stroke engines are the challenged propulsion system in high performance handheld power tools at the moment. The reasons are the extraordinary high power to weight ratio of two-stroke engines, the high energy density of liquid fuels and the reliability of the product with respect to extreme ambient conditions. Nevertheless, further improvements on emissions and fuel consumption of small displacement two-stroke engines can be realized.This research is focused on the use of alternative renewable fuels, so called biofuels, like ethanol and 2-butanol in small displacement two-stroke engines. The different physical and chemical properties of ethanol and 2-butanol can have a positive impact on the combustion process and emission composition and are a possibility to contribute future…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Overview of Different Gas Exchange Concepts for Two-Stroke Engines

Graz University of Technology-Stefan Sturm, Stephan Schmidt, Roland Kirchberger
Published 2018-10-30 by SAE International in United States
The concept of a loop scavenged two-stroke engine, controlling the intake and exhaust port by the moving piston, is a proven way to realize a simple and cheap combustion engine. But without any additional control elements for the gas exchange this concept quickly reaches its limits for current emission regulations. In order to fulfil more stringent emission and fuel consumption limits with a two-stroke engine, one of the most important measures is to avoid scavenging losses of fuel and oil. Additionally, it is necessary to follow a lambda = 1 concept for a 3-way exhaust gas after-treatment.Therefore, using internal mixture preparation systems in combination with different concepts to control the gas exchange process, the two-stroke engine could become a choice for automotive applications, especially as a Range Extender in a Plugin Hybrid Electric Vehicle (PHEV). As various scavenging concepts and several mixture preparation systems can be used for 2-stroke hybrid propulsion, the pros and cons of different concept combinations have to be compared and weighted for an optimum solution.To get an overview of possible designs…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Combustion Analysis with Residual Gas as a Design Parameter for Two-Stroke Engines

Andreas Stihl AG & Co KG-Florian Schumann
Graz University of Technology-Pascal Richard Piecha, Stephan Jandl, Stefan Sturm, Stephan Schmidt, Roland Kirchberger
Published 2018-10-30 by SAE International in United States
In a variety of applications, two-stroke engines assert their usage as a propulsion unit, for examples in off-road vehicles, scooters, hand-held power tools and others. The outstanding power to weight ratio is the key advantage for two-stroke engines. Furthermore, two-stroke engines convince with high durability and low maintenance demand. However, an increasing environmental awareness, the protection of health and the shortage of fossil resources are the driving factors to further enhance the internal combustion process of two-stroke engines. The reduction of emissions and fuel consumption with a constant power level is focused on.Developments deal with the optimization of the combustion process itself or the enhancement of the exhaust gas aftertreatment. Especially in very small two-stroke engines an exhaust gas aftertreatment system is rarely applied, due to disadvantages regarding component temperatures and product costs. Beside different parameters, the exhaust gas back pressure mainly influences the residual gas content as well as the gas exchange in two stroke engines. Both are essential for the combustion process quality, which can be determined by values of 50% MFB, COV,…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Artificial Neural Network Based Predictive Real Drive Emission and Fuel Economy Simulation of Motorcycles

Graz University of Technology-Johannes Hiesmayr, Stephan Schmidt, Stefan Hausberger, Roland Kirchberger
Published 2018-10-30 by SAE International in United States
As the number of different engine and vehicle concepts for powered-two wheelers is very high and will even rise with hybridization, the simulation of emissions and fuel consumption is indispensable for further development towards more environmentally friendly mobility. In this work, an adaptive artificial neural network based predictive model for emission and fuel consumption simulation of motorcycles operated in real world conditions is presented. The model is developed in Matlab and Simulink and is integrated into a longitudinal vehicle dynamic simulation whereby it is possible to simulate various and not yet measured test cycles. Subsequently, it is possible to predict real drive emissions RDE and on-road fuel consumption by a minimum of previous measurement effort. The modelling approach is adaptive in terms of usability for different engine and exhaust gas treatment systems as the model does not require specific knowledge of technical vehicle parameters, which might be unknown due to manufacturers’ concealment. Backpropagation is used as supervised learning technique for training the neural networks and various learning inputs are investigated and evaluated. The paper expands…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Practicability and Influencing Factors of a Lean Burn Mode for Two-Stroke Engines in Hand-Held Powertools

Andreas Stihl AG & Co KG-Florian Schumann, Tim Gegg
Graz University of Technology-Pascal Piecha, Christoph Ninaus, Stephan Schmidt, Roland Kirchberger
  • Technical Paper
  • 2017-32-0043
Published 2017-11-05 by Society of Automotive Engineers of Japan in Japan
For many applications, such as scooters, hand-held power tools and many off-road vehicles, two-stroke engines are used as a preferred propulsion unit. These engines convince by a good power to weight ratio, a high durability and low maintenance technology and are therefore the first choice in this field of application. In general, already much development effort has been expended to improve those systems. However, an increasing environmental awareness, the protection of health and the shortage of fossil resources are the driving factors to further enhance the internal combustion process of those adapted two-stroke engines. The current focus here is on the reduction of emissions and fuel consumption with an at least constant power output.An approach to address an improvement of engine efficiency can be covered by applying a lean combustion burn mode. In almost all combustion technology sectors, including furnaces, gas turbines and many internal combustion engines, a lean combustion is utilized. Possible advantages of a combustion process under lean conditions are low pollutant emissions and high efficiencies, because flame temperatures are typically low. Nevertheless,…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Thermodynamic Loss Analysis of a High Power Motorcycle Engine with Focus on Alcohol Blended Fuels

BRP-Powertrain GmbH & Co KG-Stefan Leiber
Graz University of Technology-Stephan Jandl, Patrick Pertl, Hans-Juergen Schacht, Stephan Schmidt
  • Technical Paper
  • 2017-32-0070
Published 2017-11-05 by Society of Automotive Engineers of Japan in Japan
The development of future internal combustion engines and fuels is influenced by decreasing energy resources, restriction of emission legislation and increasing environmental awareness of humanity itself. Alternative renewable fuels have, in dependency on their physical and chemical properties, on the production process and on the raw material, the potential to contribute a better well-to-wheel-CO2-emission-balance in automotive and nonautomotive applications. The focus of this research is the usage of alcohol fuels, like ethanol and 2-butanol, in motorcycle high power engines. The different propulsion systems and operation scenarios of motorcycle applications in comparison to automobile applications raise the need for specific research in this area. In comparison to conventional gasoline physical and chemical properties of alcohol fuels are changing, which has a direct impact on mixture formation, combustion process, exhaust gas and exhaust gas after treatment of motorcycle applications. The combustion process is directly influenced by the mixture formation and the chemical composition of the liquid fuel and determines the boundary conditions for the exhaust gas after treatment. On this account, this study concentrates on the thermodynamic…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Current Findings in Measurement Technology and Measurement Methodology for RDE and Fuel Consumption for Two-Wheeler-Applications

AVL List GmbH-Roland Wanker, Hubert Friedl
Graz University of Technology-Johannes Hiesmayr, Stephan Schmidt, Stefan Hausberger, Roland Kirchberger, Christian Zinner, Patrick Filips
  • Technical Paper
  • 2017-32-0041
Published 2017-11-05 by Society of Automotive Engineers of Japan in Japan
Real world operating scenarios have a major influence on emissions and fuel consumption. To reduce climate-relevant and environmentally harmful gaseous emissions and the exploitation of fossil resources, deep understanding concerning the real drive behavior of mobile sources is needed because emissions and fuel consumption of e.g. passenger cars, operated in real world conditions, considerably differ from the officially published values which are valid for specific test cycles only [1].Due to legislative regulations by the European Commission a methodology to measure real drive emissions RDE is well approved for heavy duty vehicles and automotive applications but may not be adapted similar to two-wheeler-applications. This is due to several issues when using the state of the art portable emission measurement system PEMS that will be discussed.Hence, the aim of this paper is to present current experimental investigations in measurement technology and methodology for RDE and fuel consumption with measurement equipment that is used in automotive applications and was adapted for a motorcycle. Aside the installation and calibration, cross influences of these measurement instruments and side effects will…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Results, Assessment and Legislative Relevance of RDE and Fuel Consumption Measurements of Two-Wheeler-Applications

AVL List GmbH-Roland Wanker, Hubert Friedl
Graz University of Technology-Johannes Hiesmayr, Stephan Schmidt, Stefan Hausberger, Roland Kirchberger, Christian Zinner, Patrick Filips
  • Technical Paper
  • 2017-32-0042
Published 2017-11-05 by Society of Automotive Engineers of Japan in Japan
The reduction of environmentally harmful gases and the ambitions to reduce the exploitation of fossil resources lead to stricter legislation for all mobile sources. Legislative development significantly affected improvements in emissions and fuel consumptions over the last years, mainly measured under laboratory conditions. But real world operating scenarios have a major influence on emissions and it is already well known that these values considerably differ from officially published figures [1]. There are regulated emissions by the European Commission by means of real driving scenarios for passenger cars. A methodology to measure real drive emissions RDE is therefore well approved for automotive applications but was not adapted for two-wheeler-applications yet [2].Hence measurements have been performed on-road and on chassis dynamometer for motorcycles with the state of the art RDE measurement equipment to be prepared for possible future legislation. The collected data led to insights into driving dynamic of motorcycles. Therefore, synthetic RDE test cycles on test rig and dynamic trip indicators are discussed to gain a better understanding of the determining influencing factors for RDE and…
This content contains downloadable datasets
Annotation ability available