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Technical Paper

Application of Electrically Driven Coolant Pumps on a Heavy-Duty Diesel Engine

2019-01-15
2019-01-0074
A reduction in CO2 emissions and consequently fuel consumption is essential in the context of future greenhouse gas limits. With respect to the thermodynamic loss analysis of an internal combustion engine, a gap between the net indicated thermal efficiency and the brake thermal efficiency is recognizable. This share is caused by friction losses, which are the focus of this research project. The parasitic loss reduction potential by replacing the mechanical water pump with an electric coolant pump is discussed in the course of this work. This is not a novel approach in light duty vehicles, whereas in commercial vehicles a rigid drive of all auxiliaries is standard. Taking into account an implementation of a 48-V power system in the short or medium term, an electrification of auxiliary components becomes feasible. The application of electric coolant pumps on an Euro VI certified 6-cylinder in-line heavy-duty diesel engine regarding fuel economy was thus performed.
Technical Paper

Highly Dynamic Intake and Exhaust Back Pressure Control

2019-01-09
2019-26-0147
Measuring emissions of internal combustion engines-not only at steady-state conditions, but also with highly dynamic test cycles-is an important issue in modern engine development. Due to the fact that ambient conditions have an essential influence on power and emissions of internal combustion engines, test beds used for such measurements typically incorporate intake air and exhaust back pressure control for reasons of repeatability, accuracy and comparability. As test cycle dynamics get faster and legal pressure tolerances get narrower, pressure control becomes more demanding and simple PI control schemes are pushed to their limits; therefore, more sophisticated control schemes are necessary. In this paper, a linearised model is first derived and then used to both simplify and optimise PI controller tuning. This is done by means of frequency domain methods. Limitations to such controllers and possible approaches to overcome them are discussed.
Technical Paper

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

2018-10-30
2018-32-0030
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.
Technical Paper

Overview of Different Gas Exchange Concepts for Two-Stroke Engines

2018-10-30
2018-32-0041
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).
Technical Paper

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

2018-10-30
2018-32-0045
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.
Technical Paper

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

2018-10-30
2018-32-0044
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.
Technical Paper

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

2018-10-30
2018-32-0077
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.
Technical Paper

Multimethod Concept for Continuous Wear-Analysis of the Piston Group

2018-04-03
2018-01-0839
Friction losses as well as lube oil consumption at the piston group are key factors for future engine downsizing concepts regarding to emissions and consumption. This means an early identification of friction losses and wear is essential within development. The main problem is that the wear assessment is based on long durability tests which are typically performed in a later phase. This may lead to the fact that an early optimized configuration with respect to friction can cause a potential wear problem later in the durability test program. Still ongoing trends in combustion engine engineering lead to both the minimized oil supply in the tribocontact piston bore interface and improved wear resistance. One is forced to the conclusion that understanding and quantifying wear will be a key driver for the future engine development process. The aim is a holistic concept that combines different methods to investigate wear and furthermore its combination with friction loss studies.
Technical Paper

System Design Model for Parallel Hybrid Powertrains using Design of Experiments

2018-04-03
2018-01-0417
The paper focuses on an optimization methodology, which uses Design of Experiments (DoE) methods to define component parameters of parallel hybrid powertrains such as number of gears, transmission spread, gear ratios, progression factor, electric motor power, electric motor nominal speed, battery voltage and cell capacity. Target is to find the optimal configuration based on specific customer targets (e.g. fuel consumption, performance targets). In the method developed here, the hybrid drive train configuration and the combustion engine are considered as fixed components. The introduced methodology is able to reduce development time and to increase output quality of the early system definition phase. The output parameters are used as a first hint for subsequently performed detailed component development. The methodology integrates existing software tools like AVL CRUISE [5] and AVL CAMEO [1].
Technical Paper

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

2017-11-05
2017-32-0041
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.
Technical Paper

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

2017-11-05
2017-32-0042
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.
Technical Paper

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

2017-11-05
2017-32-0043
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.
Technical Paper

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

2017-11-05
2017-32-0070
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.
Technical Paper

Investigations of Lean NOx Trap (LNT) Regeneration Strategies for Diesel Engines

2017-09-04
2017-24-0124
To minimize nitrogen oxide (NOx) as well as carbon monoxide (CO) and hydrocarbon (HC) emissions to fulfil the new European real driving emissions (RDE) legislation, the LNT operation strategy - especially for DeNOx events (rich mode) - has to be optimized. On one hand the DeNOx purges should be long enough to fully regenerate the lean NOx trap, on the other hand the purges should be as short as possible to reduce the fuel consumption penalty from rich mode. Fundamental experiments have been conducted on a synthetic-gas-test-bench, purposely designed to test LNT catalysts. This methodology allowed to remove NOx from the gasfeed after the lean storage phase. The actually reduced amount of NOx could be easily calculated from the NOx storage before a regeneration event minus the NOx that was desorbed during the DeNOx event and afterwards thermally desorbed NOx.
Journal Article

Modular Fault Diagnosis System for Engine Test Bed Measurements

2017-03-28
2017-01-0386
To achieve high power output and good efficiency and to comply with increasingly stricter emission standards, modern combustion engines require a more complex engine design, which results in a higher number of control parameters. As the measurement effort and the number of sensors for engine development at the test bed continue to increase, it is becoming nearly impossible for the test bed engineer to manually check measurement data quality. As a result, automated methods for analysis and plausibility checks of measurement data are necessary in order to find faults as soon as they occur and to obtain test results of the highest possible quality. This paper presents a methodology for automated fault diagnosis on engine test beds. The methodology allows reliable detection of measurement faults as well as the identification of the root cause of faults.
Technical Paper

Multidimensional Modeling of Injection and Combustion Phenomena in a Diesel Ignited Gas Engine

2017-03-28
2017-01-0559
Using natural gas as a fuel in internal combustion engines is a promising way to obtain efficient power generation with relatively low environmental impact. Dual fuel operation is especially interesting because it can combine the safety and reliability of the basic diesel concept with fuel flexibility. To deal with the greater number of degrees of freedom caused by the interaction of two fuels and combining different combustion regimes, it is imperative to use simulation methods in the development process to gain a better understanding of the combustion behavior. This paper presents current research into ignition and combustion of a premixed natural gas/air charge with a diesel pilot spray in a large bore diesel ignited gas engine with a focus on 3D-CFD simulation. Special attention was paid to injection and combustion. The highly transient behavior of the diesel injector especially at small injection quantities poses challenges to the numerical simulation of the spray.
Journal Article

Investigations and Analysis of Working Processes of Two-Stroke Engines with the Focus on Wall Heat Flux

2016-11-08
2016-32-0028
Small displacement two-stroke engines are widely used as affordable and low-maintenance propulsion systems for motorcycles, scooters, hand-held power tools and others. In recent years, considerable progress regarding emission reduction has been reached. Nevertheless, a further improvement of two-stroke engines is necessary to cover protection of health and environment. In addition, the shortage of fossil fuel resources and the anthropogenic climate change call for a sensual use of natural resources and therefore, the fuel consumption and engine efficiency needs to be improved. With the application of suitable analyses methods it is possible to find improving potential of the working processes of these engines. The thermodynamic loss analysis is a frequently applied method to examine the working process and is universally adaptable.
Journal Article

Evaporation and Cold Start Behavior of Bio-Fuels in Non-Automotive Applications

2016-11-08
2016-32-0034
Worldwide increasing energy consumption, decreasing energy resources and continuous restriction of emission legislation cause a rethinking in the development of internal combustion engines and fuels. Alternative renewable fuels, so called bio-fuels, have the potential to contribute to environmentally friendly propulsion systems. This study concentrates on the usage of alcohol fuels like ethanol, methanol and butanol in non-automotive high power engines, handheld power tools and garden equipment with the focus on mixture formation and cold start capability. Although bio-fuels have been investigated intensely for the use in automotive applications yet, the different propulsion systems and operation scenarios of nonautomotive applications raise the need for specific research. A zero dimensional vaporization model has been set up to calculate the connections between physical properties and mixture formation.
Technical Paper

Analysis of Conventional Motorcycles with the Focus on Hybridization

2016-11-08
2016-32-0031
The release of the “Regulation No. 168/2013” for the approval and market surveillance of two- or three-wheel motorcycles and quadricycles of the European Union started a new challenge for the motorcycle industry. One goal of the European Union is to achieve emission parity between passenger cars (EURO 6) and motorcycles (EURO 5) in 2020. The hybridization of motorcycle powertrains is one way to achieve these strict legislation limits. In the automotive sector, hybridization is well investigated and has already shown improvements of fuel consumption, efficiency and emission behavior. Equally, motorcycle applications have a high potential to improve efficiency and to meet customer needs as fun to drive as well. This paper describes a methodical approach to analyze conventional motorcycles regarding the energy and power demand for different driving cycles and driving conditions. Therefore, a dynamic or forward vehicle simulation within MATLAB Simulink is used.
Technical Paper

Comparison of Different Downsizing Strategies for 2- and 3-Cylinder Engines by the Use of 1D-CFD Simulation

2016-11-08
2016-32-0037
The internal combustion engine is still the most important propulsion system for individual mobility. Especially for the application of motorcycles and recreation vehicles the extraordinary high power density is crucial. Today, these engines are mainly 4-stroke naturally aspirated MPFI engines. The main difference to the automotive sector is the abandonment of all cost intensive technologies, like variable valve timing, intake air charging or gasoline direct injection. The need for further investigations and implementation of new technologies is given due to the very high share of total road transport emissions of motorcycles and the introduction of the emission limits of EURO5 in 2020. One possibility to reach the future emission limits is the downsizing strategy. For this, the potential for emission and fuel consumption reduction is well known.
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