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Viewing 1 to 30 of 3755
2011-04-12
Technical Paper
2011-01-0144
Kim R. Hansen, Jakob D. Dolriis, Christoffer Hansson, Claus S. Nielsen, Spencer C. Sorenson, Jesper Schramm
The paper describes the optimization of a 50 cc crankcase scavenged two-stroke diesel engine operating on dimethyl ether (DME). The optimization is primarily done with respect to engine efficiency. The underlying idea behind the work is that the low weight, low internal friction and low engine-out NOx of such an engine could make it ideal for future vehicles operating on second-generation biofuels. Data is presented for the performance and emissions at the current state of development of the engine. Brake efficiencies above 30% were obtained despite the small size of the engine. In addition, efficiencies near the maximum were found over a wide operating range of speeds and loads. Maximum bmep is 500 kPa. Results are shown for engine speeds ranging from 2000 to 5000 rpm and loads from idle to full load. At all speeds and loads NOx emissions are below 200 ppm and smokeless operation is achieved. Design improvements relative to an earlier prototype are described.
2004-03-08
Technical Paper
2004-01-0569
Peter J. Wezenbeek, David G. Evans, David P. Sczomak, John P. Absmeier, Gerald T. Fattic
Implementation of engine turnoff at idle is desirable to gain improvements in vehicle fuel economy. There are a number of alternatives for implementation of the restarting function, including the existing cranking motor, a 12V or 36V belt-starter, a crankshaft integrated-starter-generator (ISG), and other, more complex hybrid powertrain architectures. Of these options, the 12V belt-alternator-starter (BAS) offers strong potential for fast, quiet starting at a lower system cost and complexity than higher-power 36V alternatives. Two challenges are 1) the need to accelerate a large engine to idle speed quickly, and 2) dynamic torque control during the start for smoothness. In the absence of a higher power electrical machine to accomplish these tasks, combustion-assisted starting has been studied as a potential method of aiding a 12V accessory drive belt-alternator-starter in the starting process on larger engines.
2004-03-08
Technical Paper
2004-01-0557
John E. Dec, Magnus Sjöberg
An investigation has been conducted to determine the relative magnitude of the various factors that cause changes in combustion phasing (or required intake temperature) with changes in fueling rate in HCCI engines. These factors include: fuel autoignition chemistry and thermodynamic properties (referred to as fuel chemistry), combustion duration, wall temperatures, residuals, and heat/cooling during induction. Based on the insight gained from these results, the potential of fuel stratification to control combustion phasing was also investigated. The experiments were conducted in a single-cylinder HCCI engine at 1200 rpm using a GDI-type fuel injector. Engine operation was altered in a series of steps to suppress each of the factors affecting combustion phasing with changes in fueling rate, leaving only the effect of fuel chemistry.
2004-03-08
Technical Paper
2004-01-0553
Gen Shibata, Koji Oyama, Tomonori Urushihara, Tsuyoshi Nakano
A supercharged 4-cylinder engine was introduced to evaluate how fuel properties affect engine combustion and performance in homogeneous charge compression ignition (HCCI) operation. In this study, choosing from 12 hydrocarbon constituents, model fuels were mixed to have the same distillation but different octane numbers (RON=70, 80, 92). For each fuel, RON distribution against distillation is same to keep the same octane number in cylinder vapor during the air-fuel compression process. To confirm the appropriateness of model fuels and test procedures, regular gasoline (RON=90) was also included. From the combustion analysis it was clear that the low temperature heat release depends on fuel characteristics. RON92 fuel has a small low temperature heat release, and a high temperature heat release combusts slowly.
2004-03-08
Technical Paper
2004-01-0547
Barbara Westrate, Gary Coulson, Tom Kenney, Bhogineni Kumar, Matt Rogers, Corey Weaver
This paper describes the dynamometer development of a lightly stratified direct-injection spark-ignition engine. The engine was designed for stratified charge operation at speeds and loads below 2000 RPM, 2 bar BMEP. Test results detailed in this report include evaluation of part-load stratified-charge, part-load homogeneous-charge, and WOT operation. The program had aggressive goals in improving WOT performance and part-load fuel consumption compared to a baseline PFI engine while meeting Stage V emissions levels. Mini-map analysis of the engine data indicated that the engine was able to meet the emissions and fuel consumption goals.
2004-03-08
Technical Paper
2004-01-0422
Philippe Moulin, Gilles Corde, Michel Castagné, Grégory Rousseau
On diesel engines, a discrepancy between the air fuel ratio (AFR) of the cylinders can lead to a decrease of full load performances, an increase of pollutant and noise emissions and has an effect on the aftertreatment efficiency. A cylinder individual AFR estimator has been developed using Kalman filter techniques. This estimator is based on a physical model of the exhaust, and intended to be implemented in an engine management system. The time delay of the exhaust system, including the sensor, can be identified online. When applied on testbed acquisitions, the estimator gives good results over the whole operating range of the engine.
2004-03-08
Technical Paper
2004-01-0418
Graham Hunt, Anthony Truscott, Andrew Noble
Conventional engine HiL simulators use Mean Value (MV) modelling techniques to represent the plant and provide closed loop feedback parameters to the ECU. Once configured, these models require parameterising with the engine specific data. This data can be obtained from two primary sources: Test bed data - running a range of steady state/dynamic speed/load points. Engine required. WAVE* simulation model - Physical sizes of engine required for simulation. No Engine required. The accuracy of the MV model once fully parameterised is in the region of 70 - 80% assuming accurate test data. Another limitation of current techniques is that differences between individual cylinders, for example due to intake system geometrical arrangement, are ignored.
2004-03-08
Technical Paper
2004-01-1522
Debabrata Paul
In the recent times, the reduction of process variability has become very important for delivering cost-effective product. As per Taguchi's Loss Function, higher variability means higher cost also. The quantification of variability is a tremendous challenge to NVH engineers. To understand the NVH characteristics of an engine, measurements at various locations are needed. Moreover, each measurement is also a function of engine speed. In order to capture the process variability, multiple engines need to be measured. Thus, the final data is a function of engine, location, and speed. The objective of this paper is to define the various types of variability associated with the NVH data and to develop a procedure to estimate them. This paper contains the examples from the test data.
2004-03-08
Technical Paper
2004-01-1530
Carlo N. Grimaldi, Michele Battistoni, Marco Uccellani
In this paper an experimental analysis is carried out to evaluate the dependence of the flow characteristics in the intake system of a high performance 4 valve, Spark Ignition Internal Combustion Engine, on the experimental conditions at the steady flow test bench. Experimental tests are performed at different pressure levels on a Ducati Corse racing engine head, to measure the Discharge Coefficient Cd and the Tumble Coefficient NT, expanding the work already presented in a previous work by the same research group: with a new test bench, the maximum test pressure level is increased up to 24 kPa, while differently-shaped tumble adaptors are used to evaluate Nt. The study is aimed at determining the influence of the test pressure on Cd and NT measurements, and in particular of the tumble adaptor shape.
2004-03-08
Technical Paper
2004-01-1436
Mahmoud Yassine, Rajinder Dhatt, Ron Berndt, Majed Marji, Dennis Blumke, Thomas Laymac
Vehicle exhaust flow is difficult to measure accurately and with high precision due to the highly transient nature of the cyclic events which are dependent on engine combustion parameters, varying exhaust gas compositions, pulsation effects, temperature and pressure. Bag mini-diluter (BMD) is becoming one of the few technologies chosen for SULEV and PZEV exhaust emission measurement and certification. A central part of the BMD system is an accurate and reliable exhaust flow measurement which is essential for proportional bag fill. A new device has been developed to accurately and reliably calibrate exhaust flow measurement equipments such as the E-Flow. The calibration device uses two different size laminar flow elements (LFE), a 40 CFM (1.13 m3/min) LFE for low end calibration and a 400 CFM (11.32 m3/min) LFE for higher flows. A blower is used to push flow through a main flow path, which then divides into two flow pathways, one for each of the two LFE's.
2004-03-08
Technical Paper
2004-01-1438
Mahmoud Yassine, Sashi Velnati, Rajinder Dhatt, Thomas Laymac
Automakers in the United States have started using bag mini-diluters (BMD) for developing, testing and certifying vehicles, to meet PZEV and SULEV regulation requirements. The BMD system which is a new technology developed by AIGER, is being used as an alternative to the traditional CFV/CVS system for accurate ultra low-level emission measurement. BMD system has shown to have considerable advantage over CFV/CVS system, especially at ULEV/SULEV emission levels. This paper details modifications and diagnostic checks conducted with the existing BMD system at the DaimlerChrysler Tech Center emissions facility, Auburn Hills, Michigan. This paper also discusses possible scenarios where the BMD system at DaimlerChrysler could give erroneous results due to system setup, optimization issues and equipment limitations.
2004-03-08
Technical Paper
2004-01-1439
Leonidas Ntziachristos, Barouch Giechaskiel, Panayotis Pistikopoulos, Zissis Samaras, Urs Mathis, Martin Mohr, Jyrki Ristimäki, Jorma Keskinen, Pirita Mikkanen, Roberto Casati, Volker Scheer, Rainer Vogt
This paper presents a novel partial flow sampling system for the characterization of airborne exhaust particle emissions. The sampled aerosol is first conditioned in a porous dilutor and then subsequent ejector dilutors are used to decrease its concentration to the range of the instrumentation used. First we examine the sensitivity of aerosol properties to boundary sampling conditions. This information is then used to select suitable sampling parameters to distinguish both the nucleation and the accumulation mode. Selecting appropriate sampling parameters, it is demonstrated that a distinct nucleation mode can be formed and measured with different instruments. Using these parameters we examine the performance of the system over transient vehicle operation. Additionally, we performed calculations of particle losses in the various components of the system which are then used to correct signals from the instruments.
2004-03-08
Technical Paper
2004-01-1441
C. D. Bannister, J. G. Hawley, C. J. Brace, A. Cox, D. Ketcher, R. Stark
The measurement of vehicle modal emissions is technically challenging due to the major issue of determining exhaust gas mass flow rate and ensuring that it is synchronous with the emission measurement of that corresponding ‘slug’ of exhaust gas. This is very evident when attempting to measure small passive NOx catalyst conversion efficiencies. This paper highlights alignment issues with regard to the variation of time delays associated with engine and vehicle events and the CO2 tracer method for determining exhaust gas flows.
2004-03-08
Technical Paper
2004-01-1442
Mark Guenther, Mark Polster, Larry Wroza
Exhaust flow measurements are becoming increasingly important to ensure accurate emissions measurement on both a continuous and averaged (i.e. bag) basis. When performing continuous mass measurements of hydrocarbons, nitrous oxide, carbon monoxide, carbon dioxide and other pollutant/greenhouse gases, the exhaust flow measurement is critical to the task of providing an accurate result. In addition, the acceptance of the Bag Mini-Diluter (BMD) for low-level emissions measurements has amplified the need for an accurate exhaust flow measurement. With the BMD, there is a direct correlation between fuel economy/emissions accuracy and exhaust flow measurement accuracy. To meet these demands, several new exhaust meters have emerged in the last few years that encompass promising technology and unique solutions to the traditional problems that tend to complicate exhaust flow measurements.
2004-03-08
Technical Paper
2004-01-1444
Barbara Zelenka, Günter Hohenberg, Wolfgang Thiel, Peter M. Ziegler
This paper reports on the development and testing of a compact and mobile CVS system for the measurement of particulate matter emissions of diesel passenger cars. It consists of the same components as a conventional CVS system but needs much less space. Reducing the size of the CVS system was achieved by the optimization of the turbulent flow in the dilution tunnel by the use of an optimized mixing chamber, in which the engine exhaust gas is diluted with filtered ambient air. The measures taken to improve the turbulence in the dilution tunnel lead to the same effect as a tunnel with dimensions according to the legislative regulations. All the components of the mobile CVS system are arranged in a very compact design, so that the new system has a size of only about (1.70 x 0.80 x 2.10) m. Due to the mobility which is possible with such a design, the new system can be quickly adapted to different engine and vehicle test cells for passenger cars.
2004-03-08
Technical Paper
2004-01-1445
Farshid Owrang, Jim Olsson, Jörgen Pedersen
The exhaust emissions from a gasoline direct injection (GDI) engine were sampled using the bottle in bag method and analysed using gas chromatography/mass spectrometry (GC/MS). The GDI engine was run two times using two specially mixed fuels: a typical European base fuel containing additive and a fuel representing worst-case of European gasolines, which is a standardized European fuel, CEC RF 86-A-96, prone to form deposits. The engine was run 60 h for each fuel simulating city driving. Emissions were taken at times 0 h (at the start of the engine), 30 h and 60 h. As a complement, particulate emissions derived from the additized base fuel were sampled on a glass filter during the first 30 h engine run. The extractable organics contained in the filter were analysed using GC/MS analysis. Generally, the emissions were dominated by gasoline components with similar relations as in the gasoline.
2004-03-08
Technical Paper
2004-01-1431
Edward Sun, Wayne McMahon, David Peterson, Jeffrey Wong, Kazuya Tsurumi
While developing one of the first commercialized Super Ultra Low Emission Vehicles, one vehicle manufacturer also improved the method for measuring low level hydrocarbons [1]. This was accomplished by enhancing the Constant Volume Sample System, and correcting hydrocarbon measurements from the Flame Ionization Detector hydrocarbon analyzer for the effect of oxygen quench. Based on the manufacturer's results, it appears that the variation in oxygen content of the calibration gas, span gas, zero gas, and sample gas can affect the accuracy of low level hydrocarbon measurement. Within the last couple of years, the United States Environmental Protection Agency and the California Air Resources Board approved the Bag Mini Diluter method for emission sampling [2,3]. This method was developed by the American auto industry in cooperation with government agencies within the American Industry/Government Emissions Research Consortium.
2004-03-08
Technical Paper
2004-01-1454
Thomas Resch, Borislav Klarin
The target of dynamic simulation is to investigate complex engine dynamic behavior in the whole speed range under different loading conditions in the most effective way during Engine Development Process (EDP). AVL has developed a method for transient run-up analysis by using the simulation tool AVL EXCITE. The main objective of this new method is the controlled speed increase by defining a speed ramp. Transient run-up analysis is of interest for different kind of analysis during the EDP, such as crankshaft dynamics and strength, low frequency vibration analysis, bracket strength and durability analysis, acoustic analysis, etc. By using this method the time required for simulations and thus the whole project duration is significantly reduced. Conventionally the speed range is divided in single speed steps and for each speed a separate transient simulation has to be performed. The number of these simulations depends on the required speed resolution.
2004-03-08
Technical Paper
2004-01-1458
Ylva Nilsson, Lars Eriksson
It is important to determine the phasing of a measured cylinder pressure trace and crank angle with high accuracy. The reason is that erroneous determination of the position of TDC is a major error source when calculating properties such as heat release etc. A common way to determine the TDC position is to study motored cycles. Heat transfer makes the task more complicated, since it shifts the position of the maximum pressure away from TDC. In this paper a new method for determining the TDC position is proposed that does not require any additional sensors other than a cylinder pressure sensor and an incremental encoder. The idea is to find a point that the cylinder pressure from a motored cycle is symmetric around, since the volume is close to symmetric on either side of TDC. The new method and four published methods are tested and evaluated. Cylinder pressure data used for comparison are from simulations of a SAAB Variable Compression engine.
2004-03-08
Technical Paper
2004-01-1462
Jiří Vávra, Michal Takáts
New regression approach for heat release pattern prediction for various operating conditions for gas fuelled SI engines has been developed and verified. This procedure has been implemented in our engine working cycle simulation code. Crankshaft angle positions of combustion start-point, maximum rate-of-heat-release point and combustion end-point are expressed by the use of regression method as the function of engine operating point specification. Base heat-release pattern is employed in the model in a tabular form. The pattern at a new operating point is derived by stretching the pattern along the crank angle coordinate, fitting it in the most relevant points of the heat release pattern. The regression model is based on the results of experiments of both homogeneous stoichiometric and lean burn SI turbocharged engines fuelled by natural gas.
2004-03-08
Technical Paper
2004-01-1463
Eric Krengel
Historically transient combustion performance is described by attribute data, the number of misfires or slow burns or graphical with plots of IMEP. These measures help developers improve transient combustion performance but do not work well for experimental analysis methods. All design of experiments, analysis of variance, optimization methods and modeling, require variable data. A method of transient IMEP analysis has been developed to quantify tip in / out combustion and total engine combustion stability during engine start and warm up. The Cycle Standard Deviation IMEP shows sensitivity and stability making it an excellent tool for analytical analysis methods for engine calibration development.
2004-03-08
Technical Paper
2004-01-1381
Vito Melisurgo, Emilio Canuto, Domenico Vitali
Environment and A/C loop conditions strongly affect automotive evaporator performance. The aim of the activity is to identify the parameters it depends on and its functional dependence. Several evaporators, differing in size and technology, are tested on a bench, simulating a wide range of working conditions. The evaporator efficiency is introduced in order to correctly evaluate performances. The functional dependences from air velocity and humidity (key parameters) are shown, and a methodology to characterise automotive evaporators is proposed.
2004-03-08
Technical Paper
2004-01-1379
John Meyer, George Yang, Evangelos Papoulis
As powertrains continue to get more efficient, less waste heat is available for warming the passenger compartment. Although several supplemental heating devices are currently on the market, including electric heaters, viscous heaters, and fuel operated heaters, they each have shortcomings related to cost, capacity, efficiency, and/or environmental concerns[1]. In an attempt to provide superior time-to-comfort in a cost, weight, package efficient, and environmentally friendly manner, an R134a heat pump (HP) system was developed. Several technical issues were overcome while developing this system. Production vehicles have been retrofitted to incorporate the R134a heat pump system and tested in a climatic wind tunnel. Test results for a -18°C warm-up test were compared to baseline data, showing significant improvements in average discharge air and breath level temperatures.
2004-03-08
Technical Paper
2004-01-1373
Mingyu Wang, Thomas M. Urbank, Karma V. Sangwan
The present paper describes the system design for the Clear Vision auto defog system and the improvements made to the Integrated Dew Point and Glass Temperature (IDGT) sensor. The Clear Vision auto defog system has been implemented on a 2000 Cadillac DeVille. Preliminary validation tests demonstrate satisfactory performance.
2004-03-08
Technical Paper
2004-01-1369
Stefan Larsson, Stefan Schagerberg
In order to maximise engine efficiency it is of interest to find the peak pressure position (PPP) of the cylinder pressure when controlling combustion engines. Cylinder mounted pressure sensors can be used to measure the pressure, but these are expensive and suffer from limited durability. Alternative pressure estimation methods using cheaper and more durable sensors are needed. This paper shows the performance when estimating the cylinder pressure of a five cylinder SI-engine using a crankshaft integrated torque sensor. An engine model is constructed to be able to eliminate the torsional resonances in the sensed torque signal and the cylinder pressure is reconstructed using a parameterised pressure model. The performance of the estimator is studied in three different simulation cases. Finally, the performance based on measured torque is presented.
2004-03-08
Technical Paper
2004-01-1394
Rudolf Flierl, Dirk Kairies, Wilhelm Hannibal, Andreas Knecht
The ‘UniValve’ fully variable mechanical valve lift system is rated for use at engine speeds up to 8500 rpm. This system varies the valve opening period together with the amount of valve lift. When the engine is idling and valve lift is approximately 0.3 mm, the opening period is about 90 degrees of crankshaft rotation; at the full valve lift of 9 mm, the valve remains open for 320 degrees of crankshaft rotation. Valve lift is adjusted by means of an extremely rigid eccentric shaft rotating in bearings in the cylinder head. The system has been applied to a single-cylinder engine. The valve gear's dynamic behavior at engine speeds up to 8500 rpm the first results are described here, together with the fuel-consumption and torque benefits and the system's influence on emissions. The effects of the new load control system on mixture formation and the resulting nvh of the single-cylinder engine, particularly at low running speeds and loads, are also examined.
2004-03-08
Technical Paper
2004-01-1395
Mark A. Mohr, Rudolf Flierl, Wilhelm Hannibal
A fully variable mechanical valve gear has been integrated into an engine with a side-mounted camshaft. The design is specified with the peripheral package terms and the resulting criteria of ratings. The additional costs were analyzed too. The first results obtained from a dynamic simulation of the chosen design are described and assessed. Additionally to this the potential of this type of a mechanical fully-variable valve lift system is evaluated in terms of engine torque, power output and fuel consumption by simulating a cyclic process and the comparison with the potential offered by variable valve timing (VVT).
2004-03-08
Technical Paper
2004-01-1392
Thitiphol Anontaphan
In the previous study (SAE 2003-01-0022), I presented a mechanical continuous variable valve event & valve lift VRA which some versions can integrate the variable timing control. Besides the VRA, the system can be applied to various valve trains, such as DOHC, SOHC and Push rod. In this VRA part II, a few parts of VRA are developed. For example, positions of camshaft and control shaft, which are closely related, are developed to produce minimum or maximum valve event & valve lift at the least rotation of control shaft. The developments will allow the VRA to produce a faster response and require less operation. Second part of this study will present the application of the Double Intake Valve Control, which double VRA will control each intake valve separately, while only one intake camshaft is required. Furthermore, this system is expected to support various forms of the combustion, including the gasoline direct injection as well.
2004-03-08
Technical Paper
2004-01-1393
Gerhard Maas, Heiko Neukirchner, Oliver Dingel, Oliver Predelli
Under the persistent pressure to further reduce fuel consumption worldwide, it is necessary to advance the processes that influence the efficiency of gasoline engines. In doing so, harnessing the entire potential of fully variable mechanical valve trains will involve targeting efforts on optimizing all design parameters. A new type of valve timing system is used to portray thermodynamic and mechanical as well as electronic aspects of developing fully variable mechanical valve timing and lift systems
2004-03-08
Technical Paper
2004-01-1699
Eric Jaarda, Tansen Chaudhari, Dhiraj Uikey
Low speed bumper impact performance relies on the capability of the energy absorber (EA) to absorb energy efficiently through multiple impacts. Series impacts are typically assessed via physical part testing due to the difficulties of predicting multiple impacts accurately. This paper describes a predictive engineering method used to assess the performance of injection molded thermoplastic energy absorber systems in multiple impacts.
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