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Technical Paper
2014-04-01
Amey Zare, Advaita Datar, Mitsuhiko Kikuchi, Satoshi Ichikawa, Miwako Hasegawa, Shigenori Tsunekado
A flag is a global boolean variable used to achieve synchronization between various tasks of an embedded system. An application implementing flags performs actions or events based on the value of the flags. If flag variables are not implemented properly, certain synchronization related issues can arise which can lead to unexpected behavior or failure of the underlying system. In this paper, we present an automated verification technique to identify and verify flag usage patterns at an early stage of code development. We propose a two-step approach which consists of: a. identification of all potential flag variables and b. verification of flag usage patterns against predefined set of rules. The results of our experiment demonstrate that the proposed approach reduces the cost and complexity of the flag review process by almost 70%.
Technical Paper
2014-04-01
Tobias Schmidt, Shan Jin, Jens Rogalli, Thorsten Rogier, Hartmut Pohlheim, Ingo Stürmer
Requirements-based functional testing of model-based embedded software is a crucial requirement of the ISO 26262 safety standard for passenger cars [1]. Test assessment of requirements-based test cases is a laborious task and checking test results manually is prone to error. The intent of this paper is as follows: We introduce a method for requirements-based testing, which allows testing and automatic evaluation of single as well as several (grouped) requirements with one test sequence. Within a large-scale industrial project we have already shown that our new approach reduces testing expenditures and susceptibility to errors. Within this paper we shall present a method which facilitates the fulfillment of requirements traceability stipulated by ISO 26262. This method supports automated test case generation from test specifications, which then can be executed and assessed by a test tool automatically. The combination of these two methods in an efficient testing framework results in a significant reduction of testing expenditures and considerable increase in test coverage.
Technical Paper
2014-04-01
Michael Guerrero, Kapil Butala, Ravi Tangirala, Amy Klinkenberger
NHTSA has been investigating a new test mode in which a research moving deformable barrier (RMDB) impacts a stationary vehicle at 90.1 kph, a 15 degree angle, and a 35% vehicle overlap. The test utilizes the THOR NT with modification kit (THOR) dummy positioned in both the driver and passenger seats. This paper compares the behavior of the THOR and Hybrid III dummies during this oblique research test mode. A series of four full vehicle oblique impact crash tests were performed. Two tests were equipped with THOR dummies and two tests were equipped with Hybrid III dummies. All dummies represent 50th percentile males and were positioned in the vehicle according to the FMVSS208 procedure. The Hybrid III dummies were instrumented with the Nine Accelerometer Package (NAP) to calculate brain injury criteria (BrIC) as well as THOR-Lx lower legs. Injury responses were recorded for each dummy during the event. High speed cameras were used to capture vehicle and dummy kinematics. The vehicle restraint devices and their associated deployment times remained the same for each test.
Technical Paper
2014-04-01
Lokanath Mohanta, Suresh Iyer, Partha Mishra, David Klinikowski
Abstract This paper illustrates a method to determine the experimental uncertainties in the measurement of tailpipe emissions of carbon dioxide, carbon monoxide, nitrogen oxides, hydrocarbons, and particulates of medium-, and heavy-duty vehicles when tested on a heavy-duty chassis dynamometer and full-scale dilution tunnel. Tests are performed for different chassis dynamometer driving cycles intended to simulate a wide range of operating conditions. Vehicle exhaust is diluted in the dilution tunnel by mixing with conditioned air. Samples are drawn through probes for raw exhaust, diluted exhaust and particulates and measured using laboratory grade emission analyzers and a microbalance. At the end of a driving cycle, results are reported for the above emissions in grams/mile for raw continuous, dilute continuous, dilute bag, and particulate measurements. An analytical method is developed in the present study to estimate the measurement uncertainties in emissions for a test cycle, due to the buildup of measurement uncertainties as they propagate through the system.
Technical Paper
2014-04-01
Jakub Zebala, Wojciech Wach
Abstract The objective of the paper is to present the results of an investigation of the effect of reduced tire pressure on car lateral dynamics in lane change maneuver. The intended aim was attained by performing bench and road tests. The aim of the bench tests was parameterization of the mathematical model of the tested car. The road tests covered the vehicle motion with reduced and no tire pressure on a curvilinear track adequate for bypassing an unexpected appearing obstacle. Next, simulations in PC-Crash were performed, and the results were compared with those obtained in experiments.
Technical Paper
2014-04-01
Roger Bortolin, Matthew Arbour, James Hrycay
Abstract Whether large or small, a truck fleet operator has to know the locations of its vehicles in order to best manage its business. On a day to day basis loads need to be delivered or picked up from customers, and other activities such as vehicle maintenance or repairs have to be routinely accommodated. Some fleets use aftermarket electronic systems for keeping track of vehicle locations, driver hours of service and for wirelessly text messaging drivers via cellular or satellite networks. Such aftermarket systems include GPS (Global Positioning System) technology, which in part uses a network of satellites in orbit. This makes it possible for the fleet manager to remotely view the location of a vehicle and view a map of its past route. These systems can obtain data directly from vehicle sensors or from the vehicle network, and therefore report other information such as fuel economy. The fleet manager can receive alerts when high-level brake applications occur, which could be an indication of tailgating or aggressive driving behavior.
Technical Paper
2014-04-01
Mindy Heading, Douglas Stein, Jeff Dix
Abstract Ejection Mitigation testing is now required by the U.S. government through FMVSS 226 [1]. FMVSS 226 contains the requirement of using a linear guided headform in a horizontal impact test into the inflated curtain, or other ejection mitigation countermeasure that deploys in the event of a rollover. The specification provides dimensions for a featureless headform [2] but there are limited specifications for the headform skin surface condition. In the “Response to Petitions” of the 2011 Final Rule for FMVSS 226 [3], the NHTSA declined the option to include a headform cleaning procedure. This research presents a case study to quantify the effect of changes in the friction between the headform and curtain on the measured excursion. The study presented here shows that a change in friction between the headform and curtain can affect excursion values by up to 135 millimeters (mm).
Technical Paper
2014-04-01
Shai Cohen, Dhafer Marzougui, Cing-Dao Kan, Fadi Tahan
Abstract Many dynamic test systems currently exist to assess rollover. This paper introduces a new test device that combines features from a multitude of different tests. It also covers the concept development, a scaled prototype design and test results from both physical and virtual tests. The Guided Rollover Test (GRT) device subjects vehicles to repeatable initial conditions by having a cart follow a guided maneuver similar to a forward J-turn with an increasing curvature sufficient to roll most vehicles. A test vehicle is carried on the cart at constant longitudinal velocity until it rolls. The cart is fitted with a tripping edge to eliminate slipping and remove the influence of tire properties and road-surface friction. Vehicles are subjected to a rollover based on their own performance characteristics which define the dynamics and consequently the roof to ground contact. Vehicle mechanical systems (suspension), passive safety systems (roof) and occupant containment systems (airbags, seat-belts, etc.) would be assessed under dynamic rollover loading.
Technical Paper
2014-04-01
Taewung Kim, Jason Kerrigan, Varun Bollapragada, Jeff Crandall, Ravi Tangirala, Michael Guerrero
Abstract Some rollover test methods, which impose a touchdown condition on a test vehicle, have been developed to study vehicle crashworthiness and occupant protection in rollover crashes. In ground-tripped rollover crashes, speed, steering maneuver, braking, vehicle inertial and geometric properties, topographical and road design characteristics, and soil type can all affect vehicle touchdown conditions. It is presumed that while there may be numerous possible combinations of kinematic metrics (velocity components and orientation) at touchdown, there are also numerous combinations of metrics that are not likely to occur in rollover crashes. To determine a realistic set of touchdown conditions to be used in a vehicle rollover crash test, a lateral deceleration sled-based non-destructive rollover initiation test system (RITS) with a fully programmable deceleration pulse is in development. A full-size SUV vehicle dynamics model was developed and validated with static test data and curb-trip rollover test data.
Technical Paper
2014-04-01
Sheryl Janca, Kurt Shanks, Janet Brelin-Fornari, Ravi Tangirala, Massoud Tavakoli
Abstract A near-side, rear seat side impact component test, was conducted and validated utilizing a SIDIIs anthropomorphic test device (ATD). The test fixture consisted of the rear seat structure, side door, interior trim, and side airbag curtain module. Test parameters were determined from full scale tests including impact speed, angle of impact, and depth of door intrusion. A comparative assessment was conducted between the full scale test and the deceleration sled test including ATD contact with the vehicle interior, contact duration, sequential timing of ATD contact, and dummy injury measures. Validation was achieved so that the deceleration sled test procedure could be utilized for further evaluations.
Technical Paper
2014-04-01
Pawel Skruch, Gabriel Buchala
The paper presents a model-based approach to testing embedded automotive software systems in a real-time. Model-based testing approach relates to a process of creating test artifacts using various kinds of models. Real-time testing involves the use of a real-time environment to implement test application. Engineers shall use real-time testing techniques to achieve greater reliability and/or determinism in a test system. The paper contains an instruction how to achieve these objectives by proper definition, implementation, execution, and evaluation of test cases. The test cases are defined and implemented in a modeling environment. The execution and evaluation of test results is made in a real-time machine. The paper is concluded with results obtained from the initial deployment of the approach on a large scale in production stream projects.
Technical Paper
2014-04-01
Sooncheol Park, Wonwook Jung, Chunwoo Shin, Jaewung Jung
Abstract Customer vehicle usage monitoring is one of the most fundamental elements to consider in the process of developing a durable vehicle. The extant method to research customer vehicle usage takes considerable time and effort because it requires attaching a series of sensors to the vehicle-gyroscope, accelerometer, microphone, and GPS-to gather information through data logs and then to analyze data in a computer where designated analyzing software has been installed. To solve the problem, this paper introduces a new concept of integrated system developed to examine customer vehicle usage that can analyze data by collecting it from a variety of sensors installed on a smartphone.
Technical Paper
2014-04-01
Karsten Schmidt, Jens Harnisch, Denny Marx, Albrecht Mayer, Andre Kohn, Reinhard Deml
Abstract Integration scenarios for ECU software become more complicated, as more constraints with regards to timing, safety and security need to be considered. Multi-core microcontrollers offer even more hardware potential for integration scenarios. To tackle the complexity, more and more model based approaches are used. Understanding the interaction between the different software components, not only from a functional but also from a timing view, is a key success factor for high integration scenarios. In particular for multi-core systems, an amazing amount of timing data can be generated. Usually a multi-core system handles more software functionality than a single-core system. Furthermore, there may be timing interference on the multicore systems, due to the shared usage of buses, memory banks or other hardware resources. The current approach for timing analysis, often based on execution times and sequences of executions in Gantt charts, will not scale arbitrarily for high integration scenarios on multi-core systems.
Technical Paper
2014-04-01
Bjoern Lumpp, Mouham Tanimou, Martin McMackin, Eva Bouillon, Erica Trapel, Micha Muenzenmay, Klaus Zimmermann
Abstract Current exhaust gas emission regulations can only be well adhered to through optimal interplay of combustion engine and exhaust gas after-treatment systems. Combining a modern diesel engine with several exhaust gas after-treatment components (DPF, catalytic converters) leads to extremely complex drive systems, with very complex and technically demanding control systems. Current engine ECUs (Electronic Control Unit) have hundreds of functions with thousands of parameters that can be adapted to keep the exhaust gas emissions within the given limits. Each of these functions has to be calibrated and tested in accordance with the rest of the ECU software. To date this task has been performed mostly on engine test benches or in Hardware-in-the-Loop (HiL) setups. In this paper, a Software-in-the-Loop (SiL) approach, consisting of an engine model and an exhaust gas treatment (EGT) model, coupled with software from a real diesel engine ECU, will be described in detail. A virtual (SiL) test bench is realized with which the diesel engine software functions can be calibrated without any special hardware, using industry- standard calibration tools like INCA from ETAS.
Technical Paper
2014-04-01
Lijiao Yu, Hongyu Zheng, Changfu Zong
Abstract Nowadays, electric control steering system has been a main tendency. It consists of Electric Power Steering (EPS) system, Steer by Wire (SBW) system and Active Front Steering (AFS) system. EPS is more widely applied and its technology is more developed. By 2010, the cars equipped with EPS have reached almost 30%. This paper describes one integrated test bench which can test and verify electric control steering system. The main target of the paper is to design and set up a resistance loading system for the test bench referred. The paper takes EPS as a prototype to verify the designed resistance loading system. If the resistance loading system provides a precise simulated torque for the bench, the results of tests will be more approximate with vehicle tests and the acquired data will be reliable for electric control steering system's design and improvement. The linear electric cylinder applied in the loading system is used to provide simulated torque for the bench. The linear electric cylinder is combined with a kind of software independently designed.
Technical Paper
2014-04-01
Louis Chretien, Adrien Laurino
Abstract The effect of cold-working, i.e. wire drawing, on the corrosion behavior of a 6101 and a 1370 aluminum alloy was investigated in NaCl solutions. For the both alloys, a “grain size - corrosion resistance” was highlighted. The preliminary works performed on Al-Cu welds showed two scales of heterogeneity and two scales of heterogeneity of media which are not considered by the current automotive specifications. Consequently, it seems to be necessary to establish new pertinent specifications to evaluate the new Al solutions.
Technical Paper
2014-04-01
James G. McLeish, Russell Haeberle
Quality, Reliability, Durability (QRD) and Safety of vehicular Electrical/Electronics (E/E) systems traditionally have resulted from arduous rounds of Design-Built-Test-Fix (DBTF) Reliability and Durability Growth Testing. Such tests have historically required 12-16 or more weeks of Accelerated Life Testing (ALT), for each round of validation in a new product development program. Challenges have arisen from: The increasing number of E/E modules in today's vehicle places a high burden on supplier's test labs and budgets. The large size and mass of electric vehicle power modules results in a lower test acceleration factors which can extend each round of ALT to 5-6 months. Durability failures tend to occur late in life testing, resulting in the need to: perform a root cause investigation, fix the problem, build new prototype parts and then repeat the test to verify problem resolutions, which severely stress program budgets and schedules. To resolve these challenges, automakers and E/E suppliers are moving to Physics of Failure (PoF) based durability simulations and reliability assessment solutions performed in a Computer Aided Engineering (CAE) Environment.
Technical Paper
2014-04-01
Lijiao Yu, Hongyu Zheng, Changfu Zong
Abstract Nowadays, conventional steering system cannot meet consumers' requirements as their environmental awareness increasing. Electrically controlled steering system can solve this problem well [1] [2]. Electrically controlled steering system has been not only applied widely in automobile steering technique but also becomes an important section of automobile integrated chassis control technology. It is necessary for vehicles to test their every component repeatedly before every component assembled. So a test bench becomes an essential part for vehicle products' design and improvement. The electrically controlled steering system consists of Electric Power Steering system (EPS), Active Front Steering (AFS) and Steer by Wire (SBW). The similarity among them is containing pinion-and-rack mechanical structure, so it is viable to design a test bench suitable for these three systems. This paper takes EPS as a prototype to verify the design's availability. The designed test bench is also used to detect and verify the electrically controlled steering system's performance at the same time.
Technical Paper
2014-04-01
Peter Subke
Abstract In the past, the automotive industry has learned the lesson that competition on the level of bits and bytes, proprietary bus systems, data communication and diagnostic protocols is unrewarding. Too much time and money has been spent on the development of proprietary diagnostic tools. Vehicle manufacturers and suppliers realized that standardization would be the best way to overcome this situation. Furthermore, regulatory requirements in the US and the EU for such standardization have strengthened this lesson. As a result, the automotive industry has standardized the technology for the communication of external test equipment with electronic control units (ECUs) in road vehicles. Standardization serves the price, the quality and the maintainability via scale and training curve effects. This paper contains a technical introduction of internationally standardized diagnostic protocols (UDS on CAN, WWH-OBD, UDSonIP and DoIP), the D-Server (MVCI) with D-Server API and D-PDU API, the diagnostic data format (ODX) and the open test sequence exchange format (OTX).
Technical Paper
2014-04-01
Ki-Wook Shin, Shim soo Kim, Sam Min Park, Dong-Jin Lim
Abstract We report a method to automatically generate test cases for automotive embedded software from a UML-based model using XML metadata interchange (XMI). First, the software model created using UML is converted to metadata in XMI format. Then, based on this metadata (which does not depend on a specific language), software test cases for structural testing or requirement-based testing may be generated using an appropriate parser. The model does not need to be implemented using the Object Constraint Language (OCL), and software test cases may be generated using an appropriately defined parser for a given language (which may be C/C++). Because software test cases can be converted to hardware test cases via a stimulus-mapping table, which contains the information on the digital and analog signals, and the communications interface, hardware test cases may also be generated automatically. The use of automatic test-case generation for structural testing and requirement-based testing can lead to a considerable reduction in the workload involved in testing embedded software.
Technical Paper
2014-04-01
Juwan Kim, Munsung Kim, Sang-Gun Joo, Sung Pil Heo, Youngdug Yoo
Numerical durability analysis is the only approach that can be used to assess the durability of vehicles in early stages of development. In these stages, where there are no physical prototypes available, the road wheel forces (or spindle forces) for durability testing on Belgian PG (Proving Ground) must be predicted by VPG (Virtual Proving Ground) or derived from the measured forces of predecessor vehicles. In addition, the tuning parts and geometry are not fixed at these stages. This results in the variation of spindle forces during the development stages. Therefore, it is not reasonable to choose the forces predicted at a specific tuning condition as standard forces. It is more reasonable to determine the standard forces stochastically using the DB of the measured forces of predecessor vehicles. The spindle forces measured or predicted on Belgian PG are typically stationary random. To treat the force signals stochastically, it is necessary that the forces are expressed in analytic formulation.
Technical Paper
2014-04-01
Kun Diao, Lijun Zhang, Dejian Meng
Abstract Brake squeal shows a significant uncertainty characteristic. In this paper, a series of bench tests were carried out to study the uncertainty of brake squeal on a multi-function brake inertia dynamometer test bench. Then based on time-frequency analysis results, a creative squeal confirmation and determination method was presented, which can show the squeal variations in the domains of time, frequency and amplitude together. An uncertainty analysis method was also established, in which the statistical parameters of squeal frequency and sound pressure level (SPL), and probability density evaluation of frequency based on Quantile-Quantile Plot (QQ plot) were given. And a judgment method of the frequency doubling was devised based on numerical multiple and occurrence concurrence, as well as the uncertainty statistical analysis method considering frequency doubling. All the methods established were applied to the uncertainty analysis of brake squeal. It was found that, both the squeal frequency and SPL are dispersed, and each squeal has its own statistical results.
Technical Paper
2014-04-01
Ben Wen, Gregory Rogerson, Alan Hartke
Abstract Tire rolling resistance is one of tire performance indicator that represents a force needed to maintain the constant rolling of a tire. There are quite few methods and standards to measure tire rolling resistance, such as ISO-28585, ISO-18164, SAE-J1269, SAE-J2452, …. These tests have been used by tire companies, vehicle manufactures, and government agencies to evaluate tire rolling resistance performance. SAE-J1269 and SAE-J2452 are two popularly used multi-condition rolling resistance tests for passenger and light truck tires. Examining the test conditions and procedures of these two test standards showed that some key procedures and conditions from both standards are similar although there are many difference as well. The study presented here is to analyze test results from both tests and their correlation under certain conditions. If the correlation exists, one test may provide test results for both test conditions, therefore, test efficiency can be improved.
Technical Paper
2014-04-01
Rama Subbu, Baskar Anthony Samy, Piyush mani Sharma
Abstract Fierce competition in India's motorcycle industry has led to constant product innovation among manufacturers. This has resulted in the reduction of the lifecycle of the vehicle and has driven the manufacturers to alter the product design philosophies and design tools. One of the performance factors that have continued to challenge motorcycle designers is ride comfort in vertical and longitudinal direction. An essential tool in the motorcycle development process is the ability to quantify and grade the ride comfort behavior. This is performed either through subjective or objective tests. Subjective tests have the disadvantage that numerous factors influence test drivers' opinion while objective measures have the advantage of repeatability. However, objective methods provide only an approximate grading of vehicles and it is difficult to get consistent results that we can rely upon It is proposed that consistent result could be achieved if the motorcycle is run over the pave track in similar repeated cycles.
Technical Paper
2014-04-01
Joshua L. Every, Gary J. Heydinger, Dennis A. Guenther, Anmol S. Sidhu, Dale A. Andreatta, Ronald A. Bixel
The (Vehicle Inertia Parameter Evaluation Rig) VIPER II is a full vehicle mass and inertia parameter measurement machine. The VIPER II expands upon the capabilities of its predecessor and is capable of measuring vehicles with a mass of up to 45,360 kg (100,000 lb), an increase in capacity of 18,100 kg (40,000 lb). The VIPER II also exceeds its predecessor in both the length and width of vehicles it can measure. The VIPER II's maximum vehicle width is 381 cm (150 in) an increase of 76 cm (30 in) and maximum distance from the vehicle CG to the outer most axle is 648 cm (255 in) an additional 152 cm (60 in) The VIPER II is capable of performing measurements including vehicle CG height, pitch, roll, and yaw moments of inertia and the roll/yaw cross product of inertia. While being able to measure both heavier and larger vehicles, the VIPER II is designed to maintain a maximum error of 3% for all inertia measurements and 1% for CG height. When designing a system with increased capacity there are many different factors and properties that must be considered.
Technical Paper
2014-04-01
Omar Ramadan, Gary Webster, Luc Menard, Aaron Wilcox, Martin Kellen, Edgar Matida
Abstract This paper draws from several recent activities conducted at Advanced Engine Technology Ltd. (AET) which were aimed at improving the capability, precision, and durability of the Ignition Quality Tester (IQT™). The paper includes descriptions of the current Totally Automated Lab Model IQT™-TALM technology, recent experimental results such as updates to the IQT™ measurement capabilities and a summary of a Micro Intra-Laboratory Study (μILS) results. The results show that the standard deviation of Derived Cetane Number for most of the fuel samples tested was considerably lower than that obtained when those fuel samples were tested in the ASTM National Exchange Group and Energy Institute diesel fuel exchange programs.
Technical Paper
2014-04-01
Ying Wang, Fei Han, Yue Kong, Weiwen Deng
Abstract Vision-based Advanced Driver Assistance Systems (Vi-ADAS) has achieved rapid growth in recent years. Since vehicle field testing under various driving scenarios can be costly, tedious, unrepeatable, and often dangerous, simulation has thus become an effective means that reduces or partially replaces the conventional field testing in the early development stage. This paper proposes a quantitative assessment framework for model quality evaluation of 3D scene under simulation platform. An imaging model is first built. The problem of solving the imaging model is then transformed into the problem of intrinsic image decomposition. Based on Retinex theory and Non-local texture analyses, a superior intrinsic image decomposition method is adopted to evaluate the fidelity of the 3D scene model through the degree of deviation to the Reflectance and Shading intrinsic maps respectively. Some preliminary testing results demonstrate that the proposed assessment framework can produce quantitative evaluation on 3D scene models.
Technical Paper
2014-04-01
Lawrence Banasky
Abstract In an effort to reduce the cost and time associated with bench level automotive electrical and electromagnetic compatibility (EMC) validation tests, a survey was created to request advice from the test labs that perform this testing. The survey focuses particularly on the development of the test plan document and the preparation of the test setup. The survey was sent to a targeted group of individuals with experience in performing this type of testing. The invitees work at laboratories that represent the majority of labs in the world that are authorized to perform component electrical / EMC validation testing for automotive original equipment manufacturers (OEMs). There were a significant number of responses; it is possible that representatives from all of the invited laboratories responded. The survey results provide demographic information about the test labs and their participants. The participants possess a tremendous amount of test experience and are therefore qualified to provide recommendations on the subject.
Technical Paper
2014-04-01
Claudine Miraval, Pierre-Olivier Santacreu, Saghi Saedlou, Antoine Acher
Abstract The evolution of emission control standards on particulate matter and NOx has led to a significant increase of complexity of the diesel exhaust line which includes catalytic converter, particulate filter and selective catalytic reduction systems. The exhaust line is no longer a component that customers can change easily; its durability has to be studied for longer lifespan and if possible to be predicted. From a corrosion point of view, emission control systems have led to more and more severe conditions for stainless steel material used in the exhaust line. In particular, mufflers are exposed to higher temperature during the regeneration of the particle filter and also to acidification of gas condensates due to high sulphur content that can be found in diesel. To assess material performance in these severe conditions, a test method was developed to simulate the environment of the inner part of a muffler through corrosion cycles composed of oxidation steps in a furnace and dipping steps in a synthetic condensate.
Technical Paper
2014-04-01
John May, Dirk Bosteels, Cecile Favre
From 1 September 2014 new car types in the EU must meet ‘Euro 6’ emissions requirements. The ‘New European Driving Cycle’ (NEDC) is currently the main test for this, but the European Commission intends to also introduce PEMS (Portable Emissions Measurement Systems)-based procedures to ensure that emissions are well controlled in real use. ‘Random Cycles’ have also been considered and remain a possible option for ‘real world’ particle number measurement. At the same time, the UN Working Party on Pollution and Energy (GRPE) has developed the new Worldwide harmonized Light vehicles Test Procedure (WLTP) that is expected to be adopted in the EU in the near future. To identify and understand the differences in emissions that may arise between these various methodologies, AECC has conducted some initial tests on two modern light-duty vehicles. Chassis dynamometer emissions tests were conducted over the NEDC, the Common Artemis suite of test cycles (CADC), the new Worldwide Light-duty Test Cycle (WLTC - the test cycle for WLTP) and a set of cycles produced by a Random Cycle Generator based on ‘short trip’ segments from the EU database used to construct WLTC.
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