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Technical Paper

Feasibility of Particulate Mass and Number Measurement with Portable Emission Measurement Systems (PEMS) for In-Use Testing

2011-09-11
2011-24-0199
Different particulate mass (PM) portable emission measurement systems (PEMS) were evaluated in the lab with three heavy-duty diesel engines which cover a wide range of particle emission levels. For the two engines without Diesel Particulate Filters (DPF) the proportional partial flow dilution systems SPC-472, OBS-TRPM, and micro-PSS measured 15% lower PM than the full dilution tunnel (CVS). The micro soot sensor (MSS), which measures soot in real time, measured 35% lower. For the DPF-equipped engine, where the emissions were in the order of 2 mg/kWh, the systems had differences from the CVS higher than 50%. For on-board testing a real-time sensor is necessary to convert the gravimetric (filter)-based PM to second-by-second mass emissions. The detection limit of the sensor, the particle property it measures (e.g., number, surface area or mass, volatiles or non-volatiles) and its calibration affect the estimated real-time mass emissions.
Journal Article

Overview of Soot Emission Measurements Instrumentation: From Smoke and Filter Mass to Particle Number

2013-03-25
2013-01-0138
Particulate emissions cause adverse health effects and for this reason they are regulated since the 80s. Vehicle regulations cover particulate emission measurements of a model before its sale, known as type approval or homologation. For heavy-duty engines the emissions are measured on an engine dynamometer with steady state points and transient cycles. For light-duty vehicles (i.e. the full power train) the particulate emissions are assessed on a chassis dynamometer. The measurement of particulate emissions is conducted either by diluting the whole exhaust in a dilution tunnel with constant volume sampling or by extracting a small proportional part of the exhaust gas and diluting it. Particulate emissions are measured by passing part of the diluted exhaust aerosol through a filter paper. The increase of the weight of the filter is used to calculate the particulate matter mass (PM) emissions.
Technical Paper

Trends of Future Emission Legislation and its Measurement Requirements

2004-11-16
2004-01-3291
People have been altering the atmosphere on a small scale ever since they learned to make fire. Today's air pollution can influence ecosystems and transform climate worldwide. Motorized transport has become essential, today about 1000 million vehicles are on the world's roads [1]. Vehicle registrations are still sharply upward, where the future growth is most rapid in Asia and Latin America. Over the past, global pollution concerns have increased and air quality targets have been established. Also the reduction of green house gases like CO2 (Kyoto protocol) is considered. Aligned with such air quality targets automotive emission limits have been implemented. The future emission limits will require advanced engine technologies, but will also require adjustments to the measurement technologies. Furthermore new trends in the emission legislation will increase test requirements to represent the real world conditions in a more realistic way.
Technical Paper

Design impacts on CVS systems meeting future requirements for equivalent zero emissions vehicles

2000-06-12
2000-05-0347
The latest legislation requires a dramatic reduction of motor vehicle exhaust emission. This is also a big challenge for emission measurement instrumentation, because of almost zero concentrations of certain components in the exhaust. For current measurement devices, which are recommended by the legislation, it is almost impossible to determine such low emission levels with adequate accuracy. The paper describes a new Constant Volume Sampling (CVS) system with reduced dilution, warming and quick flow rate changing capability. Possible solutions are discussed and the properties of data measured with test facilities which are prepared to cover S-ULEV and EURO IV applications are described. Also the selection of used materials is of rising importance. The tests were performed on a dynamic engine test bed which was equipped with such a CVS system and with emission analyzing systems for raw exhaust and diluted measurements.
Technical Paper

Evaluation of a New Design for CVS-Systems Meeting the Requirements of S-ULEV and EURO IV

2000-03-06
2000-01-0800
The latest legislation requires the automotive industry to once again reduce the emission levels of their latest vehicles. This leads to a new challenge in the field of emission measurement, because the concentrations of certain components of the exhaust gases are extremely low. For current measurement devices, which are recommended by the legislation, it is almost impossible to determine such low emission levels with the necessary accuracy. This study evaluates the features of an improved CVS system (Constant Volume Sampling) with the possibility of heating and the ability of changing flow rates quickly. Possible solutions are discussed and the properties of data measured with test facilities which are prepared to cover S-ULEV and EURO IV applications are described. The tests were performed on a dynamic engine test bed which was equipped with such a CVS system and with emission analyzing systems for raw exhaust and diluted measurements.
Technical Paper

Study of Interferences for ULEV-CVS Measurement, Related to the Complete Measuring System, Discussion of Error Sources, Cross-Sensitivity and Adsorption

2000-03-06
2000-01-0796
Bag emission measurements on Ultra Low Emission Vehicles require measurement sensitivities in the 1 ppm range for HC and NOx and measurement resolutions well below this to obtain sufficient accuracy and repeatability. Additionally, an analysis of the C2 to C12 components is required. In these emission ranges, adsorption, desorption, diffusion and chemical reaction processes may produce significant effects to the measuring values. Therefore, improvements are necessary to avoid this as far as possible. However, for physical reasons these effects cannot be eliminated completely. For example: Particle filters are not 100% efficient and particles will slowly contaminate the surfaces. Due to physical and chemical processes with some gas components, even stainless steel and Teflon can change their characteristics. Problems resulting from the physical and chemical effects and provisions to minimize the influences to the measuring accuracy and system stability are discussed.
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

Measuring Automotive Exhaust Particles Down to 10 nm

2020-09-15
2020-01-2209
The latest generation of internal combustion engines may emit significant levels of sub-23 nm particles. The main objective of the Horizon 2020 “DownToTen” project was to develop a robust methodology and provide policy recommendations towards the particle number (PN) emissions measurements in the sub-23 nm region. In order to achieve this target, a new portable exhaust particle sampling system (PEPS) was developed, being capable of measuring exhaust particles down to at least 10 nm under real-world conditions. The main design target was to build a system that is compatible with current PMP requirements and is characterized by minimized losses in the sub-23 nm region, high robustness against artefacts and high flexibility in terms of different PN modes investigation, i.e. non-volatile, volatile and secondary particles.
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