On Board Fast Measurement of Vehicle NOx Emissions

Duckhouse, Matthew; Peckham, Mark; Bradley, Harry; Irwin, M.; Hammond, Matthew

doi:10.4271/2018-01-0646

Cited by 7 publications

(4 citation statements)

References 2 publications

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“…The analyser was configured to pass the exhaust sample through a NO x converter (based on the stainless steel method of NO 2 to NO conversion), to measure total NO x (here defined as NO + NO 2 )-and allowing for this conversion the analyser has a τ 10-90% response time of 10 ms. In order to accommodate the RDE test environment, a few modifications were made to the standard analyser set-up-as described in [11]-and, additionally, the sample probe was substantially longer, to allow measurement of the tailpipe NO x from within the bus cabin. The NO x sample point on all three vehicles tested was located roughly in the centre of the exhaust flow, after all of the exhaust aftertreatment (specified in Table 1), and a short distance before the exhaust exit, in order to ensure that the samples were taken without any risk of atmospheric dilution.…”

Section: Experimental Methodologymentioning

confidence: 99%

“…Recently, ultra-fast response gas analysers have been used to provide high spatio-temporal resolution RDE data from vehicles [11,12]. Such analysers, which have a response time of a few milliseconds, have been used for a long time in engine development, for example in cyclically resolved engine measurements [13,14], cold start [15,16], and emission reduction [17,18].…”

Section: Introductionmentioning

confidence: 99%

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Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

2020

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NO x emissions from vehicles have been a substantial cause for concern due to their impact on urban air quality. In particular, despite reducing levels of permitted emissions legislatively, such reductions have not been observed in the real world. In this work, NO x emissions from three vehicles-a Euro 5 car, a Euro V hybrid bus, and a Euro VI-bus have been measured in real driving conditions (and in the case of the buses-in full passenger service). A recently developed high spatio-temporal resolution technique combining very fast (10 ms) NO x measurement with differential GPS accurate to 1 cm allows these emissions to be resolved to a distance of less than 10 cm (worst-case-dependent on vehicle speed). The results show that acceleration events for the vehicles play a significant part in their total NO x emissions. In addition, standard events such as a speed bump and a bus stop are analysed. The temperature of any aftertreatment (catalytic converter) to reduce NO x emissions is also observed to be of substantial significance. At idle, the passenger car was observed to near-double its NO x emissions when the air conditioning was switched on. Finally, the real driving conditions are compared to the legislative compliance cycles for the certification of the buses, and those results used to further understand the observed NO x emissions.

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Section: Experimental Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

2020

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“…The duration of the urban transients are generally much shorter than this (often a fraction of a second) and therefore impossible to resolve. This paper describes a new technique for adapting a set of well-established fast response emissions analysers with millisecond response times (Duckhouse et al, 2018) to on-board use, specifically to identify and correlate real world rapid transients with engine control actuations which can help reveal the causes of emissions events. In addition, the use of two measurement channels allows for simultaneous measurement of both engine-out and tailpipe emissions data for analysis of after treatment effectiveness.…”

Section: Engine Characterization and Calibration Developmentmentioning

confidence: 99%

The Measurement of Fast Transient Emissions During Real World Driving

et al. 2020

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Some of the most challenging aspects of preparing vehicles to comply with the new RDE (Real Driving Emissions) legislation are the calibration of engines to minimize emissions during numerous short lived transients. Fast response emissions analyzers are necessary to resolve rapid transient emissions and have been deployed simultaneously in the engine-out and tailpipe exhaust gas stream of several vehicles. The methodology presented and capability of the instrumentation enables fine resolution of emissions events leading to the opportunity for fine tuning of controller performance. Data has also been logged from the vehicles' ECUs and combined with accurate GPS data. The results show that certain road lay-outs (e.g., congested junctions and speed bumps) can provoke significant tailpipe NOx emissions; often emitting very high levels near schools where traffic calming measures have been adopted for road safety. The lean excursions and insufficient rich purge during such transients are generally shown to be the cause of such emitting events.

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“…Of course, these mg/km values, whether certification or RDE, are not emitted constantly by a vehicle, these values represent an average. Vehicle emissions in practice are dictated by, amongst other things, the engine speed and load (which are a function of how the vehicle is driven) and the temperature of the aftertreatment systems and vary transiently along a journey (Duckhouse et al, 2018;Leach et al, 2020). Depending on the length of a journey, a substantial portion of emissions are emitted during the cold-start phase (where the engine and aftertreatment systems are not yet at their operating temperatures) (Stone, 2012).…”

Section: Introductionmentioning

confidence: 99%

A negative emission internal combustion engine vehicle?

Leach

2023

Atmospheric Environment

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On Board Fast Measurement of Vehicle NOx Emissions

Cited by 7 publications

References 2 publications

Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

The Measurement of Fast Transient Emissions During Real World Driving

A negative emission internal combustion engine vehicle?

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