Investigation of Methods for Improved Exhaust Emissions Measurement of Plug-in Hybrid Electric Vehicles

Rooney, Richard T.; Nevius, Tim

doi:10.4271/2012-01-0884

Cited by 2 publications

(3 citation statements)

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“…In this study, more water condensation should occur in the cold start cycle since the vehicle and connecting tube have the lowest initial temperature compared to that in the non-cold-start cycles. Thus, the portion of CO 2 , if absorbed in the condensed water as mentioned in the literature, 1 should be more in the cold start cycles and cannot be purged out. The CO, THC and the products of incomplete combustion can also diffuse into water, in the same way as the CO 2 and contribute to the calculation of equivalent CO 2 .…”

Section: Resultsmentioning

confidence: 99%

“…It is cited that the trapped CO 2 in the condensed water can be a reason for the difference of CVS and FFM in the cold start cycles. 1 This section will quantitatively address the impact of water condensation on different emission species trapped in the condensed water.…”

Section: Resultsmentioning

confidence: 99%

“…Plug-in hybrid electric vehicles (PHEVs) present difficulties for the constant volume sampler (CVS) system, which has served as a robust emission sampling system for the automobile for more than 40 years. Recent research 1–4 has been undertaken to address the issues associated with new vehicles due to their extremely low exhaust generation and the intermittent work pattern of the engine in the charge-depleting (CD) cycle. 5 Toyota Technical Center (TTC), Gardena, California; Horiba Automotive Division (HAD), Ann Arbor, Michigan, and the University of California, Irvine (UCI), California, have collaborated to implement emission testing on a TOYOTA prototype Prius Plug-in to improve the emission sampling system.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the constant volume sampler on plug-in hybrid electric vehicle cold start emission testing

Zhang

Brown

Samuelsen

2013

International Journal of Engine Research

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Previous study shows that the constant volume sampler incorrectly measures some of the exhaust gas when testing a plug-in hybrid electric vehicle in the cold start condition when comparing the CO 2 results from constant volume sampler and fuel flow meter. The main reason is likely associated with the exhaust left in the vehicle tailpipe and constant volume sampler sampling line. Other factors, such as fuel line expansion and water condensation in the exhaust system, are also considered to have contributions. This article evaluates these issues quantitatively by testing a Toyota Prius hybrid electric vehicle on the industry standard constant volume sampler system combined with both a fuel flow meter measurement and an electronic control unit record for fuel consumption. Cold start test cycles and test cycles with a system pre-purge event show that the constant volume sampler has a significant delay in measuring the exhaust, and the estimated exhaust losses for the test car are 15 g CO 2 . Tests with a purge event at the end of the driving cycle show that there are approximately 7 g of CO 2 trapped in the exhaust system and the constant volume sampler sampling line, and the possible reasons for the discrepancy of the above two points (15 and 7 g) are evaluated. The expansion and air bubble influence the fuel flow meter, and the impact of water condensation on CO 2 and CO appears to be negligible.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%