Characterization of Gaseous Emissions from Blended Plug-In Hybrid Electric Vehicles during High-Power Cold-Starts

Pham, Allen; Jeftić, Marko

doi:10.4271/2018-01-0428

Cited by 22 publications

(12 citation statements)

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“…For FTP-4BAG, the engine operation times before engine warm-up during the cold start in phase I were almost the same, resulting in similar fuel efficiencies. However, the 2.0 turbo (P)HEV (4WD) had a longer engine operation time to secure the purge volume, which resulted in decreased fuel efficiency in terms of percentage for phase III compared to phase I [22]. For FTP-4BAG (phases II, III, and IV), HWY, and US06, the fuel efficiency decreased due to differences in power source operating line strategies in response to the evaporative gas regulations.…”

Section: Mode Test Analysis Resultsmentioning

confidence: 99%

Operating lines for plug-in hybrid turbo charger systems meeting LEV III evaporative gas regulations

Park

2021

J Mech Sci Technol

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In 2020 the California Air Resources Board (CARB) implemented even more stringent regulation of vehicle emissions, its low-emission vehicle III (LEV III) program. In a (P)HEV T-GDI vehicle, the vehicle operates in EV driving mode when the engine is off, making it similarly difficult to comply with evaporative gas regulations. Automotive OEM strategy development to reduce vehicle evaporative gas and exhaust gas is in progress as these new emissions regulations are being implemented. Unlike in a naturally aspired engine, in a turbo gasoline direct injection (T-GDI) engine, the main operating area is the turbo boosting area. It operates in the positive pressure area rather than the negative pressure area, making it difficult to meet the requirements of the new evaporative gas regulationsI. The (P)HEV T-GDI characteristics showed the evaporative gas standards of LEV III, as well as regulations on CO 2 , fuel efficiency, and exhaust gas. 2.0 T-GDI single purge system vehicles showed 1.8 times engine operation time test results satisfied with evaporative gas test regulation values. Additionally, exhaust gas emissions in hot mode showed that CO(g/mile) affects 2.0 L T-GDI vehicles 2~3 times more than 3.0 L V6 T-GDI dual purge system vehicles. Fuel efficiency test results, confirming that the 3.0 V6 had about 15 % FTP, 20 % HWY, 18 % US06 better fuel efficiency compared to the 2.0 L T-GDI vehicles. Furthermore, the properties of the operating lines optimized for two plug-in hybrid turbo charger systems to assess whether they can meet the evaporative gas standards of LEV III, as well as regulations on CO 2 , fuel efficiency, and exhaust gas. The 2.0 L T-GDI vehicle bears fuel economy loss, increases the engine operating time, and responds to the regulation of evaporative gas, and the 3.0 V6 confirms that the engine operating time, fuel economy, exhaust gas, and evaporative gas are optimized. To respond to LEV III evaporative gas regulations, 2.0 L T-GDI PHEV vehicles take longer engine operation time, fuel economy loss, and respond to evaporative gas, CO 2 , emission regulations, 3.0 L V6 T-GDI PHEV vehicles confirmed that engine operation time, fuel economy, exhaust gas, and evaporative gas were optimized. They can meet the evaporative gas standards of LEV III, as well as regulations on CO 2 , fuel efficiency, and exhaust gas.

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Section: Mode Test Analysis Resultsmentioning

confidence: 99%

Operating lines for plug-in hybrid turbo charger systems meeting LEV III evaporative gas regulations

Park

2021

J Mech Sci Technol

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“…Researchers at CARB devised a methodology to compare the start emissions from high-power cold start acceleration cycles with emissions from regulated emission certification test cycles and found that high-power cold starts could be producing significantly higher exhaust emissions than those observed during regulated emission test cycles (4). For instance, for the 2016 Hyundai Sonata blended test PHEV used in their study, three acceleration cycles had NO x emissions that were five to seven times higher than the Federal Test Procedure test cycle (4).…”

Section: Literature Reviewmentioning

confidence: 94%

“…PHEV drivetrains can typically be classified as series systems, parallel systems, or series-parallel hybrid systems (4). For series systems, the drive wheels will solely receive mechanical power from the electric motor; for the parallel systems, the drive wheels are powered by the electric motor and the ICE together (4). In series-parallel hybrid systems, the wheels can be powered by any combination of the aforementioned modes.…”

Section: Literature Reviewmentioning

confidence: 99%

“…In series-parallel hybrid systems, the wheels can be powered by any combination of the aforementioned modes. The propensity for an ICE start in PHEVs is dependent on many factors, including the available battery energy or state-of-charge (SOC), the available electric motor torque to propel the drive wheels, the mechanical limits of the powertrain, and the vehicle road load (4).…”

Section: Literature Reviewmentioning

confidence: 99%

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Emission Implications of Plug-in Hybrid Electric Vehicles Through an Empirical Exploration of Engine Starts

Karanam

Tal

2021

Transportation Research Record: Journal of the Transportation R

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This paper aims to characterize the engine start activity profiles and emission potential of various plug-in hybrid electric vehicle (PHEV) models by examining the characteristics associated with engine starts, identifying the travel conditions that trigger engine starts, and determining the frequency of different types of engine starts. The study analyzed on-road vehicle data from six PHEV models: Toyota Prius Plug-in, Ford C-Max Energi, Ford C-Max Fusion, Toyota Prius Prime, Chrysler Pacifica, and Chevrolet Volt. An analysis on travel conditions before engine starts revealed that low state-of-charge is the dominant engine start trigger for PHEVs with high all-electric range whereas high vehicle power requirement is the most critical trigger for PHEVs with low all-electric range. For PHEVs with mid-range capabilities, several vehicle specifications, ranging from peak electric motor power to curb weight, could be engine start determinants. A strong inverse correlation exists between battery capacity and the annual frequency of engine starts but this relationship does not hold for cold and high-power cold starts. Both the low and the high battery capacity PHEVs logged fewer cold starts than the mid-sized battery vehicles, indicating that there could be a fundamental tradeoff between engine start emissions and fuel displacement for PHEVs to a certain degree. Despite this tradeoff, all PHEV models in the study logged fewer cold starts than comparable conventional internal combustion engine vehicles, performing the same trips. Ultimately, long-range PHEVs with high battery capacity are found to be ideal for both curbing start emissions and reducing fuel use.

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“…This supports the increased emission observed in several other studies. In this way, Pham et al [11] demonstrated high regulated emissions during high-powered cold starts. The results exceeded more than 9 times Federal Test Procedure (FTP) gaseous emissions for cold starts.…”

Section: Introductionmentioning

confidence: 94%

Impact of Exhaust Gas Recirculation on Gaseous Emissions of Turbocharged Spark-Ignition Engines

et al. 2020

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Exhaust gas recirculation is one of the technologies that can be used to improve the efficiency of spark-ignition engines. However, apart from fuel consumption reduction, this technology has a significant impact on exhaust gaseous emissions, inducing a significant reduction in nitrogen oxides and an increase in unburned hydrocarbons and carbon monoxide, which can affect operation of the aftertreatment system. In order to evaluate these effects, data extracted from design of experiments done on a multi-cylinder 1.3 L turbocharged spark-ignition engine with variable valve timing and low-pressure exhaust gas recirculation (EGR) are used. The test campaign covers the area of interest for the engine to be used in new-generation hybrid electric platforms. In general, external EGR provides an approximately linear decrease of nitrogen oxides and deterioration of unburned hydrocarbon emissions due to thermal and flame quenching effects. At low load, the impact on emissions is directly linked to actuation of the variable valve timing system due to the interaction of EGR with internal residuals. For the same external EGR rate, running with high valve overlap increases the amount of internal residuals trapped inside the cylinder, slowing down combustion and increasing Unburnt hydrocarbon (HC) emissions. However, low valve overlap (i.e., low internal residuals) operation implies a decrease in oxygen concentration in the exhaust line for the same air–fuel ratio inside the cylinders. At high load, interaction with the variable valve timing system is reduced, and general trends of HC increase and of oxygen and carbon monoxide decrease appear as EGR is introduced. Finally, a simple stoichiometric model evaluates the potential performance of a catalyst targeted for EGR operation. The results highlight that the decrease of nitrogen oxides and oxygen availability together with the increase of unburned hydrocarbons results in a huge reduction of the margin in oxygen availability to achieve a complete oxidation from a theoretical perspective. This implies the need to rely on the oxygen storage capability of the catalyst or the possibility to control at slightly lean conditions, taking advantage of the nitrogen oxide reduction at engine-out with EGR.

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Characterization of Gaseous Emissions from Blended Plug-In Hybrid Electric Vehicles during High-Power Cold-Starts

Cited by 22 publications

References 0 publications

Operating lines for plug-in hybrid turbo charger systems meeting LEV III evaporative gas regulations

Operating lines for plug-in hybrid turbo charger systems meeting LEV III evaporative gas regulations

Emission Implications of Plug-in Hybrid Electric Vehicles Through an Empirical Exploration of Engine Starts

Impact of Exhaust Gas Recirculation on Gaseous Emissions of Turbocharged Spark-Ignition Engines

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