Light Duty Hybrid Vehicles - Influence of Driving Cycle and Operating Temperature on Fuel Economy and GHG Emissions

2006 ◽  
Author(s):  
Lisa Graham ◽  
Martha Christenson ◽  
Deniz Karman
Keyword(s):  
Fuel Economy ◽  
Operating Temperature ◽  
Ghg Emissions ◽  
Hybrid Vehicles ◽  
Driving Cycle ◽  
Light Duty

Meeting the Challenge: A Stochastic Assessment of the U.S. Light-Duty Vehicle Fuel Economy Standards

2012 ◽  
Author(s):  
Parisa Bastani ◽  
John B. Heywood ◽  
Chris Hope
Keyword(s):  
Fuel Economy ◽  
Ghg Emissions ◽  
Corporate Average Fuel Economy ◽  
Passenger Cars ◽  
Policy Model ◽  
Light Duty ◽  
Stochastic Transport ◽  
Light Trucks ◽  
Light Duty Vehicle ◽  
The U.S

The U.S. Department of Transport and EPA have recently proposed further regulation of the light-duty vehicle corporate average fuel economy and GHG emissions for model years 2017 to 2025. Policy makers are setting more stringent targets out to 2025 in a context of significant uncertainty. These uncertainties need to be quantified and taken into account systematically when evaluating policies. In this paper, a stochastic technology and market vehicle fleet analysis is carried out, using the STEP (Stochastic Transport Emissions Policy model), to assess the probability of meeting the proposed CAFE targets in 2016 and 2025, and identify factors that play key roles in the near and midterm. Our results indicate that meeting the proposed targets requires (a) aggressive technological progress rate and deployment, (b)aggressive market penetration of advanced engines and powertrains, (c) aggressive vehicle downsizing and weight reduction, and (d) a high emphasis on reducing fuel consumption. Three scenarios are examined to assess the likelihood of meeting the proposed targets. The targets examined here, 32.5 and 34.1 mpg in 2016 and 44 and 54.5 mpg in 2025, are reduced from the nominal CAFE values after allowing for the various credits in the proposed rulemaking. The results show that there is about a 42.5% likelihood of the passenger cars average fuel economy falling below 32.5 mpg and a 5.3% likelihood of it exceeding 34.1 mpg in 2016, and about a 4% chance of it exceeding 44 mpg in 2025, under the plausible-ambitious scenario. Under the EPA/DOT preferred alternative scenario, the likelihood of passenger cars average fuel economy meeting or exceeding 34.1 mpg in 2016 and 44 mpg in 2025 increases to about 74% and 34.5% respectively. The probability of meeting these combined CAFE targets drops to less than 1% in both near and mid terms, once light trucks are included in the mix. This analysis quantifies the probability of meeting the targets therefore to enable risk-based contingency planning, and identifies key drivers of uncertainty where further strategic research is needed.

Effects of Bearing Preload, Oil Volume, and Operating Temperature on Axle Power Losses

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hai Xu ◽  
Avinash Singh ◽  
Ahmet Kahraman ◽  
Joshua Hurley ◽  
Sam Shon
Keyword(s):  
Fuel Economy ◽  
Environmental Protection Agency ◽  
Power Loss ◽  
Operating Temperature ◽  
Driving Cycle ◽  
Power Losses ◽  
Driving Cycles ◽  
Gear Oil ◽  
Operating Temperatures ◽  
Bearing Preload

In order to boost the fuel economy of their vehicles, automotive Original Equipment Manufacturers (OEMs) and suppliers have been investigating a range of options from alternate vehicle propulsion systems down to optimized component level technologies. The hypoid gear set in a rear axle is one of the least efficient drive train components, and as such, provides unique opportunities for improvements. It has therefore attracted significant attention from researchers to reduce the power losses. Both loaded and unloaded power losses have been studied before and found to vary significantly with load and speed conditions. This paper will focus on the effects of the axle pinion bearing preload, axle gear oil levels, and operating temperatures on axle power losses during the fuel economy driving cycles where both axle load and speed vary significantly. In this paper, power loss measurements from experiments conducted on an automotive rear drive axle on a dedicated dynamometer will be presented. Tests were conducted under a range of speed and load conditions that were developed from Environmental Protection Agency (EPA) fuel economy driving cycles. Both urban and highway cycles were included in the tests. Separate tests were conducted for unloaded spin losses and loaded power losses. The tests were conducted at a few different controlled levels of gear oil operating temperatures, gear oil volumes, and pinion bearing preloads, and their influence on power losses was quantified. The measured power losses at a matrix of load and speed conditions provide a series of power loss maps as a function of gear oil operating temperature, oil volume, and bearing preload. Using these power loss maps, the overall axle efficiency or power loss during any driving cycle can be quantified by integrating the instantaneous power losses as the axle goes through the driving cycles. Similar maps can be created for other influences and the proposed procedure can be utilized to quantify their influences on a given driving cycle. Results from this study indicate that with the combination of appropriate preloads, gear oil volume, and temperature control, axle efficiency can potentially be improved by roughly 3% in the tested axle.

Investigation of the Contribution of Deceleration Fuel Cut-off and Start/Stop Technologies to Fuel Economy by Considering New European Driving Cycle

2022 ◽  
pp. 036119812110669
Author(s):  
Merve Tekin ◽  
M. İhsan Karamangil
Keyword(s):  
Fuel Consumption ◽  
Fuel Economy ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Ghg Emissions ◽  
Driving Cycle ◽  
Consumption Values ◽  
Transportation Sector ◽  
Light Commercial Vehicle ◽  
Fuel Consumption And Emissions

Greenhouse gas (GHG) emissions released into the atmosphere cause climate change and air pollution. One of the main causes of GHG emissions is the transportation sector. The use of fossil fuels in internal combustion engine vehicles leads to the release of these harmful gases. For this reason, since 1992, several standards have been introduced to limit emissions from vehicles. Technologies such as reducing engine sizes, advanced compression-ignition or start/stop, and fuel cut-off have been developed to reduce fuel consumption and emissions. In this study, the contribution of deceleration fuel cut-off and start/stop technologies to fuel economy has been examined considering the New European Driving Cycle. Therefore, the fuel consumption values were calculated by creating a longitudinal vehicle model for a light commercial vehicle with a diesel engine. At the end of the study, by using the two strategies together, fuel economies of 17.5% in the urban driving cycle, 3.7% in the extra-urban cycle, and 10% in total were achieved. CO2 emissions decreased in parallel with fuel consumption, by 10.1% in total.

Effects of Bearing Preload, Oil Volume and Operating Temperature on Axle Power Losses

2011 ◽  
Author(s):  
Hai Xu ◽  
Avinash Singh ◽  
Ahmet Kahraman ◽  
Joshua Hurley ◽  
Sam Shon
Keyword(s):  
Fuel Economy ◽  
Power Loss ◽  
Operating Temperature ◽  
Driving Cycle ◽  
Power Losses ◽  
Component Level ◽  
Driving Cycles ◽  
Gear Oil ◽  
Operating Temperatures ◽  
Bearing Preload

In order to boost the fuel economy of their vehicles, automotive OEMs and suppliers have been investigating a range of options from alternate vehicle propulsion systems down to optimized component level technologies. A rear axle differential with a hypoid gear set is one of the least efficient drive train components, and as such, provides unique opportunities for improvements. It has therefore attracted significant attention from researchers to reduce the power losses. Both loaded and unload power losses have been studied before and found to vary significantly with load and speed conditions. This paper will focus on the effects of the axle pinion bearing preload, axle gear oil levels and operating temperatures on axle power losses during the fuel economy driving cycles where both axle load and speed vary significantly. In this paper, power loss measurements from experiments conducted on an automotive rear drive axle on a dedicated dynamometer will be presented. Tests were conducted under a range of speed and load conditions that were developed from EPA fuel economy driving cycles. Both urban and highway cycles were included in the tests. Separate tests were conducted for unloaded spin losses and loaded power losses. The tests were conducted at a few different controlled levels of gear oil operating temperatures, gear oil volumes and pinion bearing preloads, and their influence on power losses were quantified. The measured power losses, at a matrix of load and speed conditions provide a series of power loss maps as a function of gear oil operating temperature, oil volume, and bearing preload. Using these power loss maps, the overall axle efficiency or power loss during any driving cycle can be quantified by integrating the instantaneous power losses as the axle goes through the driving cycles. Similar maps can be created for other influences and the proposed procedure can be utilized to quantify their influences on a given driving cycle. Results from this study indicate that with the combination of appropriate preloads, gear oil volume and temperature control, axle efficiency can potentially be improved by roughly 3% in the tested axle.

scholarly journals Drive cycle simulation of high efficiency combustions on fuel economy and exhaust properties in light-duty vehicles

2015 ◽  
Vol 157 ◽  
pp. 762-776 ◽  
Author(s):  
Zhiming Gao ◽  
Scott J. Curran ◽  
James E. Parks ◽  
David E. Smith ◽  
Robert M. Wagner ◽  
...  
Keyword(s):  
Fuel Economy ◽  
High Efficiency ◽  
Drive Cycle ◽  
Cycle Simulation ◽  
Light Duty ◽  
Light Duty Vehicles

Role of Trip Information Preview in Fuel Economy of Plug-In Hybrid Vehicles

2009 ◽  
Author(s):  
Chen Zhang ◽  
Ardalan Vahidi ◽  
Xiaopeng Li ◽  
Dean Essenmacher
Keyword(s):  
Dynamic Programming ◽  
Fuel Economy ◽  
Substantial Reduction ◽  
Hybrid Vehicles ◽  
Hilly Terrain ◽  
Additional Increase ◽  
Charging Station ◽  
Complete Knowledge ◽  
Deterministic Dynamic

This paper investigates the role of partial or complete knowledge of future driving conditions in fuel economy of Plug-in Hybrid Vehicles (PHEVs). We show that with the knowledge of distance to the next charging station only, substantial reduction in fuel use, up to 18%, is possible by planning a blended utilization of electric motor and the engine throughout the entire trip. To achieve this we formulate a modified Equivalent Consumption Minimization Strategy (ECMS) which takes into account the traveling distance. We show further fuel economy gain, in the order of 1–5%, is possible if the future terrain and velocity are known; we quantify this additional increase in fuel economy for a number of velocity cycles and a hilly terrain profile via deterministic dynamic programming.

The WLTC vs NEDC: A Case Study on the Impacts of Driving Cycle on Engine Performance and Fuel Consumption

2021 ◽  
Vol 18 (3) ◽  
pp. 9071-9081
Author(s):  
Jakub Lasocki
Keyword(s):  
Fuel Consumption ◽  
Combustion Engine ◽  
Engine Performance ◽  
Driving Cycle ◽  
Performance Characteristics ◽  
Pollutant Emission ◽  
Strong Impact ◽  
Light Duty ◽  
Light Duty Vehicles

The World-wide harmonised Light-duty Test Cycle (WLTC) was developed internationally for the determination of pollutant emission and fuel consumption from combustion engines of light-duty vehicles. It replaced the New European Driving Cycle (NEDC) used in the European Union (EU) for type-approval testing purposes. This paper presents an extensive comparison of the WLTC and NEDC. The main specifications of both driving cycles are provided, and their advantages and limitations are analysed. The WLTC, compared to the NEDC, is more dynamic, covers a broader spectrum of engine working states and is more realistic in simulating typical real-world driving conditions. The expected impact of the WLTC on vehicle engine performance characteristics is discussed. It is further illustrated by a case study on two light-duty vehicles tested in the WLTC and NEDC. Findings from the investigation demonstrated that the driving cycle has a strong impact on the performance characteristics of the vehicle combustion engine. For the vehicles tested, the average engine speed, engine torque and fuel flow rate measured over the WLTC are higher than those measured over the NEDC. The opposite trend is observed in terms of fuel economy (expressed in l/100 km); the first vehicle achieved a 9% reduction, while the second – a 3% increase when switching from NEDC to WLTC. Several factors potentially contributing to this discrepancy have been pointed out. The implementation of the WLTC in the EU will force vehicle manufacturers to optimise engine control strategy according to the operating range of the new driving cycle.

Fuel economy optimization of power split hybrid vehicles: A rapid dynamic programming approach

Energy ◽  
2019 ◽  
Vol 166 ◽  
pp. 929-938 ◽  
Author(s):  
Yalian Yang ◽  
Huanxin Pei ◽  
Xiaosong Hu ◽  
Yonggang Liu ◽  
Cong Hou ◽  
...  
Keyword(s):  
Dynamic Programming ◽  
Fuel Economy ◽  
Hybrid Vehicles ◽  
Programming Approach ◽  
Dynamic Programming Approach ◽  
Power Split
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