Simulated Real-World Energy Impacts of a Thermally Sensitive Powertrain Considering Viscous Losses and Enrichment

Jehlik, Forrest; Wood, Eric; Gonder, Jeffrey; Lopp, Sean

doi:10.4271/2015-01-0342

Cited by 8 publications

(6 citation statements)

References 9 publications

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“…Prior research investigating thermal impacts on vehicle fuel economy involved applying Typical Meteorological Year (TMY) temperature profiles during powertrain simulations [20,21] . Incorporating TMY temperatures was not pursued during this investigation because similar real-world weighted temperature effects can be captured by applying several static ambient temperatures and adjusting for the distribution described by Figure 21.…”

Section: Real-world Simulationsmentioning

confidence: 99%

Determining Off-cycle Fuel Economy Benefits of 2-Layer HVAC Technology

Jehlik

Chevers

Moniot

et al. 2018

SAE Technical Paper Series

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his work presents a methodology to determine the off-cycle fuel economy benefit of a 2-Layer HVAC system which reduces ventilation and heat rejection losses of the heater core versus a vehicle using a standard system. Experimental dynamometer tests using EPA drive cycles over a broad range of ambient temperatures were conducted on a highly instrumented 2016 Lexus RX350 (3.5L, 8 speed automatic). These tests were conducted to measure differences in engine efficiency caused by changes in engine warmup due to the 2-Layer HVAC technology in use versus the technology being disabled (disabled equals fresh air-considered as the standard technology baseline). These experimental datasets were used to develop simplified response surface and lumped capacitance vehicle thermal models predictive of vehicle efficiency as a function of thermal state. These vehicle models were integrated into a database of measured on road testing and coupled with U.S. typical meteorological data to simulate vehicle efficiency across seasonal thermal and operational conditions for hundreds of thousands of drive cycles. Fuel economy benefits utilizing the 2-Layer HVAC technology are presented in addition to goodness of fit statistics of the modeling approach relative to the experimental test data. FIGURE 1 2-Layer air flows © SAE International FIGURE 2 2016 Lexus RX350 test vehicle on APRF dynamometer for testing.

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Section: Real-world Simulationsmentioning

confidence: 99%

Determining Off-cycle Fuel Economy Benefits of 2-Layer HVAC Technology

Jehlik

Chevers

Moniot

et al. 2018

SAE Technical Paper Series

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“…Vehicle modeling in this analysis builds off a previous effort to develop thermally sensitive maps of engine efficiency driven by lumped capacitance models of engine oil, engine coolant, and exhaust catalyst temperature [4]. A schematic of the overall simplified approach is shown in Figure 12.…”

Section: Vehicle Modelingmentioning

confidence: 99%

“…The approach includes backward facing calculations that start with the power required at the wheels which is scaled based on component efficiency for the transaxle, gearbox, torque converter, and engine. In addition to the existing models for thermally sensitive engine efficiency [4], a simplified model of transmission efficiency and its sensitivity to thermal conditions is implemented. As with the thermal models of engine and exhaust temperatures, the transmission oil temperature is modeled using a lumped capacitance approach.…”

Section: Vehicle Modelingmentioning

confidence: 99%

On-Road Validation of a Simplified Model for Estimating Real-World Fuel Economy

Wood¹,

Gonder²,

Jehlik³

2017

SAE Int. J. Fuels Lubr.

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On-road fuel economy is known to vary significantly between individual trips in real-world driving conditions. This work introduces a methodology for rapidly simulating a specific vehicle's fuel economy over the wide range of real-world conditions experienced across the country. On-road test data collected using a highly instrumented vehicle is used to refine and validate this modeling approach. Model accuracy relative to on-road data collection is relevant to the estimation of "off-cycle credits" that compensate for real-world fuel economy benefits that are not observed during certification testing on a chassis dynamometer.

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“…Combining the sales-weighted baseline efficiency values, results translate percent into absolute benefit of 1.5 gCO 2 /mi (cars) and 3.2 gCO 2 /mi (light-duty trucks). In previous works that focused on real-world effects on powertrain efficiency [5,7] simplified thermal models of a conventional vehicle were developed from experimental testing data to predict real-world effects on vehicle efficiency. From this work it was shown that regional temperature variations play a significant role in vehicle engine efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…The data from this effort were then used to develop a simplified thermally sensitive transmission efficiency model that could be used to investigate transmission warming technology impacts under real world conditions. The goal of this approach is to ultimately integrate all results into an experimentally data derived, simplified model [5,7,8], that allows for analysis of fuel efficiency gains of technologies applied to real world conditions.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Transmission Warming Technologies at Various Ambient Conditions

Jehlik

Iliev

Wood

et al. 2017

SAE Technical Paper Series

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This work details two approaches for evaluating transmission warming technology: experimental dynamometer testing and development of a simplified transmission efficiency model to quantify effects under varied real world ambient and driving conditions. Two vehicles were used for this investigation: a 2013 Ford Taurus and a highly instrumented 2011 Ford Fusion (Taurus and Fusion). The Taurus included a production transmission warming system and was tested over hot and cold ambient temperatures with the transmission warming system enabled and disabled. A robot driver was used to minimize driver variability and increase repeatability. Additionally the instrumented Fusion was tested cold and with the transmission pre-heated prior to completing the test cycles. These data were used to develop a simplified thermally responsive transmission model to estimate effects of transmission warming in real world conditions.For the Taurus, the fuel consumption variability within one standard deviation was shown to be under 0.5% for eight repeat Urban Dynamometer Driving Cycles (UDDS). These results were valid with the transmission warming system active or passive. Using the transmission warming system under 22°C ambient temperature, fuel consumption reduction was shown to be 1.4%. For the Fusion, pre-warming the transmission reduced fuel consumption 2.5% for an urban drive cycle at -7°C ambient temperature, with 1.5% of the 2.5% gain associated with the transmission, while consumption for the US06 test was shown to be reduced by 7% with 5.5% of the 7% gain associated with the transmission. It was found that engine warming due to conduction between the pre-heated transmission and the engine resulted in the remainder of the benefit. For +22°C ambient tests, the pre-heated transmission was shown to reduce fuel consumption approximately 1% on an urban cycle, while no benefit was seen for the US06 cycle. The simplified modeling results showed gains in efficiency ranging from 0-1.5% depending on the ambient temperature and drive cycle.

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Simulated Real-World Energy Impacts of a Thermally Sensitive Powertrain Considering Viscous Losses and Enrichment

Cited by 8 publications

References 9 publications

Determining Off-cycle Fuel Economy Benefits of 2-Layer HVAC Technology

Determining Off-cycle Fuel Economy Benefits of 2-Layer HVAC Technology

On-Road Validation of a Simplified Model for Estimating Real-World Fuel Economy

Investigation of Transmission Warming Technologies at Various Ambient Conditions

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