Road Load Measurement and Dynamometer Simulation Using Coastdown Techniques

Chapin, C. E.

doi:10.4271/810828

Cited by 26 publications

(4 citation statements)

References 9 publications

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“…First, the longitudinal vehicle dynamics model allows to compute the tractive effort F veh as a function of the vehicle's speed v veh and acceleration a veh using a set of road-load coefficients f 0 , f 1 , f 2 [30], [31]…”

Section: Vehicle Modelmentioning

confidence: 99%

Online Temperature-Aware Equivalent Consumption Minimization Strategy for Mild Hybrid Electric Powertrains

Acquarone,

Miretti,

Anselma

et al. 2024

IEEE Trans. Veh. Technol.

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In this work, an online energy management strategy for mild hybrid electric vehicles is developed to minimize the fuel consumption while simultaneously preventing battery overheating. Since mild hybrids are typically equipped with a passively cooled battery pack, the energy management strategy design needs to keep the battery temperature below an upper limit, preventing accelerated aging and thermal runaway. To address this issue, the equivalent consumption minimization strategy (ECMS) approach is extended to develop a real-time capable controller, termed thermal ECMS (Th-ECMS), that is sensitive to the thermal dynamics of the battery and that can enforce constraints on its temperature. The rationale for our formulation is based on Pontryagin's minimum principle from optimal control theory. The online Th-ECMS is developed on the basis of the offline version of Th-ECMS, introduced in a previous work. Exploiting the a priori knowledge of the driving mission, the offline Th-ECMS calibrates the equivalence factors and obtains the optimal solution, which is compared with the globally optimal dynamic programming solution. This offline calibration method is run on a large number of driving missions and the collected data is used to train a feed-forward neural network that estimates optimal equivalence factors as functions of the battery state of charge, battery temperature, and distance yet to travel. The trained network is then used to populate two lookup tables mapping the equivalence factors, and implementable on the vehicle electronic control unit. Finally, the online Th-ECMS obtains the equivalence factors through the look-up tables in realtime. The online strategy was tested in four different driving missions, achieving a fuel economy remarkably similar to the optimal solution and successfully avoiding battery overheating.

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Section: Vehicle Modelmentioning

confidence: 99%

Online Temperature-Aware Equivalent Consumption Minimization Strategy for Mild Hybrid Electric Powertrains

Acquarone,

Miretti,

Anselma

et al. 2024

IEEE Trans. Veh. Technol.

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“…First, the total vehicle resistance force was evaluated as a function of the vehicle speed v veh using a set of coast-down coefficients [15], [16]. Then, the required tractive effort, equal to the sum of the resistance force and the vehicle equivalent inertia, is translated into a torque request to the thermal engine and the e-machine via a torque-split coefficient α:…”

Section: Simulation Modelmentioning

confidence: 99%

Impact of Predictive Battery Thermal Management for a 48V Hybrid Electric Vehicle

Miretti¹,

Anselma²,

Spessa³

2022

Preprint

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Overheating of battery packs in electrified vehicles is detrimental to their lifetime and performance. Unfortunately, designing a control strategy that ensures battery protection without jeopardizing fuel economy is not a straightforward task. In this paper, we investigate battery temperature-sensitive optimal energy management for a 48V mild-hybrid electric vehicle to prevent overheating with minimal fuel consumption increase. Indeed, this family of hybrid architectures is challenging due to the absence of an active cooling system. In particular, we modeled a p0 parallel-hybrid with a 48V battery pack and we employed dynamic programming to numerically investigate the fuel economy capability while tracking the battery pack temperature. First, we tuned a battery current-constrained powertrain control strategy in order to avoid battery overheating, which could be easily implemented on-board. Then, we implemented a predictive temperature-constrained strategy that exploits the a priori knowledge of driving conditions and temperature constraints to maximize fuel economy. Results show that both strategies are able to meet the battery temperature constraints, although the predictive temperature-constrained control strategy outperforms the current-constrained strategy in terms of fuel economy. This case study demonstrates the theoretical benefits of a predictive battery thermal management for 48V mild hybrids.

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“…Currently, J2263 serves as the standard norm for road load testing in North America. Both test methods are based on the same method: accelerating the test vehicle over a certain speed on a sufficiently long, straight, and flat road; shifting the gear to neutral and letting the vehicle run via inertia only; measuring the duration of deceleration; and translating it into road load [5,[7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Study on the Criteria for the Determination of the Road Load Correlation for Automobiles and an Analysis of Key Factors

et al. 2016

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Abstract:To determine the fuel economy and emissions of a vehicle using a chassis dynamometer, the load to which the vehicle is subjected when it actually runs on a road, or the road load specifications, must be simulated when the dynamometer is applied. The most commonly used method to measure road load specifications is coastdown testing. Currently, road load is measured and provided by the manufacturer of the vehicle. Verification of the accuracy of the manufacturer's reported road load specifications by a third party may reveal that the specifications are inaccurate, possibly because of different testing locations, test drivers or test equipment. This study aims at identifying key factors that can affect a vehicle's road load correlation by using experimental design and deriving criteria for determining the correlation based on the energy difference.

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Road Load Measurement and Dynamometer Simulation Using Coastdown Techniques

Cited by 26 publications

References 9 publications

Online Temperature-Aware Equivalent Consumption Minimization Strategy for Mild Hybrid Electric Powertrains

Online Temperature-Aware Equivalent Consumption Minimization Strategy for Mild Hybrid Electric Powertrains

Impact of Predictive Battery Thermal Management for a 48V Hybrid Electric Vehicle

Study on the Criteria for the Determination of the Road Load Correlation for Automobiles and an Analysis of Key Factors

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