Benchmarking of Dedicated Hybrid Transmissions

Parallel hybrid drivetrains for passenger cars have additional electric drives compared to conventional drivetrains. In the event of vehicle deceleration, the electric drives are operated as generators, thus recovering kinetic energy through regeneration. If these drives are positioned upstream of the transmission input, regeneration power must be transferred by the transmission. This creates additional loads on the individual machine elements, which has a negative effect on the transmission lifetime. This paper investigates the influence of hybridization in terms of regeneration on the lifetime of bearings as highly critical elements in a dual clutch transmission. The vehicle simulation model employed in this study consists of an internal combustion engine, an electric motor, a mechanical drivetrain and the vehicle body, as well as a driver and a simple operating strategy. In this model, a detailed transmission model including its controls is embedded to determine its component loads. The resulting load spectra are used in a methodical approach to calculate the bearing lifetime of the transmission. The results show that the additional regenerative power flow reduces the bearing lifetime so that additional loads must be taken into account in the development and operation of transmission systems.

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“…Here, it is assumed that the group of bearings fails as soon as one bearing fails. The underlying Boolean relationship is given in Equation (7).…”

Section: System Modelmentioning

confidence: 99%

Influence of Drivetrain Hybridization on Transmission Lifetime

et al. 2020

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“…Hybridized powertrains can be generally of a dedicated or an add-on type [6,7]. Dedicated Hybrid Transmissions (DHT) use custom designed transmissions that can be mostly of a planetary gear train type [6,7].…”

Section: Introductionmentioning

confidence: 99%

Study of the Impact of E-Machine in Hybrid Dual Clutch Transmission Powertrain

et al. 2022

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Recent studies show that hybrid powertrains with dual clutch transmission are becoming more common. This is mainly influenced by the fact that they have higher efficiency, allow power-on shifting, and are more compact. However, the electric motor attached to the primary shaft of the transmission might represent some critical issues in statics and dynamics due to additional torque, inertia, and working irregularities. This paper aims to investigate the influence of the electric motor integration in the transmission on the reliability of the overall system. The focus is on the investigation of potential over stresses of the ICE bearings due to the bending of the gearbox primary shaft. To achieve the aim, the static and the rotor dynamic analysis of the inner and outer primary shafts is performed. The numerical analyses show the potential critical issues that can arise from the excessive manufacturing and assembling tolerances, the interaction of the e-machine torque irregularities and inertia with the bending dynamics of the primary shafts.

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“…The power flows within the powertrain are handled by a power-split unit (PSU) made up of planetary gear sets (PGs) and ordinary gear sets (OGs). Multi-PG PSU enables the minimization of the electric machines' power size by deploying a multi-mode power-split continuously variable transmission (PS-CVT), where some clutches operations lead to several constructive arrangements to select under the desired driving conditions [6][7][8][9][10]. Nevertheless, the more complex the transmission constructive layout is, the trickiest the identification of the occurring power flows is [11][12][13], as well as their management [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Power Losses Minimization for Optimal Operating Maps in Power-Split HEVs: A Case Study on the Chevrolet Volt

Castellano

Cammalleri

2021

Applied Sciences

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The power-split architecture is the most promising hybrid electric powertrain. However, a real advantage in energy saving while maintaining high performance can be achieved only by the implementation of a proper energy management strategy. This requires an optimized functional design before and a comprehensive analysis of the powertrain losses after, which could be rather challenging owing to the constructive complexity of the power-split transmission, especially for multi-mode architecture with multiple planetary gearing. This difficulty was overcome by a dimensionless model, already available in the literature, that enables the analysis of any power-split transmission, even in full electric operation. This paper relies on this approach to find the operating points of the internal combustion engine and both electric machines which minimize the total power losses. This optimization is carried out for given vehicle speed and demanded torque, by supposing different scenarios in respect of the battery capability of providing or gathering power. The efficiency of the thermal engine and the electric machines is considered, as well as the transmission mechanical power losses. The aim is to provide a global efficiency map that can be exploited to extract data for the implementation of the most suitable real-time control strategy. As a case study, the procedure is applied to the multi-mode power-split system of the Chevrolet Volt.

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Benchmarking of Dedicated Hybrid Transmissions

Cited by 12 publications

References 10 publications

Influence of Drivetrain Hybridization on Transmission Lifetime

Influence of Drivetrain Hybridization on Transmission Lifetime

Study of the Impact of E-Machine in Hybrid Dual Clutch Transmission Powertrain

Power Losses Minimization for Optimal Operating Maps in Power-Split HEVs: A Case Study on the Chevrolet Volt

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