Automotive Transmissions

Naunheimer, Harald; Bertsche, Bernd; Ryborz, Joachim; Novak, Wolfgang

doi:10.1007/978-3-642-16214-5

Cited by 197 publications

(77 citation statements)

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“…Oerlikon Graziano SpA has developed an in-house mathematical model that estimates the transmission power loss contributions in steady-state conditions (see references [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] for the relevant literature on the topic). Based on the transmission design parameters, the model generates the transmission power loss maps as functions of the input torque, input speed, and operating temperatures of the transmission and clutch lubricant.…”

Section: Transmission Power Loss Modelmentioning

confidence: 99%

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On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions

et al. 2017

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Abstract:The main benefits of dual clutch transmissions (DCTs) are: (i) a higher energy efficiency than automatic transmission systems with torque converters; and (ii) the capability to fill the torque gap during gear shifts to allow seamless longitudinal acceleration profiles. Therefore, DCTs are viable alternatives to automated manual transmissions (AMTs). For vehicles equipped with engines that can generate considerable torque, large clutch-slip energy losses occur during power-on gear shifts and, as a result, DCTs need wet clutches for effective heat dissipation. This requirement substantially reduces DCT efficiency because of the churning and ancillary power dissipations associated with the wet clutch pack. To the knowledge of the authors, this study is the first to analyse the detailed power loss contributions of a DCT with wet clutches, and their relative significance along a set of driving cycles. Based on these results, a novel hybridised AMT (HAMT) with a single dry clutch and an electric motor is proposed for the same vehicle. The HAMT architecture combines the high mechanical efficiency typical of AMTs with a single dry clutch, with the torque-fill capability and operational flexibility allowed by the electric motor. The measured efficiency maps of a case study DCT and HAMT are compared. This is then complemented by the analysis of the respective fuel consumption along the driving cycles, which is simulated with an experimentally validated vehicle model. In its internal combustion engine mode, the HAMT reduces fuel consumption by >9% with respect to the DCT.

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Section: Transmission Power Loss Modelmentioning

confidence: 99%

“…The synchroniser power loss values, P synchro,i , are based on the experimentally measured drag torque characteristics of the specific synchronisers. The power loss of the i-th oil seal, P seal,i , facing the respective rotating part of the transmission [25], is modelled as:…”

mentioning

confidence: 99%

On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions

et al. 2017

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“…The safety factor for bending stress F S is calculated as follows [7] [8] Figure 5. Bending stress at the tooth root.…”

Section: Tooth Bending Stressmentioning

confidence: 99%

Optimisation of Effective Design Parameters for an Automotive Transmission Gearbox to Reduce Tooth Bending Stress

Bozca¹

2017

MME

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Optimisation of effective design parameters to reduce tooth bending stress for an automotive transmission gearbox is presented. A systematic investigation of effective design parameters for optimum design of a five-speed gearbox is studied. For this aim contact ratio effect on tooth bending stress by the changing of contact ratio with respect to pressure angle is analysed. Additionally, profile modification effects on tooth bending stress are presented. During the optimisation, the tooth bending stress is considered as the objective function, and all the geometric design parameters such as module, teeth number etc. are optimised under two different constraints, including tooth contact stress and constant gear centre distance. It can be concluded that higher the contact ratio results in a reduced tooth bending stress, while higher the pressure angle caused an increase in tooth bending stress and contact stress, since decreases in the contact ratio. In addition, application of positive profile modification on tooth reduces tooth bending stress. All of the obtained optimum solutions satisfy all constraints.

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“…The 5-speed manual gearbox (GB) is comprised of a train of spur gears (Harald Naunheimer, Bernd Bertsche, Joachim Ryborz, 1994). Such gears are commonly used in automotive applications because they are 98-99% efficient (Norton, 1992).…”

Section: Discrete Gearboxmentioning

confidence: 99%

“…As the sun gear turns, it will force the planet gears to turn in the opposite direction, which turns the ring gear. The planet carrier can also turn, which causes the planet gears to rotate around the sun gear allowing for different speed outputs (including negative speeds) at the ring gear (Norton, 1992;Harald Naunheimer, Bernd Bertsche, Joachim Ryborz, 1994). The Powersplit Device is described using 6 variables and 3 algebraic equations, thus allows 3 Degrees-of-Freedom (DOF).…”

Section: Powersplit Devicementioning

confidence: 99%

Automated topology optimisation of hybrid electric vehicle powertrains

Ing

McPhee

2015

IJEHV

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Abstract:Hybrid Electric powertrains are comprised of gasoline and electric powertrains components. These components can be connected in numerous configurations; as the number of components increase, the number of configurations increase exponentially. In this research, an algorithm was developed to automatically assemble and compare all possible hybrid electric powertrain configurations. Combinatorics was used to discover all possible combinations of: an internal combustion engine, high-torque low-speed electric motor, low-torque high-speed electric motor, planetary gearset, five-speed discrete gearbox, and battery. The Graph Theoretic Method was used to generate the powertrain models. The steadystate system models were solved symbolically, and Dynamic Programming was used to determine the optimal control law that minimized fuel consumption. To save computation time, topologies were evaluated using a multi-stage screening process. The component sizes of the top 24 topologies were optimized and ranked by fuel consumption. It was found that the Parallel and Powersplit-like topologies with discrete gearboxes were most efficient. The best performing topology is a Powersplit Hybrid type, with a discrete gearbox connected to the final drive and the output gear of the planetary carrier and electric motor in parallel.Keywords: hybrid electric vehicles; hybrid electric powertrains; topology optimization; linear graph theory; Graph Theoretic Method; design automation Biographical notes: IntroductionConventional transportation vehicles use combustion engines for propulsion because fossil fuels are energy dense and relatively inexpensive. Rising fuel prices, depletion of fossil fuels, and public environmental awareness have made electric vehicles an attractive alternative. Electric vehicles use electricity instead of gas for propulsion. They are more efficient, quieter, and do not create tailpipe emissions. Unfortunately, conventional electric vehicles are heavily reliant on batteries for energy storage. Batteries are expensive, heavy, and require charging equipment. Fuel cells have been proposed as an alternative to batteries, but hydrogen fuelling infrastructure is not widely available, and high pressure hydrogen storage technology is not mature. As an intermittent step from gasoline to electric vehicles, Hybrid Electric Vehicles (HEVs) have emerged in the marketplace.Hybrid Electric powertrains combine elements from traditional gasoline powertrains and electric powertrains. This is advantageous because they operate 10-20% more efficiently, and can refuel at any gasoline station (Chen et al., 2009;del Re et al., 2010;Chan, 2007). Including additional powertrain components create challenges. Complex controllers are required to ensure the system is operating efficiently. Cost and weight also increase with the number of components.The number of potential powertrain configurations increase exponentially as more components are included. Novel powertrain architectures can be identified through human

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Automotive Transmissions

Cited by 197 publications

References 0 publications

On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions

On the Energy Efficiency of Dual Clutch Transmissions and Automated Manual Transmissions

Optimisation of Effective Design Parameters for an Automotive Transmission Gearbox to Reduce Tooth Bending Stress

Automated topology optimisation of hybrid electric vehicle powertrains

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