ZF New 8-speed Automatic Transmission 8HP70 - Basic Design and Hybridization-

Scherer, Heribert; Bek, Manfred; Kilian, Stefan

doi:10.4271/2009-01-0510

Cited by 38 publications

(15 citation statements)

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“…An example planetary drive train from a rear-wheel-drive automatic transmission (Scherer et al (2009)), shown in Fig. 2, is analyzed in this section for its mechanical power losses.…”

Section: An Example Analysismentioning

confidence: 99%

Modelling of steady-state mechanical power losses in planetary gear trains of automatic transmissions

Janakiraman

Kahraman

Talbot

2017

JAMDSM

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In this study, steady-state mechanical power loss model of an automatic transmission gear train consisting of multiple stages of planetary gear sets is developed. Load dependent (mechanical) power losses at the internal (ring-planet) and external (sun-planet) gear meshes and planet bearing interfaces are included through elastohydrodynamic lubrication (EHL) based power loss formulations. At the end, efficiency of an 8-speed automatic transmission is studied under representative operating conditions to quantify the contribution of various loss mechanisms to the total loss under variable speed, load and temperature conditions. Impact of gear surface roughness amplitudes on the resultant power losses is also described. Keywords

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“…An example planetary drive train from a rear-wheel-drive automatic transmission (Scherer et al (2009)), shown in Fig. 2, is analyzed in this section for its mechanical power losses.…”

Section: An Example Analysismentioning

confidence: 99%

Modelling of steady-state mechanical power losses in planetary gear trains of automatic transmissions

Janakiraman

Kahraman

Talbot

2017

JAMDSM

View full text Add to dashboard Cite

show abstract

“…Base ratios for the six-speed transmission are based on the GM6T40 transmission from the Chevy Malibu, scaled down to compensate for the default final drive ratio used in this study (3.23 versus 2.89 for the Malibu, 5 th gear ratio would normally be 1:1) [12]. Base ratios for the eight-speed transmission are inspired by the ZF8HP70 from ZF [13] but differ slightly.…”

Section: Step Gear Transmission Ratio Progressionsmentioning

confidence: 99%

Modeling the Effects of Transmission Gear Count, Ratio Progression, and Final Drive Ratio on Fuel Economy and Performance Using ALPHA

Newman¹,

Dekraker²

2016

SAE Technical Paper Series

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The Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) tool was created by EPA to evaluate the Greenhouse Gas (GHG) emissions of Light-Duty (LD) vehicles [1]. ALPHA is a physicsbased, forward-looking, full vehicle computer simulation capable of analyzing various vehicle types combined with different powertrain technologies. The software tool is a MATLAB/Simulink based desktop application. The ALPHA model has been updated from the previous version to include more realistic vehicle behavior and now includes internal auditing of all energy flows in the model [2]. As a result of the model refinements and in preparation for the mid-term evaluation (MTE) of the 2022-2025 LD GHG emissions standards, the model is being revalidated with newly acquired vehicle data. This paper presents an analysis of the effects of varying the absolute and relative gear ratios of a given transmission on carbon emissions and performance. Energy-based methods of selecting absolute gear ratios are considered and the effects of alternative engine selections are also examined. An algorithm is presented for automatically determining ALPHAshift parameter sets based on the selected engine and transmission combination. It is observed that no single ratio progression optimizes fuel consumption for all applications, however, fuel consumption is also relatively insensitive to progression which implies a fixed set of ratios can still be used for a range of applications without necessarily compromising consumption. The energy-based ratio analysis may prove useful in determining the optimal overall top gear ratio for a given engine-vehicle combination and also helps to explain the relative insensitivity to ratio progression. Individual performance metrics can show high sensitivity to ratio progression, final drive ratio and shift calibration, in particular 30-50 and 50-70 MPH passing times.

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“…Equation 3 comprehends the split torque between hydrodynamic and mechanical paths and is valid whether the torque converter clutch is fully released, fully locked or controlling to a specified slip level. Alternatively, transmission net input torque for a friction launch device, which does not have torque multiplication, is calculated using Eq (4), (4) With net transmission input torque determined using either Eq (3) or (4); the clutch torque for inertia phase given the free body diagram of Figure 6 is calculated as follows, (5) where R c is the kinematic relationship of the controlling clutch's torque with respect to the input shaft of the transmission. This variable is referred to as the clutches lever ratio, see [8 and 12].…”

Section: Inertia Phase Equationsmentioning

confidence: 99%

A Two Degree of Freedom, Lumped Inertia Model for Automatic Transmission Clutch-to-Clutch Shift Dynamics

Robinette¹

2014

SAE Int. J. Passeng. Cars - Mech. Syst.

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This paper presents a methodology to represent automatic transmission clutch-to-clutch shift dynamics with a two degree of freedom, lumped inertia model. The method of reducing the automatic transmission to a lumped, two inertia model as a function of shift and input shaft acceleration is detailed using a full kinematic representation of the automatic transmission. For a given clutch-to-clutch shift maneuver there are two dependent equations that utilize the two lumped inertias and represent the response of the transmission system from input to output shaft. Applicability of the method is shown for planetary automatic and layshaft dual clutch transmissions. Typical clutch-to-clutch shift maneuvers are illustrated with the two inertia model for power on upshifts and downshifts. The simplification of automatic transmission shift dynamics using this method enables rapid synthesis of a given transmission powerflow for estimation of shift quality potential, required clutching torques, inertia phase engine torque intervention and output torque through all phases of a shift event.

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ZF New 8-speed Automatic Transmission 8HP70 - Basic Design and Hybridization-

Cited by 38 publications

References 0 publications

Modelling of steady-state mechanical power losses in planetary gear trains of automatic transmissions

Modelling of steady-state mechanical power losses in planetary gear trains of automatic transmissions

Modeling the Effects of Transmission Gear Count, Ratio Progression, and Final Drive Ratio on Fuel Economy and Performance Using ALPHA

A Two Degree of Freedom, Lumped Inertia Model for Automatic Transmission Clutch-to-Clutch Shift Dynamics

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