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Automatic Transmission Shift Quality Powertrain-in-the-Loop High-Dynamic Simulation System

IP.com Disclosure Number: IPCOM000249969D
Publication Date: 2017-May-10
Document File: 4 page(s) / 591K

Publishing Venue

The IP.com Prior Art Database

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Automatic Transmission Shift Quality Powertrain-in-the-Loop High-Dynamic Simulation System

Automatic transmission shift quality, in other words shift feel quantification, is necessary in new and

upcoming vehicle development. During the automatic transmission gear shift process, power

interruption, shift disturbance and other problem always occur and worsen the riding comfort and

shorten the life of component because of the torque disturbance of each clutch engagement

/disengagement and impact caused by backlash induced from the contact between various gears. In

general, the most of automatic transmission shift quality is focused on the magnitude of acceleration

/jerk/shock/kick during the shift event in the frequency range of up to 20Hz. Due to the complexity of

the mechanism inside automatic transmission, however, it is not easy to evaluate and improve the

automatic transmission shift quality only with the numerical approach. To overcome the limitations of

numerical approaches, on-road test measurement is recently used. The most critical issue of the current

test-based shift quality evaluation is the manufacturing costs for prototype vehicles. The growth of

complexity of power train (P/T) lineups and the efforts to cut down the cost of the prototype production

lead the change of the shift quality strategies from vehicle to bench test.

In order to avoid the limitations for both numerical-based and test-based procedure, the shift-quality

hardware-in-the-loop real time simulation (HIL/RTS) work bench has been developed, which is basically

hybrid approach with test and numerical approaches.


This work bench is constructed based on a dynamometer test system shown in Figure 1. In conventional

dynamometer test setup marked in blue, a high inertia dynamometer is implemented to represent the

vehicle inertia. This conventional dynamometer test is just used for key-life test or durability test

purpose for powertrain performance, not for the shift-quality evaluation. All the high transient effects

such as kick, jerk, and shock at the gear shift are disappeared due to the high inertia in a dynamometer.

In order to mimic this high transient event, the inertia of dynamometer used in this work bench is 100

times smaller. It consists of a real combustion engine and transmission with a powertrain control

module (PCM) which is connected via a connecting shaft to high dynamic dynamometer. The connecting

shaft is specifically designed for required stiffness and damping, in order to transfer an accurate

transmission output torque to the vehicle model. Only the engine, the transmission and the PCM are

physically installed in the system. The rest of vehicle components are replaced via numerical modeling.

While the torsional excitation of the driveline (up to 20Hz) is measured directly by the coupling of real

engine and transmission with the driveline system in the high fidelity CAE model at the low inertia

dynamometer, the complete powertrain 3D rigid body dy...