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Performance analysis of the Impulse Shift CVT. Ro ë ll van Druten Bas Vroemen Alex Serrarens Michiel Pesgens Drivetrain Innovations BV The Netherlands www.dtinnovations.nl. Outline. Zero Inertia (ZI) ZI & Impulse Shift Drivetrain model Performance results Agility criteria & results
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Performance analysis of the Impulse Shift CVT Roëll van Druten Bas Vroemen Alex Serrarens Michiel Pesgens Drivetrain Innovations BV The Netherlands www.dtinnovations.nl
Outline • Zero Inertia (ZI) • ZI & Impulse Shift • Drivetrain model • Performance results • Agility criteria & results • Conclusions
Zero Inertia project goal: eliminate jet start behaviour engine planetary set inertia CVT Impulse Shift development wheel 1997 2002 2004
Zero Inertia principle Vengine 4000 rpm @80kph Vvehicle Vflywheel low overdrive overdrive
Zero Inertia principle Vengine zero speed Vvehicle Vflywheel low low overdrive
Zero Inertia test results • Improved pedal-in and pedal-out response (no jet start behaviour) • Very comfortable cruising • 22% fuel saving @120kph
Further development targets • Reduce inertia size and weight • Integration into transmission • Additional functionality
decouple variator Impulse Shift (IS) ZI & Impulse Shift power through CVT becomes zero ZI down shift
Drivetrain layout 50% reduced inertia size 3.3L V6 engine DNR clutch torque converter
Expected benefits of IS principle • faster flywheel speed down gives immediate inertia-assist • faster engine speed up enables quick engine power availability • 1&2 enable further downsizing of flywheel inertia • no additional controls using drive clutch (DNR)
IS ZI Impulse Shift simulation results 3 2.5 ] 2 2 1.5 vehicle acceleration [m/s CVT 1 0.5 0 -0.5 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 time [s]
IS ZI Flywheel power assist 60 50 40 30 20 flywheel power [kW] 10 0 -10 -20 -30 0 2 4 6 8 10 time [s]
IS ZI CVT from 2200 rpm baseline: CVT from 1350 rpm Vehicle leads matched for IS and ‘comfort-mode’ CVT 6 5 4 3 vehicle lead w.r.t. CVT [m] 2 1 0 -1 0 1 2 3 4 5 6 time [s]
Comparison IS-CVT and comfort mode CVT • engine speed while cruising @80 kph: • 1350 rpm for IS-CVT • 2200 rpm for comfort-mode CVT • comfort mode CVT uses 15% more fuel than IS-CVT @80 kph • IS-CVT and comfort mode CVT have similar performance
‘pI’ mean(dTq/dt) Agility criteria (Frei et al. 2004)
invert Agility results 80-120 km/h: CVT : 5.9 s ZI : 5.7 s IS : 5.4 s CVT-C : 5.4 s
Conclusions • Impulse Shift (IS) adds substantial kickdown performance to Zero Inertia (ZI) without extra components or actuators • Agility of ZI-CVT comparable to ‘comfort-mode’ CVT while saving 13% fuel @80 kph • Agility of IS-CVT superior to ‘comfort-mode’ CVT while saving 13% of fuel • Future work...
Transmission integration • flywheel wrapped around torque converter • 50% reduction in flywheel inertia • planetary gear integrated with DNR • drive clutch = Impulse Shift actuator Zero Inertia evolution