Development of a positive drive icvt

Transcription

1 6th International CTI-Symposium Innovative Automotive Transmissions 3 7 December 2007, Berlin, Germany Development of a positive drive icvt (Incremental Continuously Variable Transmission) Dr. J.J. Naude Barloworld CVT Technologies South Africa Dr. J.J. Naude, Barloworld CVT Technologies

2 Presentation content 1. Naudic icvt concept 2. icvt operation 3. icvt ratio shifting 4. icvt prototype 5. Different design configurations 6. On-highway commercial vehicle simulation 7. Conclusion

3 1. Naudic icvt Concept The old basis for a CVT is a chain/belt running between two movable conical sheaves, with the sheaves being movable on their axis, thus adjusting the radius at which the chain/belt rests with chain/belt sides in friction drive with the sheaves. The NAUDIC icvt transforms above old concept into a new mechanically positively linked positive drive concept which: Eliminates the frictional and control losses Can be scaled to meet any torque or power requirement Allows small incremental ratio shifts without power interruption

4 2. icvt operation Variator Drive bars operating in slots in the conical disks Idlers Chain throat Partial drive Chain with extended pins Conical disk

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6 2. icvt operation Chain Chain links Chain pins Chain rollers Drive bar Chain pins ONLY position chain on sheaves Drive bars roll into position on chain rollers Drive bars are positively locked in place by the chain links

7 2. icvt operation Drive bar synchronization Video clip of drive bar synchronization in the chain throat

8 Input driver 2. icvt operation Model in low ratio Slack idler Throat Idler Chain throat Throat Idler Input driver

9 Input driver 2. icvt operation Model in high ratio Slack idler Throat Idler Chain throat Throat Idler Input driver

10 2. icvt operation Input drive Sprag incorporated input driver icvt input Slack idler tensioning system Sprag incorporated input driver

11 3. icvt ratio shifting Geneva wheel based Geneva drivers icvt shifting requires an index on demand in both directions mechanical device Based on the proven Geneva indexing wheel Geneva wheel Accurate and synchronized mechanical shifting Simple and robust design for generation of high speed and high torque shifting. Simple solenoid activation of a pure mechanical shifting sequence

12 3. icvt ratio shifting Animation

13 3. icvt ratio shifting Model shifting Solenoid pin Barrel cam icvt shifter as implemented in the icvt model Very similar to icvt shifter implemented in the icvt test vehicle Geneva wheel is actuated by a barrel cam Barrel cam is activated by a solenoid pin Geneva driver Geneva driver

14 4. icvt prototype Vehicle Controlling PC in cockpit of test vehicle icvt prototype fitter to the rear of the test vehicle

15 4. icvt prototype Drive train configuration

16 4. icvt prototype Variator

17 Metal band chains proven in commercial friction drive CVT s 5. Design configurations Composite metal band chain Every second link adapted for positive drive in ribbed sheaves Very small pitch typically 4mm Very small ratio increments Commercial friction drive band chain Composite metal bands Driver links in blue and Spacer links in orange

18 5. Design configurations Composite metal band chain Alternating drive links positively engage driver cavities and sheave ribs Ribs Sheave Driver links in blue Driver cavity

19 5. Design configurations Rocker pin chain Rocker pin chains proven in commercial friction drive CVT s Rocker pin tips profiled to engage sheave ribs Composite metal bands Rocker pins provide robust and silent drive Commercial friction drive rocker pin chain

20 5. Design configurations Rocker pin chain Alternative rocker pin ends, positively engage driver cavities and sheave ribs Driving rocker pin ends Ribs Sheave Driver cavity

21 6. Simulations VBDrive All simulations were done on a software package, VBDrive, originally developed for the South African military Input data to the simulations included: Current VBDrive users include: Engine fuel consumption and performance data GPS plotted routes Other vehicle and drive train specifications

22 Simulation highlights - fully laden (8 ton) truck 13.59% fuel consumption reduction on highway conditions (speed limit 120 km/h) 14.3 % reduction in acceleration time 0-80km/h 6. Simulations 8 ton commercial truck

23 7. Conclusion icvt concept provides CVT capability Mechanical efficiency comparable to manual transmissions icvt concept can be scaled up to accommodate any power or torque range icvt concept proven in icvt test vehicle and can be test driven by interested parties. icvt CONSEPT is patented in 13 countries based on WO2005/036028

24 Contact details Contact: Richard S. Michelson Barloworld CVT Technologies 180 Katherine Street Sandton P.O. Box Linden 2104 South Africa Tel Fax Cell Web