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nonsequitur · Apr 3rd, 2003, 01:06 AM

Here is an interesting bit. The CVT is built by ZF for MINI and the product is called Ecotronic Type VT1F.

It uses a 24mm wide, 450 segment, jointed steel drive belt to transfer torque between Primary and Secondary V-shaped pulleys with one fixed half and one movable half. This belt and pulleys are lubricated and cooled by oil jet. The pulleys are positioned (to create the continuously variable drive ratios) by hydraulics.

Two clutch packs (one for forward, one for reverse) connect the engine drive shaft (input) to the Primary pulley. These clutch packs contain three plates (six surfaces) to smoothly transfer power. Friction is controlled by hydraulics and they are lubricated and cooled by oil.

Oil pressure is supplied by an internal (transmission) geared pump, driven by, and running at, engine speed. Many functions run on oil pressure, and oil pressure is determined by engine speed.

All of this may partially explain some of the comments about launch and very low speed behaviors. It takes a moment for oil pressure to come up to as much as 40 bar.

Apr 3rd, 2003, 01:06 AM	#20
nonsequitur Moderator Join Date: Nov 2002 Location: Seattle area, WA Local Time: 11:16 PM Posts: 1,466 Offline	Here is an interesting bit. The CVT is built by ZF for MINI and the product is called Ecotronic Type VT1F. It uses a 24mm wide, 450 segment, jointed steel drive belt to transfer torque between Primary and Secondary V-shaped pulleys with one fixed half and one movable half. This belt and pulleys are lubricated and cooled by oil jet. The pulleys are positioned (to create the continuously variable drive ratios) by hydraulics. Two clutch packs (one for forward, one for reverse) connect the engine drive shaft (input) to the Primary pulley. These clutch packs contain three plates (six surfaces) to smoothly transfer power. Friction is controlled by hydraulics and they are lubricated and cooled by oil. Oil pressure is supplied by an internal (transmission) geared pump, driven by, and running at, engine speed. Many functions run on oil pressure, and oil pressure is determined by engine speed. All of this may partially explain some of the comments about launch and very low speed behaviors. It takes a moment for oil pressure to come up to as much as 40 bar. '02 MINI Cooper CVT (prod. date: 6/12/2002; Indi Blue/Black roof, R-81 7-hole 15x5.5" or NZO 16x6.5") '67 Austin Cooper S 1275 Mk1 (build date: 6/26/1967; Tartan Red/Black Roof, Minilite 10x4.5" or 10x6.0")