Two speed belt drive system

A two speed belt drive system comprising:

• a crankshaft module (200) comprising a first pulley (213) engaging a first belt (10) and a second pulley (206) engaging a second belt (20), the crankshaft module further comprising an inertia member (2010) mounted thereto by an elastomeric member (212);
• a clutch module (100) engaging the first belt and the second belt, the crankshaft module driving the clutch module with the first belt;
• the second belt driving an engine accessory;
• the crankshaft module having a clutch spring (205) for frictional driving of the second pulley, the clutch spring releasable during a predetermined condition;
• and
• the clutch module having an electromagnetic clutch (57) for selectively driving the second belt during an engine idle condition at a speed that is greater than during an engine off-idle condition.

A two speed belt drive system comprising:

• a crankshaft module (200) comprising a first pulley (213) engaging a first belt (10) and a second pulley (206) engaging a second belt (20), the first pulley further comprising an inertia member (2010) mounted to a hub (300) by an elastomeric member (212);
• a clutch module (100) engaging the first belt and the second belt, the crankshaft module driving the clutch module with the first belt;
• the second belt driving an engine accessory;
• the crankshaft module having a clutch spring (205) for frictional driving of the second pulley, the clutch spring releasable during an overrun condition;
• and
• the clutch module having an electromagnetic clutch (57) for selectively driving the second belt during an engine idle condition at a speed that is greater than during an engine off-idle condition, the electromagnetic clutch is engaged during an engine idle condition.