Patent ID: 7784277
Filing Date: 2010-08-31
Classification: B60K,F16D,Y02T

Abstract:
1. A hydraulic drive system for storing and releasing hydraulic fluid comprising: a high pressure storage device; a low pressure storage device; a pump-motor operating at a range of pump-motor speeds for converting between hydraulic energy and mechanical energy, said pump-motor disposed between said high pressure storage device and said low pressure storage device; a switch for controlling flow of said hydraulic fluid from said high pressure storage device, said switch in a first state for enabling release of said hydraulic fluid from said high pressure storage device when a pressure within said high pressure storage device is above a predefined threshold, and said switch in a second state for substantially blocking release of said hydraulic fluid from said high pressure storage device when said pressure within said high pressure storage device is below said predefined threshold, said predefined threshold being adjusted as said switch changes from said first state to said second state.