Patent ID: 8141355
Filing Date: 2012-03-27
Classification: F16H

Abstract:
1. A hydraulic system for an automatic transmission that is operatively connected to an internal combustion engine, said hydraulic system comprising: a hydraulic energy source to supply the hydraulic system with hydraulic energy during an operating phase of the internal combustion engine and during a stopped phase of the internal combustion engine, wherein the hydraulic energy source is connected to a pilot hydraulic circuit and to a main hydraulic circuit of the hydraulic system, and wherein the pilot hydraulic circuit provides a pilot pressure for controlling operation of hydraulic components of the main hydraulic circuit; a mechanically driven hydraulic pump driven by the internal combustion engine to supply the hydraulic system with hydraulic energy during the operating phase of the internal combustion engine; and at least one electrically driven hydraulic pump included in the hydraulic energy source to supply the hydraulic system with hydraulic energy during a stopped phase of the internal combustion engine, and switching means wherein the electrically driven hydraulic pump is switched on as needed during the operating phase of the internal combustion engine to supply additional hydraulic energy.