Patent ID: 7631627

Claim:
A vehicle comprising: an engine; at least one auxiliary vehicle system; a controller adapted for selectively turning off said engine when the vehicle is at a standstill; a motor/generator operable for cranking and starting said engine when the vehicle is launching from said standstill; an energy storage device (ESD) having a direct-current (DC) auxiliary voltage; a voltage inverter for converting said DC auxiliary voltage into an alternating-current (AC) auxiliary voltage during said cranking and starting of said engine, wherein said AC auxiliary voltage is suitable for powering said motor/generator during said cranking and starting of said engine; and a voltage sag prevention device (VSPD) that is electrically connected to said ESD and to said voltage inverter, said VSPD being operable for isolating a DC cranking support voltage from said DC auxiliary voltage during said cranking and starting of said engine; wherein said at least one auxiliary system is powered exclusively by said DC cranking support voltage during said cranking and starting of said engine, and by said DC auxiliary voltage after said engine is running, thereby preventing a sag in a level of voltage supplied to said at least one auxiliary vehicle system during said cranking and starting of said engine.