Patent ID: 8151918

Claim:
Energy management method for a hybrid vehicle drive system, comprising a heat engine supplying mechanical energy to the vehicle wheels, at least one electric machine supplying electrical energy to the vehicle wheels, means for recovering electrical energy, means for storing electrical energy, and means for transmitting mechanical and electrical energy to the vehicle wheels, comprising: in a first step, determining a fuel consumption gain (G) of the heat engine in real time by figuring the difference between a fuel consumption with the heat engine on and an equivalent consumption with the engine off, independently of other sources of energy outside the heat engine, the equivalent consumption being calculated from a set coefficient (K) corresponding to a ratio between a difference in fuel consumption and a difference in engine power for a set engine speed; in a second step, deciding to turn the heat engine on or off based on a comparison between a criterion (C) and the consumption gain (G), wherein the criterion (C) is dependent on a level of energy recovery of the electrical energy recovery means, and determined in such a way as to increase the use of the electrical energy storage means and turn off the heat engine as often as possible, wherein the consumption gain (G) is expressed by the following formula: G=[Pmth·K+b ( Nmth )]−[ Pmth·K/ηelec 2 ] where: Pmth=power provided by the heat engine K=proportionality coefficient Nmth=engine speed b=the part of fuel consumption that is solely dependent on the engine speed Nmth ηelec=electrical system efficiency.