Patent ID: 9193251
Filing Date: 2015-11-24
Classification: B60K,B60W,F16H,Y02T

Abstract:
1. A powertrain for a hybrid vehicle having drive wheels, comprising: a combustion engine; a drive shaft connected at one end to said combustion engine to be driven by said combustion engine and operatively connected at a second end to said drive wheels; a coupler in said drive shaft, said coupler dividing said drive shaft into a first part connected to said combustion engine and a second part operatively connected to said drive wheels; said coupler being switchable between an engaged mode in which said first and second parts of said drive shaft are connected and a disengaged mode in which said first and second parts of said drive shaft are independent of each other; a first variable displacement hydraulic machine connected to said drive shaft first part such that said first variable displacement hydraulic machine is driven by, or can drive, said shaft first part; a second variable displacement hydraulic machine connected to said drive shaft second part to be driven by, or to drive, said drive shaft second part; and a hydraulic pressure accumulator which stores energy, said first and second hydraulic machines being in fluid communication with said pressure accumulator; a hydraulic circuit comprising said first and second variable displacement pumps and said hydraulic pressure accumulator; said hydraulic circuit defining a high pressure circuit and a low pressure circuit; a high pressure sensor in said high pressure circuit; a low pressure sensor in said low pressure circuit; and a control unit; said controller receiving signal from said high and low pressure sensors indicative of the pressure in said high and low pressure circuits, respectively; wherein the first and second variable displacement hydraulic machines are each operable in a pump mode to charge said pressure accumulator and a drive mode to drive said first and second portions, respectively, of said drive shaft; and whereby when said coupler is in its said engaged mode, said first and second hydraulic machines are operated in parallel and are operable to both drive said wheels or both charge said accumulator; and when said coupler is in its said disengaged mode, said first hydraulic machine is operable to charge said accumulator or drive said shaft first part to operate as a starter for said engine and said second hydraulic machine is operable to charge said accumulator or drive said shaft second part to drive said wheels; and wherein control unit is configured for regulation of the displacement of each hydraulic machine used as a motor or as a pump as a function of the desired torque on its shaft and the pressure difference between high and low pressure circuits supplying the respective hydraulic machine.