Hybrid electric transmission for hydraulic fracturing
A hydraulic fracturing system includes a hybrid electric transmission assembly to transfer power from an internal combustion engine to a hydraulic fracturing pump. The transmission assembly includes a first driveshaft coupled to the engine and a second driveshaft coupled to the pump with a primary drivetrain gear assembly coupling the first driveshaft to the second driveshaft. An electric drive gearset is disposed between the primary drivetrain gear assembly and the pump. An electric motor is couplable to the electric drive gearset, thereby allowing power to be passed from the electric motor to drive the pump and bypass the primary drivetrain gear assembly during the gear change. The system may include a plurality of electric motors each having an electric motor axis and an output gearset coupled to the electric drive gearset, where each of the electric motor axii are spaced radially outward from the first and second driveshafts.
1 . A hybrid hydraulic fracturing system comprising:
an internal combustion engine;
a hydraulic fracturing pump;
a transmission assembly having a first driveshaft, a second driveshaft with at least one of the first or second driveshafts extending along a transmission primary axis, a primary drivetrain gear assembly having at least three gear ratios, the primary drivetrain gear assembly coupling the first driveshaft to the second driveshaft; an electric drive gearset separate from the primary drivetrain gear assembly and mounted on one of the first driveshaft or the second driveshaft apart from the primary drivetrain gear assembly; and a transmission housing having a first end and a second end and enclosing the primary drivetrain gear assembly, with the first driveshaft extending from the first end of the housing and operatively coupled to the internal combustion engine, and the second driveshaft extending from the second end of the housing and operatively coupled to the hydraulic fracturing pump; and
a plurality of electric motors disposed externally of the transmission housing, each of the plurality of electric motors having an output gearset disposed along an electric motor axis with each output gearset couplable to the electric drive gearset, wherein the electric motor axis of each of the plurality of electric motors is parallel with but spaced radially outward from the transmission primary axis and the transmission housing, and wherein each output gearset is separate from the primary drivetrain gear assembly.
2 . The hybrid hydraulic fracturing system of claim 1 , wherein each of the plurality of electric motors are supported on the transmission housing adjacent the first end of the transmission housing.
3 . The hybrid hydraulic fracturing system of claim 1 , wherein each of the plurality of electric motors are supported on the transmission housing adjacent the second end of the transmission housing.
4 . The hybrid hydraulic fracturing system of claim 3 , wherein the transmission assembly further comprises a supplemental electric drive gearset disposed along the second driveshaft between the primary drivetrain gear assembly and the hydraulic fracturing pump with at least a portion of the plurality of electric motors couplable to the supplemental electric drive gearset.
5 . A hybrid hydraulic fracturing system comprising:
an internal combustion engine;
a hydraulic fracturing pump;
a transmission housing having a first end and a second end with an input driveshaft extending from the first end of the transmission housing and an output driveshaft extending from the second end of the transmission housing with at least one of the driveshafts extending along a transmission primary axis, the input driveshaft coupled to the internal combustion engine and the output driveshaft coupled to the hydraulic fracturing pump; a primary drivetrain gear assembly disposed in the transmission housing and having at least three gear ratios, the primary drivetrain gear assembly coupling the input driveshaft to the output driveshaft; an electric drive gearset separate from the primary drivetrain assembly and coupled to one of the input driveshaft or the output driveshaft so as to be spaced apart from the primary drivetrain assembly; and
at least two primary electric motors mounted on the transmission housing, wherein each of the at least two primary electric motors are coupled to the electric drive gearset.
6 . The hybrid hydraulic fracturing system of claim 5 , wherein the at least two primary electric motors mounted on the transmission housing comprises three primary electric motors mounted on the transmission housing and each of the three primary electric motors coupled to the primary electric drive gearset.
7 . The hybrid hydraulic fracturing system of claim 5 , wherein the input driveshaft extends along the transmission primary axis and each electric motor mounted on the transmission housing has an electric motor axis that is parallel with but spaced radially outward from the transmission primary axis.