The invention relates to an improved system of electro-mechanical hydraulic valve lifters for piston engine automobiles that increases fuel economy and reduces fuel emissions. The electro-mechanical hydraulic valve lifters enclose a magnetorheological fluid chamber, containing magnetorheological fluid. A control module manages voltage sent to the magnetorheological fluid in the magnetorheological fluid chamber. The control module introduces various amounts of magnetic flux to the magnetorheological fluid in the magnetorheological fluid chamber. The magnetorheological fluid's viscosity changes based on the amount of magnetic flux applied to it from the electromagnets and, along with the magnetorheological fluid chamber spring, controls how much an intake and exhaust port of the spark plug engine opens to control the amount of fuel used and exhaust let out of the engine.

The invention relates to an improved system of electro-mechanical hydraulic valve lifters for piston engine automobiles that increases fuel economy and reduces fuel emissions. The electro-mechanical hydraulic valve lifters contain that enclose a magnetorheological fluid chamber, containing magnetorheological fluid. A control module manages voltage sent to the magnetorheological fluid in the magnetorheological fluid chamber. The control module introduces various amounts of magnetic flux to the magnetorheological fluid in the magnetorheological fluid chamber. The magnetorheological fluid's viscosity changes based on the amount of magnetic flux applied to it from the electromagnets and, along with the magnetorheological fluid chamber spring, controls how much an intake and exhaust port of the spark plug engine opens to control the amount of fuel used and exhaust let out of the engine.

Methods and systems are provided for a drivetrain system comprising: a first prime mover for supplying a torque to a front axle; a second prime mover for supplying a torque to a rear axle; and a controller configured to, in response to a torque reversal, command the front axle and the rear axle to cross lash zones sequentially.

Methods and systems are provided for a drivetrain system comprising: a first prime mover for supplying a torque to a front axle; a second prime mover for supplying a torque to a rear axle; and a controller configured to, in response to a torque reversal, command the front axle and the rear axle to cross lash zones sequentially.