Mixer drum drive with variable displacement motor

A drum drive system for a vehicle, the drum drive system comprising:

• a non-transitory computer-readable storage medium having instructions stored thereon that, upon execution by one or more processors, cause the one or more processors to:
• operate a prime mover, a variable displacement motor, and a variable displacement pump to drive a drum of the vehicle, wherein the variable displacement pump is mechanically coupled to the prime mover and the variable displacement motor is fluidly coupled to the variable displacement pump;
• acquire pressure data from a pressure sensor, the pressure data indicative of a pressure of a fluid flowing between the variable displacement pump and the variable displacement motor;
• and
• in response to the pressure of the fluid being below a threshold pressure and a transmission of the vehicle being in neutral, and while maintaining a drum speed of the drum:
• reduce a prime mover speed of the prime mover, which thereby decreases a pump speed of the variable displacement pump;
• reduce a motor displacement of the variable displacement motor;
• and
• increase a pump displacement of the variable displacement pump.

A drum drive system for a vehicle, the drum drive system comprising:

• a controller configured to control a prime mover, a variable displacement pump, and a variable displacement motor of the vehicle to provide a target drum speed for a drum of the vehicle, wherein to provide the target drum speed, the controller having programmed instructions to:
• (i) initially operate the variable displacement motor at a maximum motor displacement and operate the variable displacement pump at a pump displacement that provides the target drum speed without needing to actively manipulate a prime mover speed of the prime mover;
• (ii) increase the pump displacement and decrease a motor displacement without needing to actively manipulate the prime mover speed while still providing the target drum speed;
• and
• (iii) increase the prime mover speed if necessary to maintain the target drum speed in response to the pump displacement reaching a maximum pump displacement and the motor displacement reaching a minimum motor displacement.