Systems and methods for vehicle hill control

A method for a vehicle, comprising:

• during a first vehicle stopped condition, actively engaging a low clutch and a mid clutch of a transmission, wherein actively engaging the low clutch and the mid clutch mechanically locks the transmission and inhibits movement of wheels of the vehicle, the transmission having a plurality of power inputs including receiving input from a first electric machine and a prime mover;
• before an operator torque request and after an operator releases a service brake, releasing the low clutch and concurrently adjusting an output magnitude of the first electric machine in a speed control mode to control to a zero vehicle speed;
• during a second vehicle stopped condition, operating with the low clutch and the mid clutch engaged to mechanically lock the transmission;
• and
• responsive to operator application of the service brake, releasing the low clutch, and, after releasing the low clutch and while the service brake is released, concurrently adjusting an output magnitude of the first electric machine in a speed control mode to control to the zero vehicle speed,
• wherein the transmission is an electromechanical infinitely variable transmission (EMIVT) that includes:
• a power split planetary gear set that is rotationally coupled to a second electric machine,
• wherein the low clutch is grounded to a frame of the vehicle at a first fixed component, and
• wherein the mid clutch is grounded to the frame of the vehicle at a second fixed component.

A system for a vehicle, comprising:

• a transmission including:
• a low clutch;
• a mid clutch;
• and
• a plurality of power inputs;
• a service brake;
• an internal combustion engine coupled to a first power input of the transmission;
• a first electric machine coupled to a second power input of the transmission;
• and
• a controller having instructions for execution, the instructions for:
• during a vehicle stopped condition, actively engaging both the low clutch and the mid clutch, wherein actively engaging both the low clutch and the mid clutch mechanically locks the transmission and inhibits movement of wheels of the vehicle;
• release the low clutch;
• and
• while releasing or in response to releasing the low clutch, adjusting an output magnitude of the first electric machine in a speed control mode to control to a zero vehicle speed,
• wherein the controller further has instructions to, in response to brake pedal release or the low clutch release, operating the first electric machine in a torque control mode, wherein the low clutch is coupled to an output coupling planetary, and wherein the mid clutch is coupled to an output planetary,
• wherein the transmission is an electromechanical infinitely variable transmission (EMIVT) that includes:
• a power split planetary gear set that is rotationally coupled to a second electric machine,
• wherein the low clutch is grounded to a frame of the vehicle at a first fixed component, and
• wherein the mid clutch is grounded to the frame of the vehicle at a second fixed component.

A system for a vehicle, comprising:

• a transmission including:
• a low clutch;
• a mid clutch;
• and
• a plurality of power inputs;
• a service brake;
• an internal combustion engine coupled to a first power input of the transmission;
• a first electric machine coupled to a second power input of the transmission;
• and
• a controller having instructions for execution, the instructions for:
• during a vehicle stopped condition, actively engaging both the low clutch and the mid clutch, wherein actively engaging both the low clutch and the mid clutch mechanically locks the transmission and inhibits movement of wheels of the vehicle;
• release the low clutch;
• and
• while releasing or in response to releasing the low clutch, adjusting an output magnitude of the first electric machine in a speed control mode to control to a zero vehicle speed,
• wherein the controller further has instructions to, in response to brake pedal release or the low clutch release, operating the first electric machine in a torque control mode, wherein the low clutch is coupled to an output coupling planetary, and wherein the mid clutch is coupled to an output planetary, and
• wherein torque corresponding to a power split planetary is balanced by torque corresponding to the mid clutch, the low clutch, and a second electric machine of the transmission, and wherein the second electric machine of the transmission is coupled to the output planetary.