Work vehicle power system with dynamic auto-ignition assistance compression ratios

A work vehicle, comprising:

• a chassis;
• a drive assembly supported on the chassis;
• a power system supported on the chassis and configured to power the drive assembly, the power system comprising:
• an intake arrangement configured to intake charge air;
• and
• a compression ignition engine including:
• a plurality of piston-cylinder sets configured to receive, ignite, and combust intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas, wherein at least a first piston-cylinder set of the piston-cylinder sets includes:
• a cylinder defining an intake port and an exhaust port;
• a piston positioned at least partially within the cylinder to from a combustion chamber in between that defines a compression ratio, the combustion chamber being in fluid communication with the intake port and the exhaust port;
• an intake valve configured to open and close the intake port;
• an exhaust valve configured to open and close the exhaust port;
• and
• a fuel injector configured to inject fuel into the combustion chamber;
• and
• a plurality of piston actuation arrangements, including a first piston actuation arrangement coupled to the piston of the first piston-cylinder set and configured to be repositioned to dynamically modify the compression ratio of the first piston-cylinder set;
• an exhaust sensor configured to sense a temperature of the exhaust gas;
• and
• a controller coupled to command the first piston actuation arrangement such that,
• in an auto-ignition assistance mode, the first piston actuation arrangement places the first piston into a first configuration resulting in a first compression ratio;
• and
• in a nominal mode, the first piston actuation arrangement places the first piston into a second configuration resulting a second compression ratio that is lower than the first compression ratio;
• wherein the controller is configured to command the first piston actuation arrangement to adjust the first piston-cylinder set between the first compression ratio and the second compression ratio based on signals from the exhaust sensor associated with the exhaust gas temperature.