Dual fuel common rail transient pressure control and engine using same

An engine that comprising:

• an engine housing that defines a plurality of cylinders within which a plurality of respective pistons reciprocate to define a compression ratio greater the 14:1;
• a gaseous fuel common rail and a liquid fuel common rail fluidly connected to each of a plurality of fuel injectors that each include a gaseous nozzle outlet set and a liquid nozzle outlet set positioned for direct injection into one of the cylinders;
• means, including electronic controller configured to execute a first rail pressure control algorithm to maintain a liquid rail pressure greater than a gas rail pressure before and after a transient, and execute a second rail pressure control algorithm to maintain the liquid rail pressure greater than the gas rail pressure during the transient, for inhibiting migration of gaseous fuel into liquid fuel within the fuel injector;
• wherein the transient includes changing from a high fuel demand state of a first speed and load to a low fuel demand state of a second speed and load.