Variable compression ratio diesel engine

A diesel opposed piston engine comprising:

• two opposed pistons each having one or more swirl canceling features on their respective crown and each individually coupled to one of two crankshafts,
• an inlet port configured to deliver inlet air as a single flow field to a combustion chamber defined at least in part by the crowns of the two opposed pistons, wherein the swirl canceling features form two pockets within the combustion chamber as the two pistons come together near a top dead center position to thereby cause the inlet air to be divided into separate co-rotating swirls within the two pockets, the two co-rotating swirls experiencing high shear with each other at a center of the combustion chamber as the two pistons move apart from the top dead center position;
• and
• an engine controller, the engine controller performing operations comprising:
• operating the diesel opposed piston engine with a first compression ratio to supply engine power in response to a first engine load;
• and
• changing the first compression ratio to a second compression ratio to supply engine power in response to a second engine load, the second engine load being larger than the first engine load, the second compression ratio being smaller than the first compression ratio.

A diesel opposed piston engine comprising:

• a combustion chamber defined at least in part by crowns of two pistons each having one or more swirl canceling features coupled to two crankshafts;
• and
• an engine controller, the engine controller performing operations comprising:
• determining, based on engine operation information, a predicted peak combustion chamber temperature that will occur in the combustion chamber;
• identifying a target set of engine operation parameters when the predicted peak combustion chamber temperature exceeds a threshold temperature at which an acceptable level of nitrogen oxide pollutants (NOX) is expected to be formed in the combustion chamber;
• and
• applying the target set of engine operation parameters to modify one or more current engine parameters to thereby maintain the peak combustion chamber temperature below the threshold temperature.