Method for controlling a marine internal combustion engine

A method for controlling a marine internal combustion engine, the method being carried out by a control module and comprising:

• operating the engine according to an initial set of stored, input-output mapped parameter values configured to achieve a first fuel-air equivalence ratio in a combustion chamber of the engine;
• measuring current values of engine operating conditions;
• comparing the engine operating conditions to predetermined lean-burn mode enablement criteria;
• and
• in response to the engine operating conditions meeting the lean-burn mode enablement criteria, doing one of the following:
• (a) automatically retrieving a subsequent set of stored, input-output mapped parameter values configured to achieve a second, lesser fuel-air equivalence ratio in the engine's combustion chamber and transitioning from operating the engine according to the initial set of stored, input-output mapped parameter values to operating the engine according to the subsequent set of stored, input-output mapped parameter values;
• and
• (b) presenting an operator-selectable option to transition from operating the engine according to the initial set of stored, input-output mapped parameter values to operating the engine according to the subsequent set of stored, input-output mapped parameter values, and in response to selection of the option, commencing the step of transitioning;
• wherein the initial and subsequent sets of stored, input-output mapped parameter values respectively include data related to a quantity of fuel to be supplied to the combustion chamber, a quantity of air to be supplied to the combustion chamber, and a timing of activation of a spark plug associated with the combustion chamber, and the step of transitioning comprises:
• (1) first beginning to transition between operating the engine according to fuel quantity data in the initial set of stored, input-output mapped parameter values and operating the engine according to fuel quantity data in the subsequent set of stored, input-output mapped parameter values;
• (2) after a first enable delay after beginning step (1), beginning to transition between operating the engine according to air quantity data in the initial set of stored, input-output mapped parameter values and operating the engine according to air quantity data in the subsequent set of stored, input-output mapped parameter values;
• and
• (3) after a second enable delay after beginning step (1), and after beginning step (2), beginning to transition between operating the engine according to spark plug activation timing data in the initial set of stored, input-output mapped parameter values and operating the engine according to spark plug activation timing data in the subsequent set of stored, input-output mapped parameter values.