Internal combustion engine with camshaft phase shifting and internal EGR

A method for operating a multi-cylinder, four-stroke cycle reciprocating internal combustion engine on fewer than the maximum number of cylinders, comprising the steps of:

• providing an intake manifold having a common plenum;
• providing an exhaust system connected to the cylinders;
• sensing a plurality of engine and vehicle operating parameters, including at least engine load and engine speed;
• comparing the sensed operating parameters with predetermined threshold values;
• issuing a fractional engine cylinder operation command in the event that the sensed parameters exceed said threshold values so as to deactivate at least one cylinder of said engine;
• adjusting the timing of at least one camshaft which operates poppet intake and exhaust valves of the cylinders to be deactivated so that valve lift events for both intake and exhaust valves are shifted out of phase of standard timing;
• providing an exhaust gas oxygen sensor in the common plenum;
• monitoring an equivalence ratio in the common plenum with the exhaust gas oxygen sensor;
• comparing the sensed equivalence ratio with a desired equivalence ratio;
• and
• adjusting the timing of the at least one camshaft based on the comparison of the sensed and desired equivalence ratios so that an desired amount of exhaust gas flows out past the poppet intake valve of the cylinders that are deactivated into the common plenum.

A method for operating a multi-cylinder, four-stroke cycle reciprocating internal combustion engine on fewer than the maximum number of cylinders, comprising the steps of:

• providing an intake manifold having a common plenum and intake manifold runners between the common plenum and each of the cylinders;
• providing an exhaust system connected to the cylinders;
• sensing a plurality of engine and vehicle operating parameters, including at least engine load and engine speed;
• comparing the sensed operating parameters with predetermined threshold values;
• issuing a fractional engine cylinder operation command in the event that the sensed parameters exceed said threshold values so as to deactivate at least one cylinder of said engine;
• adjusting the timing of at least one camshaft which operates poppet intake and exhaust valves of the cylinders to be deactivated so that valve lift events for both intake and exhaust valves are shifted out of phase of standard timing;
• providing an exhaust gas oxygen sensor in one of an intake manifold runners of one of the cylinders to be deactivated;
• monitoring the equivalence ratio in one of the intake manifold runners of one of the cylinders to be deactivated with the exhaust gas oxygen sensor;
• comparing the sensed equivalence ratio with a desired equivalence ratio;
• and
• adjusting the timing of the at least one camshaft based on the comparison of the sensed and desired equivalence ratios so that the desired amount of exhaust gas flows out past the poppet intake valve of the cylinders that are deactivated into the common plenum.