Cylinder deactivation apparatus

A cylinder deactivation system for an internal combustion engine having a cylinder block with a plurality of deactivatable cylinders each having at least one selectively deactivatable intake valve and at least one selectively deactivatable exhaust valve, the system comprising:

• a main source of pressurized oil;
• a plurality of switching hydraulic lifters operable to deactivate the deactivatable cylinders in response to a pressurized oil signal;
• an oil manifold assembly defining a control passage and at least one feed passage, said control passage being in fluid communication with said main source of pressurized oil;
• at least one solenoid-actuated hydraulic control valve;
• wherein a first of said at least one solenoid-actuated hydraulic control valves is operable to selectively communicate pressurized oil from said control passage to a first of said at least one feed passage;
• wherein a second of said at solenoid-actuated hydraulic control valves is operable to selectively communicate pressurized oil from said control passage to a second of said at least one feed passage;
• wherein said first feed passage selectively communicates pressurized oil to respective ones of said plurality of switching lifters disposed within a first cylinder bank of the cylinder block to effect cylinder deactivation;
• wherein said second feed passage selectively communicates pressurized oil to respective ones of said plurality of switching lifters disposed within a second cylinder bank of the cylinder block to effect cylinder deactivation;
• and
• wherein the number of at least one solenoid-actuated hydraulic control valves is fewer than the plurality of deactivatable cylinders.

An internal combustion engine comprising:

• a cylinder block defining a plurality of cylinders at least two of said plurality of cylinders being selectively deactivatable by a plurality of switching hydraulic lifters;
• a source of pressurized oil;
• at least one solenoid-actuated hydraulic control valve;
• an electronic control unit in electrical communication with said at least one solenoid-actuated hydraulic control valve;
• a plurality of selectively deactivatable intake valves each of which is in mechanical communication with a respective one of said plurality of switching hydraulic lifters;
• and
• a plurality of selectively deactivatable exhaust valves each of which is in mechanical communication with a respective one of said plurality of switching hydraulic lifters;
• wherein each of said at least one solenoid-actuated hydraulic control valve is operable to selectively communicate pressurized oil from said source of pressurized oil to actuate said plurality of switching hydraulic lifters thereby deactivating said at least two of said plurality of cylinders;
• wherein the number of said at least one solenoid-actuated hydraulic control valves is fewer than the number of said at least two of said plurality of cylinders that are selectively deactivatable;
• wherein said electronic control unit is operable to command said at least one solenoid-actuated hydraulic control valve to selectively deactivate said plurality of selectively deactivatable exhaust valves prior to said plurality of selectively deactivatable intake valves;
• and
• wherein said electronic control unit is operable to command said at least one solenoid-actuated hydraulic control valve to selectively reactivate said plurality of selectively deactivatable exhaust valves prior to said plurality of selectively deactivatable intake valves.