An internal combustion engine having a cylinder block defining a plurality
of cylinders at least half of which are selectively deactivatable by a
plurality of switching hydraulic lifters. A source of pressurized oil is
provided. Additionally, at least one solenoid-actuated hydraulic control
valve operates to selectively communicate pressurized oil from the source
of pressurized oil to actuate the plurality of switching hydraulic
lifters thereby deactivating the selectively deactivatable cylinders. The
number of the solenoid-actuated hydraulic control valves is fewer than
the number of selectively deactivatable cylinders.