Split type internal combustion engine

Claim 1

An internal combustion engine comprising: (a) first and second cylinder units each including at least one cylinder; (b) an induction passage having therein a throttle valve, said induction passage being divided downstream of said throttle valve into first and second intake passages respectively communicating with said first and second cylinder units, said second intake passage having a stop valve near its entrance; (c) an exhaust passage; (d) an EGR passage connected from said exhaust passage to said induction passage downstream of said throttle valve, said EGR passage having therein an EGR valve whose position determines the flow area for exhaust gases through said EGR passage; (e) a control unit for closing said stop valve and disabling said second cylinder unit to shift said engine from full engine operation to split engine operation when the engine load falls below a predetermined value, said control unit comprising a computer responsive to signals indicative of engine speed and engine load, said computer including: memory means having first and second tables, said first table storing signals with values indicative of EGR ratio as functions of engine load and engine speed for said engine being in full engine operation, said second table storing signals with values indicative of EGR ratio as functions of engine load and engine speed for said engine being in split engine operation; said computer being operable to select a signal having a value indicative of EGR ratio corresponding with the conditions of engine load and engine speed from said first table when said engine is in full engine operation or from said second table when said engine is in split engine operation; and means responsive to the selected signal having a value indicative of EGR ratio for controlling the position of said EGR valve.