Patent ID: 7587898

Claim:
An internal combustion engine comprising: a combustion chamber; first and second inlet valves controlling flow of air into the combustion chamber; first and second exhaust valves controlling flow of combusted gases out of the combustion chamber; and first and second turbo-chargers; wherein: the first turbo-charger is connected to the first inlet valve and the second turbo-charger is connected to the second inlet valve; charge air supplied to the combustion chamber via the first inlet valve is pressurised only by the first turbo-charger; charge air supplied to the combustion chamber via the second inlet valve is pressurised only by the second turbo-charger; the first turbo-charger is connected to the first exhaust valve and receives only combusted gases expelled via the first exhaust valve; the second turbo-charger is connected to the second exhaust valve and all combusted gases expelled via the second exhaust valve flow to the second turbo-charger without passing through the first turbo-charger; and a valve operating means for controlling operation of the first inlet valve and first exhaust valve independently from the operation of the second inlet valve and second exhaust valve thereby providing variation in the ratio of the mass of charge air supplied to the combustion chamber via the first inlet valve to the mass of charge air supplied to the combustion chamber via the second inlet valve, wherein said valve operating means for operating in different modes of operations, including: a first operating mode in which the second inlet valve and the second exhaust valve are deactivated whereby all charge air supplied to the combustion chamber is pressurised by the first turbo-charger and delivered via the first inlet valve; a second operating mode in which the first and second inlet valves and the first and second exhaust valves operate simultaneously whereby charge air supplied to the combustion chamber is pressurised by both of the first and second turbo-chargers and delivered via both the first and second inlet valves; and a third operating mode in which the first inlet valve and the first exhaust valve are deactivated whereby all charge air supplied to the combustion chamber is pressurised by the second turbo-charger and delivered via the second inlet valve.