Back to results
US 5,657,630 AGranted
Large supercharged diesel engine
AssigneeMan B&W Diesel A/S
InventorsNiels Kjemtrup, Peter Berg-Sonne
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeMan B&W Diesel A/S
InventorsNiels Kjemtrup, Peter Berg-Sonne
Estimating the term…
Exhaust gas in a supercharged internal combustion engine is recycled from the high pressure side of the turbocharger to the charging air system of the engine. At least part of the recycled exhaust gas is humidified to largely 100 percent relative humidity. This on one hand cools the gas to that the temperature at initiation of the combustion in the engine cylinders is lowered, and on the other hand the heat capacity of the steam in the gas restricts the temperature raise occurring during the combustion. These factors both act to reduce the amount of NO.sub.x produced by the combustion. The addition of water is effected by a scrubber (16) which purifies the recycled gas. A blower (17) augments the pressure of the recycled gas. The scrubber may be made to generate fresh water by designing it with several stages where sea water is supplied to the first stage and fresh water to the last stage.
A large supercharged diesel engine (1), such as a main engine of a ship, comprising a turbocharger having an exhaust gas-driven turbine (6) and a compressor (9) driven by the turbine and supplying charging air to the engine cylinders, and a recycling passage for returning part of the exhaust gas to the engine cylinders, characterized in that the recycling passage (15, 11) includes a unit for humidification of the exhaust gas with water, that the humidification unit is a scrubber (16, 19) having a number of water atomizer stages (20, 29, 25), that the recycling passage comprises a conduit (15) which branches off from the exhaust conduit (5) upstream of the turbine (6) and is connected with the charging air conduit (11) downstream of the compressor (9), and that the conduit is connected with the scrubber (16) and with a blower (17), for augmentation of the pressure in the recycled exhaust gas.
Dependencies are inferred from the claim text.