A large low-speed turbocharged two-stroke internal combustion engine of the uniflow type with crossheads, said engine comprising: a plurality of cylinders, each cylinder being provided with two or three primary fuel valves and each cylinder being provided with two or three secondary fuel valves, a primary fuel supply system operating with a first type of fuel and comprising a primary fuel tank for said first type of fuel, a primary fuel pump that receives said first type of fuel from the primary fuel tank and delivers pressurized first type fuel to said primary fuel valves for delivering said first type of fuel to the combustion chambers in said cylinders, a secondary fuel supply system operating with a second type of fuel different from said first type of fuel, and comprising a secondary fuel tank for a second type of fuel, a secondary fuel pump that receives said second type of fuel from the secondary fuel tank and delivers pressurized second type fuel to said secondary fuel valves for delivering said second type of fuel to the combustion chambers in said cylinders, and an electronic control unit (ECU,CCU) configured to control and operate said primary fuel system and said secondary fuel system, said electronic control unit (ECU,CCU) being configured to operate a selected number of said plurality of cylinders with said second type of fuel via said secondary fuel system delivering pressurized secondary fuel with said secondary fuel pump to the secondary fuel valves of said selected number of said plurality of cylinders and said electronic control unit (ECU,CCU) being configured to operate the remaining cylinders of said plurality of cylinders with said first type of fuel via said primary fuel system delivering pressurized first fuel with said primary fuel pump to the primary fuel valves of said selected number of said plurality of cylinders. a plurality of cylinders, each cylinder being provided with two or three primary fuel valves and each cylinder being provided with two or three secondary fuel valves, a primary fuel supply system operating with a first type of fuel and comprising a primary fuel tank for said first type of fuel, a primary fuel pump that receives said first type of fuel from the primary fuel tank and delivers pressurized first type fuel to said primary fuel valves for delivering said first type of fuel to the combustion chambers in said cylinders, a secondary fuel supply system operating with a second type of fuel different from said first type of fuel, and comprising a secondary fuel tank for a second type of fuel, a secondary fuel pump that receives said second type of fuel from the secondary fuel tank and delivers pressurized second type fuel to said secondary fuel valves for delivering said second type of fuel to the combustion chambers in said cylinders, and an electronic control unit (ECU,CCU) configured to control and operate said primary fuel system and said secondary fuel system, said electronic control unit (ECU,CCU) being configured to operate a selected number of said plurality of cylinders with said second type of fuel via said secondary fuel system delivering pressurized secondary fuel with said secondary fuel pump to the secondary fuel valves of said selected number of said plurality of cylinders and said electronic control unit (ECU,CCU) being configured to operate the remaining cylinders of said plurality of cylinders with said first type of fuel via said primary fuel system delivering pressurized first fuel with said primary fuel pump to the primary fuel valves of said selected number of said plurality of cylinders.