Method of starting gas delivery from a liquefied gas fuel system to a gas operated engine and a liquefied gas fuel system for a gas operated engine

A method for starting gas delivery from a liquefied gas fuel system to a gas operated engine in which a fuel tank is filled with liquefied gas by a filling procedure,

• the fuel system comprising a main evaporator in a fuel conduit leading from the fuel tank to an engine, the main evaporator is arranged in connection with the fuel tank and evaporating the liquefied gas in the fuel tank while the engine is operated by gaseous gas, and
• the engine started and operated and producing waste heat,
• the waste heat produced by the engine utilized in a heat transfer medium circuit, in which heat transfer medium is flowing through the main evaporator,
• pressure in the fuel tank controlled by controlling the operation of a pressure build up system which is arranged in a conduit leading from the bottom section of the fuel tank to the upper section of the fuel tank,
• the heat transfer medium by means of which the waste heat produced by the engine is utilized, flowing through a pressure build up evaporator and the main evaporator being successively connected in series,
• the filling procedure resulting in that the pressure in the tank is at least at an operational pressure required by the engine, and after the filling procedure the pressure build up evaporator controlled by controlling the flow rate of the evaporated gas in the conduit while the heat transfer medium is allowed to flow unconstrained through the pressure build up evaporator and the main evaporator.