Internal combustion engine with a fuel reformer and exhaust gas recirculation

An internal combustion engine assembly comprising:

• a fuel tank, connected via a fuel supply duct to a first fuel inlet of at least one of a number of cylinders, the cylinders being with an outlet connected to an exhaust system,
• exhaust gases from the exhaust system being in heat exchanging contact with a reformer unit for steam reforming of alcohol, the reformer unit being with a reformer outlet connected to a second fuel inlet of the cylinders for supplying hydrogen to the second fuel inlet,
• an alcohol evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to an alcohol supply unit and with an outlet connected to a first reformer supply duct that is connected to an inlet of the reformer unit via a first control valve, for supplying alcohol steam to the reformer unit,
• a water evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to a water tank and that is with an outlet connected to a second reformer supply duct that is connected to the inlet of the reformer unit via a second control valve for supplying water steam to the reformer unit,
• a reformer purge duct extending from the exhaust system to the inlet of the reformer unit via a purge control valve, adapted for feeding exhaust gases into the reformer unit and via the reformer outlet to the second fuel inlet of the cylinders, and
• a controller adapted to carry out a start sequence comprising:
• starting combustion of fuel in the cylinders,
• opening of the purge control valve to flow exhaust gases through the reformer unit, a buffer tank and the cylinders for removal of O2,
• start producing of alcohol steam and water steam until the pressures in the first and second reformer supply ducts reach a respective predetermined value,
• closing of the purge control valve and opening of the second control valve to flow water steam through the reformer unit and the buffer tank, and
• opening the first control valve to start the process of fuel reforming in the reformer unit.

A vehicle comprising:

• an internal combustion engine assembly comprising:
• a fuel tank, connected via a fuel supply duct to a first fuel inlet of at least one of a number of cylinders, the cylinders being with an outlet connected to an exhaust system,
• exhaust gases from the exhaust system being in heat exchanging contact with a reformer unit for steam reforming of alcohol, the reformer unit being with a reformer outlet connected to a second fuel inlet of the cylinders for supplying hydrogen to the second fuel inlet,
• an alcohol evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to an alcohol supply unit and with an outlet connected to a first reformer supply duct that is connected to an inlet of the reformer unit via a first control valve, for supplying alcohol steam to the reformer unit,
• a water evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to a water tank and that is with an outlet connected to a second reformer supply duct that is connected to the inlet of the reformer unit via a second control valve for supplying water steam to the reformer unit, and
• a reformer purge duct extending from the exhaust system to the inlet of the reformer unit via a purge control valve, adapted for feeding exhaust gases into the reformer unit and via the reformer outlet to the second fuel inlet of the cylinders.

A method of operating a vehicle comprising an internal combustion engine assembly comprising:

• a fuel tank, connected via a fuel supply duct to a first fuel inlet of at least one of a number of cylinders, the cylinders being with an outlet connected to an exhaust system,
• exhaust gases from the exhaust system being in heat exchanging contact with a reformer unit for steam reforming of alcohol, the reformer unit being with a reformer outlet connected to a second fuel inlet of the cylinders for supplying hydrogen to the second fuel inlet,
• an alcohol evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to an alcohol supply unit and with an outlet connected to a first reformer supply duct that is connected to an inlet of the reformer unit via a first control valve, for supplying alcohol steam to the reformer unit,
• a water evaporator that is in heat exchanging contact with the exhaust gases and that is with an inlet connected to a water tank and that is with an outlet connected to a second reformer supply duct that is connected to the inlet of the reformer unit via a second control valve for supplying water steam to the reformer unit, and
• a reformer purge duct extending from the exhaust system to the inlet of the reformer unit via a purge control valve, adapted for feeding exhaust gases into the reformer unit and via the reformer outlet to the second fuel inlet of the cylinders,
• the method comprising performing a starting sequence comprising:
• starting of the at least one of the number of cylinders until reaching a lambda of 1,
• opening of the purge control valve and feeding inert exhaust gases via the reformer unit to the cylinders to purge the system with inert exhaust gas,
• closing of the purge control valve after a predetermined period of time,
• supplying water steam to the reformer unit to prime the reformer unit with water and avoid coke forming in the reformer unit, and
• supplying alcohol steam to the reformer unit to start the fuel reforming process.