NOVELTY - A vehicle-mounted electric power generation system (1) comprises an internal combustion engine (11) provided with exhaust pipe (17) for connecting to an engine and discharging exhaust gas from the engine. A first device (3) which carries out an electric polarization is provided by supplying the exhaust gas which temperature goes up and down sequentially. A second device (4) is provided for taking out electric power from the first device. A filter is arranged rather than the first device in the exhaust pipe at flow direction upstream of exhaust gas. A heater is provided for heating the filter.    USE - Electric power generation system for mounting in vehicles, particularly motor vehicle.    ADVANTAGE - The soot which are contained in exhaust gas can be collected by a filter in the exhaust-gas flow direction upstream of the first device, thus contamination of device can be suppressed.    DETAILED DESCRIPTION - A vehicle-mounted electric power generation system (1) comprises an internal combustion engine (11) provided with exhaust pipe (17) for connecting to an engine and discharging exhaust gas from the engine. A first device (3) which carries out an electric polarization is provided by arranging in the exhaust pipe and supplying the exhaust gas which temperature goes up and down sequentially. A second device (4) is provided for taking out electric power from the first device. A filter is arranged rather than the first device in the exhaust pipe at the flow direction upstream of exhaust gas. A heater is provided for heating the filter. A controller is provided for operating the heater at a predetermined timing.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic block diagram which shows the vehicle-mounted electric power generation system.    Vehicle-mounted electric power generation system (1)    First device (3)    Second device (4)    Control unit (7)    Motor vehicle (10)    Internal combustion engine (11)    Ignition plug (15)    Exhaust pipe (17)    Fuel supply apparatus (20)