12 parts and accessories for land vehicles, particularly with internal combustion engines, namely, vacuum boxes, vacuum switches and vacuum actuators, suction pipes, throttle-valve connections, thermal valves, fuel pumps, swirl pots therefor, fuel valves, fuel filters, fuel separators, air pumps and air blowers, air on/off valves, water-circulating pumps, vacuum pumps, vacuum control valves, exhaust-gs return valves and control valves for detoxification of exhaust gas, exhaust-gas valves