Abstract: A liquid cooling circulation system for power and working machines (especially internal combustion engines) contains an air-separating tank (17) in a by-pass vent line (14) which is arranged at the high point (5') of the radiator inflow (5). A fill inlet (19) with connecting openings (5" and 17') to the radiator inflow (5) and air-separating tank (17) have a closure cover (20) which closes off these connecting openings with respect to one another. Excess pressure, vacuum and vent valves (21 and 22) are contained in the closure cover 20 which controls a line connection (25) to an atmospheric, or to an excess pressure expansion tank (27). A highly effective venting function in conjunction with an engine operation at strong rotational speed changes exists, since the line connection (25) is opened at least at low cooling medium temperature by means of a temperature-controlled vent valve (22).

Abstract: A volume expansion, venting and reservoir tank for the liquid-cooling system of internal combustion engines with two chambers connected by means of an overflow line, which are formed from plastic molded parts welded together. The overflow line as well as further connections and openings are molded integrally with the molded parts at a filler inlet. The tank is constructed favorable from a manufacturing point of view and is applicable alternatively to different cooling systems for different pressure control possibilities of the two chambers depending on the arrangement of one closure cover or two closure covers with pressure control valves at the two chambers.

Abstract: Cooling circuit for internal combustion engines, with an excess-pressure valve which, when the cooling circuit is under full thermal load, limits the pressure in the feed to a value at which the pressure on the suction side of the coolant pump is always above the boiling pressure of the cooling medium, even at full delivery level of the coolant pump. The efficiency of the cooling function is improved as also the structural expenditure in connection with the cooling circuit is reduced thereby and also by the central arrangement, in the filling stub, respectively, the cap thereof, of additional excess-pressure and vacuum valves, of a throttle for a venting flow, of a level float switch for the filling level indication in the cooling circuit and of a blocking device against the opening of the cap which is under pressure.

Abstract: In a cooling circuit for internal combustion engines which includes a cooling jacket of the engine, a coolant pump, a radiator, a mixing thermostat, and an expansion tank, an excess-pressure valve is connected in the area between the cooling jacket and the radiator and a vacuum valve is connected in the area between the radiator valve of the mixing thermostat and the suction side of the coolant pump; both valves are connected with the coolant reservoir in the expansion tank which in communication with the atmosphere, is without excess pressure; high excess pressure values as well as low vacuum values in the cooling circuit are precluded thereby; a vent valve provides for an especially effective venting of the cooling circuit into the expansion tank in cooperation with the sucking back of coolant into the cooling circuit by means of the vacuum valve.

Abstract: In order to test at least one of the operating and capacitating conditions of an automotive vehicle, plural parallel circuits are included in a test circuit associated with sensors for each condition to be tested. These parallel circuits contain at least one pilot lamp and at least one switching unit. The switching unit may have simple switch contacts or may contain an electronic switching element. During normal operating conditions, the switching units are closed to provide a conductive path therethrough. During non-normal operating conditions and/or capacity conditions, the switching units open. For testing any condition, an individual test switch, which energizes each pilot lamp in the plural parallel circuits, is connected in series with the switching contacts and/or the conductive electronic switching elements of the switch units and with the pilot lamps in the plural circuits.