Abstract: A tank-venting system has the following features: a tank 10; an adsorption filter 13 which is connected to the tank via a tank-connecting line 12 and which has a venting line 14 which can be closed off by a shut-off valve 15; and, a tank-venting valve 16 which is connected to the adsorption filter via a valve line 17; a pressure connection 21 on the valve line close to the tank-venting valve; and, a pressure sensor 11 on the tank.With the aid of this tank-venting system, the following method can be carried out: closing the tank-venting valve and the shut-off valve; supplying compressed air to the pressure connection; measuring the pressure in the tank; and, checking if the pressure satisfies a pregiven pressure condition and determining the tank-venting system as being inoperable in the event that this is not the case.

Abstract: A method and an arrangement for carrying out the method are proposed whose fundamental concept is to perform a diagnosis of the heating device of an exhaust-gas probe, which emits a control signal for closed-loop controlling the air/fuel mixture of an internal combustion engine. The diagnosis is based on that the exhaust-gas probe is heated more rapidly because of the switching-in of the heating device than by mere heating by the exhaust gases which flow past the exhaust-gas probe. The heating device includes at least the probe heater, devices which supply the probe heater with the necessary heating power, and the supply leads therefor.

Abstract: A two-stage polymerization process using a modified supported catalyst gives ethylene polymers with very good processability and excellent finished component properties. The supported catalyst used is formed by reaction of a magnesium alcoholate with a titanium-IV compound in suspension and subsequent reaction with a halogen-containing organoaluminum compound and activation of the solid thus obtained by an aluminum trialkyl or aluminum isoprenyl.

Abstract: Polyolefins having a broad molecular weight distribution are obtained in a very high yield even using a catalyst based on a reaction product of a magnesium alcoholate with titanium tetrachloride, if the hydrocarbon-insoluble product of the reaction of the magnesium alcoholate with titanium tetrachloride is heated to a fairly high temperature with a chloroalkoxytitanate, in order to split off alkyl chlorides.

Abstract: Polyolefins having a broad molecular weight distribution are obtained in a very high yield even using, as the catalyst, a product from the reaction of a magnesium alcoholate with titanium tetrachloride, if the reaction between the magnesium alcoholate and the titanium tetrachloride is carried out at a relatively low temperature and the reaction mixture is then heated to a fairly high temperature in order to split off alkyl chlorides.

Abstract: The high activity rate of known polymerization catalysts on the basis of metal alcoholates can be considerably increased by after-treating these catalysts with acid halides of the 3rd or 4th main group or the 4th subgroup of the Periodic Table.

Abstract: When reacting the reaction product of silicon dioxide and/or a metal oxide and a Grignard compound with a soluble titanium compound, there is obtained a catalyst for the polymerization of 1-olefins, which gives a very high yield and allows a good control of the molecular weight by means of hydrogen without making necessary a separation of the excess of metallo-organic compounds and/or the excess of titanium compounds from the catalyst carrier.