Abstract: The EGR controller 1 controls the EGR actions wherein exhaust gas from the cylinder cut-off engine 3 which can change over the running condition between the all-cylinder run and the cut-off-cylinder is recirculated to the induction. The EGR controller 1 comprises an EGR control valve 6 for opening and closing the EGR pipe 13, a water temperature sensor 5 for detecting cooling water temperature TW and an ECU 2, and the ECU 2 controls the EGR actions so as tobe executed if the cooling water temperature TW is higher (determined as “Yes” at Step 10) than the upper limit value TWE1H while at the all-cylinder run (determined as “No” at Step 2) or if the cooling water temperature TW is higher than the lower limit value TWE1L while at the cut-off-cylinder run (determined as “Yes” at Step 2).

Abstract: In an apparatus for controlling a multi-cylinder internal combustion engine with partial cylinder switch-off mechanism which is switchable between an all-cylinder operation mode in which all cylinders are operated and a partial-cylinder operation mode in which operation of partial cylinders is suspended, the operation of intake valves and exhaust valves is suspended or resumed in a predetermined order with respect to all of the suspended cylinders irrespective of a rotational frequency of the engine. There are provided a solenoid valve on an intake side and a solenoid valve on an exhaust side for switching input hydraulic pressures for hydraulically operated switching devices respectively on the intake side and on the exhaust side between the driving state and the drive-free state. At the time of switching the operation, one of the solenoid valves on the intake side and the exhaust side is driven in advance. The subsequent number of rotations of a crankshaft is counted.

Abstract: In the present invention, alumina is produced by a process comprising leading a starting aqueous slurry containing a seed alumina hydrate to a circulating system, the aqueous slurry being circulated and returned to the starting aqueous slurry, wherein an aqueous solution of an aluminum salt and an aqueous solution of a neutralizer are added to the aqueous slurry being circulated and mixed together at a pH value of 6 to 11 to thereby cause the aqueous slurry to contain formed alumina hydrate prior to the return to the starting aqueous slurry.

Abstract: An exhaust emission control device includes an HC convening first catalytic converter mounted in close proximity to an engine, and an HC converting second catalytic converter connected to the first catalytic converter through an exhaust pipe. A time point of starting of HC conversion by the second catalytic converter is set between a time point of completion of HC adsorption in the second catalytic converter and a time point of completion of HC desorption from the second catalytic converter. Thus, it is possible to reduce the amount of HC desorbed.

Abstract: Catalyst compositions and a process for making the same are disclosed. The composition finds application in the cracking of heavy hydrocarbon feedstock containing vanadium and other metal contaminants. It essentially comprises a crystalline zeolite, a metal trapping or passivating agent and an inorganic oxide matrix precursor and is characterized by minimum elution of an alkaline earth metal in the catalyst.

Abstract: An exhaust gas containing a nitrogen oxides is passed at a temperature of 250.degree. to 550.degree. C. in the presence of a reducing agent through a catalyst bed filled with a molded denitration catalyst comprising at least the following three catalyst components(A) an oxide of at least one metallic element selected from the group consisting of Ti, Si and Zr,(B) an oxide of at least one metallic element selected from the group consisting of Mo and W, and(C) an oxide of Vsuch that the concentrations of the oxide (B) and/or the oxide (C) in the exhaust gas inlet site of the catalyst bed are higher than in the other site thereof.The molded denitration catalyst is also described.

Abstract: A catalyst for denitrizing nitrogen oxides contained in waste gas which contains a substantial amount of arsenic compounds therein, which comprises:(a) titanium, and(b) at least one element selected from the group consisting of arsenic and manganese. The catalyst is resistant to deactivation by arsenic compounds and retains high denitrizing activity over a long period of time. The catalyst may further contain at least one base metal selected from the group consisting of V, W, Mo, Cu, Fe, Cr, Co, Ni, Zn and Sn.

Abstract: A process for removing nitrogen oxides from an exhaust gas containing the nitrogen oxides and an arsenic compound, which comprises bringing said exhaust gas into contact with a reducing gas in the presence of a catalyst to reduce the nitrogen oxides in the exhaust gas and render them nontoxic. There are disclosed two types of catalysts: (1) a catalyst comprising (A) an oxide of titanium, (B) an oxide of at least one metal selected from tungsten and molybdenum, (C) an oxide of vanadium, and (D) an oxide and/or a sulfate of at least one metal selected from the group consisting of yttrium, lanthanum, cerium and neodymium, and (2) the above (A), (B), (C) components and (D)' at least one metal selected from the group consisting of yttrium, lanthanum, cerium, neodymium, copper, cobalt, manganese and iron, the component (D)' being deposited on zeolite.

Abstract: A catalyst for removing nitrogen oxides in an exhaust gas, said catalyst containing a first group of many pores having a diameter of 1.times.10.sup.2 .ANG. to less than 1.times.10.sup.3 .ANG. and a second group of many pores having a diameter of 1.times.10.sup.3 .ANG. to 1.2.times.10.sup.5 .ANG., the pore volume of the first group being at least 10% based on the total pore volume of the first group and the second group, and said catalyst comprising titanium and at least one metal selected from molybdenum, tungsten and vanadium as metal elements of catalytically active ingredients.

Abstract: Here is provided an adsorbent for adsorbing and removing an arsenic compound which becomes a catalyst poison in a selective contact reduction process for removing nitrogen oxides (NOx) from a combustion exhaust gas by the use of an ammonia as a reducing agent and a denitrating catalyst.The adsorbent of the present invention comprises a material in which the total volume of pores is 0.2 to 0.7 cc/g and the volume of the pores having a pore diameter of 300 .ANG. or more is 10% or more with respect to the total pore volume, and the material is a specific element, its oxide, an ion-exchanged zeolite or the like.In addition, the present invention is directed to a method for removing the arsenic compound from the combustion exhaust gas by injecting the adsorbent into the flow of the gas on the upstream side of the denitrating catalyst.

Abstract: A process for removing nitrogen oxides from an exhaust gas containing the nitrogen oxides and an arsenic compound, which comprises bringing said exhaust gas into contact with a reducing gas in the presence of a catalyst to reduce the nitrogen oxides in the exhaust gas and render them nontoxic. There are disclosed two types of catalysts: (1) a catalyst comprising (A) an oxide of titanium, (B) an oxide of at least one metal selected from tungsten and molybdenum, (C) an oxide of vanadium, and (D) an oxide and/or a sulfate of at least one metal selected from the group consisting of yttrium, lanthanum, cerium and neodymium, and (2) the above (A), (B), (C) components and (D)' at least one metal selected from the group consisting of yttrium, lanthanum, cerium, neodymium, copper, cobalt, manganese and iron, the component (D)' being deposited on zeolite.

Abstract: A denitration catalyst comprising an oxide of titanium, an oxide of tungsten and an oxide of vanadium as catalytically active ingredients and having a specific surface area, measured by the BET method, of 80 to 200 m.sup.2 /g and a pore volume, measured by the mercury penetration method, of 0.1 to 0.5 cc/g.

Abstract: An extrusion die for forming a honeycomb stucture has a lattice molding groove formed in the outlet surface of the die body. In the inlet surface of the die body there are formed plural independent supply passages that are opposite to the intersecting portions of the molding groove and extend toward the outlet surface. A through hole is designed to communicate adjacent supply passages at a place that forms part of the partition wall between the supply passages and contacts with the molding groove. This through hole takes the combined shape of a trapezoid with the width of the molding groove as its top side and with the diameter of the supply passage as its maximum base side and a semicircle having said base side as its diameter.