Abstract: Disclosed is a secondary air feeding device for feeding secondary air into the exhaust passage located upstream of the catalytic converter. A diaphragm type secondary air control valve is provided for usually controlling an amount of secondary air fed into the exhaust passage. Said secondary air control valve stops the feeding operation of secondary air at the time of idling.

Abstract: Disclosed is an improvement of an exhaust gas purifying device for use with an internal combustion engine incorporating both an exhaust gas recirculation system and a secondary air supply system, the improvement comprising variable restriction means disposed in an exhaust pipe downstream of an exhaust gas intake port of the exhaust gas recirculation system for varying the flow cross sectional area of the exhaust pipe and control means responsive to the difference between the signal representative of the volume of exhaust gas and the signal representative of the volume of intake air for controlling the variable restriction means in such a way that the former signal may be proportional to the latter signal, whereby the volume of exhaust gas to be recirculated may be made optimumly proportional to the volume of intake air independently of the variation in rotational speed and load of the engine.

Abstract: A damper door is swingably disposed in an exhaust system downstream of an afterburning device to open or close the exhaust tube or pipe in response to movement of a throttle valve of an air-fuel mixture supply means such as a carburetor.

Abstract: This invention relates to a catalytic converter for transforming polluting gases into non-polluting gases comprising a housing having an inlet for the polluting gases and an outlet for the non-polluting gases, a silver coated grill within said housing adjacent to the housing inlet, a mesh, intermediate said silver coated grill and the housing outlet, said mesh comprising an alloy base consisting essentially of from 1.0% to 1.9% silicon, from 10% to 29% chrome, from 1% to 5.1% copper, from 1.1% to 9.1% molybdenum, from 0.11% to 0.5% titanium, from 0.1% to 1.9% carbon and from 0.5% to 0.9% iron and a coating of silver or palladium on said alloy.

Abstract: A valve disposed in the central space of the manifold normally divides the space into two halves to avoid mutual interference of exhaust gas flows. At low engine speeds, the valve causes the exhaust gas flows from all branches to be disturbed and to mix with each other, to promote oxidation of HC and CO.

Abstract: An air-pollution preventive arrangement for use with an internal combustion engine for motor vehicles, adapted to reduce the concentrations of noxious compounds such as unburned hydrocarbons and carbonmonoxides contained in the engine exhaust gases. The arrangement comprises a thermal reactor for primarily re-combusting the exhaust gases and a catalytic converter for secondarily recombusting the exhaust gases passed from the thermal reactor so as to oxidize the residual unburned compounds. An air injection unit supplies additional air which is admixed, in a limited proportion, to the exhaust gases entering the thermal reactor to aid in the primary re-combustion of the exhaust gases therein. The noxious unconsumed hydrocarbons and carbon-monoxides are thus converted into innocuous compounds at efficiencies which are far higher than those attained where the thermal reactor or the catalytic converter is employed independently.