Abstract: A catalytic converter arrangement incorporated in an exhaust system of an internal combustion engine includes an exhaust manifold for ducting emissions from the engine; and first and second catalytic converters. The first catalytic converter is connected to and positioned immediately downstream from the exhaust manifold. The first catalytic converter has a ceramic catalyst support on an upstream side thereof and a metal catalyst support on a downstream side thereof. The second catalytic converter is connected to the first catalytic converter through an exhaust pipe and positioned downstream from the first catalytic converter. The second catalytic converter has a ceramic catalyst support. Thus, overheating of the metal catalyst support of the first catalytic converter can be prevented due to absorption of heat from emissions by the ceramic catalyst support of the first catalytic converter.

Abstract: A material for valve seats comprising a wear resisting sintered ferro alloy formed by dispersing particles of a high speed steel in a matrix in which hard alloy particles are dispersed. Steps for forming include mixing particles of a matrix material, carbide material and a hard alloy, and blending the mixture with high speed steel particles, pressurizing and compacting the mixture after blending, then sintering them at 1000.degree. to 1200.degree. C. In the preferred method, at least one element of Fe, C, Ni, Co, Si or Mn is included as the matrix material, and at least one element of Fe, Cr, Mo or V as the carbide material and at least one element of Fe, Cr, Mo, Co, C or W as the hard alloy are prepared. Furthermore, the ferro alloy preferably includes the following amounts of the above mentioned elements, 0.5 to 2.0 wt % of C, 1 to 25 wt % of one or more of Cr, Mo, V, or W and 1 to 15 wt % of one or more of Co, Ni, Mn, or Si.

Abstract: A chain tensioner comprises a body which is received in a bore formed through a side wall of a chain case, and includes a generally cylindrical portion. A plunger is slidably received in the cylindrical portion so as to press a timing chain. A check valve is arranged in the body. A damping chamber is defined by the cylindrical portion and the plunger, and is fluidly communicated with an oil pump via an oil supply passage. On the other hand, an oil reservoir is defined by the bore and the body, and is fluidly communicated with the damping chamber through the check valve via an oil passage, and also with the damping chamber via a flow restrictor.