Abstract

The object of the present invention is a two-stroke endothermic engine (1), specifically designed for the reduction of polluting emissions, comprising a single transfer port (109) for the transfer of the fresh mix (MF) or fresh mix + lubricating oil (MF&O) and for the transfer of the scavenging air (AL) in the cylinder (106). Said scavenging air (AL) is of a sufficient volume to expel from the chamber (107) substantially all of the flue gases (GC) formed in the second phase (b) of "expansion-suction end" or "top dead centre" (PMS).

IPC Classes  ?

• F02B 21/00 - Engines characterised by air-storage chambers
• F02B 25/14 - Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both inlet and outlet ports arranged near bottom of piston stroke
• F02B 25/22 - Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports, not provided for in, or of interest apart from, groups by forming air cushion between charge and combustion residues
• F02B 33/04 - Engines with reciprocating-piston pumpsEngines with crankcase pumps with simple crankcase pumps, i.e. with the rear face of a non-stepped working piston acting as sole pumping member in co-operation with the crankcase
• F02B 33/12 - Engines with reciprocating-piston pumpsEngines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the pumping cylinder situated between working cylinder and crankcase, or with the pumping cylinder surrounding working cylinder the rear face of working piston acting as pumping member and co-operating with a pumping chamber isolated from crankcase, the connecting-rod passing through the chamber and co-operating with movable isolating member
• F02B 33/44 - Passages conducting the charge from the pump to the engine inlet, e.g. reservoirs
• F02B 75/02 - Engines characterised by their cycles, e.g. six-stroke

Abstract

The object of the present application is a power modulator (1) to be connected upstream of a standard arc welder (2) with coated electrode (4). Said power modulator (1) is adapted to modulate the power of the electric arc (6) during welding, by acting on the time intervals (low power time TBP, high power time TAP) in which said welder (2) is switched off or on. In this way the operator obtains an electric arc (6) of an average reduced power, but in any case suitable and sufficient for the welding to be performed, avoiding excessive and unnecessary energy consumption and achieving a number of advantages otherwise not achievable with the prior art welders, not provided with said power modulator (1).

IPC Classes  ?

• B23K 9/00 - Arc welding or cutting
• B23K 9/09 - Arrangements or circuits for arc welding with pulsed current or voltage
• B23K 9/12 - Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
• B23K 9/29 - Supporting devices adapted for making use of shielding means