The 2-liter-diesel engine of a "Qashqai" crossover, the new compact Nissan vehicle similar to the Nissan Rogue. Take a look inside a diesel engine factory on the next page.
FLAME ARRESTORS AND SHIELDING The intention of the requirement to shield the valve discharge was to reduce the possible danger to personnel from flame emission. However explosion testing has shown that whilst a flame arrestor will work satisfactorily when shielding is not fitted, when shielding is fitted, the energy from the discharge is focussed in one direction, and there will be an emission of flames during an explosion. The fitting of shielding also reduces the effective outflow area of a valve. Since July 2002 it has been a Lloyds Register rule requirement to fit flame arrestors and to test the relief valve with any proposed shielding to be fitted to the valve when installed on the engine. A test procedure for new crankcase relief valves has been developed over the past four years by MAN B&W, The Physical Test Institute in the Czech Republic , Hoerbiger, and various classification socie...
There are two methods of oil mist detection, Obscuration and Light Scatter . The earlier forms of oil mist detector used an obscuration type detector, the most well known type being the early Graviners. Schaller use obscuration in their Visatron range of OMDs. Light scatter is a modern method of oil mist detection used by QMI and the Latest Graviner Mk6 OBSCURATION The older type of obscuration type of detector consists of two parallel tubes of equal size, each having a photoelectric cell at one end which generates an electric current directly proportional to the intensity of the light falling on its surface. Lenses are fitted to seal the ends of each tube but allow light to pass. Two identical beams of light from a common lamp are reflected by mirrors to pass along the tubes onto the cells which are then in electrical balance. The samples drawn from the crankcase are drawn in turn along the m...
The Crosshead
The crosshead pin connects the piston rod to the connecting rod. On either side of the crosshead pin are mounted the crosshead slippers. The slippers run up and down in the crosshead guides as the piston and rod are reciprocating and prevent the top of the connecting rod from moving sideways. The crosshead pin sits in the crosshead bearing which is either a forked type (shown left), where the bearing housings are mounted on the top of the connecting rod either side of the piston rod, or of the continuous type (shown above and below), where the bearing housing is formed by the top of the connecting rod. On the forked type, the piston rod passes through a hole in the crosshead pin and is secured by a nut. On the continuous type, the piston rod has a foot which is bolted onto the top of the crosshead pin. Modern engines are fitted with the continuous type of bearing. The crosshead bearing is difficult to lubricate effectively. Because the top of the connecting rod s...
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