How is crosshead lubricated?

Oil supply to the crosshead is via a telescopic pipe from the main LO supply at a pressure of about 2.5 bar. The lower bearing shell (tin aluminium with overlay) has oil grooves with machined wedges . The oil enters via the cut out channel in the centre.

Which type of lubrication system is used in two-stroke engine?

In two-stroke engines, mist lubrication is used where crankcase lubrication is not suitable. In a two-stroke engine, as the charge is compressed in the crankcase, it is not possible to have the lubricating oil in the sump. Hence, mist lubrication is adopted in practice.

How are two-stroke engines lubricated?

Emissions. Crankcase-compression two-stroke engines, such as common small gasoline-powered engines, are lubricated by a petroil mixture in a total-loss system. Oil is mixed in with their petrol fuel beforehand, in a fuel-to-oil ratio of around 32:1.

Why do engines need a cross head?

A crosshead is a mechanism used as part of the slider-crank linkages of long reciprocating engines and reciprocating compressors to eliminate sideways pressure on the piston. Also, the crosshead enables the connecting rod to freely move outside the cylinder.

Why are telescopic pipe used for oil lubrication?

In B&W Engines Telescopic pipe is used for supplying oil to the crosshead which supplies oil to the inlet pipe of piston rod.

How do you use a lubricant oil sample?

Three sampling procedures commonly associated with engine oil sampling include: sampling a pressurized line before the system filter; using a drop tube in the dipstick tube; and procuring a sample midstream from a drain port while draining the engine.

What is the main purpose of the lubricant?

A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces.

What is scavenging air?

Scavenging is the process of replacing the exhaust gas in a cylinder of an internal combustion engine with the fresh air/fuel mixture (or fresh air, in the case of direct-injection engines) for the next cycle. Scavenging is equally important for both two-stroke and four-stroke engines.

What is a cross head bearing?

n. a sliding member of a reciprocating engine for keeping the motion of the joint between a piston rod and a connecting rod in a straight line.

Why is there no crosshead in a 4 stroke engine?

In four stroke or trunk piston engines the skirt has arrangement for gudgeon pin, which transmits power from the piston to the gudgeon pin or top end bearing. As there are no cross head guides in four stroke engines, these skirts help in transferring the side thrust produced from the connecting rod to the liner walls.

How is the crosshead of a marine engine lubricated?

Crosshead Lubrication. The type of motion of the crosshead of a marine diesel engine is oscillatory in nature wherein it oscillates to a few degrees on either side of the center of oscillation. Apart from that the speed of oscillation is not very significant which in turn means that it will not generate a pumping action for lubrication unlike…

What kind of lubrication does a marine engine use?

Crosshead Lubrication The type of motion of the crosshead of a marine diesel engine is oscillatory in nature wherein it oscillates to a few degrees on either side of the center of oscillation.

When to use journal bearing lubrication in diesel engines?

Lubrication of the journal bearing in diesel engines (mainly during starting and stopping of engine). Piston rings and when cylinder liner is at TDC and BDC position when the piston direction changes and if the relative speed is very slow.

Which is better support for a crosshead pin?

The connecting rod design can be modified in a manner which provides better support for the crosshead pin. Apart from that the pin is also made thicker that what is required from calculations of load so that the large surface area of the thicker pin reduces load per unit area.