A dry sump oil pump is what?
Extra oil in a dry sump is kept in a tank outside the engine as opposed to the oil pan. In a dry sump, there are at least two oil pumps: one that removes oil from the sump and transfers it to the tank, and another that removes oil from the tank and lubricates the engine. And if your questions about the purpose of oil sump (and not sump oil), it is used to store oil and collect back the circulating oil. It acts as a reservoir and oil is delivered from there to various parts of the engine using an oil pump and an oil filter. The oil sump can either be a wet oil sump (more common) or a dry oil sump (less common, has 2 oil pumps, more expensive and efficient).
What is the purpose of sump oil in a car engine?
Sump oil is just another name for engine oil. It's called so because it is stored in the sump, which is an oil pan at the bottom part of the engine.
Oil's main purpose is to lubricate all the parts of the engine. Besides that, it also prevents excessive wear of parts, cleans the surfaces, keeps the engine cool, inhibits corrosion, and keeps the engine sealed properly.
Dry sump systems add cost, complexity, and weight.
The extra pumps and lines in dry sump engines require additional oil and maintenance.
Performance-enhancing features of dry sump lubrication can damage a car's daily drivability. The car had a high oil capacity and a dry sump system to cope with continuous high-speed racing while racing. Owners found, in general use, that the oil never reached the correct operating temperature because the system was so efficient at cooling the oil. The oil temperature has been raised by blocking the airflow to the oil cooler as a makeshift fix.
The large external tank and pumps can be difficult to place around the engine and inside the engine compartment due to their size.
Since the wrist pins and pistons depend on lubrication and cooling, respectively, as oil is sprayed into the crankcase, these parts may have inadequate lubrication if the pump is drawing too much oil. Installing piston oilers can get around this problem, but at additional cost and complexity for the engine.
If too much oil vapor is pulled from the area, especially with multi-stage pumps, this can also cause the upper valvetrain to not be well oiled.
Why do some engines use a dry sump oil system?
In circuit racing or drifting, where there's very hard cornering, the engine is constantly kept under pressure by an external oil pump which is supplied with oil from an external oil tank, unlike in a conventional wet sump lubrication system where its internal oil pump which supplies the crankshaft & camshaft bearings with oil via an oil pickup tube from the oil pan. Well, during hard cornering, the oil can briefly slosh away from the oil pickup tube inlet screen & cause the pump to suck air into the pump instead of oil, which can lead to crankshaft & camshaft bearing failure.
Even though the oil pan has baffles, oil can still leak out of the oil pickup tubes' inlet screen when the car turns very sharply. This can stop the oil supply for a short time and damage the engine.
Does a dry sump have any advantages or disadvantages compared to a wet sump?
The biggest advantage to having a dry sump engine is the lack of any windage. As a crankshaft rotates through a bath of oil, the hydraulic resistance causes a loss of power, which increases exponentially as the RPM increases. While many engines have a windage tray, which is a type of splash shield to minimize windage, it’s still an issue.
Other advantages are the fact that riding orientation/attitude have no effect on lubrication. Whether you’re banked hard into a corner, stopping at full power, or accelerating hard, the engine will continue to get pressurized oil, provided the oil tank is filled.
Since the oil reservoir is usually in a tank, it is easy to increase the oil capacity, and the tank itself can help get rid of extra heat.
Finally, because there is no need for a gravity-filled oil sump under the crankshaft, the engine can be mounted lower to the ground, improving the center of gravity.
Some of the disadvantages are the fact that a dry sump system is more complex and thus failure prone. They are more prone to leaks, and because many rely on a check valve, it means a vehicle can develop a hydro-locked crank case if this valve fails.
On a motorcycle, a dry sump system also takes up more space, typically in the frame and under the seat.
"However, it is a difficult question whether it is effective for commercial vehicles." Whether or not the engine can be mounted low is also related to the transmission, so I don't think it's effective. However, I think that it is effective in terms of performance by being able to spread the oil to every corner of the engine.
If you can supply oil stably, you can improve the performance of the engine in various aspects. Among the several functions of engine oil, those of lubrication and cooling directly affect performance.
In addition, since the oil pan disappears or becomes thinner, the mounting position of the engine can be lowered. Instead, a new reservoir tank will be installed or the amount of oil used will increase, so whether or not there is an advantage in terms of exercise performance depends on the case.