Plain bearings in internal combustion engines

Hello, the following question was asked in our forum:

Wo kommen denn überall Gleitlager im 4-Takt Verbrennungsmotor vor?
Und wo werden Wälzlager verwendet?
Can someone answer this question for me?

You can also reply directly here in our automotive forum; here's the link to the post:

http://www.kfz-auskunft.de/autoforum/ftopic90.html

Thank you in advance.

Sincerely,
Thomas Borst.
Kfz-Auskunft.de

Hello Tommy!

Today, virtually all bearings in combustion engines are designed as plain bearings. This includes the crankshaft bearings, connecting rod bearings, camshaft bearings, and piston pin bearings. I once had a Honda XBR 500, which only used roller bearings. That was quite complex. The only advantage I see is better performance under emergency conditions with inadequate lubrication. In the past, roller bearings were more common because the materials, oils, and manufacturing techniques weren't advanced enough to produce plain bearings that could match the performance of roller bearings.
Regards,
mcgregg

Hello,

"When oil is available under pressure, a plain bearing is almost always superior to a roller bearing. The contact surfaces are much larger, resulting in surface pressures that are many times smaller. You'll typically find roller bearings in two-stroke engines without pressurized oil lubrication."

Best regards,
Christian.

Sure, thanks for that.

You have helped me a lot.

Best regards, Tomy.

Hi,
I would like to add something:

Rolling bearings have less friction, which is one reason why their use is repeatedly considered or has been considered.
However, they are louder and cannot be disassembled into two halves for installation (excluding any special designs that I am not familiar with), which is typical for crankshafts and camshafts of a more conventional design.
In stationary applications, plain bearings last indefinitely, while rolling bearings typically have a limited lifespan, which wouldn't be such a critical issue in automobiles.

Hello!

A rolling bearing is completely unthinkable in the connecting rod assemblies of a large four-stroke engine.

The piston pin bearing must absorb the majority of the cylinder pressure; otherwise, it will be destroyed. The remaining portion is transferred as normal force to the cylinder wall (force triangle).

From a frictional performance perspective, the rolling bearing would have an advantage; however, this difference is far less than one might assume, as there is no contact between the friction surfaces in operation of a plain bearing. The majority of friction in such plain bearings is due to fluid friction.

Regards,

Stubby.

...which is why it's clear that the oil is the most heavily stressed component (or part) of the engine.

knubbi wrote:

A roller bearing is completely unthinkable for the connecting rod bearings in a "large" four-stroke engine.

Hello,

fast alle Rennmotoren in den ersten paar Nachkriegsjahrzehnten waren wälzgelagert, eben um Reibung einzusparen, das ist nicht so wenig, wie man denkt. Um die Montage der Lager zu ermöglichen, wurden die Kurbelwellen geteilt ("Hirthverzahnung"). Die Gaskräfte der modernen Dieselmotoren sind gewaltig, aber die Massenkräfte (sie nehmen quadratisch mit der Drehzahl zu) der Benziner damals waren sicher auch keine Peanuts (daher nahm man wo zulässig Titanpleuel). Wie siehts eigentlich mit der aktuellen Formel 1 aus? WaDo they have storage space?

Best regards, Uli.

Formula 1 cars use plain bearings, just like all other racing car engines (DTM, Formula 3, Le Mans, etc.).

To truly take advantage of the friction-reducing benefits of rolling bearings, one must not over-lubricate. A good example is oil mist lubrication, but things are done differently in a "typical" engine.