The Rolls-Royce business unit Power Systems has developed a sliding bearing for its mtu engines that reduces their fuel consumption by 1%. That achievement has won it the Environmental Technology Prize awarded by the Ministry for the Environment in the state of Baden-Württemberg. Minister of the Environment Thekla Walker handed the prize to Dr Otto Preiss, COO and CTO of Rolls-Royce Power Systems, on 4 November 2021. The new bearings significantly reduce the amount of friction arising between bearing and crankshaft and also enable prediction of when maintenance will next be required. “This is an innovation with huge potential, because the new bearings can simply replace the existing bearings in a whole range of applications,” said Thekla Walker, Environment Minister of Baden-Württemberg, in the awards ceremony.
The bearing surface, instead of being entirely smooth, is furbished with fine grooves, which, together with the lubricant, produce an acquaplaning-like effect which functions as an antifriction layer. This anti-friction layer reduces, for example, the friction-induced losses arising between crankshaft and bearing by 20-35%, depending on the operating mode. The innovative bearing is the result of a collaborative effort between a small project team in Friedrichshafen, bearing manufacturer Miba, and the MontanUniversität Leoben in Austria.
“The technology behind sliding bearings is very mature and very well established and to genuinely improve it you need outstanding engineering expertise and innovative talent. So we're very proud that along with our partners, we've succeeded in developing an optimized metal slide bearing that can be installed in our engines without the need for further modification. With just one easy production step extra, a 1% reduction in fuel consumption can be achieved that not only lowers costs, but avoids emissions,” pointed out Dr Otto Preiss, COO and CTO at RollsRoyce Power Systems. mtu engines produced in higher volumes by the company are to be fitted with the new sliding bearing in the near future. mtu engines already in service shall be gradually retro-fitted in the course of overhauls. The future plan is for the new bearing to be marketed as an individual component by Miba AG.
Use of the bearing in the engine reduces friction-induced losses, and while power output is maintained, fuel consumption drops by around 1%. That does not sound like very much, but a little goes a long way, as the following simplified example shows: A mining truck powered by a large engine whose power output is roughly equivalent to that of twenty medium-sized passenger cars runs for around 20 hours a day, consuming some 400L of fuel per hour under full load. Installed in the engine, the new bearing alone therefore enables a fuel saving of around 80L per day.
Furthermore, the innovative bearing technology indicates when the next major maintenance work will be due by producing a change in the sound signature of the bearing which can be interpreted accordingly. That enables the service life of the bearing to be fully exploited. Premature maintenance is avoided and excessive wear identified in good time, saving both material and operating costs.
The bearing, for which a patent is pending, is not only suitable for use in mtu engines from RollsRoyce: “It is suitable for all equipment in which sliding bearings must withstand high loads – for example utility vehicle engines, turbines and wind power plants, which, thanks to the new bearing, go into operation a little more quickly than before and are therefore productive for longer,” explained Dr Thomas Kottke, who is heading up the project.