How do we...clean engine components?

The biggest and most high-tech washing machine at mtu is in Plant 2 in Friedrichshafen and is used to clean crankcases. The process is rather like a car wash. Before the crankcase is conveyed into the washing machine, it is pre-rinsed. Just as in some car washes you have to clean the wheels by hand first, so it is with the clean-oil bores in the crankshaft, which have to be flushed. Then a production technician secures the crankcase onto a fixture and off it goes into the washing machine. The door opens, the crankcase goes inside and the door closes. This is when it really gets exciting, although from the outside you can only see through four small bullseye windows what is happening.

Crankcase completely submerged

“Inside the washing machine is what looks like a gym wheel which rotates the crankcase so that it can be cleaned and dried better,” he explains. Then the washing chamber is flooded with 7,000 l of water and the crankcase completely submerged. The water, which is heated to 70°, is swirled through the holes in the crankcase using high-pressure pumps. After nine minutes, the water is drained off along with all the coarse dirt particles, and the rinsing water is pumped into the washing chamber. Once again, the highpressure pumps rinse out the crankcase.

After another nine minutes, the crankcase is clean. The water is pumped back into the tanks and filtered along the way so that it can be re-used. “We monitor the quality of the washing water constantly in the lab so that we always have exactly the right concentration of detergent. As a result, we only have to change the water once a year,” says Rommel proudly. He points out that the machine is one of the most modern available on the market at present. “This machine is a total-immersion unit. The entire crankcase is put under water and flushed through under high pressure. So even shavings in deep bores that water jets cannot normally reach are rinsed away,” he explains.

Drying and cooling

After it has been vacuum-dried in the washing chamber, the crankcase moves fully automatically out of the machine and into the cooling chamber. When it emerges from there, it is ready for the next machining stage. However it will not be too long before it comes back to the washing machine. A crankcase is washed up to eight times before it is finally assembled in an engine. Because where there is drilling, milling and
deburring taking place, there is automatically dirt.