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Neander turbodiesel

Steam engine

The Neander engine is put through its paces at the Department of Internal Combustion Engines at the Munich University of Applied Sciences. MOTORRAD visited the development team at work.

M.Engine stories have become rare lately. The common four-cylinder in-line engine has long since been scrutinized according to all the rules of motor journalism, BMW is still building the boxer and even Ducati’s Desmodromic no longer lures a dog behind the stove. So it has to be something very special when an engine is featured in particular.

The Neander motor is such a specialty. A diesel with a turbocharger and a cylinder head in which the intake and exhaust valves are not arranged in pairs, but opposite one another. And with
a crank drive that distributes the power of combustion not to one connecting rod per piston, but to two each. Two toothed and thus counter-rotating crankshafts are set in rotation. It is no longer surprising that the four connecting rods of the two-cylinder are overhung on the crank pins. The high rigidity of the cylindrical crankshafts enables such a wild construction.

The amazing thing is that the engine actually works. And how! The exhaust manifolds glow red during the full load measurement on the engine test bench at the Munich University of Applied Sciences. There, Professor Werner Bauer teaches the specialty of internal combustion engines in the mechanical engineering department and has devoured the Neander people and their project. “I think it’s unbelievable the energy and skill with which Rupert Baindl and his people work on the engine. We just have to support that, "he says and increases the speed of the diesel, which is already clearly trying, by another 300 rpm." So far it has run for 55 hours on the test stand without anything breaking. "

55 hours in which the professor and his students invested all their knowledge in the further development of the project. Because there is still a lot to be done. The noise and exhaust gas limits for future road approval must be achieved. For this purpose, the maps of the injection time and length are recorded and optimized across all load and speed points. Sisyphean work that takes months, especially since the turbocharger’s boost pressure has to be taken into account. And then you want to have a lot of power and torque, it should be around 100 hp and 200 Nm. The values ​​can only be achieved if the maximum possible injection quantity can be increased using eight-hole nozzles. There is still no supplier on offer. But Baindl is optimistic: "Bosch probably wants to make some for us now. "

Until then, 90 hp and 175 Nm will have to be sufficient. In the meantime, however, other things are being revised. A wet clutch will run much quieter than the current dry clutch. A higher mass balance together with more flywheel mass should ensure that the engine runs more smoothly at low speeds. There is still a bit of a problem at the moment. And the steel pistons weighing almost 1,000 grams are being replaced by significantly lighter ones with narrower piston rings. "We’re getting 800 grams!" Whispers Baindl, whom everyone calls rupi, behind his hand. Engine connoisseurs consider this a sensation for a diesel with a 108 millimeter bore.

The consumption map is not yet sensational. In the so-called shell diagram, in which lines of constant specific consumption are drawn over load and speed, there is an island with 230 grams per kilowatt hour. The best engines achieve 200 grams per kilowatt hour. So there is still a lot of fine-tuning required, because the Neander people’s claim is clear: "We want to keep up with the best. ??

Performance and consumption

The power and torque development make drivers of gasoline engines jealous, with over 160 Nm of torque already at 2000 rpm. At least 90 hp can be extracted from the 1400 cm3 twin so far. In what is known as the shell diagram, the engine shows typical consumption behavior. The lines of constant specific consumption show an island of 230 grams per kilowatt hour between 2400 rpm and 2900 rpm and high load. That means: in this area the engine runs pretty well. If you give less gas or turn lower or higher, you are wasting valuable diesel fuel. The best engines come from VW and achieve a value of 200 g / kWh.

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