Wieland motor
The Wieland engine , also called Blechwankel, was a rotary piston engine made of stamped sheet steel parts that was welded and soldered together . It was created in the early 1970s at Audi AG in NSU based on the ideas of planning manager Werner Wieland . The engine ran on the test bench and was tested in the Ro 80 .
construction
The engine is one of the few in the history of engine development and the only rotary engine made from sheet steel parts. Compared to the Wankel engine manufactured in the casting process, this design brought advantages in terms of weight, cooling, smoothness, manufacturing costs and durability.
In the wake of the worldwide turning away from the Wankel engine (exceptions: Mazda and experimental aircraft engines), the Wieland engine never got ready for series production. However, it also offers potential as a range extender for e-cars in the future: light, quiet, small design, low-vibration and another 22% lighter than the cast motor. Weight savings mean more range. It is also very suitable as a hydrogen engine.
The construction received the following patents:
- Housing for rotary piston internal combustion engines of the trochoid design and process for its manufacture.
- Polygonal piston for KKM
- Intermediate part for KKM
- Sealing strips especially for sheet steel design - KKM.
During the construction, it was assumed that the difficulties encountered in a casting process, such as possible misalignment of the casting cores and the resulting rejects as well as core sand residues that can get into the cooling circuit, are to be avoided. The special and cost-reducing advantages are a significant reduction in weight of 22% and thus more favorable cooling due to thinner walls as well as a reduction in manufacturing and manufacturing costs and, in the case of the rotary lobes, also in the uniformity of the individual parts, which avoids imbalance.
The proposed rotary piston consists practically exclusively of sheet metal parts, namely under the same segment-shaped piston flanks that form the outer surface, inserts inserted at the apex edges, two flange-shaped rings for the piston hub with bearing that meet at their inner diameter, and oil guide plates seated on the piston hub in the area of the oil openings , the side parts piercing pressure equalization tubes and two triangular plates as piston end walls, one of which contains the pre-machined, hardened and reworked ring gear.
The outer contours of the piston end walls are dimensionally so precisely manufactured that paste-like soldering agents can be applied here as well as at the connection points of all individual parts, which can optionally also be applied galvanically and in this case also means additional surface protection. Then the individual parts were joined together tightly and free of scale.
The housing shell is mainly made from sheet metal parts, namely from a flat iron forming the peripheral wall, angled and bent several times, in which the openings for the spark plug, inlet and outlet as well as cooling water circulation are already prepared, from the trochoid forming the running surface. Its shape consists of two flat irons that are uniformly drawn and welded, whereby the heat dissipation can be influenced by their wall thickness, and also of reinforcement troops that support the trochoid against the outer wall, of several tubular spacer sleeves, each of a pipe socket for the one - and outlet from a funnel-shaped receiving piece for the spark plug, from two arched water baffles inserted in the cooling chamber as well as from bolts for the threaded blind holes of the screw-on parts and a pre-drilled square piece for the carburetor preheater. The side walls, including the bores, are die-cut, the inner opening having the dimensionally accurate outer contour of the trochoid, so that a radial soldered connection is created here.
The intermediate part consists mainly of sheet metal parts, namely a flat iron that forms the circumferential wall, angled and bent several times, in which the openings for the oil inlet and outlet are already worked, of several tubular spacer sleeves and axially arranged cooling water flow pipes, of pre-formed, separating the oil circuit Flat iron, made up of several comb-shaped flat iron, which are used for stiffening and determine the cooling circulation, as well as the die-cut side walls.
The stapling and soldering process of the jacket and the intermediate part is done in the same way as with the piston. The production of the side parts is also as described here.
A number of problems occurred with the cast rotary piston engine: chatter marks, sunken running surfaces, faster wear, resulting in high consumption. All these circumstances encouraged Werner Wieland all the more to manufacture the rotary lobes and the housing parts from several sheet steel parts. The problems of the cast KKM could be solved easily and quickly with the sheet steel engine.
After each test run, changes were possible in the next engine. Reinforcements in the hot arc, other water baffles, new materials and hardening options that were possible in one operation with soldering. Often several pairings of materials were running simultaneously in the same engine.
The unsatisfactory sealing strips on the rotary engine prompted Werner Wieland to intervene with patents here too.
The result: a round shaft in a carrier part that could rotate similar to a roller bearing also solved this problem.
Test results
The cast KKM 871 had 2 × 750 cm³ chamber volume and made 170 hp. The consumption in the Ro 80 at 210 km / h was 15.2 l / 100 km normal gasoline. The Blechwankel with the version number KKM 871/1 also had 2 × 750 cm³ chamber volume and made 188 hp at 6500 rpm. Consumption improved to 12.7 l / 100 km regular gasoline.
At least 250 engines were built and driven in trials and in the vehicle fleet. Werner Wieland himself drove a RO 80 with a sheet metal roll for a long time.
literature
- Gerhard Bauer: Wielandmotor for over forty years, everything made of sheet metal or what? In: Wankel Journal, Issue 67, June 2013 pp. 25–28 ( online at ro80club.org).
- Christian Gleichauf: As insolence won in: Heilbronner Voice from September 10, 2013 ( online at Stimme.de ).
Patents
- Werner Wieland: Built-up rotor construction for rotary mechanisms Patent No. US 3920358 A ( [1] )
- Werner Wieland: Polygonal piston for rotary piston internal combustion engine and process for its production DE 2355738 A1 ( [2] )
- Werner Wieland: Housing for circular piston combustion engine of trochoid type and method of producing the same ( [3] )