Reduction of Mass & Parts Count


Through the introduction of the concepts described previously, the following table shows how the mass of the prototype engine compares with the existing engine.

 COMPONENT CHANGE (g)
CRANKCASE ASSEMBLY +3879.5
BARRELS -10876.5
STUDS +2720.1
PISTONS/GUDGEON PINS +166.4
CYLINDER HEADS -1271.4
  -5381.9g
Table 3– Mass savings for the protype engine (per engine)

As can be seen in Table 3, increasing the stiffness of the crankcase and gudgeon pins has resulted in an increase in mass of those parts. Additionally, the main and side studs were redesigned to cope with the higher clamping loads (to deal with the higher cylinder pressures).The shank diameter of the main studs increased from 10.5mm to 12.8mm, the side studs increased from 7.6mm to 8mm. These changes resulted in the increase in the mass of the studs shown in Table 3.

However, the changes introduced through the proposed cylinder heads and barrels have realised a reduction in mass of those parts of 12.1Kg. Overall, the proposed engine is 5.4Kg lighter than the existing engine.

Reduction of parts count

When considering the areas of the engine which have been reviewed as part of this project, another benefit to the proposed changes has been a reduction in the number of parts required.

As a brief summary, Table 4 shows the number of unique components, and the total quantity of components which make up the existing and prototype engine, within the sub-assemblies listed.

  SR305-230E Ilmor Prototype
  UNIQUE PARTS TOTAL QTY UNIQUE PARTS TOTAL QTY
Crankcase 9 25 4 18
Barrel 18 80 6 52
Studs 9 92 8 68
Piston 5 20 5 20
Head 2 12 5 36
Total 43 229 28 194

Table 4 – Comparison of parts count between existing and prototype engines

The prototype engine has reduced the individual types of components (in this selection of sub-assemblies) by 35%, and the total number of parts by 36. This would have a subsequent beneficial effect on manufacturing costs, build time and logistics.

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This project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 686533