Thursday, 10 March 2016
Audi lifts secrecy cloak around 4-litre TDI
Following our earlier posting, Audi has now decided to lift the cloak of secrecy that mysteriously surrounded the bore and stroke of its new 4-litre TDI diesel engine.
Officials now confirm the bore and stroke of the new engine are identical to those of the 3-litre TDI, as suspected in our earlier article today.
The bore and stroke are 83.0 x 91.4mm, giving a stroke/bore ratio of 1.1.
The engine’s compression ratio is 16.0 to 1.
Officials also confirm the new engine does have a compacted graphite iron (CGI) vee cylinder block but continue to refuse to name the supplier.
However, the vee six-cylinder block in CGI for the smaller 3.0-litre TDI is supplied by Eisenwerke Bruhl GmbH which claims to be Europe’s leading supplier of engine cylinder blocks and heads in cast iron material.
Bruhl’s website notes that “GJV 450 (CGI) has proven itself as ZKG material for the Audi V6 3.0 litre TDI engine”.
The implications of the ‘new’ engine sharing the same bore and stroke dimensions as the V6 3-litre cannot be overlooked, bearing in mind their close association with machining and assembly, as well as various components’ purchase and supply chains.
Bruhl’s website also notes the foundry supplies engine castings for the Ford 2.2-litre I4 Puma engine in Transit, the 1.8-litre I4 Gen 111 engine in Opel’s Insignia, the 1.3-litre I4 diesel in the Fiat 500, an I4 engine for the Audi A4, an I4 engine block for the VW golf and a V6 block of 3.3 litres and 3.8 litres for the Jeep Ranger.