(12-13-2014, 05:14 PM)DiseaselWeasel Especially MB seems very concerned with noise emissions, I think that's why they clinched to the pre-chamber principle for so long...
Indeed, same with BMW which trialed M47 4 cylinder diesel engine with DI and VP44 pump. They concluded it has inferior running quality, noise and emisions, therefore unsuitable for use with 5er (E) and 7er (S) and left it for lower class 3er cars ©. So they sticked with prechamber M51 until common-rail M57 was available for mass production. Only premium car maker who didnt seem to care about tractor like noise was Audi, they came up with 1.9TDI in passenger car as soon as 1992 I believe and few years later clatering ticking and smelling (but good) AEL 5 cylinder made its way in Audi A6 (E).