Is there not ways to dampen the engine noise a bit? Would different exhaust options help it out?
Thanks
The noise/rattle is something that is related to the way diesel fuel burns.
In a gasoline engine, the fuel is either fully vaporized or very close to fully vaporized at ignition, this means the flame front expands at a consistent rate.
Computer modeling can get close, but there is always a random element with diesel fuel. When injected, the fuel is atomized but is still in liquid form. These atomized droplets then vaporize and combust, but there is no way to predict how the flame front will progress and what will vaporize first.
Remember, it's not the liquid fuel that burns, it's the vaporized fuel that burns.
So this is where the characteristic diesel knock comes from, the uncontrolled portion of combustion. Multiple injection events, higher injection pressures and thus finer atomization help to alleviate this. Modern design logic to dampen the noise have made significant strides in the noise levels of diesel engines as well. My guess is that the ISV will be at least as quiet at idle as the 6.7L powerstroke and possibly as quiet as the v6 TDI in the Audi A6.