vw ea189 vs ea288

[svizomang]

I daily drive two cars with either of the engines and must say that ea288 consumes way less fuel even though it is isntalled in tiguan where ea189 is instaled in A4.

Here is VW self study program for either of the engines.

http://pics3.tdiclub.com/data/517/820433_EA288.pdf

http://www.jameshalderman.com/images/vw/2_liter_tdi_common_rail.pdf

what i see they both have same bore and stroke, similar compression, bot have 4 valves per cylinder, both have VGT, spark plugs with cylinder pressure sensor, both use high and low EGR, both have 16V, ea 189 have fill and swirl chanel on the intake while ea288 have vavle configured in the way that on the same camshat there are 2 intake and 2 exhaust valves per cylinder. the intake channels are thus shorter and longer what contributes to vertical swirl. Ea288 even has VVT but mainly for emission purposes - high pressure EGR. EA288 even has SRC while EA189 has only catalitic converter and PDF.
Main plus I see for the ea288 is exhaust manifold integrated into the head what warms the car quicker and thus boosting cold start fuel efficiency.

What i don't get is where does ea288 realy achieves better milage.

 

[BrianPetersen]

The presence of SCR alone allows the engine to be tuned towards economy/performance. The old engine had to be tuned to emit less engine-out NOx, and we now know that it actually wasn't, except under some conditions.

The EA288 has the catalyst system attached to the engine with very short paths between components, thus it's faster to heat up the catalyst and it stays hotter. And, the DPF and the SCR are one and the same (the EA288's AdBlue injector is between the oxidizing catalyst and the DPF/SCR). The old engine needed to work harder to keep the catalyst system up to temp and it was less effective at doing so. The EA288 has much less intake-system volume between the low-pressure EGR mixing point and the engine because of the liquid-cooled intercooler that is built directly into the intake manifold - this would lead to faster response time between EGR command and the EGR getting to the engine.

A bit of optimizing can go a long way.

It's also worth noting that the EA288 configuration had a hope of complying with emission standards after VW reprogrammed them to use more DEF and added components to address OBDII compliance. The EA189, we now know, had no chance, not even in the Passat that has SCR (which is downstream, under-floor as opposed to attached to the engine and one-piece with the DPF).