The new Mrs Arragonis-mobile

[Arragonis]

Originally Posted by cRiPpLe_rOoStEr

A turbocharger can do miracles in a CNG-powered engine, since it can be fitted with an overbooster to emulate a variable-compression ratio.

Would it be as efficient as a long stroke 1.6 DI Diesel with a variable geo turbo and intercooler though ?

This is a rhetorical question really as it all "depends" on the scenario.

[cRiPpLe_rOoStEr]

You know, it's not just about efficiency. The main reason for some growing interest in CNG (and even LPG) in Europe is basically due to taxes and the complexity of the emissions-control devices fitted to newer Diesels. Also, spark-ignited engines tend to be deemed more suitable to start-stop because they usually get in the operational temperature quicker than a Diesel after the start-up. Anyway, nothing prevents a dedicated-CNG (or a bi-fuel optimized for CNG) to feature direct injection, VGT and intercooler.

But then it's a whole different thread...

[Arragonis]

Agreed. But this is a Diesel. With start stop. Very aggressive start stop too.

[cRiPpLe_rOoStEr]

At least direct-injection and the lower operational temperatures in newer Diesels make it more suitable to start-stop than older ones. Anyway, have you ever considered to apply some thermal insulation to its head and the oil sump in order to conserve more heat between the stops and restarts?