2013 Diesel Cruze?

[gone-ot]

...sounds as though GM is making a "back-handed" approach in using the Eco-diesel as it's "sporty" engine for the Cruze, rather than as it's 'High-Milage' "fuel economy" vehicle?!?

[theycallmeebryan]

If car makers really cared about economy and efficiency, we'd be driving a car that looks like the AERO template with an electric drive train.

[Diesel_Dave]

A turbodiesel engine has quite a bit of low-end torque, hence the "sportiness". That's not necessarily contradictory to good fuel economy. In fact, low rpm & high torque generally results in good fuel economy.

The 2011 VW Jetta TDI has an EPA rated highway mpg of 42 with 236 ft-lbs or torque. A 2012 Toyota Yaris has 92 ft-lbs of torque and gets only 38 highway mpg.

[BHarvey]

Yep, make em' all low rpm high torque, tall gearing and get rid of the turbo.
My 85 Jetta diesel got 50 in town and 60 on the highway, which could have been more with taller gearing. Had all of 40 HP!

[rmay635703]

Originally Posted by Daox

Here is a little bit more info on the diesel cruze... not much though. Sounds like they won't be going for the ultimate mileage machine here, but more of a 'semi-sporty yet thrifty at the pump' kind of car.

2014 Chevrolet Cruze Diesel: More Details Released By GM

The diesel Cruze comes in at about 50mpg US per the reports, which isn't too bad, I would rather see it higher still, I can peak 50mpg summer on a gasser Cobalt, not sure what a diesel would allow but might be interesting.

I hope they offer the diesel in an ECO varient.

Something I think that has been lost is the fact that a GDI and TDI engine are nearly identical and all the old new reports on them stated they were to be multifuel because of the infinate possibilities with the timing of the fuel injection and spark. Theoretically a GDI engine could run 18:1 compression and still run on 87 octain pump

The volt in fact was to be multifuel capable (aka diesel, gas, e85,lpg, CNG)
its unfortunate that didn't materialize because the volt would be much more interesting as a bi or tri fuel varient.

[Diesel_Dave]

Being able to run both gas and diesel sounds good but, unfortunately, it often doesn't materialize too well. Just look at GM's 350 experiment. That's not saying it can't be done. I'm just saying it needs to be done properly and it often isn't. I think that's particularly true when a gasoline (spark-ignited) engine has been "adapted" to diesel. From what I've seen the diesels that have been adapted to spark-ignited fare much better. I know Cummins as well as Caterpillar at others have spark-ignited natural gas verisons of many of thier diesel engines that do quite well.

[euromodder]

Multifuel engines tend not to be optimized for any fuel, so run less efficiently than would be possible on all fuels. Every engine is a compromise - imaging having to include all compromises, and having to comply to all emission standards.

Multifuel is an asset when the supply of fuel can be an issue - i.e. in military situations or extremely remote areas - but it's just not worth it on vehicles for everyday use.

[gone-ot]

...but, with todays' use of computer-controlled EVERYTHING in the engine, either (a) multiple table-mappings or (b) field-reprogramming should solve or at least mitigate the problem of non-optimization to a BIG degree.

[Daox]

The last big optimizations left for ICE engines to allow multifuel use (and general higher efficiency) are variable compression ratio and electronically actuated valves. If we can get those two things built into an engine it would be incredibly flexible and efficient. Until then I agree with Euromodder, you can't design an engine to run on multiple fuels and do them all efficiently.

[rmay635703]

Originally Posted by Daox

The last big optimizations left for ICE engines to allow multifuel use (and general higher efficiency) are variable compression ratio and electronically actuated valves. If we can get those two things built into an engine it would be incredibly flexible and efficient. Until then I agree with Euromodder, you can't design an engine to run on multiple fuels and do them all efficiently.

I disagree, we already can burn LPG, CNG & gasoline efficiently in the same engine. Diesel & E85 would just be icing on the cake.