2013 Diesel Cruze?

[Daox]

Thanks, thats good to know.

I guess I was thinking of just gas, ethanol, and diesel. I hadn't thought about the others. I see ethanol as the big up and comer of the pack. Especially with the building of cellulosic ethanol plants.

[Diesel_Dave]

Originally Posted by rmay635703

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

Combining gas and diesel (spark-ignited & compression-ignited) in the same engine is very tricky. Variable compression ratio is one thing, but changing from 10:1 to 20:1 is a big challenge. Modern common rail diesels also run fuel pressures up to and above 30,000 psi. Piston shapes are much different. Cylinder heads & ports are shaped differently. Plus, these days you need aftertreatment (catalytic converters, DPF, SCR, etc.) which are completely different for gas vs diesel.

That's not to say it can't be done. I think it was Case/Farmall that made a tractor engine that started on gasoline and then switch over to diesel.

[Daox]

After treatment is a difference. However, Mazda's skyactiv direct inject engines have pistons quite similar to a diesel.

[Diesel_Dave]

Originally Posted by Daox

After treatment is a difference. However, Mazda's skyactiv direct inject engines have pistons quite similar to a diesel.

There are a wide variety of piston bowl shapes, but it you put that thing in a diesel it would smoke like a chimney. Here's a more typical diesel piston


In a direct injection gasoline engine the fuel is injected a long way before top dead center, with the goal being to vaporize and mix the fuel before ignition. In a diesel the piston bowl distributes the burning fuel plume. For this reason, a gas direct injection injector is pointed almost directly downward. A diesel injector is typically more horizontal than vertical, because the fuel in injected near TDC and the shape of the piston spreads out the fuel to mix with the air.

[rmay635703]

Originally Posted by Diesel_Dave

There are a wide variety of piston bowl shapes, but it you put that thing in a diesel it would smoke like a chimney.

In a direct injection gasoline engine the fuel is injected a long way before top dead center, with the goal being to vaporize and mix the fuel before ignition. In a diesel the piston bowl distributes the burning fuel plume. For this reason, a gas direct injection injector is pointed almost directly downward. A diesel injector is typically more horizontal than vertical, because the fuel in injected near TDC and the shape of the piston spreads out the fuel to mix with the air.

There already have been motors that had multiple injectors on the same cylinder. Perhaps (2) for each, 2 fuel tanks and an MIT concept to improve performance and emissions on diesel engines -> E85 injection

If the vehicle had sensors to know what type of fuel was in the tank it could ration and time it appropriately. Gas, ethanol + diesel mixes operate much like plain diesel with no plug but they require multiple rationed firing events per stroke.

Develope a spark plug or ignition system that can tolerate detonation inside a diesel and a true CNG/Diesel or true e85/diesel motor is possible, then we just need to get rid of pesky emissions BS and get it more standardized.

Oh and I wouldn't mind controlled water injection either but I digress.

So many possibilities, so little capital

[niky]

LPG needs higher compression than gasoline for maximum efficiency. It can run perfectly fine as is, but we leave a whole lot of economy and power on the table by using a dual-fuel LPG system.

Though with regular gasoline engines now hitting 13:1 to 14:1 compression ratios, the point is nearly moot. An ideal situation would be using LPG with liquid injection (the more common ones still spray gaseous propane) via direct injection... but that would leave more injectors in the chamber than we probably have space for.

What's funny is Mazda is running their SkyActiv Diesel at an ultra-low 14:1. I wonder how hard it would be to merge the SkyActiv Diesel and Gas motors...

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I just drove the 2011 Cruze diesel last month for a review article. Good engine. Decent torque (though nowhere near what the Ford PSA TDCi and VW TDi units have), decent top end. Our test unit smoked a bit... it's likely the previous tester put in a contaminated batch of fuel, because it cleared up after two or three days.

Fuel economy averaged between 30-38 mpg on the highway. This unit used a six-speed automatic with a locking converter. The big issue is that sixth gear is so long, I had a hard time getting it to lock up on the highway below 70 mph... Most of the time I was slurring around at around 1500 rpm with the torque converter happily bleeding away power. It should do near-50 mpg easily, but getting higher would require a very long trip and more aggressive TC locking in 5th gear.

Ford and VW use a superior dual-clutch unit, but a traditional torque converter is smoother in stop-and-go, which is why Chevrolet went with that.

As for the "sporty" part, the Cruze has a great chassis, and the extra diesel power does give it some oomph over the naturally aspirated Cruze, but the long-geared, slow-shifting and indecisive automatic, plus that heavy iron-block up front make it less thrilling to drive than a small Ford or VW diesel sedan.

[Ladogaboy]

I'd rather wait for the diesel Volt...

[niky]

Difficult, unless you decontent the diesel.

To keep prices down, you'd have to remove the variable geometry turbocharger (not necessary anyway, if you're maintaining constant engine speed) and go with a fast spooling low output unit. It'd still be more expensive than the gasoline unit, and weight would be a problem unless you give it an aluminum block... which would cost more still.

A perfect match would be a 1 liter 2 cylinder or a 1.5 liter 3 cylinder. You would need extra work to make them smooth enough... but maybe the vibration from the engine would be incentive for people to plug in their cars more regularly.

[rmay635703]

Originally Posted by niky

I just drove the 2011 Cruze diesel last month for a review article.

Fuel economy averaged between 30-38 mpg on the highway. This unit used a six-speed automatic with a locking converter.

Sucky fuel economy considering the gasser is the same.

[PaleMelanesian]

Originally Posted by niky

I just drove the 2011 Cruze diesel last month for a review article. Good engine. Decent torque (though nowhere near what the Ford PSA TDCi and VW TDi units have), decent top end. Our test unit smoked a bit... it's likely the previous tester put in a contaminated batch of fuel, because it cleared up after two or three days.

Fuel economy averaged between 30-38 mpg on the highway.

Originally Posted by rmay635703

Sucky fuel economy considering the gasser is the same.

My understanding is that they're developing a related but new engine for the US Cruze diesel. It may not be the same thing you tested.