MtViewGuy88

One of the secrets about diesel cars in Europe is that they have more generous emission regulations than here in the USA; that's why you still see some smoke coming out of turbodiesel engines in Europe. However, with the EU soon tightening up diesel emission regulations and the 2007 rules coming into effect in the USA, this is why the Mercedes-Benz Bluetec technology is so important; the specs for Bluetec pretty much eliminates all the smoke and the distinctly smelly exhaust of diesel engines thanks to improved particulate filters, better catalytic converters to remove NOx output, and urea gas injection into the exhaust stream to reduce NOx even further.

Honda's much-lauded i-CTDi turbodiesel engine sold in Europe is very well-liked because the engine has a very clean exhaust by diesel engine standards. This is why Honda has installed this engine in the European Honda Accord sedan/wagon, European Honda FR-V "tall wagon," European Honda CR-V small SUV and European Honda Civic five-door hatchback. Because of its high torque peak (something like 241 pound-foot at only 1800 rpm!), this engine has gives the car a lot of low-end acceleration power. Indeed, Steve Cropley of Autocar magazine wrote in a very recent commentary while he was driving a Porsche 911 Carrera (996 model) he could barely keep up with a Honda Accord sedan powered by the i-CTDi engine on a motorway (as freeways as known in the UK) onramp!

jaje

the Accord broke several long standing diesel engine records including acceleration and top speed...it takes Honda to reinvent the diesel engine to make it better than it ever was

Schneegz

That's great, and I sincerely hope advancements in Diesel engine technology and biodiesel production make Diesel cars more popular in the US. When our family outgrows our current vehicles, my wife would like to buy a Honda Pilot. I'd love it if we could buy one with a non-stinky turbocharged Diesel V-6, instead of a gasoline engine, simply because of the fuel economy.

However, let's not get too carried away on the potential popularity of Diesels in the US. Take Germany for example. Roughly 50% of the cars sold here are Diesels. Gasoline costs about $5/US gallon. Diesel costs less.

Think about that for a minute.

That means that roughly 50% of Germans would rather pay $5/US gallon, AND get worse fuel economy, than drive a Diesel, which is cheaper to fill up, AND gets better fuel mileage.

Now, how do you propose to persuade Americans, who pay $2/US gallon, to pay more for a gallon of Diesel?

Here's my proposal. Put Diesel engines in the most popular SUVs and pickups. The Honda Pilot, Toyota 4Runner and FJ Cruiser, Nissan Pathfinder and Exterra, should all have a Diesel option. They'll never be as popular in the States as they are in Europe, because of all the artificial boosts European governments give Diesels, but they could very well take up 10-20% of total car sales, and maybe 40-50% of light truck sales.

jaje

Honda is working on HCCI that uses compression ignition with gasoline getting 30-40% better fuel economy (on par with diesel)

i believe that will be the most significant technology we'll start to see by 2010 and much more efficient than hybrids or clean diesels (gasoline is already clean and cheaper)

MtViewGuy88

Interesting you mention that because when Honda admitted working on a US-legal V-6 turbodiesel, they said this engine will primarily end up on the Acura MDX, Honda Pilot and Honda Ridgeline models. Indeed, I see the biggest impact of cleaner turbodiesels in the SUV, light truck and possibly minivan market, where the high torque peak and 30-35% better fuel economy compared to equivalent gasoline engines would be welcome. Indeed, this is why companies like Catepillar and Cummins are working on clean-burning turbodiesels for pickup trucks and SUV's from the Big Three auto manufacturers over the next few years. In short, don't be surprised that the Cadillac Escalade offers a next-generation Duramax turbodiesel engine with very low emissions, no visible exhaust and no diesel rattle within the next two years.

Schneegz

That sounds great, and it brings up yet another topic of discussion. Ethanol. E85 (85% ethanol, 15% gasoline, for those who don't already know) is even cleaner than gasoline, and although more expensive to produce right now, production technology is improving. Furthermore, it has an octane rating of over 100, which makes high-compression applications, such as HCCI, much easier to manage (just as Diesel does).

Schneegz

Exactly. Diesel fuel economy is most noticeable in larger vehicles, and all that low-end torque is more welcome in larger vehicles, where it's most needed to move all that mass, and for towing and cargo hauling.

Hopefully the Pilot will be available with a TurboDiesel by the time I return to the US (late 2007), and hopefully I can convince the Wife (ie, the family CFO) to buy one.

Edit: I forgot to add that Honda needs to keep the price of a TurboDiesel Pilot close to that of a comparably equipped gasoline-powered Pilot. Toyota piqued my interest with the Highlander Hybrid, then lost it when I saw the price. Also, a Diesel Pilot need not out-accelerate a gasoline-powered Pilot, as the Tuareg Diesel eclipses the gasoline Tuareg. As long as the Diesel performs no worse than the gasoline version, gets better fuel economy, and costs no more than $1-$2K more, I'd be happy.

MtViewGuy88

However, there is one BIG downside to ethanol--the fuel efficiency is quite a bit lower than gasoline, because you have to burn more fuel for the same power output. This is why E85 isn't such a good idea.

Schneegz

What you say about ethanol is true. However, a heat engine's efficiency is determined by its compression ratio. This is why Diesel engines are more efficient than gasoline engines; Diesels run far higher compression ratios. E85 allows much higher compression ratios than straight gasoline, therefore, an engine that runs on E85 can be made to return similar mileage to that of a comparable gasoline engine despite the lower specific energy content of E85.

The problem is that flex fuel engines of today are not optimised to run on E85. They are optimised to run on gasoline. The only difference between flex fuel engines and standard gasoline engines is that the flex fuel engines have components, like fuel lines and injectors, made of materials that resist ethanol's corrosiveness.

So, how does one design an engine that is optimised to run on gasoline AND E85. Well, you can't, because that would require an engine with variable compression ratios. Saab tried that. It didn't work.

However, you CAN get close with modern electronics, direct injection and a variable geometry supercharger driven by an electric motor. Detection equipment would tell the ECU what kind of fuel is being used. The ECU would then optimise the supercharger's boost level depending on RPM, fuel type, barometric air pressure, etc.

Such a system would be very expensive to build right now, but I bet in the not-too-distant future, with biofuels growing in popularity, we will see something similar.