Ok, so it is now official. Hybrid is less expensive than Diesel.

In 2006 Honda publicly announced they would introduce a diesel engine in the US that would meet Tier 2 Bin 5 emission standards without urea injection. By doing so Honda would have beaten the Germans at their own game because at the time VW, BMW, and Mercedes were cooperatively working on an urea injection system to meet T2B5 emissions standards. So what has changed since 2006? Honda's engine couldn't meet emission standards without urea injection when combined with an automatic transmission. Since an automatic is mandatory for a luxury car in the US that very effectively killed the program. Now Honda isn't abandoning diesels altogether. They will still sell diesels in Europe since having a good diesel engine is mandatory for the European market. Honda just won't be bring those diesels to the US.

It never really made sense for Honda to bring a diesel to the US anyway. The US currently has no market for diesel passenger vehicles. It is a tiny niche. Honda isn't known for diesel engine technology and is not an industry leader in the diesel world. Why would Honda attempt to be the manufacturer that creates a market in the US?

The Germans on the other hand are the undisputed leaders when it comes to diesel technology. Both VW and Mercedes sell the majority of their vehicles with diesel engines and their R&D and manufacturing is set up around designing and building world class diesels. They bring a large economy of scale to these engines. So it only makes sense if any manufacturers will be able to expand the diesel niche in America it will be the Germans.

So far the Germans have been doing well with the diesels that they have introduced:

80% of VW Jetta Sportwagens
30% of VW Jetta Sedans
25% of Mercedes M-Class
21% of Mercedes GL-Class
20% of BMW X5's

VW, BMW, and Mercedes will all be expanding the range of vehicles offered with diesel engines in the US.

I welcome any reduction in oil use. To me it doesn't matter whether the vehicle has a gasoline, diesel, hybrid, or electric drivetrain.

Yea, I remember about Honda using plasma so they wouldn't need to use urea. I wonder what happened with plasma. I guess they are going with plan B.

IMA is not suitable for bigger cars than compact size. I can't wait to see if Honda is going to do with IMA to make it suitable for larger vehicles.

Why wouldn't IMA work for bigger vehicles? With a stronger motor, even electric-only capability could be expanded.

I believe the fundamental idea for IMA is to replace the flywheel with a SINGLE electric motor/generator (MG). This MG is connected to the ICE and revs at the same RPM.

If this MG is too heavy, acceleration will suffer. Sure, the MG can use battery to power and assist the ICE as well but remember there is no second MG to generate electricity (like HSD). With the lack of active electricity available, the MG has to create resistance to charge the battery. This furthers rob the ICE torque (on top of traditional serpentine belt). For those reasons, there seems to be a limitation on the size/power of this MG.

HSD does not have this parallel hybrid architecture limitation. Instead, HSD tabs into the benefit of a series hybrid architecture. Remember, HSD is a power split hybrid (power can split between parallel or series path). Therefore, the ICE in HSD can rev at any RPM and the electricity can be generated at any time (due to two MGs).

A NOx catalyst for a diesel engine uses similar technology as a catalytic converter in a gasoline car. The use of a NOx catalyst is limited by the amount of airflow through the engine or the size of the catalyst area. The greater the airflow the greater surface area needed for the catalyst to change pollutants into base elements or other acceptable compounds. Right now the catalyst material used in NOx catalysts is platinum so increasing the surface area in the catalyst is expensive. The other option is to reduce airflow which effectively means reducing the power of the engine. Right now the 140 HP VW Jetta is right at the tipping point. All the more powerful diesels sold in the USA use urea injection to reduce NOx emissions.

Of course right now diesel NOx catalyst are in their first generation. Like first generation catalytic converters for gasoline cars they are very expensive and use a lot of platinum. As more research is done and more diesel vehicles use a NOx catalyst; engineers and chemist will find other less expensive materials to use as catalysts. In 2012 the EU will reach their next step in emission regulations. At this point all new diesels in Europe will need to meet regulations similar to those that went into effect in the US in 2008. So the US market is a good test arena for the Germans to test their new NOx catalyst technology.

As to IMA not being effective in large vehicles, that is pure crap. IMA is a very simple hybrid system and one that is easily adapted to many vehicles. Today at the New York Auto Show Mercedes is introducing their S400 Hybrid and ML450 hybrid. The Mercedes hybrid system is very similar to Honda's IMA. They are using a thin electric motor/generator that fits between the engine and a conventional automatic transmission replacing the flywheel. The electric motor assists the gasoline engine during acceleration and uses regeneration to capture braking energy. This allows the V6 to have the performance of a larger V8 model while getting fuel economy that is slightly better than the V6. Considering that both the S-Class and ML-Class weigh more than 4,000 pounds I would call them large vehicles.

IMA can be applied to any size of the vehicle. The benefit diminishes after certain point and the system just become the ICE "start-stop" with minor torque assist.

It seems the MG in the Mercedes S400 hybrid is rated at 20 hp bumping up only 7 hp at peak. The Accord hybrid had 16hp MG with the V6 and it also had a similar setup. The Accord hybrid failed due to low benefit (in MPG, acceleration and emission).

Show me one parallel hybrid with 67hp (50kW as in Prius) or more MG power.

That's great news. It's only going to get tougher on manufacturers to get past the emissions laws for diesels. I'd love to see what new hybrid drive systems Honda comes up with.

Why the arbitrary goal of a 67 hp motor/generator? I don't care how powerful the electric motor is, I care about the results.

The S400 hybrid has a 20 hp / 118 lb-ft motor generator. That is good enough to improve fuel economy by 21% compared to the S350. To me improving fuel economy 21% is good.

Yes, the Honda Accord Hybrid failed. The hybrid system didn't have low benefit. It was the most fuel efficient and fastest Accord you could buy. It failed because Honda marketed it to people that were only concerned fuel economy. By your standards all the Lexus hybrids are failures because they have minimal fuel economy improvements over their conventional counterparts. $60-$100K luxury cars are a very different market than $30K Accords.

My position again = all improvements in fuel economy are good.

When are the Mercedes hybrids due to hit the US showrooms? Not that we have one here in western S. Dakota! Nor that I'm in the Mercedes market. Just wanted to know if anyone knows when all these hybrids will become real.

I agree, but they are not always equal. Less pollution for equal FE improvements is better.

For what it is worth, I have always thought IMA was best suited for small cars too. But I don't consider that to be a disadvantage. Not being amenable to PHEV is a problem for the long term, but inexpensive small cars that get 50 - 100 mpg will have a healthy consumer market for a long time.

JSH, we have the same fundamental position. I am in favor of even the mild hybrids with only start/stop engine technology as it can cut down 15% in fuel. If an ASSIST hybrid can cut 21%, even better.

However, accelerating the car just by the MG is something a parallel hybrid can NOT do. You can't expect a MG of flywheel size/weight to power the entire car. The way I see, this is the dead end to plug-in option or EV.

The 67hp is not an arbitrary number. ICE to MG hp ratio is a good way to look at. FULL hybrids have MG almost as powerful as the ICE (+ or - 30%). This allows the car to be powered by MG and enable the plug-in option leading to pure EV (future).

I wonder which path Honda is going to take... the same affordable hybrid with minimal benefit or will they put a more powerful MG in their larger hybrids.

BTW, Accord hybrid failed because it gained minor MPG, slightly faster acceleration and no emission level improvement (same LEV-II).

All Lexus hybrids are SULEV with major boost in city MPG and a boost of 2 additional cylinders performance (V6->V8 or V8->10 cylinders). They double the MPG of the comparable luxury non-hybrids.

Mercedes Hybrids:
The S400 and ML450 will be in dealer showrooms in August as 2010 models.

IMA + PHEV:
Honda's IMA is compatible with PHEV technology. People have been adding batteries to IMA hybrids to make PHEV's since the first Honda Insights. Honda's IMA system cannot be used in electric only mode so a PHEV IMA vehicle would burn some gas on every trip but less than a normal IMA vehicle. Considering that the first factory PHEV's are expected to have less than 10 miles of electric only range and this will be limited to low speed operation even a factory PHEV Prius would most likely use gasoline on most trips. (Yes I know some people go less than 10 miles per trip but most don't)

TRANSLATION: We are done with fossil fuel research. Done. We are now devoting all of our research to hybrid and electric development.

I used to think that I would be able to convert my Prius to a PHEV and run in pure EV mode. Years later it has become very clear that the speed limitation and expensive of a PHEV conversion do not make that a practical option. I could purchase a real EV for the price of converting my Prius and have better performance and an extra vehicle.

That simple isn't the case.

2006 Honda Accords:
EX 2.4L w/ 5 Auto: ---------- 21/25/31 ------ LEVII -------- $22,450
EX 3.0L w/ 5 Auto: ---------- 18/21/26 ------ LEVII -------- $27,300
3.0L Hybrid: ----------------- 22/25/31 ----- SULEVII ----- $30,990
(Fuel economy and emissions level from Fuel Economy.gov, prices from MSN Autos)
(0-60 times vary by source but most have the hybrid ~ 0.5 seconds faster than the standard V6)

2009 Lexus GS:
GS350 ----------------------- 19/22/26 ------- ULEVII --------- $44,850
GS460 ----------------------- 17/20/24 ------- ULEVII --------- $53,320
GS450h ---------------------- 22/23/25 ------ SULEVII -------- $56,400

The Accord Hybrid offered the fuel economy of the 4 cylinder with the performance of the V6. However it cost $3690 to get that extra fuel economy. (13.5% more than V6)

The Lexus GS450h offers the fuel economy of the GS350 with the performance of the GS460's V8. It cost $3080 more to get that fuel economy. (6% more than the GS460)

There is the key. $3K was enough to put off Accord buyers that were looking at car that cost $20K to $30K. Luxury car buyers aren't nearly as put off about spending $3K for a hybrid option. When you are spending $50K to $100K for a car what is another $3k? Luxury car buyers also like to have the newest gadgets on their cars. Hybrids fall right into that need for new technology.

I don't see SULEVII for the Accord hybrid on fueleconomy.gov. Can you provide the document/source you are looking at?

Accord hybrid deactivated 3 cylinders causing the engine to vibrate with extra noise. The noise was canceled in the cabin through the sound system but it could be heard from the outside.

It was not an elegant solution. It made the car more complex. I believe it is one of the reason it failed.

1. Fuel Economy
2. Compare side by side
3. 2006
4. Honda
5. Accord Hybrid
6. Show Detailed Air Pollution Information

It is SULEVII for CARB and T2B2 for EPA

Not that the air pollution score really matters if we are talking about the success or failure of a vehicle. I don't know of a single person outside of PriusChat that has used the emissions rating as a factor in new car buying.

I see they improved it in the 2006 model year. If you look at 2005 Accord Hybrid, it is rated ULEV-II. Strange that 2005 Accord non-hybrid is listed twice as LEV-II AND ULEV-II in CARB states.

Hybrid benefit is a combination of low emission, better fuel economy, better power responsiveness, smoothness, quietness, affordable price, etc... as a whole package. Something unique, a level above in refinement that traditional non-hybrid can not achieve.

HSD delivers the whole package. I have not seen any other solutions (IMA or Diesel) offer the same dimension of benefits. We have yet to see what the pure series hybrid can offer (Volt).

I may sound like I am bashing Honda... I just expect more from them.