Diesel-Hybrid SUV

2005 Chevrolet Equinox Converted to Diesel-Hybrid
Moovada was the entry from the University of Wisconsin at Madison that took 2nd place in Year Two of Challenge X. The team converted the donated 2005 Chevrolet Equinox to a flex-fuel, diesel-hybrid.
(Photo: University of Wisconsin-Madison).

“Hybrids aren’t new,” starts the TG Daily.

Nor are diesel hybrids, for that matter. This blog has reported:

On the success of the Orion diesel-electric, serial hybrid, transit bus
About the first diesel-hybrid passenger car, a concept shown last year by French auto maker Citroen and promised to the European market in 2008
Even about the Mercury Meta One, which, unless another vision prevails, still may be the first production diesel-electric SUV to appear in a market that heats up everyday the price of oil climbs.

Nevertheless, as Wolfgang Gruener noted in the TG Daily article, “Moovada”, the Wisconsin Hybrid Vehicle Team‘s entry into Year Two of the Challenge X competition, was interesting because the competition sponsor, General Motors, “is not really known to build the most fuel efficient cars around.”

The “Moovada” power train was a diesel engine that provides not only more torque, but also is more fuel efficient at higher speeds. And, like the PSA Peugeot Citroen, it featured a turbo to boost performance. It demonstrated an increase in fuel efficiency of more than 50%, to about 35 mpg, up from 15-20mpg from the standard, Chevrolet Equinox power train.

Both the Wisconsin-Madison entry that took second and the third place entry, another diesel-hybrid entered by Mississippi State University, ran on B20 (a diesel blend with 20% biodiesel), which brings it very close to becoming a plug-in, flex fuel, diesel hybrid, one of the power trains now being tested by DaimlerChrysler in their Sprinter vans. (Moovada also had a high voltage battery pack donated by Johnson Controls.)

In the May 8 issue of the Wall Street Journal, Joseph B. White posed the question: “Should American Give Diesel Another Chance?” Unfortunately, no one writing for the WSJ, NYT, etc. is yet asking, “But, Where’s the Plug?” The Virginia Tech entry bested “Moovada” to take top honors in Year 2 Challenge X, perhaps because this flex-fuel vehicle was a gasoline hybrid running on E85 (an ethanol blend with only15% gasoline) and since it is expected that many more American flex-fuel, passenger cars will be running on ethanol than biodiesel.

Unfortunately, the TD Daily article was another story perpetuating the myth that American consumption can continue with slight adjustments, e.g., “a vehicle with today’s horsepower range and tomorrow’s fuel efficiency requirements as well.”

In the Alumni Newsletter (Summer 2006, pp. 24-28) has more about Moovada’s story, freelance writer Eric Ness noted:

Although it may have been a financial boondoggle, the EV1 is a foundation for the automotive future. Without its innovation, the U.S. hybrid effort would be even further behind companies such as Toyota and Honda, which have the best-selling models. GM is gambling that lessons learned in building the EV1 will help minimize its hybrid investment and shift the paradigm to an all-electric car
powered by a fuel cell.

One Comment

jcwinnie

Posted 2006-6-9 at 8:06 pm | Permalink

Not to mention the diesel-hybrid CUV (crossover utility vehicle) concept that Mike Millikin reported FEV and Ssangyong of Korea co-developed.

This vehicle is equipped with a 5-cylinder, 2.7-liter turbocharged diesel engine mated to an automatic transmission with an integrated 34kW synchronous electric motor. The result is a CUV with excellent low-end torque and a greater than 24% improvement in fuel economy compared to a baseline diesel vehicle. This represents a likely improvement over today’s conventional gasoline vehicles of about 50%.

The CUV diesel-hybrid concept uses start/stop operation as part of the operating strategy. Also, engine run time is reduced, dramatically reducing particulate emissions and cutting nitrous oxide emissions below the baseline vehicle’s levels. Using the electric motor also results in a 25% increase in the 0-60 miles-per-hour performance of the vehicle. The diesel-electric hybrid CUV offers a 20-30% improvement in mid-speed acceleration.

Rafael Seidl comments that you can combine GDI and hybridization; it’s just that both technologies are fairly new, which increases both the cost and the risk of combining them beyond a sufficient volume in sales for the immediate future:

Right now, hybrids have a marketing advantage in the US, engine-internal solutions one in the EU. The differences may even out as carmakers on either side of the Atlantic obtain patents on variations on these themes. Both markets are in rapid flux.

Turbocharging gasoline engines is absolutely worth it, but it’s tricker than for diesels. As long as you stick with lambda=1, the mass flow ratio between idling and full power is about 1:75. This can be dealt with using lean burn at low load (requires an NOx store catalyst or SCR), by adding a VTG turbocharger, shifting into higher gears at lower RPM and, by adding a hybrid electric motor to downsize the engine and mask what turbo lag remains.

Another problem stems from the extreme temperatures (>1050 degC) a gasoline turbocharger is exposed to at full power, necessitating the use of extremely expensive materials for VTG technology. The temperature is higher than for diesels because the compression ratio is lower – gasoline starts to knock beyond 11.5 best case. An engine designed for monovalent CNG or E100 operation features an intermediate compression ratio and hence, the maximum temperature in the turbo can be lower. Same if you sacrifice maximum power by detuning the intake valve timing (Miller or Atkinson cycle).

Ergo, a downsized turbocharged GDI engine with a beefy integrated starter-alternator-motor (ISAM) fed by ultra caps would be perfect. Subaru is apparently developing a hybrid drive train featuring just that minus the GDI (for now). FEV recently published a similar concept the developed for Audi, to achieve performance comparable to a 3.0L NA engine with a thriftier 1.8L power plant.

After Gutenberg