Swedish lorry and bus manufacturer AB Volvo said on Friday that it had developed a hybrid diesel-electric engine for trucks and buses which could go into production by 2009. Hybrid technology, which allows vehicles to run alternately on diesel or electricity or both simultaneously, has become increasingly popular for passenger cars, but Volvo said it was the first to produce hybrid technology for heavy vehicles.
“Hybrid technology has been used for cars for five or 10 years now. The oil price, technology and the lower cost of batteries now makes it an efficient option for trucks and buses, too,” Volvo Technical Director Lars-Goeran Moberg told AFP.
“Within a few years we will show you a real vehicle that really works with hybrid technology for trucks and buses,” chief executive Leif Johansson said at a presentation.
The fuel bill for city buses, for example, could be cut by a third, which would allow operators to recoup the higher costs of buying hybrid engines within two years, he said.
Actually, a couple dozen American cities have started to move into diesel-electric hybrid buses. Including Albuquerque, just down the road from me. Unsurprising — like the Canadian buses in Albuquerque — they’re either manufactured outside the U.S. or by foreign-owned companies.
Given Volvo’s prominence in the hauler market, I expect they’ll deliver a successful product.
I hope its not in anyway related to Toyota’s system. If so then the big, bad patent trolls at Solomon will go after them.
http://www.consumeraffairs.com/news04/2006/02/prius_patent.html
Then again, maybe Volvo will will use someone elses obscure patent and that little, piss ass company will sue them too.
This type of system has been used for years on heavy Cat and Komatsu haul trucks used in mines.
Wayne — Ford owns the Volvo car division. The Swedes kept the truck division.
cj — what you’ve seen in mining is called “series” hybrid rather than the “parallel” hybrid at use in cars and, now, haulers.
In the former, diesel engines produce electricity which in turn powers electric motors driving the wheels. A system which a lot of engineers think may eventually come to street and highway transportation — especially with the sort of constantly variable transmissions used by Honda and DAF. Transmissions which American manufacturers have — in their infinite wisdom — tried to ban.
The parallel system, a la Prius and Volvo, allows for either the internal combustion engine or the electric motor to drive the wheels.
I have a feeling the HP you get from a eletric motor is far more efficient then direct HP we get out of a car now.
Can someone tell me how much fuel you would use to get on the freeway vs. the amount used by a traction motor in series?
Elk Grove, CA (suburb of Sacramento) has a fleet of hybrid deisel/electric busses.
jeremyrobbins….. a manual transmission vehicle is much more efficient than an electric motor.
I’ll say it again: THE MAJOR ADVANTAGE OF A HYBRID DRIVETRAIN IS THE ABILITY TO RECOVER ENERGY DURING BRAKING. So, in stop and go traffic (Like for the Buses and Local Route trucks pictured in this post) The hybrid drivetrain can be more efficient than an engine coupled to a manual transmission.
The reason that hybrids like the Prius and Insight get decent mileage is because they are LIGHT, SMALL vehicles with SMALL engines. If you put a small diesel engine in either car, it will get MUCH better fuel economy than a gas/electric hybrid.
Eideard and I have gone back and forth a little bit about diesels vs. hybrids here at DU…. this article makes us both happy because it has both.. a diesel hybrid. All the efficiency of a diesel and all the benefits of energy recovery in a hybrid drivetrain. These are the perfect applications for this technology.
Regards,
Ryan
Ryan
I understand that an electric engine is more efficient then a direct drive (manual) transmission / internal combustion engine simply because it converts Horse Power to Torque during acceleration and Torque to Horse Power during constant load. Internal combustion engines generally produce a constant HP to Torque ratio which contributes to their inefficiency.
Any mechanical transmission will use energy, be it a direct drive or hydraulic drive, so placing electric motors directly on the wheels would remove that one source of energy loss. There are other advantages to electric motors on the wheels, including wheel traction and weight distribution. The added weight of the electric generator and motors offsets the loss the the transmission and drive components though.
The other thing I believe to be true is that gasoline engines have become so much more efficient that Diesels no longer have the same advantage that they did even 15 years ago. Diesels still have much of their disadvantages including being a dirty engine emitting a lot of particulate matter.
It has been many years since I studied all that stuff so not only is my brain a little more aged, but I haven’t kept up with all the progress. Any corrections are welcomed.
Mr. Fusion,
You can’t compare electric motor efficiency to transmission efficency, since they are different devices for different purposes.
Horsepower is simply the amount of torque you are currently providing at a certain speed. Electric Motors don’t “convert” from one to the other, and neither do internal combustion engines. Neither IC or electric motors have a constant torque to HP ratio. They both have “torque curves” of which, as I said, HP is a function of load at current speed.
You are correct about placing electric motors in each wheel being better for weight distritbution, and for eliminating the need for a transmission.
However, you have to look at the efficiency of the entire system… Engine, propulsion (transmission or electric, etc) body design.
The best gasoline engines are rougly 30% efficent, the best diesels are around 50%. (the highest I’ve seen is 55%… in a research environment) This is measured by the amount of energy available in the fuel vs the amount of energy available at the flywheel. This is a limitation of the combustion process…. Gasoline engines will never be able to “close the gap” here, although they may be able to narrow it some.
In vehicle with a standard transmission, losses to the wheels are 10-15%. With a hybrid, getting energy from the flywheel to the wheels requires several steps: 1. Converting mechanical energy to electrical (85-90% efficient) 2. Converting electrical energy back to mechanical (again, 85-90% efficent) 3. feeding that mechanical energy into a transmission (85-90% efficient)
You can see that getting energy from the engine to the wheels is *less* efficent in a hybrid drivetrain than a standard transmission. HOWEVER, hybrids are able to regain energy that would normally be lost as heat (regenerative braking) and also can run their engines at a constant speed and load (while charging batteries) which contributes greatly to overall efficiency.
Let go of your preconceived notion of diesels being “dirty.” Most passenger diesels emissions are on par, or just slightly higher, than their gasoline counterparts. PM emitted by diesels “look” bad simply because you can see them with the naked eye. While they are unsightly, they pose *less* health risk to humans than the smaller particles emitted in higher quantities by gasoline engines. In 2007, new regulations on PM will hit the Heavy Duty truck market… In effect eliminating visible black smoke from diesels. I work with the development of these trucks daily. I can tell you from personal experience that if you are able to see black smoke from a 2007 compliant truck, there IS something wrong with the truck. The PM filters used will limit PM emissions to roughly 5-10% opacity, which is not normally visible to the naked eye.
As for other emissions, CO and VOC are much lower with diesel. NOx will continue to be higher than gasoline due to higher combustion temps and excess oxygen present in-cylinder. CO2 is lower for diesels. Why? Because they burn less fuel. Better fuel economy is the BEST way to reduce CO2 emissions.
OK. I’ve said enough.
Ryan
Thank you for the post. I am truly interested and found your condensed explanation well worth the read. Maybe I should start doing some research in this area.
“I have a feeling the HP you get from a eletric motor is far more efficient then direct HP we get out of a car now.”
Sadly feelings amount to little in engineering and scientific matters.