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Capstone to Demonstrate Heavy-Duty Hybrid Electric Drive System with Major US Truck OEM

Capstonehdhev
Capstone HEV truck solution. Source: Capstone. Click to enlarge.

Capstone Turbine Corporation has initiated a demonstration project with a major US manufacturer of Class 5 through Class 8 heavy duty trucks that will utilize a Capstone 65 kW microturbine as a range extender in a hybrid electric drive system. In June, Capstone released configurations of the C30 (30 kW) microturbine as a range extender meeting California Air Resources Board (CARB) requirements for New On-Road Heavy-Duty Engines for Urban Bus - Hybrid service with no aftertreatment.(Earlier post.)

This truck will be the first to take advantage of the complete Capstone Drive Solution, which includes the Capstone microturbine along with liquid cooled power electronics, permanent magnet traction drive motor and vehicle power control system.

The electric hybrid vehicle market is in a significant growth phase, with essentially every manufacturer of trucks, buses and automobiles looking for the right solution to serve their customers. Capstone’s microturbine technology offers many benefits for these applications, including our extremely low emission levels that meet the most stringent CARB and EPA 2010 requirements without any exhaust after-treatment.

I am pleased that a major OEM in the heavy duty truck market is investing its time and resources to demonstrate the Capstone Drive Solution and that the demonstration will include getting this vehicle in the hands of some of their key customers as well.

—Darren Jamison, Capstone President and CEO

Capstonehev
Capstone’s HEV drive system. Source: Capstone. Click to enlarge.

The Capstone Drive Solution will make it easier for vehicle manufacturers to integrate microturbines into a series hybrid electric drivetrain. As part of a recent joint development agreement with CalMotors, the Capstone HEV product offering will now include inverter drives, traction motors and a vehicle power control module that will seamlessly integrate with Capstone 30kW and 65kW microturbines.

The inverters and traction motors are mobile hardened versions of the proven Parker Hannifin industrial motor drive products. (Earlier post.) The Capstone microturbines are able to operate on traditional liquid fuels such as diesel and biodiesel but can also utilize alternative fuels such as natural gas without sacrificing efficiency.

This demonstration project is the first of several vehicle applications we are working on that will use the new Capstone Drive Solution. The other projects include Class 4 commercial trucks and Class 8 tractors and utilize both new OEM applications like this one and retrofits to existing vehicles. We are also pursuing marine applications for both auxiliary power and propulsion. Our new Capstone Drive Solution offering will open a lot of opportunities for electric drive systems where our ultra-low emissions and high efficiency have an advantage over more traditional prime movers.

—Jim Crouse, Executive VP of Sales and Marketing

Comments

richard schumacher

Is that front wheel drive? It's hard to make out in the graphic.

RFH

Its RWD if you look at the picture close up.

How is replacing a 40-45% thermal efficient HD diesel engine with an unrecuperated gas turbine engine at 20-30% efficient a good idea?

I just dont see how the gt could operated in a more efficient point than a CI engine, especially in a HD appication like a Class 8 vehicle.

HarveyD

These small micro-turbines seem to be as efficient and run as cleanly (if not more so) than the ICE's currently used for PHEV gensets. They are probably much lighter and a smaller unit (15-20 Kwh) could be ideal in a mid size PHEV. With a lighter genset, a larger battery pack could be used to further reduce the use of the genset and fuel consumption.

When mass produced, those micro-turbines may even be cheaper than 4-cyls units.

Thomas Pedersen

No way GTs run more efficiently than ICEs!

If 60kW is what you need, just take a two-litre TDI engine and hook it up to a four-pole synchronous generator at 1800 rpm and you have close to 40% electrical efficiency. And at fixed rpm you should be able to muffle it to very low sound level. And you still get 70-80% turndown in torque and power. And best of all: at the same combined cost as the power converter from the Capstone GT (guessing here!).

Seriously, a 'ruggedized' version of a very efficient and proven small diesel engine is the right way to go for hybrid trucks. No unfamiliar components! Except perhaps the traction motor.

3PeaceSweet

http://www.greencarcongress.com/2010/02/navistar-20100209.html

http://www.greencarcongress.com/2010/01/hdi112-20100118.html

A simple 4 cylinder diesel dual fuelling with natural gas driving the front wheels with an electric motor driving the rear axle or two would be a good option

GreenPlease

You have to look at system efficiency. Thermal efficiency is only part of the story.
-Thermal efficiency: diesel wins no doubt
-Mechanical efficiency: turbine wins. Much lower frictional losses than an ICE. Note that ME is not taken into consideration when calculating TE.
-System efficiency: the lack of exhaust gas after-treatment for the turbine leads to lower back pressure and therefore lower pumping losses.
-Power density: generally turbines are more power dense.

When you look at the system level, turbines and diesel engines come out very very close in fuel consumption (the diesel engine will have to produce more power in order to put X kW to the generator but it will be done more efficiently thus fuel consumption is nearly equal). However, turbines have lower maintenance costs and lower costs in mass production.

UnnaturallyAspirated

guys, this is ridiculous. if you don't have first hand knowledge or credible sources, please stop making claims about the relative performance of small gas turbines and ICEs. There is simply no comparison. at these power levels (<100 kW) gas turbines are an order of magnitude more expensive than ICEs. I know...i've participated and reviewed the results of multiple comparisons over the past decade by a company that makes gas turbines and works closely with most ICE manufacturers. Even with this cost discrepancy, the ICE usually exceeds the gas turbine efficiency by 10pts. it is true that an unrecuperated gas turbine would be smaller and lighter than an ICE, but recuperation has a huge influence on efficiency and can not easily be eliminated without dropping the efficiency by 1/3 or more. The weight could be 0 and it would not likely compensate for the difference in purchase and operating cost. The reality is that unless an application is very sensitive to size and weight, or requires massive amounts of power, ie. aircraft, gas turbines are not as great as people want to believe.

sorry,

UA

Wes

If efficiency were the point, we wouldn't be funding grants to subsidize fueling of transit buses with natural gas over diesel. This article is about an alternative powertrain that can meet CARB's standards for smog-forming pollutants without aftertreatment, and can do so burning traditional liquid fuels. This powertrain can also use alternative fuels without the same fuel economy penalty typically seen in ICEs. This is a major issue because the obvious compliance path for meeting the standard for smog-forming emissions is to switch from diesel to compressed natural gas, which means switching from diesel cycle to Otto cycle and taking a huge efficiency penalty. Then there's the cost and packaging considerations of ultra high-pressure CNG tanks.

As usual, we are so interested in efficiency and CO2 emissions that we forget that there are other pollutants that are still of concern, such as NOx.

HarveyD

Well said Wes. Near future PHEVs with higher performance batteries may not use the on-board genset that often, typically less than 5% of the time. For higher overall performance, a PHEV would require the lightest mass produced genset available, but not necessarily the one with least fuel consumption or longer durability. Comparative cost may be more a matter of mass production, automation and labor cost. There are no good reasons why a mass produced smaller micro-turbine should cost that much more than a heavier ICE. Cleaner, less noisy, less vibration, smaller volume micro-turbines should be further developed as an alternative to traditional ICE powered gensets.

UnnaturallyAspirated

Wes....i don't get your argument. you say it isn't about efficiency, then use the loss of efficiency in changing from diesel to otto cycle as justification for not moving to CNG. which is it? additionally, you imply that the technologies that receive subsidies are the same that are the most technically or logically sound. this doesnt give much consideration to politics or lobbying.
Also, which commercial vehicle manufacturers you are working with which have changing to CNG as their prime path strategy for meeting emissions targets. everyone i work with has CNG as a small part of their portfolio, but only for niche markets which demand it, CNG is not replacing liquid fuels as you claim, though it may increase somewhat in its market share to help spread the energy demand to more domestic sources.
FInally, what is wrong with Aftertreatment? in principal it is what most of the world uses to reach low emission on just about every gasoline car out there.

UA

SJC

A truck driver that might use 1000s of gallons of fuel each year can reduce their fuel bill with CNG. Some will talk about clean air and domestic supply, but the bottom line wins.

ejj

What if Fiat-Chrysler made their own BEV Volt-like vehicles equipped with multi-air engines for electricity generation? Seems to me they keep ranting and raving about how efficient multi-air is - there might be some significant gains in overall mileage with a multi-air engine charging your batteries instead of a standard ICE. Would multi-air be better then a microturbine? How about on the larger heavy duty applications? What's more efficient?

ai_vin

Multi-air is meant to optimize the engine's efficiency across its performance curve. Volt-like vehicles don't need this because they can keep the engine at the most efficient point on its performance curve.

SJC

Fiat/Chrysler COULD do lots of things if they had the money. That is the problem of running it down to zero, you have no maneuvering room.

ejj

Oh, okay...thanks ai_vin.

Engineer-Poet

Multi-air or any unthrottled, Atkinson/Miller engine is going to be more efficient than GM's stock 1.4 liter 4. A Twinair would be more than enough power, plus smaller and lighter. All the Twinair models exceed the Volt sustainer's 53 kW rating, and they could be run right at the point of best BSFC except for maximum demand.

Capstone isn't in the running in the efficiency contest. Capstone's published efficiency curve peaks at 26% and slides downward in hot weather. Even the old Lister-type single cylinder diesels hit 30%.

I can see Fiat/Chrysler ads touting "Look what I can do with two!".

ejj

Interesting Engineer-Poet...thanks! Seems to me Capstone's selling points are that they can use multiple fuels, including biofuels, and meet California's emissions requirements. But ultimately it will come down to economics and performance - if the system is cheap enough to produce and the performance (MPG under high load conditions) is good enough, it might be a winner. Nowhere in the article do they mention potential MPG though.

HealthyBreeze

So, this is a loser to me because it doesn't seem to lower fuel costs, solves a versatile fuels problem that doesn't need to exist for truckers, would make a lousy PHEV because truckers need to drive 700 miles a day, and although you could charge a lot more for a truck if it saved you a lot of fuel costs (think ROI over 1 million miles driven) this doesn't seem to justify its higher costs.

I've heard free-piston hydraulic motors are incredibly efficent, though I've not found data. I've heard hydraulic transmissions are less efficient than mechanical transmissions. Does anybody have any data which might suggest that such a low-tech hydraulic hybrid would allow engines to run at their cleanest, most efficient point on the curve, and still come out ahead on fuel efficiency?

TXGeologist

While the ideal efficiency of a class 8 diesel engine might be 40% this is only in steady state and at high loads, a class 8 truck experiences large load swings accelerating from a stop varying speeds in traffic ect. That 40% much celebrated diesel in reality spends most of its time at low load where 20~% is a more real number or at very high load where again 20~% the turbine on the other hand will operate at a fixed speed at its most efficient point a recouped turbine can hit 35~% and these turbines are recuperated this is plainly obvious as inlet is in the front of the turbine as is the exhaust which clearly shows a counterflow arrangement the only reason to couterflow is for recuperation of exhaust heat. So this turbine will spend all of its time running at its most efficient speed thanks to the hybrid drive train.

What also should be noted is that turbines can burn any gas or liquid fuel or micronized none slaging solid fuel or slurry fuel all while meeting CARB air with out tens of thousands of dollars worth of exhaust after treatment. Also the mean time between failure for a air bearing turbine of which a capstone is can be from 20000-50000 hours this is an order of magnitude more than a class 8 diesel only having one moving part spinning on contactless air bearings makes maintenance simple and infrequent. Operation and maintenance cost on a diesel are a significant portion of the net operating cost of a class 8 truck. Turbines will be cheaper in O&M plus save Fuel it’s win win for the industry the payback time for the hybrid will be in a few years not tens of years.

Engineer-Poet

I think you're way underestimating the cruising efficiency of a semi diesel. Diesels don't have a steep dropoff in efficiency as power is reduced, and the bottom of the BSFC curve is around the point of max torque at around 2/3 of redline. Look at some Cummins data sheets if you want to confirm that.

UnnaturallyAspirated

Tex,

EP is right and commercial vehicle duty cycles are highly loaded. Together this means that average drive cycle efficiency is relatively high. In fact, engine manufacturers tailor engine efficiency as much as possible to align with where most fuel is burned, typically 60-70% load for on highway truck. they tend to be most efficient at higher loads, but you have to get below 25% load before efficiency falls off much.

as for operating cost....fuel is the single biggest expense. ave. 6 mpg, 120k miles/yr, $3.50/gallon = $70k/yr. truck cost is around $150k. most fleets own trucks for 4 yrs at which time the fuel expense is 2X vehicle cost. engines have 500,000-1,000,000m between rebuilds and commensurate warranty for most major items.

FYI....a 35% efficient 400kw gas turbine, something that could replace the prime mover on a class 8 truck, sells for a substantial loss in the commercial airline business for around $150k. consider that in a hybrid, you still have to provide a generator and motor of similar power as well as the power electronics to couple it all together and things are not pretty. of course with high volumes the cost would come down, but the reality is that the required precision and exotic materials required to operate a gas turbine efficiently are not cheap and the economies of scale only take you so far.

in summary, gas turbine hybrid truck will cost more to buy and more to operate. it never pays back unless there is a fuel that only the gas turbine can burn which is substantially cheaper than diesel.

UA

TXGeologist

There is a reason the turbine is a 65kw version this is very close to the steady state load a class 8 truck needs to cruise on a highway. While the diesel is in the 400kw range so running a 400kw diesel at 65kw cruise power is much less than 25% power at part load as such there is no way a diesel is north of 30% efficiency. You are wrong about the engines being sized for max eff at cruising class 8 engines are sized for peak power needed to climb hills with 80,000lbs of GVW. This simple fact is that turbines hit emissions standards without after treatment, last ten times longer between overhauls as there MTBF is 20000+ hours and can burn any fuel, if they happen to equal or exceed the mpg so be it but the cost of running a fleet is the balance of fuel costs, operation & maintenance expense and initial capital costs of the fleet if the turbine burns more fuel but cost less to run and maintain over its useful life the fleet manager only cares about bottom line. The 2010 CARB standards take significance engineering to hit and the aftertreatment add one are running in the $20000-50K dollar range. Given that this is a hybrid one can expect it to improve on the MPG while sidestepping the aftertreatment and being multifuel to boot its little wonder fleets would want to use a turbine if Capstone can get the initial capital cost down enough which it appears they have. My other Master's Degree is Finance as a small company owner the bottom line is king.

TXGeologist

There is a reason the turbine is a 65kw version this is very close to the steady state load a class 8 truck needs to cruise on a highway. While the diesel is in the 400kw range so running a 400kw diesel at 65kw cruise power is much less than 25% power at part load as such there is no way a diesel is north of 30% efficiency. You are wrong about the engines being sized for max eff at cruising class 8 engines are sized for peak power needed to climb hills with 80,000lbs of GVW. This simple fact is that turbines hit emissions standards without after treatment, last ten times longer between overhauls as there MTBF is 20000+ hours and can burn any fuel, if they happen to equal or exceed the mpg so be it but the cost of running a fleet is the balance of fuel costs, operation & maintenance expense and initial capital costs of the fleet if the turbine burns more fuel but cost less to run and maintain over its useful life the fleet manager only cares about bottom line. The 2010 CARB standards take significance engineering to hit and the aftertreatment add one are running in the $20000-50K dollar range. Given that this is a hybrid one can expect it to improve on the MPG while sidestepping the aftertreatment and being multifuel to boot its little wonder fleets would want to use a turbine if Capston can get the initial capital cost down enough which it appears they have. My other Master's Degree is Finance as a small company owner the bottom line is king.

Engineer-Poet
There is a reason the turbine is a 65kw version this is very close to the steady state load a class 8 truck needs to cruise on a highway.
65? Try 154 kW (Figure 12, page 26).

Tex, you have to stop BSing. We can smell BS a mile away, and it is too easy to find true figures in this age of search engines. You may have an MSc, but if you had a PE you wouldn't keep it for long being so sloppy.

UnnaturallyAspirated

Tex,

Knock yourself out and buy some stock in Capstone if you are so confident in your Masters Degrees. I cant claim to have such a big brain as you, but I happen to work closely with just about every truck and engine manufacturer and multiple recovering Capstone engineers and will not be making such investments myself.

UA

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