Volvo developing extended-range electric vehicle concepts with three different technology combinations
11 July 2011
Volvo is taking the next step in its electrification strategy by producing test electric vehicles with range extenders. (Earlier post.) Supported by the Swedish Energy Agency and the EU, the project comprises three potential technology combinations: one a series-hybrid range extender configuration; and two parallel-hybrid range extender configurations. Tests of the concepts will get under way in the first quarter of 2012.
The concepts all use three-cylinder flex fuel (gasoline and E85) engines to complement the front-wheel electric drive. Two of the solutions are based on the Volvo C30 Electric. In both cases, the standard battery pack has been somewhat reduced in size to make room for the combustion engine and its fuel tank.
This is an exciting expansion of our increasing focus on electrification. Battery cost and size mean that all-electric cars still have a relatively limited operating range. With the Range Extender, the electric car has its effective range increased by a thousand kilometers, yet with carbon dioxide emissions below or way below 50 g/km.
—Derek Crabb, Vice President Powertrain Engineering at the Volvo Car Corporation
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| Technical concept I. Click to enlarge. |
Technical concept I: Volvo C30 with series-connected range extender. This is based on a C30 Electric with a three-cylinder combustion engine producing 60 hp (45 kW) installed under the rear load compartment floor. The car also has a 40 liter fuel tank.
The combustion engine is connected to a 40 kW generator. The power it generates is used primarily to drive the car’s 111 hp (82 kW) electric motor, but the driver can also choose to let the generator charge the battery, thus increasing the car’s operating range on electricity.
The range extender increases the electric car’s range by up to 1,000 km (621 miles),on top of the 110 km (68-mile) range provided by the car’s battery pack.
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| Technical concept II. Click to enlarge. |
Technical concept II: Volvo C30 with parallel-connected range extender. In this implementation, the car gets a more powerful three-cylinder combustion engine at the rear and a 40 liter fuel tank. The difference between this and the first solution is the parallel connection, whereby the turbocharged 190 horsepower engine primarily drives the rear wheels via a six-speed automatic transmission.
This gives a better fuel efficiency rating when driving with the combustion engine cruising on the highway. Via a 40 kW generator the battery can also be charged to give the car increased range on electricity alone.
Here too the electric motor is a 111 hp (82 kW) unit. The two power sources give the car more than 300 hp in total, and acceleration from 0-100 km/h of less than six seconds.
The range extender increases the electric car’s range by more than 1,000 km in addition to the range of up to 75 km (47 miles) provided by the car’s battery pack.
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| Technical concept III. Click to enlarge. |
Technical concept III: Volvo V60 with parallel-connected range extender. This is a solution whereby the entire drive package is installed under the hood at the front. The 111 hp (80 kW) electric motor is supplemented with a three-cylinder turbo engine producing 190 hp (140 kW), a two-stage automatic transmission and a 40 kW generator. Power from the combustion engine drives the front wheels via the gearbox and recharges the battery pack whenever needed.
Up to 50 km/h (31 mph), the car is always powered solely by electricity. The combustion engine is activated at higher speeds and charges the battery pack when its charge drops below a predetermined level.
The battery pack is located under the rear load floor and it gives the driver a range of 50 km on electricity alone. The car also has a 45 liter tank.
The range extender increases the car’s total range by more than 1,000 kilometers.
The series-hybrid range extender in the C30 is part of an EU project in which the Volvo Car Corporation is the only car manufacturer among eight partners. The company’s two parallel-hybrid range extender solutions are being developed with a grant of SEK 10.8 million (US$ 1.7 million) from the Swedish Energy Agency.
I hope they do well with this, all three seem like practical designs.
Posted by: SJC | 11 July 2011 at 07:11 AM
I think that the Technical concept I: Volvo C30 with series-connected range extender is less costly to build , less complicated and better performance of the 3 concepts. Way less complications with a serial ice generator and better ice combustion optimization for the generator.
Posted by: A D | 11 July 2011 at 07:51 AM
We are convinced that some type of range-assist solution is necessary in an electric vehicle. The range-assist allows drivers the most flexibility and the least "range-anxiety". We also think a smaller range assist engine of between 15-20kW will provide adequate power.
Posted by: citizen | 11 July 2011 at 08:58 AM
Why aren't car manufacturers considering combined battery and supercapacitor systems? Considering how much more braking energy can be recovered by even a small supercap, I would think especially these EREVs with small batteries would integrate supercaps to increase efficiency and stretch battery life.
The only thing I can figure is that they can't see behind the cost of the supercaps (should be less than $500 though) or the electronics to manage where power goes and comes from and conditions the voltage. That or patents.
Anyone else have an insight?
Posted by: HealthyBreeze | 11 July 2011 at 09:14 AM
They seem to have enough batteries for good regeneration. AFS Trinity has some patents on cap/battery designs, but like all patents they have to defend them and that is where the action happens.
http://afstrinity.com/
Posted by: SJC | 11 July 2011 at 09:20 AM
@AD,
You're right that Concept I is less costly to build, but can you sell it?
Fist of all, the car is rather anemic at only 80 kW of maximum power. Concept II and III give you 223 kW of power, or almost 3 times the oomph...
Second, in Concept I and II, the battery pack intrudes into the passer compartment, reducing seating capacity from 5 to 4, and/or reduce passenger comfort. A full and uninterrupted back seat bench is a must for young people on a date! Remember back in the good old days when all domestic cars have full uninterrupted Front seat bench AND back seat bench, plus a silky-smooth V-8 engine. Great for double dates (2 couples).
The engine in Concept I and II intrudes in the trunk space and making it much less usable.
Ergo, Concept III is the best in term of sale potential. Full and uninterrupted rear seat bench is available. The smaller battery pack is neatly tucked under the floor of the rear trunk space, allowing a full and contigous trunk space available for the weekend shoppers.
It clearly states in the article that parallel hybrid increases highway fuel efficiency while in engine combustion mode in comparison to serial hybrid. Concept III uses only the electric motor in city driving under 30 mph, and the electric motor's torque will be magnified by the two-stage automatic transmission, thus making for pretty neck-snapping, zippy driving while in the city even in the electric-only mode. Great for in-city drag-racing when the traffic lights turn green. Eco-driving should be fun, and I think that Concept III has the highest FQ (Fun Quotient...and more!).
Posted by: Roger Pham | 11 July 2011 at 03:36 PM
"Volvo is taking the next step in its electrification strategy by producing test electric vehicles with range extenders."
The dateline says "11 July 2011", i assume that ios a typo and it's really from 11 July 1960; one of those "50 years ago today" items.
Posted by: ToppaTom | 11 July 2011 at 11:32 PM
Millsean CIHT power delivers between 2.7 and 5.3 times input power. While this may not be on-demand energy for a while... Volvo would be crazy not to be ramping up a full production line of EVs - not "test" vehicles.
What's to test? We have cheap electricity coming. We know fossil is destructive. Gasoline costs $9/gallon in Europe. And Volvo owners are world's biggest Treehuggers.
What is so hard to figure out Volvo??
Posted by: Reel$$ | 12 July 2011 at 08:40 AM
Didn't Nash have folding front seats for a larger play field?
Posted by: HarveyD | 12 July 2011 at 06:06 PM
Roger Pharm,
I think Volvo team really are heading for option III since the less battery pack the more practical design. I support Roger Pharm. Option I has 110 km electrical range vs 75 km option II and only 50 km option III. Do they want demonstrate that option I architecture is simply not practical? Would it be fair to compare "apples to apples" installing identical battery packs?
Posted by: Darius | 13 July 2011 at 05:46 AM
Actually, I think they're admitting that their target market outside of Sweden doesn't want a low HP vehicle. Option I drive train with Option III's small battery would be pretty efficient on gas, electricity, and Kroners, right?
Posted by: HealthyBreeze | 13 July 2011 at 08:43 AM
What a shame. Engaging so much public money to re-invent the Volt1, in a not so good manner, instead of at least trying to invent the Volt2 or 3, ahead of GM... Shame.
For me starting point should have been at least a 2X Battery - versus Current 18-24KWH standard - Let's say 50KWH capacity, but set with also 2X Instant Power, not just more capacity.
Use better Electric engines, more powerfull ones that can do zero to 130KMH on one fix gear (Like recent UK demo on SuperCharged.com). Put 2 : One per Axis, or even 4 : one per weel, with electronics to control them properly.
Having that base line set, you can move to a full electric drive train, the ICE engine being only used as a pure Generator Range Extender optimized for constant speeds and high power generation (Micro Gaz Turbines...), never having to assist mechanically in tracting the car, like it has to in current Volt due to not enough Instant Power available in its current battery (For High Motorway speeds and mountains).
Means central gearbox and transmission can be cut, and room and weight, and $ freed can be used to fund the greater battery pack.
You put all that in an SUV Formfactor, price it <$60K and I buy one next year. Simple. Invent the future, not the past.
Posted by: CARL75014 | 15 July 2011 at 09:20 AM
@CARL,
Some day your ideal vehicle will become practical. At the present, I believe that Concept III is the best that present technology level can offer to make a car that Volvo can actually sell at a modest profit. Battery and power electrics are still too expensive, so they have to keep these to a minimum in order to make the car affordable.
Posted by: Roger Pham | 15 July 2011 at 04:59 PM
Artemis proved the efficiency of the hydraulic hybrid automobile in an actual conversion.
How fast would this proposed vehicle be going at 223 KW on a level motorway with no winds?
TZERO proved the actuality of a range extender as an optional trailer for its TZERO and drove across the US with it at full motorway speeds twenty years ago or more with less than 40 kW.
All three options are too expensive. Small diesel automobiles are efficient enough.
Electric automobiles are for short trips; and if assist is needed returning from a few to many miles, one or two kilowatts from a HONDA like engine-generator is enough to travel at an average of 20 miles per hour in cities.
Wright, of Wrightspeed, is right; hybrids or HYdrids are best for large inefficient vehicles. ..HG..
Posted by: Henry Gibson | 16 July 2011 at 09:31 PM