And less hung over.

I am with you on the range extender.

Enough to drive at 60 mph on the level would do it (and some). Might be more than 10KW, but no matter.
It may not have to be that efficient, just small and quiet and easy to top up.

In cold climates such as those of northern and eastern Europe, an ICE genset is essential to supply cabin heat, defrosting heat, and battery-warming heat. Renewable fuels for these genset will be essential in order to remain CO2 neutral.

In a smaller PHEV, a 20-kW ICE will be all that'll be needed to provide unlimited driving range and for winter heat, all for much lower cost, if this ICE is in the form of a parallel hybrid. With exhaust heat recuperation for cabin heating and defrosting, thermal efficiency of this PHEV may be over 90%.

It does not. However, parallel-hybrid is cheaper and lighter, and is more efficient due to the direct coupling of engine to drive train at cruise, hence may find more market penetration. A battery-centric PHEV will not need a transmission unit, or at most, a two-speed unit for use in cruise only. A parallel-serial hybrid will have a small engine driving a small generator (20kW), and at low speed, it will run in serial mode. At cruise speed, the engine will be coupled directly to the drive train, thereby eliminating electrical loss. The electric motor will provide boost for acceleration when needed at cruise, thereby preventing downshift. Because the engine provides additional torque at cruise speed from 40-80 mph, the motor and the power inverter can be smaller, thereby saving weight and cost and internal space.

Look at the Volt's hwy mpg when on engine power alone (35-40 mpg), vs. the Prius' hwy mpg(48-50 mpg), and you can see that the 75% mechanical torque coupling of the Prius has resulted in much higher hwy mileage. There may be other factors in the Prius' higher mpg, but I think that the direct mechanical coupling is largely responsible for this gain.

A serial-parallel HEV or PHEV will combine the torque from both the engine and the motor when maximum power is desired, allowing a smaller motor and power inverter for a given level of performance. There is no need for "full performance in EV mode," since full performance in combined mode is more fitting of a hybrid.

In the "Power mode," the engine will be kept warm and will be restarted once every 5 minutes or so to keep the catalytic converter warm enough, in case a power boost will be needed in the battery-dominant mode.
In the "Economy mode," as selectable by the driver, the engine won't be started until the battery is sufficiently depleted. Economy-conscious drivers will not need the extra boost from the engine, and power-oriented drivers can sacrifice some efficiency.

Agree that fuel consumption of a taxi could be halved by operating the engine at the optimal speed/load point. That's why we have serial-parallel HEV with an electric-only mode at low speeds and low loads, when the ICE would be least efficient. The ICE would only be started when it can deliver optimal efficiency. The ICE is downsized enough so that it can run with optimal efficiency when coupled directly to the drive train at cruise speeds.

http://gas2.org/2010/08/24/chevy-volt-achieves-less-than-30-mpg-after-battery-depleted/

(testimony of a real-world driver)

Skimping in power electric is false economy?

Let's consider the $41,000 price tag of the Volt, vs. $22,500 for the Prius. The battery in the Volt costs ~$8000. The Prius' battery costs~1000 wholesale, may be ~$2000 retail. Substracting $1000 from the $8000 and adding this $7000 to the MSRP of $22,500 of the HEV Prius will give $28,500 for the cost of a hypothetical PHEV Prius with LG Chem's 16kWh Li-ion battery pack. So, $28,500 vs. $41,000, and this is false economy?

One may think that operating a serial PHEV in heat-led mode in the winter by running the ICE, efficiency does not matter much, since waste heat is utilized. However, even in the heat-led mod whereby waste heat is utilized, the waste heat from electrical losses may be too cool for defrosting or even for cabin heating in the deep freeze of Moscow or Berlin. If the motor and power electronics are to be air cooled, then, this waste heat may not be recoverable for cabin and windshield defrosting. So, minimizing electrical losses and drive train losses will still be the best approach to increase overall efficiency, even in the heat-led mode, so that coolant heat and exhaust heat can be used to the best extent.

Would you not get a sweet spot with a ~2-5 kWh battery and ~100kW output, such a system could cover all non highway travel of a vehicle, and still provide enough power reserves for overtaking and accelerating to highway speeds.

I think its a shame the volt didn't go for a smaller atkinson cycle range extender

Roger, you're really not getting the point.

To match this 110 kW power rating when designing a serial-parallel hybrid with same payload rating, we can start with a 55 kW motor#1, a 30 kW engine and a 30 kW generator/motor#2.

Now, then, ask yourself, why do we need 16 kWh of battery capacity

1. 40 miles of AER while
2. limiting the charge/discharge range to achieve the specified warranty figures of 10 years and 150,000 miles.

Thanks, MG, for many interesting points and your referral to the interesting patent by Stridsberg.

Certainly, gear box can significantly augment acceleration and efficiency for electric motors, also. A 110-kW motor rated at 3000 rpm cannot generate 110 kW output at 1500 rpm at all, since hp=torque x speed. It can certainly draw in 110 kW of power, but probably almost half of it will end up as heat, when the motor's efficiency will drop from >90% @ 3000 rpm to ~50% @ 1500rpm when facing a very current draw.

In a fixed-gear BEV, the full-rated output of the motor cannot be realized at lower speeds, but only at near its rpm of maximum output.
So, EP, the Volt's 110-kW motor can't deliver this rated power at lower speeds, either, since it does not have gear shift in order to maximize output and efficiency at lower speeds.

My PHEV design, having a two-speed transmission, can better deliver the engine and motors' maximal output at lower speeds than the Volt.

Now, then, why is 16 kWh battery capacity not needed:

1) You can get ~25 mi all electric range from a 8 kWh battery, and you can plug it in at work or at shopping centers, or other places. This is a perfect excuse for obtaining a parking spot as close to the building as possible without a handicap sticker.
You're paying very little $ for getting all the perks of owning a PHEV, like HOV lanes and other perks like those given in Britain for EV's.

2) Why carrying around 200-lbs of dead weight all the time, (and draining $4000-5000 in your bank account) when you will be able to charge your PHEV at work and at business centers?

3) Batteries will lose capacity with time, even without any usage. That is known as calendar life. Why subject your $8000-10000 investment to unnecessary risk, when you can invest only 1/2 of the amount now, and then this 8 kWh pack is worn out, replace another fresh pack and enjoy fresh battery capacity again? This is especially true if you don't drive very much. With the dropping price of batteries, your second 8 kWh pack will be cheaper than the first 8 kWh pack.

4) WRT OEM's battery warranty: 8yr/100,000 mi warranty for an HEV's battery is to satisfy federal requirement for emission equipment of the vehicle. Even a very heavily-used 8-kWh pack is likely to retain a capacity of 4 kWh after 8 years, or 50% loss of capacity. This is still perfectly good to serve the vehicle as an HEV battery pack. The Prius only has a 1.3 kWh battery pack. Therefore, the OEM does not have to pay to have the battery replace, since emission-wise, the HEV will still do just fine with 4-kWh of battery capacity. The owner, however, can elect to trade in this pack for a newer pack at his/her own discretion. The vehicle's on-board computer can be programmed to stop accepting charge from the grid when the battery pack's capacity is down to 2 kWh, in order to prevent the OEM from having to replace the pack for free.

MG, I'll get to comment on the Stridberg's patent after having the chance to review it in detail.

Quoth Roger:

A 110-kW motor rated at 3000 rpm cannot generate 110 kW output at 1500 rpm at all, since hp=torque x speed.

You can't use 110 kW all the time anyway. At 10 mph, that's almost 25 kN of thrust (over 5500 lb). If T/W is limited to 0.5 the Volt wouldn't be able to put the full 110 kW to the ground until it hit 32 MPH. That's fine by me.

As a Scientist, Engineer and former Physics Teacher it totally astounds me that everybody here is either blind to or not being trampled by the Elephant in the room. Hey did you guys ever Hear about the CONSERVATION OF ENERGY LAW (It's taught in 9th grade General Science i think. Just to Refresh:

Energy in a system may take on various forms (e.g. kinetic, potential, heat, light). The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant.

No matter how you cut it ELECTRIC CARS are no "Greener" than Cars that run directly on Fossil Fuels in fact if you crunch the numbers they are far LESS Efficient and in the End THEY ARE STILL RUNNING ON FOSSIL FUEL as over 85% of the Electrical Grid (modest estimation) is produced by FOSSIL FUEL. The only thing here that is somewhat differnet is simply that you use a 3 pronged wall plug to fuel rather than a GAS Pump Hnadle but you are STILL RUNNING YOUR TOTALLY INFERIOR, IMPRACTICAL, (WAY) OVERPRICED, UNDERPOWERED, UNCOMFORTABLE,SMALLER, LESS SAFE, MUCH HIGHER MAINTENANCE, WEATHER (temperture) SENSATIVE AUTOMOBILE, MUCH THE SAME FOR 100 OR SO YEARS ON FOSSIL FUEL!!!!!

The only difference is that the Power Comes from BLACK Coal or Crude Oil probably produced in parts of the Country where lower income families live who can't afford Electric Cars or Hybrids (which also run on Fossil Fuel Directly)so they are gagging on the Toxic "Horrors" produced by Creating Watts, Creating the "Green House Gasses" and theoretically causing the Earth to Suffer a Heat Stroke just far enough away from your ELectric Toy Cars and your Lower Upper Class Neighboorhoods and don't get a Federal Tax Rebate that will compensate them for their Myraid of Medical Problems and the Huge Bills that go along with them etc (squared)
IN FACT if you factor in simple OHMS LAW (I=E/R) or In H.S. Physics E =I/R It becomes fairly clear than SHIPPING ELECTRICITY TO AREAS FAR AWAY FROM "GREENSVILLE" ADDS UP TO A MUCH HIGHER AMOUNT OF FOSSIL FUEL IN THE LONG RUN THAN THE CURRENT MUCH MORE EFFICIENT SYSTEM OF SHIPPING PROCESSED FOSSIL FUEL
BY SEA OR PIPELINE ETC BECAUSE OF THAT PESKY "R" FACTOR THAT RAPES THE "I" FACTOR AND DOESN'T EVEN SEEM TO BE CONVICTED OF THE COST OF A PARKING TICKET!

Think of it this way. In order for you to get your
220 VAC or 120 etc in your GREEN Socket Cover say MANUFACTURED say 1000 miles away so you cant see the BLACK smoke from the eww so filthy Fossilized Dinasaur Dung trees, and perhaps a few Ancient Aliens who dropped dead here millions of years ago from the fowl O2 and Pristiene crystal clear H20 in Virgin Springs untouched by CO, Acid Rain and the like, is ASTRONIMICAL difficult to sum up as it varies extensively but according to a National Geographic Definitive study in 2010
There are three power grids in the United States: the Eastern, Western and Texas grids. The amount of power lost along these transmission lines, by moving it along long distances, could power "14 cities the size of New York," according to a 2010 National Geographic report:

"There are three power grids in the United States: the Eastern, Western and Texas grids. The amount of power lost along these transmission lines, by moving it along long distances, could power "14 cities the size of New York,"

And that is NOT counting the Myraid of Step Down Transformers wasting it in the(energy form) of HEAT needed to reduce the 120,000 Volds to 120 inefficient old home wiring etc etc, Lack of storage Capacity so it's running like Niagra Falls all the time (but not providing the relatively CHEAP and CLEAN hydro-dynamic source of ENERGY, about 5% of the National Grid (in the FORM of Water power simply put i.e same energy, different form but =). So 10x MORE Watts (kilowatt hours or however you want to think of it) has to be generated to Power your little Toy Elecric Car or Golf Carts literally which Senior Citizens are buying FLEETS of in Retirement Communities in FLorida and now using to line up at the "Drive Up" Bank teller or more appropriately "Golf Cart Up" a bit lower windows to deposit their $6,000 FED TAX REBATE CHECKS used to pay for at least 3/4ths the price of the new improved cheaper vehicles (that qualify for that "Rube Goldburgish" type grant).