ydooby

Doesn't look like the little bike engine is taking up too much space. This could be a good option for the Model X and the RAV4 EV to have (I mean, why would anyone buy an SUV that can't go on a road trip?).

http://insideevs.com/bmw-details-ran...-miles-on-gas/

BMW Details Range Extender Option On Upcoming i3, 160 More Miles On Gas

An interesting aspect of the all electric i3 when in comes to showrooms in the fall of this year, is that it doesn’t have to be all electric at all.

For a price (which is still undetermined), buyers of the 90+ mile electric vehicle, can also add a range extender engine option to enable the car to travel even further, while taking the worry (and the wait) out of finding a charger when the vehicle is away from home and low on power.

“I imagine many buyers will order the range extender to cure their range anxiety, discovering later they need it very seldom,” Herbert Diess, BMW’s head of Research & Development Diess told Automotive News at the NAIAS this week.

This extender is not on par with the likes of the Chevrolet Volt, or C-Max Energi, but is intended to serve more as a back-up to primarily driving on electric power.

The 2 cylinder motor is taken from a motorcycle and is housed smartly in the rear. The unit does not directly connect to the wheels, but rather to a generator that charges the battery, so output (and performance) is sure to be very low.

We imagine that being under-powered when switching to gas, is still much more preferable than being completely out of energy to drivers of the BMW plug-in.

The range extender option adds about 160 more miles of range to the vehicle, bringing the total range up to about 250 miles according to Mr. Diess

“I imagine many buyers will order the range extender to cure their range anxiety, discovering later they need it very seldom. For those who plan a daily use of the range extender, the i3 is probably not the right choice and a plug-in hybrid model is a more suitable solution.”

The BMW boss says he expects about 50% of the i3s sold initially to be optioned with this feature, but eventually settling down to about 20%. It is expected full pricing details on the standard i3 (estimated around $45,000) and the range extender will be announced at the Frankfurt Motor Show next September just before the car goes on sale.

spwolf

seems like horrible solution really, it will have 30-40hp max so it will be basically able to "tow" your car to nearest charge spot at minimal speeds. Problem is that you are paying for it already, so why not have some efficient PHEV? Or spend that money into more batteries.

ydooby

Not really. BMW wouldn't be talking about a "160+ mile extended range" if it means driving your car at towing speeds. You have to remember the difference between a 40hp engine powering the transmission and a 40hp engine acting as a power generator is that, while the former certainly limits the car's peak propulsion power to 40hp, a car in the latter case is actually driven by a motor of much higher peak power as the 40hp engine constantly and consistently generates its peak 40hp power into the energy pool for the more powerful traction motor to draw power from. One does not need nearly the peak power just to cruise at legal speeds on a highway, for example, and only needs it when accelerating to get up to the cruising speeds or during occasional overtaking maneuvers. When the traction motor is not running near its peak power, which should be the case for most parts of normal driving, the battery would have more than enough opportunity to get recharged rather than discharged.

Sulu

Because the engine is ONLY used to charge the battery, it does not need to be very large and powerful, as long as it starts to re-charge before the battery level gets down too low. The car is always driven by the electric motor (from the battery) and not the gasoline engine, unlike the Volt, which uses its engine to drive the car (essentially bypassing the battery) when the battery level gets low.

spwolf

you guys dont understand how this works.

This is similar system to what is used in Volt, please check out real life mpg of Volt.

Somehow you are thinking that they will get better performance and mpg by making engine power up motor which then powers up the wheels. Thats impossible due to extra losses introduced at that point.

Efficiency and performance of power generator aka engine in this case is lowered from normal vehicles and PHVs. This is why BMW itself recommends buying PHEV if you plan to use the engine.

So to repeat it again, it is less efficient to use engine as a generator instead of driving the wheels directly. This is why Volt gets really bad real life mileage while Prius PHV gets 50 MPG + real life (both when running out of battery).

ydooby

Huh? When did I even mention "efficiency"? Of course PHEV is more efficient if you plan on using the gas engine regularly, but the idea here is simply to avoid being stranded or forced to drive/own/rent a different car when the extra range is needed.

Unlike the fake EV Volt, which is really a PHEV that requires the gas engine to directly drive the wheels when reaching 70mph, the i3 is a pure electric car with a 170hp motor capable of a top speed of 93mph on just electric power. The gas engine option in the i3 merely provides a backup power and will not consume one bit of gas until the i3 nearly runs out of battery power. It's a great option to have for those wanting their electric cars to handle 100%, rather than 95%, of their driving needs.

spwolf

yeah but you are paying extra for limp mode, why not spend little bit more for real deal.. But ok, lets see how it works in real life.

ydooby

What's the "real deal" you're talking about anyway? All the current PHEVs require gas consumption all the time. The Volt requires gas engine at 70+mph, and the Prius plug-in does so at 62+mph. Those speeds happen to anyone's highway commute on a daily basis. With the range extender option in the i3 on the other hand you would still be driving a pure EV without consuming any gas, but have the safety net of a backup power should the need arises. That to me is more "real deal" than a PHEV that still consumes gas all the time.

LexFather

250 mile range with ghe extender is good. Wonder how this will sell?

Hoovey689

iTrader: (16)

should be interesting to see. BMW is at an interesting chapter adding this "i" line of cars vs their traditional RWD petrol and diesel cars

spwolf

same way they allow for gas extender, they could allow for bigger gas extender.

At the end, the goal is efficiency and lower bills, no matter what type of fuel we are using, right?

bagwell

you wanna know REAL LIFE VOLT MPG ????

spwolf

thats not real mpg, but with EV mode. Basically it could be 999 like that.

What I meant was MPG without EV mode, when you depleted those 30-40 miles of EV.
Then it is 35 mpg for Volt, 50 mpg for Prius PHEV.

This is difference between using power generator and using similar engine that directly drives the wheels. You could have same type of power as in Prius PHEV, just with longer EV range and it would get better mpg and be usable for more people.

There are plenty of upcoming PHEVs that do this, such as Ford Energi's and Accord PHEV. To me this would be a much better choice than some 80 mile EV that can limp home if you misjudge your charge. EV's motors are really inefficient for higher speeds anyway, so it would be actually better to run in gas mode at high speeds.

So I am not talking about agendas credentials, I am talking about what is better for everyone.

bagwell

if you're talking about everyone (in the US anyway) then you should mention the average commute (distance) is 32 miles round-trip.

spwolf

so why are they putting 80 miles in i3 and range extender? Obviously not needed right? Or why is Tesla spending all that money on 300 mile range batteries?

Because it is not that simple, and low range EVs and PHEVS sales suck and are way under expectations.