Ford Fusion Hybrid Due March 2009!

[usbseawolf2000]

I believe all these advancements are already in 2004 Prius. Ford went up one higher with the 47 MPH EV limit.

[Flying White Dutchman]

Originally Posted by MountainStone

Wow. Brake-by-wire and electronic wedge brakes are pretty high-zoot technologies for automobiles. Stuff like this normally debuts on platforms such as the Mercedes S-class. Good on Ford if the above presumption is accurate; the successful deployment of this braking technology has implications for every vehicle.

I hate bleeding brakes, and it will be nice to eliminate the vacuum (or hydraulic or electric) booster and master cylinder from the engine bay. Plug-and-play calipers will make brake jobs much easier, as well.

your joking right?

[Rybold]

Excellent !!!! I will be looking forward to seeing these in dealer showrooms.

And it will make GM look really stupid for showing up at the U.S. Capitol in a Volt, and then all of a sudden Ford is actually selling the Fusion Hybrid but GM's Volt is no where to be seen.

[Road Fan]

Originally Posted by drees

As an engineer with a bit of electrical engineering knowledge, this seems to be flat out backwards.

Electrical losses are due to resistance.

For example, if you have a 100V supply and you need to supply 100W, this requires 1 amp of current.

If you have a 200V supply and need to supply 100W, this requires 0.5 amps of current. Electrical loses compared to the 100V system are 1/4 of the losses and thus efficiency is 4 times higher.

Am I missing something?

Drees, no you are not missing anything regarding the fundamentals. In fact you are a lot clearer than I in making the same point - we posted nearly simultaneously.

Of course it's possible to optimize a system based on engineering fundamentals such as Ohm's Law at the beginning of a design project. I've done this several times in designing power systems for space vehicles. Once one has run a good distance down the road however, such as, in Ford's case start of production minus 12 months, there are a lot of constraints in place. All the components and subassemblies have been validated, investing months of test time for each part, and cannot be significantly changed after that.

Assuming Ford discovered the battery sizing had been too conservative (perhaps based on instrumented "mule fleet" testing) and had excess system voltage, to down-size the cell stack and lighten the automobile seems like an improvement to system efficiency, even though it does not greatly affect electrical subsystem efficiency. There is no possibility at this point in the automotive ready-for-production cycle to re-wind motors, power MOSFETS, power filtering, or other "big EE" stuff - it's all been proven out and cannot be changed without serious impact to the launch date, and the non-recurring engineering cost.

So what you may have been missing is the impact of product life cycle on the available decision space. You presentation of the fundamentals was perfect.

Road Fan

[donee]

Hi All,

The main reason the Prius, and presumably this new Fusion use the lower battery voltage than motor voltage is to improve regeneration recovery and a secondary benefit of brake life improvement.

When braking the motor has a constant voltage/rpm ratio. Remember the MG2 is fix geared to the wheels. So, as the car slows the voltage gets smaller and smaller. At some point, the voltage is too low to pump current into a battery. By using a motor that is twice the voltage than the battery, this makes it easier to get more energy out of a slowing car. Since the generation voltage will be higher to a lower speed.

Losses for accelleration are not a big issue in a hybrid, because the cars use the engine for accelleration, primarily. Because the engine at civilian accelleration powers are in their most efficient regime.

At speed maintaining electrical loads, the resistance losses can be designed to be sufficiently low for good effect. Also remember the number of cells effects the the series resistance of the pack. The more cells, the more cell-to-cell connections. And the heat these connections make not only waste power, but hurt battery life. So, there is probably a happy medium between too low a voltage and wire/inverter losses, versus too high a voltage and too much loss from cell-to-cell connections. Look at the elaborate battery cooling system in the Tesla for an example of too many cells for a medium performance, low maintenance prodcution car (not what the Tesla is).

These are the Hybrid car/ EV tradeoffs. An EV needs much bigger wires, inverters and batteries to be able to efficiently accellerate electrically. A Hybrid does not. A Hybrid needs excellent regeneration.

[usbseawolf2000]

A great explanation for the same advancement made for 2004 Prius.

Any idea how many voltage Ford is boosting up to?

[snead_c]

I'm pleased to see that Ford is moving in the right direction so quickly...I see no mention of accceleration performance? Perhaps more is coming.

[usbseawolf2000]

More detail information about Fusion hybrid at GCC.

Variable-Voltage Converter (VVC). The new powertrain’s inverter assembly utilizes a DC-DC buck-boost converter, which Ford refers to as a Variable-Voltage Converter, to step up the voltage potential of current from the battery pack before it is synthesized into a three-phase AC waveform to power the transaxle’s two electric motor-generators.

Every model-year 2004 and up Toyota/Lexus hybrids utilizes a buck-boost converter; however, this is the first time that the architecture has been employed in a mass-produced passenger hybrid vehicle built by another manufacturer.

[rgathright]

Originally Posted by hampdenwireless

1.3Kw/hr is not a small amount of power and is way more power then required to brew a 12 cop pot of coffee. It should run a fridge for a day unless you open it too much.

Way more if you consider having a couple hundred watts left is ok.

Please try monitoring the power usage of coffee maker with a Fluke or Kill-A-Watt meter. I am sorry, but I disagree with your statement.

[HayaiKuruma]

For those of you celebrating the chance to buy a domestically built hybrid, it depends on your definition of "domestic." The L.A. Times car blog reported last week that the Fusion hybrid is being built in Mexico.