OK it likely wont work but.....

[Lumberjack]

All the talk about the genset got me thinking that they should use two smaller gensets instead of a single one. The smaller displacement engine will use less gas and be a bit more efficient. For light driving only one genset would need to be on but if the driving got fun then the second genset could kick in and supply the extra juice. It could also be a good way to provide a sport and economy model without having two different rear ends.

:Beer:

[rogwild]

It is my impression that Vv will be going for the smallest engine that will have the power and torque to turn the generator. Perhaps two 'smaller' generators would allow smaller engines, but you would have to have dual or redundant cooling and exhaust systems for each engine. Not sure if there would be a significant (if any) saving in total weight/economy/cost.=n:
It is my understanding that the 'genset' is used ONLY to charge the batteries; you would recieve NO MORE POWER to the electric motor with the 'genset' ON or OFF, only what 'power' is currently stored in the battery. The second 'genset' would only charge the battery FASTER and allow the ICE/s to shut down sooner. That is one difference between a Series Hybrid EV (V-1) and a Parallel Hybrid EV (Prius).=y:
The 'sport' or 'economy' function can be controlled through software that regulates how much and at what rate energy can be drawn from the batteries (Ian already stated that they are planning that feature, I believe).=D
Other opinions?:IDEA:

[Lumberjack]

Almost rog. The electric motors that drive the vehicle produce horsepower by using electricity in direct proportion. Cruising uses a lot less juice then heavy acceleration does. The genset has to keep up with the average amount of electricity being used by the motors and the batteries store the differance.

For short hops around the city a tiny genset is all that is really needed. The genset can recharge the batteries slowly even while the vehicle is parked. A long run in the country however needs a much larger genset to provide enough juice to keep going without stopping to wait for the genset to catch up. For short city hops a 1 kw genset would be plenty but for open road driving you would need a 15 kw genset.

By splitting the genset into two 7.5 kw units you open up a lot more options and halve the motor size as well. A 440 is 3 times as large an engine as a 220. and weighs 4 times as much. The exhaust and other components like the cat are also reduced by more then half as well. One could configure a commuter version with a single genset saving a considerable amount of weight. You could simply swap in the second genset for long trips or fun rides where economy may not be as important. For even more economy one could even swap in a 1 kw genset.

Reliability is a weird consideration too. Dual gensets means twice as much to break but the redundancy would allow you to limp along untill it could be fixed.

I hope I am not spreading confusion making myself clear.....

[Mark Tomlinson]

Some ICEs have been introduced that shut down a cylinder or two when they are not needed. Perhaps that's not appropriate for something as small as a genset. But it makes me wonder if the engine could be set to run at two or three different speeds (or even variable speed) depending on the rate the battery is being depleted.

[AZEqualizer]

Interesting concept... not sure of the balance between benefits and detriments.... using a different point of view is never bad... just different.

[rogwild]

Mark, I thought one of benefits of using the ICE/generator combo was that the ICE could be selected to run at its most efficient 'rpm' (increasing engine life and efficiency) and simplifying ICE control. When it comes on it is running at peak efficiency and providing max charge rate for the generator. Why would anyone want to run it slower, take longer to recharge the batteries, and use more fuel?
Lumberjack; I'm sure the 'engineers' are working on the figures and data, but I believe the concept is that the generator will be able to recharge the batteries at a rate equal to or in excess of 'normal' driving conditions (so that you could still move if the batteries got too low).
I like the idea of 'redundancy' to keep you going, but if you had two equal generators or a large and a small 1kw one. I doubt if you could run (without stored battery power) on 1/2 output or only 1kw. So the 'redundancy' would only help if the 1kw generator failed.
Also I fail to see your relationship between the 'genset' size and the size/output of the electric drive motors. The ICE/generator determine how much juice is put into the batteries and how long the recharge takes. The electric drive motor(s) determine how much power can be put to the wheels. If you half the drive motor; ("By splitting the genset into two 7.5 kw units you open up a lot more options and halve the motor size as well") you will not have the acceleration or cruise speed figures that are projected.
Perhaps I totally misunderstand your concept.
I'm sure that the Power/Drivetrain will be a major 'headache' for the engineers; trying to fit the electric power motor(s), recharging/regulating hardware, ICE, Cat converter, exhaust, cooling system, fuel tank, suspension, brakes.....ALL into the Power Pod. Seems they have already had to move the batteries into the passenger compartment (fumes, heat, possible fire/shock). Do I see more 'DELAYS' ahead?
Hopefully they will go with the smallest, safest, most efficient and reliable option; whether it be ONE or.....TWO, THREE, or FOUR ICE's.

[Miracleman89]

I am not really familiar enough with this stuff to say one way or the other. However I will say that according to Ian. Awhile back he said that the sport version would have a switch that would allow it to go from economy to sport. The difference in power would come from the generator supplying power directly to the motors coupled with the power it was getting from the batteries. If the gen-set can accomplish the same performance or better while lowering cost, I say go for it! If it will raise cost, weight or lower performance, I say it isn't worth it. But like I said when I started I don't know enough about the technical stuff. Heck when it comes to electrical stuff I don't know squat! I had a VW cabriolet special edition (i forget how to spell the name of the edition now) but it had an electrical problem that would kill the engine. the lights on the dash would go out just a few seconds before it would die! Never could figure out what the heck was causing it! The battery charge was always good when tested , i even replaced it once to be sure. Checked and even replaced the alternator, still no change! All the fuses were good! I even took the car into a specialist to have all the fusible links check or replaced, he replaced one because he said it looked worn but shouldn't have caused a problem. Sure enough still would die! I gave up and sold it after it sat for three months while I tried to figure out the problem! I hated to sell it, I really enjoyed driving it around, but I couldn't drive it anymore so it had to go. Anyway that is about the extent of my electrical knowledge, so take my comment for what it is worth.

[rogwild]

"MM"; I did find a quote by Ian:
"2.) The hybrids can be run in EV mode, to a point where the batteries are depleted to 20% (80% DOD), at which time the IC engine/generator kicks in."

This make me think that the power from the 'genset' MAY be able to be 'diverted' entirely (or partially) directly to the drive motor(s) in addition to the battery power to be used during 'high demand' periods. I haven't been able to find anything that directly supports this, but it could be possible. That would help explain why the e50 and Q100's have a higher 'top speed' (100-120mph vs 75+), besides having larger output electric motors.

[Mark Tomlinson]

Rog, regarding your earlier post. You are right, of course, that varying the speed of the engine will decrease efficiency. I was just running with the idea of multiple charging rates. Considering weight, engineering, maintenance, expense and fuel savings, it seems better to have a "fast charge" setting that is less efficient.

However, I've been thinking about it and the whole discussion is irrelevant! Here's the deal - batteries, especially Li-ion, have a discharge and recharge range. Recharge a battery too slow and you're wasting time and fuel. Much of the energy in the gasoline goes out the tailpipe as heat rather than into the battery. Recharge a battery to fast, and you run the risk of thermal runaway. Much of the energy is thrown off the battery as heat and you get a big battery fire.

So the genset needs to be matched to the optimum efficiency of the battery recharge rate. Any faster or slower and you're wasting energy.

Assume, then we make the genset AND the batteries replaceable. Now we've changed the battery discharge dynamics and need to replace the motor controller as well. So the only way we can accommodate for city versus highway driving is to replace the genset, batteries, motor controllers, and possibly the motor.

Bottom line, IMHO, is to get the fastest recharging possible and just run the genset more often during highway driving.

[Bladerunner]

Interesting idea but I think the idea behind a serial genset is that the engine that powers the generator is tuned to its most efficient level considering what it is hooked up to and sound /emission equipment. It would add a level of complexity and added parts that wouldn’t be IMO a good trade off for any benefit it might have in a vehicle for the masses.

[Lumberjack]

The battery is only a storage device and has an optimum charge and discharge rate. All the power must either come from the genset or a wall socket.

The wheel motors can draw power from the genset directly or from the battery or from both. In a way this is all about getting a balance between the power used to drive the motor and the amount of power produced by the genset. To recharge the battery the genset must produce more power then the motor is useing but the amount of power used is not a constant. Under heavy acceleration or when climbing a hill the power draw is very high. When going down hill or slowing the power used is very low.

Say for instance the wheel motors draw 30 kw accelerating up a hill. A 15 kw genset will never supply enough power to directly drive the motor but the battery can supply the other 15 kw. when going down hill the motor may only need 5 kw and the genset produces 15 kw then the battery recharges for the next hill...

Generators tend to produce power efficiently at a fixed speed. If it is exceeded for very long the the coils will burn up. Below that speed the efficiency drops severly. If the battery is large enough you can store all the gensets output and then shut down for a while untill the battery becomes low. Unfortunately batteries are very heavy relative to gensets so it is a lighter option to have the genset run most if not all the time and use a much smaller set of batteries. This is of course where the real engineers have to step in because the calculations needed to balance things out are a bit outside my experiance. Driving habits and trip length are also a part of the equation as the genset can continue running after the trip to recharge the batteries on short trips.

Too big a genset and you drag around useless weight
too little a genset and you run out of power and will have to sit by the side of the road waiting to recharge.

Too big a battery and you again are stuck with useless weight.
Too small a battery and you run low on power again.

Weight is a critical component of the V-1 as it requires more power to accelerate and drive it. This means the drive motor gets bigger and the batteries get bigger as well. There is a point where all this begins to run away and becomes impractical.

Stangely enough untill the thing is actually built and tried the engineers wont know for sure if they have all the specs right. I just hope they leave themselves enough room to make last minute adjustments.

[Bladerunner]

Don't have a whole lot of experience there other than the generator I have for camping runs all the time and seems to be at a constant speed even when the load changes... but then again I have no way to measure this other than sound and I could be way off base.
So I will take your word on it and trust in the VVside.133

[MikeB]

It's a creative idea, but I think having two sets of engines & generators is more inefficient than one well-tuned engine and a larger battery.

As long as the battery has a pretty good capacity (like the 20 minutes planned for the hybrid), you can draw extra power from it when accelerating and still recharge just fine when cruising.

I did some basic computations for the V1 back in Feb, and the current sizes seem well thought out. The generator will put out 15-20kW. The hybrid battery holds 3kWh. The electric hub motors will consume about 7kW for 60mph cruising, and up to 50kW (or 100kW) for max acceleration. Play around with some scenarios based on those numbers, and you'll probably like what you see.

[evCommuter]

In a few years... I could supe-up my Venture Q100 by dropping in the Hybrid system from my 07 Ford Escape Hybrid SUV.
Maybe the weight would be about the same and it still gets 100mpg!
Keep the fuel tank, not the 15-gallon fuel tank. Watch this video “About the Technology” of the Ford Escape Hybrid system: http://www.fordvehicles.com/suvs/escapehybrid/ (http://www.fordvehicles.com/suvs/escapehybrid/)

Gasoline Engine
Engine type


2.3L I4 Atkinson Cycle Engine and Electric Motor (javascript:UADWin(11420);)
Engine electronics


Electronic engine controls
Displacement


2.3L (2,261 CC)
Horsepower (SAE net@rpm)


133 @ 6000 rpm
Torque (lb.-ft.@rpm)


124 lb-ft @ 4,250 rpm
Compression ratio


12.3:1
Fuel delivery


Sequential multi-port electronic fuel injection
Fuel recommended


Regular unleaded
Fuel economy


FWD - 34 mpg city/30 mpg highway
4WD - 29 mpg city/27 mpg highway
Transmission type


Electronically Controlled Continuously Variable


Electric Motor
Motor type


Permanent Magnet AC synchronous motor
Battery


330-volt Nickel-Metal-Hydride (NiMH) (javascript:UADWin(11421);)
Power (rpm)


94 hp (70 kW) @ 5,000 rpm


In a few years... If I works good then I'll let you know and maybe Ford would partner up.

evCommuter [not yet]
“Venture To Lean!”
:Beer:

[evCommuter]

Business Proposition:

For $60,000 and two months I will delivery [drive to you] the vehicle that I describe above. Target spec: 150 mph, 200 mpg.

evCommuter
"Venture to Lean"
:cool:...:confused:...:cool: (my crew)

[evCommuter]

But of course I also need the Venture Q100 that you have right now to build the XStream.
=D
evCommuter
"Venture to Lean"