That electric car on Top Gear last night

Presumably you can charge your electric car at home using electricity generated using non-duty paid fuel (including a private generator running on red diesel, or such). So whats the deal with ‘electic’ cars like that 1 last night ?

I think that the petrol engine runs at a fixed optimum rpm to charge the batteries and is therefore not at the mercy of leadfoot drivers.
Gives a sportscar performance for family saloon economy, costs a lot more to run that a pure battery driven car.

Well, for one it was petrol.

Since you are using the fuel to power the car only it is a hybrid, like a Prius. No more complex than that.

I think Brian’s car was better & he’s funny an all like, pet/marra.

not quite SC.

The prius petrol engine provides drive via a gear box. The car last night has a generator that charges batteries. The batteries power an electrical motor.

I think the idea is that this minimises generation/conversion losses. No gear box, optimum revs in the petrol engine, etc.

SC – Yeah, I’m sure you can by non duty paid petrol.

Thats how I understood it Stoner.

Probably not an issue for HMRC to worry about at the moment, but might not be long before they have to.

If anything I think its less complex than a Prius.

I quite like the idea TBH, masses of torque and good acceleration from a tiny engine.

EDIT: Isn’t this along the same lines as that Jag that used two turbines to provide electrickery?

all that torque sounded good, but the 2.5 tonne weight didnt!

Not like a Prius at all. Pruis has a combustion engine as well as electric motor/s.
The Fisker does not have a combustion enigine.

Makes the defender look light !

I reckon a little ‘turbine’ charging the batteries rather than a ‘traditional 4 stroke’ is the way forward.

yes it does. It has an onboard petrol generator.

And I think it’s a Fista 😉

Ive just had an AWESOME idea!

You know you can now get Baxi combis that produce 1kW of electrical energy from a Stirling combustion engine – well how about putting a tank of calor gas in the boot, a ocmbi boiler on the back seat, and then running that through some batteries and an electrical motor??!? Bonus – you could have a hot bath at the same time!

I think that the petrol engine runs at a fixed optimum rpm to charge the batteries and is therefore not at the mercy of leadfoot drivers.

Even if the rpm is fixed the engine still has to respond to the demand from the battery/motor so it will still be at the mercy of leadfoot to some extent.

Set the timer on the boiler and have auto defrost / pre-warming of the car on a winter morning – genius

What you really need, is one of these 😀

http://www.fiskerautomotive.com/en-us/karma/specifications

Since you are using the fuel to power the car only it is a hybrid, like a Prius. No more complex than that

I didn’t see this – are you talking about the Vauxhall Ampera? Series hybrid, as opposed to the Prius/Lexus etc which is a parallel hybrid.

Nice idea the Ampera but needs proper big batteries unlike the Prius ones which are really quite tiny.

Presumably you can charge your electric car at home using electricity generated using non-duty paid fuel (including a private generator running on red diesel, or such). So whats the deal with ‘electic’ cars like that 1 last night ?

Probably okay so long as you only charge it in the garage, or take the generator out and leave it at home.

Stil can see how it’s more efficient than just a petrol engine though

Maybe they just need a big space in the bonnet where you can stick whatever you like to provide the electricity, batteries, petrol generator, miniature nuclear power station etc.

Stil can see how it’s more efficient than just a petrol engine though

Good job you’re not an automotive engineer then 🙂

Vauxhall seem to have this technology up and running already – in fact they have for a while now.

Vauxhall Ampera

Same concept – Electric motors powered by batteries that are charged/backed up by an onboard small petrol generator.

Range 360 miles
Price £37k

Didn’t see Top Gear, but it sounds like most of our machinery at work uses a similar system, they’re diesel electric drives.

The engine is on the top (12-14 litre v6 turbo diesel) and just has a generator coupled almost directly off the end of the crank I believe. Four of the eight wheels are electrical driven all 8 wheels steer. The engine has 2 speeds idle and Go! The hoist and hydraulics are all electrically driven too, our newest ones have energy recovery systems also from breaking and lowering the containers etc a bit like a Prius. MPG is still shocking though, improving but they’re big machines with heavy loads.

[Edit]They don’t use batteries as such but do have some form of giant capacitors for short term storage[/Edit]

If they have got all the generation and conversion losses down to the point where they’re equal to or less than efficiency of a conventional combustion and transmission setup that’s genuinely impressive. Thermodynamics, innit.

Additionally you have the additional weight of the batteries to contend with.

If you can get in it with empty batteries and drive further than you could in a conventional car, it’s a winner.

In fact why not get rid of the majority of the batteries and just drive the motor more or less straight off the alternator if it’s that good? Would save a lot of raw materials and charging points…

oliverd1981 yep that’s what our straddle carriers do pretty much, the first diesel electric drives came in here about 6 years ago ish
they are becoming more refined though

I think this is at the moment the most clever solution. Instead of having a 2.5 tons sports car you could use a one ton 106 like car powered using the same technology. But with for example a 125 2 stroke engine or even as stoner suggest a stirling motor.

I thought that sort of technology had been around in ships for years – first it was steam turbines generating electricity for the motors that drive the prop shafts (eg USS Saratoga from WW2) and then it went to diesel engines then to gas turbines. I just assumed the car thing was a breakthrough in packaging the system for better size & weight.

I thought that sort of technology had been around in ships for years

And trains.

Two main advantages as I see it – you can run your combustion engine very efficiently – a small engine running flat out to produce 40 hp is more efficient than a large engine running on part throttle producing 40 hp and you can go to a zero tailpipe emissions in towns using batteries.

I thought that sort of technology had been around in ships for years

Perhaps the motor industry, being obsessed with trying to make viable all-electric cars, missed the blindingly obvious solution of having an on-board petrol/diesel generator…

In fact why not get rid of the majority of the batteries and just drive the motor more or less straight off the alternator if it’s that good?

The issue is variable demand. A car needs large amounts of power to accelerate for short periods, but only a little to cruise. So the battery stores extra power and can deliver it instantly when needed. This is how Prius and other parallel hybrids work, just a small battery for a little boost.

The principle is still the same for the Ampera even though it’s a series hybrid, but the drivetrain is powerful enough to work on electricity only, and you can charge it at home. It has a 40 mile electric range so you could commute in it and drive to town all year long and never need any petrol.

The main difference between the trains and this is that in this car the engine isn’t needed all the time.

Perhaps the motor industry, being obsessed with trying to make viable all-electric cars, missed the blindingly obvious solution of having an on-board petrol/diesel generator

The Ampera has been in development for absolutely ages, almost a decade, they had endless troubles with the batteries apparently.

I think this is why Prius only has a small battery with simple tech. I don’t think Toyota missed much – they were working on electric cars in the Clinton years and the original Prius (which is a generator as well as traction motor) came out in 1997 so it must’ve been in development from the same time at least.

The UK Navies new T45 Destroyers are diesel electric –
Gas turbines turning an alternator, which produces electricity, which in turn powers the propulsion motors..

Main advantages are –
Simplicity (no gearboxes etc)
100% torque from zero revs
Better weight distribution (generator sets are remore from propolsion motors etc)
Reliability (any of the 4 ‘prime movers’ can be configured to produce electricity used by either of the propolsion motors) so if one ‘engine’ dies, you just switch over to another one..

The reason diesel trains are series hybrids is because they could never make a clutch strong enough.

The little petrol engine that it uses isn’t very efficient 35.7L (8.25 gallons) capacity and has a total driving range of 300 miles and that includes 50 miles on the batteries. Ok it might be economical for its speed/power but its not as good as I was hoping. That means it does about 30 to the gallon!

And why would the need a

2.0L turbocharged direct injection 4-cyl gasoline engine

it seems a little overkill.

The way the Fisker works is the real world solution to the problem of electric vehicles. No worries about finding a charging point as you’ve got one on board. For many people the 50 mile electric range is plenty for the majority of the journeys they do. If you need to go further it is not an issue. The only problem now is the weight and predicted life of the batteries. I reckon we are about 5 years away from the first EV that will actually compete with an efficient diesel.

If they can get it working, Jaguar/TATA/Bladon Jets micro gas turbine solution looks promising…
Jaguar Concept

And why would the need a

2.0L turbocharged direct injection 4-cyl gasoline engine
it seems a little overkill

Yeah, the Ampera is an Atkinson-Miller 1.4l NA engine afaik. A lower power engine won’t make the car any slower (that’s dictated by the electric motors and the battery) but it will mean you can’t thrash it for as long before it slows down.

The way the Fisker works is the real world solution to the problem of electric vehicles

It is if you ignore cost.