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Sun 18 Jul 2010 22:25

why doesn't anyone develop something like this? - likerocks

A different take on hybrid technology......

A car with wholly electric drive with the power and talk equivalent of (say) a modern 1.6 turbo diesel at least.

Electricity for steady state running (and by that I mean enough for steady-state motorway speeds) generated by a small, simple, quiet petrol/diesel/biofuel generator.

Reserve power for (say) 60 seconds of full bore acceleration provided by batteries charged by main generator when not under full load / regenerative braking.

Without knowing specifics about energy density, charging rates, electric motor performance etc, I would have thought this would provide the answer to a lot of problems relating to heavy "full hybrid" drivetrains and large battery packs. By making the drive electric only, no gearbox would be required and the generator would be decoupled from road speed meaning that it could run at its most efficient settings all of the time.

Driver controls could determine parameters like electric-only running for short periods or adjust the amount of battery reserve to be maintained for economy or performance.

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Mon 19 Jul 2010 16:11

why doesn't anyone develop something like this? - craig-pd130

I've often wondered why manufacturers don't take exactly the approach you've described.

However I will be very interested to test drive the new Peugeot Hybrid4 cars when they come out next year. They've taken a simple and direct approach which seems to work well.

www.telegraph.co.uk/motoring/carreviews/6061771/Pe...l

Apparently this drivetrain will be available in the new 508 saloon / estate and the MPVs, and in 'sport' mode will give combined output of 200bhp / 370lb-ft in short bursts for overtaking etc

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Mon 19 Jul 2010 16:24

why doesn't anyone develop something like this? - madf

"Electricity for steady state running (and by that I mean enough for steady-state motorway speeds) generated by a small, simple, quiet petrol/diesel/biofuel generator."

If you theink it through, at motorway speeds, the engine will be driving the generator flat out just to keep running.. So you will need a LARGE generator...and your engine will be neither simple nor small...

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Mon 19 Jul 2010 16:33

why doesn't anyone develop something like this? - Lygonos

If I remember correctly, to maintain a car at 60-70mph requires something like 25-30bhp - this doesn't in itself require a large engine (an unstressed 400-500cc unit can manage this), but as madf says - to produce this in electricity terms would need a big generator (~15-20kW - perhaps the equivalent of 20-30 alternators) running a sizeable electric motor.

Improvements in battery/motor/generator technology are always being made but they are not cheap, and a very significant amount of energy is required to create the vehicle in the first place.

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Mon 19 Jul 2010 16:24

why doesn't anyone develop something like this? - Lygonos

"Without knowing specifics about energy density, charging rates, electric motor performance etc, I would have thought this would provide the answer to a lot of problems relating to heavy "full hybrid" drivetrains and large battery packs. "

There's your problem ;-)

Remember, having an engine generating electricity that then runs an electric motor will generally be less efficient than having the engine hooked straight to the wheels.

ps. it's 'torque' not 'talk'.

Saracasm aside, you are obviously aware of the various problems when making a 'hybrid' vehicle. This is where various manufacturers will vary their approaches.

Because of the USA-centric view of the current hybrid-tech leaders (Toyota and Honda) petrol-electric are the hybrids of choice. From a thermo-dynamic perspective (ie. maximum efficiency) a diesel-electric would be the better option. These are in development by some Euro makers at present. Expect 100+mpg (at least in the emissions/economy tests!) when these hit the road.

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Mon 19 Jul 2010 16:49

why doesn't anyone develop something like this? - Sofa Spud

As long as it works properly and delivers the claimed benefits, I think the range-extender hybrid (like the Chevrolet Volt) will become the leading type.

This is basically a battery electric car with a petrol-engined generator that starts up to keep the battery topped up after about the first 40 miles on battery power alone. The primary source of power for the car is from charging the battery from the mains overnight.

Of course, a range-extender could be made even more efficient if the petrol engine, as used on the Volt, is replaced by a diesel.

QUOTE:...""Remember, having an engine generating electricity that then runs an electric motor will generally be less efficient than having the engine hooked straight to the wheels."" Yes, but if it's done in conjunction battery propulsion and regenerative braking, then it's more efficient for most of the time - the exception being prolonged high-speed cruising.

Edited by Sofa Spud on 19/07/2010 at 16:51

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Mon 19 Jul 2010 17:29

why doesn't anyone develop something like this? - jc2

There are two types of hybrid-parallel and series.Series are the ones that have an i.c. engine that can be assisted by a battery powered electric motor and the battery can be charged usually by running the electric motor as a generator(for example-Lexus).A parallel type type uses battery power to an electric motor and the battery is charged by the i.c. engine-this type can run on either power source.ie.it can run on battery or i.c. engine.(for example-Prius). It appears that the OP is suggesting a petrol/diesel electric vehicle.

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Mon 19 Jul 2010 18:03

why doesn't anyone develop something like this? - davecooper

Jaguar are currently working on a drivetrain that uses a miniature gas turbine driven generator in an electric vehicle. This is to be used as what they call a "range extender", presumably to back up and charge the batteries. The gas turbine is being developed on the Isle of Man apparently.

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Mon 19 Jul 2010 20:31

why doesn't anyone develop something like this? - daveyjp

Jaguar are working on a system which uses updated batteries and a small back up engine.

Batteries allow 30 miles at up to 50mph and then when required a three cylinder 1.2 petrol engine fires up which provides direct electricity for a brushless motor (194bhp and 400 Nm torque) and also recharges the batteries. Car can also be recharged using domestic power outlets.

At 80mph 28kw powers the motor for traction and 7kw recharges the battery. Press on and the power reduces to ensure charging still takes place.

1200 miles from a tank of fuel at 57mpg.

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Mon 19 Jul 2010 23:20

why doesn't anyone develop something like this? - Leif

I'm rather sceptical about these hydrids. The problem is the weight of the batteries and the electric motors in addition to a conventional engine. So on longish journeys it is far more efficient to have the conventional engine on its own. On shorter journeys it might be a bit better due to regenerative braking, but overall? And the space inside must be reduced. Oh, and add on the extra cost of the batteries and motors and the extra maintenance, and the associate resources needed to make the batteries and motors, and you have to ask if it really is a good idea, or just a way to make us feel good inside about supposedly being green. Perhaps a cheaper and better approach would be to have more efficient engines (possible?) and lighter cars using composites and/or plastics instead of steel.

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Mon 19 Jul 2010 23:32

why doesn't anyone develop something like this? - corax

and lighter cars using composites and/or plastics instead of steel.

Thats the way forward. Cars are so heavy now. Combine lightness with efficient new engines, and the cars would be faster, more economical, and better handling. Combining lightness with crash resistance and doing it at reasonable cost is the key. I'm not keen on the looks of the new car Gordon Murray has designed, but his concepts are the way forward.

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Tue 20 Jul 2010 09:25

why doesn't anyone develop something like this? - Leif

I'm not keen on the looks of the new car Gordon Murray has designed, but his concepts are the way forward.

It looks like a nice shopping trolley and town car. Maybe a bit small for long journeys though. I wonder what comfort is like. Far better than any electric/hybrid surely.

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Tue 20 Jul 2010 20:07

why doesn't anyone develop something like this? - daveyjp

The Jag system fits into the current XJ bodyshell - most of the extra drivetrain equipment going where the autobox currently sits. No loss of any interior space.

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