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Militant EV driver!
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Interesting presentation I came across.

http://www.altairhtc.com/europe/EHTC201 ... resent.pdf

But I totally disagree with the long term goal of hydrogen. A complete waste of energy, as detailed here: http://www.efcf.com/reports/E21.pdf


I went to a supplier meeting today. I asked if I could plug in, which I could. There was so much interest that it got held up for 20 minutes while I explained the car to them and gave the guided tour. When I left, half the office turned out.

The car sells itself.
 

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Very interesting power flow diagrams, in that they include a path by which the engine (labelled as such!) can supply power to the transaxle. Just as if GM had never insisted otherwise.

The Voltec drivetrain, as I understood it, was designed so that different powerplants could easily be used ie they could fit fuel cells if they ever became viable, or with next year's Volt, a more powerful petrol engine.
I guess that means the surplus of Astra engines is about used up
 

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Why are they using a more powerful petrol engine? I tbought range extenders were going smaller and three cylinder?

The new Ford 1.0 3 cylinder in the Focus would be great RE engine - fits on a page of A4!
 

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Discussion Starter #4
I'm not aware of next year's Volt getting a more powerful petrol engine. It's getting 10% more battery range but nothing on the petrol side is changing.

However, GM has announced that the small engines like our 1.4l (Family 0) which are getting long in the tooth will be updated in the not too distant future.

If we're keeping this engine for a bit, the HCCI version seems like a good interim step. In the longer term, direct methanol fuel cells would be a good choice. Methanol can be distributed via existing infrastructure. (Hydrogen has so many problems, it's just the gold at the end of the rainbow.)
 

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proddick said:
Why are they using a more powerful petrol engine? I tbought range extenders were going smaller and three cylinder?
The new Ford 1.0 3 cylinder in the Focus would be great RE engine - fits on a page of A4!
A range extender has to be able to run the car for the duration when there is no extra capacity available, ie for hour after hour on the motorway at top speed. - that is the design minimum that you are looking for, and why the Ampera needs a 74bhp engine. If you can't get the drag coefficient down low then you need a bigger range extender.

This also applies to Fuel cell extenders, which I think will come, but I think Methanol is the way to go over Hydrogen. Methanol is similar materials handling-wise to petrol so would be a relatively easy change to roll-out. and methanol fuel cells are already quite advanced. in fact pretty much ready to go, but I think all this talk of Hydrogen is preventing someone from taking the first step with Methanol.
 

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I agree, hydrogen is a dead end for public uses. I do think that it might find niche uses for fleet or other commercial uses where the issues of generation/transport/storage/safety are easier to solve especially on a larger scale, but for normal car use I really don't see it happening.

As others have said, the range extender needs to produce enough electrical power to run the motor at full speed/power. That means it must be man enough to generate that much power as a normal petrol engine if it is to produce that much electricity... if fact because there are losses in the generation process it typically should be bigger! In fact, the Ampera petrol generator is not big enough to do that. It is only 75hp... the electric motor is about 150hp. That is why MOUNTAIN mode exists. To make sure that the battery has some power still remaining should the car go up steep hills and need more electrical power than the generator can provide on its own.

So already the generator is smaller than the max power needed. To go even smaller with an even less powerful generator would mean that the MOUNTAIN mode would probably need to hold back even more battery power. Also, to absolutely max power available would be down too because at high power/speed the electric motors and generator all contribute. If the batteries and electric motors remain the same but the generator engine was reduced in power so the overall max power would be down.

The type of configuration of the Voltec System pretty much requires that the generator be of a significant size to deliver the power when it is needed. However, a different configuration with a much smaller generator engine could be employed but it would need to then rely more on battery power at all times to deliver max power. Perhaps longer term, that is the way to go anyway... larger batteries, more powerful motors but smaller generator which is used more to charge/top up batteries than is the case with Voltec which uses the generator more to directly power the motors in normal driving.
 

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The Ford 1.0 produces 99 bhp even in lower spec. Going to a smaller and lighter engine seems sensible to me.

Perhaps in the US GM perceives that a 1.4 litre engine doesn't market well?
 

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I agree that there must be a better option that the Astra 1.4 that is used today but it will always still need to be a fairly hefty lump or it won't power the car!

I suspect that they had a manufacturing capacity for the 1.4 and that that may have had a significant bearing on which engine was used initially. If it wasn't that then perhaps some other commercial consideration rather than it being a design issue. I expect a smaller and more suitable engine to be incorporated into later models of car that uses Voltec.
 

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proddick said:
The Ford 1.0 produces 99 bhp even in lower spec. Going to a smaller and lighter engine seems sensible to me.
You have to bear in mind if that 99bhp is within the engine efficiency band or if that is full tilt/max power, if the little 1.0 revs to 8000rpm to give 99bhp and the 1.4 delivers 99bhp at 4000 revs then you can see which is more efficient (ignoring weight considerations - which we shouldn't but I don't have enough figures on the cost of weight!)
 

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BTW, I understand the technology folks - I have been following the tech since before it was launched in the US Volt. Remember too that the Opel engineers could not find a single mountain in Europe that needs mountain mode!

In reality, the main impact of the current engine is to limit top speed performance. The current 100mph is mainly dictated by the power required to overcome the increasing drag at higher speeds. Increasing the engine power would allow then to increase this, but is a higher top speed necessary?

A more powerful engine won't improve acceleration as that is limited by the current motors.
 

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Parax said:
proddick said:
The Ford 1.0 produces 99 bhp even in lower spec. Going to a smaller and lighter engine seems sensible to me.
You have to bear in mind if that 99bhp is within the engine efficiency band or if that is full tilt/max power, if the little 1.0 revs to 8000rpm to give 99bhp and the 1.4 delivers 99bhp at 4000 revs then you can see which is more efficient (ignoring weight considerations - which we shouldn't but I don't have enough figures on the cost of weight!)
To be clearer I should have said it is the Fuel Consumption to achieve required power, that is important to greener vehicles. the lil' 1 litre maybe able to produce the power but at what fuel cost? hence a bigger engine might be more efficient if it can produce the same power with less fuel, the 1.0 verses 1.4 is not indicative of fuel consumption, the revs and capacity together will give an indication of the combustion volume over time
 

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Obviously it isn't of much use to the driver when driving an Ampera but it would be interesting to have a tacho and see the RPM at different stages of operation :)
 

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I don't have figures to hand, but I would expect a newer tech engine to be more efficient and most of the time run well within its power band. Remember too that at higher speeds the mechanical connection from engine to drivetrain improves the efficiency of running on petrol.

The Volt concept used a 3 cylinder engine but I suspect the financial woes prevented development so they went with what they had. However, I think they did a brilliant job, at lower power output you can barely hear it.

The Ford engine won 2012 new engine of the year. Voltec won green 'engine'
 

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In a range extender, using an engine with a flat torque curve is desirable to match petrol output with required electric demand. For the Ford 1.0 they state

Maximum torque of both power output versions is 170 N·m (125 lb·ft)—10 N·m (7.3 lb·ft) better than the 1.6-L. The EcoBoost’s torque curve is remarkably flat, producing the maximum figure from 1400 to 4000 rpm for the 73.5-kW version
As it took Ford 5 years to develop this engine, hopefully GM have been quietly plugging away at something new.
 

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Discussion Starter #15
if fact because there are losses in the generation process it typically should be bigger! In fact, the Ampera petrol generator is not big enough to do that. It is only 75hp... the electric motor is about 150hp. That is why MOUNTAIN mode exists. To make sure that the battery has some power still remaining should the car go up steep hills and need more electrical power than the generator can provide on its own.
This isn't strictly true. You only need about 50 bhp to move a car the size of the Ampera at 80 mph on the flat. So the current 74 bhp ICE is plenty big enough for that.

When you go uphill for a bit, or accelerate hard, then you may need more than 74 bhp. The 150 bhp electric motor then dips into the battery buffer that is built up for this purpose (if I remember correctly it is 6% of the full battery).

Mountain mode is only needed for when you are going to climb a hill that will require more than 74 bhp for longer than the buffer can supply it for. It is reckoned there are no hills in the UK that need this.

The only other time I saw the buffer deplete in CS mode was when I had to go over a series of speed bumps. The regen was not recuperating enough to compensate for the energy needed to accelerate and on the 4th, the engine revved right up.
 
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