RE: Hybrids are the 'next diesel': Tell Me I'm Wrong
Discussion
The mk4 Prius's drivetrain is enormously impressive; anyone with any interest in cars at a technical level should try to understand how it works.
Basically the engine runs constantly at WoT (I'm not even sure if the engine actually has a throttle?) regardless of load at the wheels; the drive-train then moves the RPM up and down the range and uses the motor/generator unit to brake/drive the system as required to give the correct power for the demand being placed on the overall system by the driver. This means that the engine is running at pretty much peak efficiency all of the time; and of course it being Atkinson-cycle rather than Otto-cycle, peak efficiency is higher than it would be on other engines.
The overall result is an end-to-end power-train efficiency under almost all circumstances of >30% where other cars will struggle to average 15% in mixed use.
Basically the engine runs constantly at WoT (I'm not even sure if the engine actually has a throttle?) regardless of load at the wheels; the drive-train then moves the RPM up and down the range and uses the motor/generator unit to brake/drive the system as required to give the correct power for the demand being placed on the overall system by the driver. This means that the engine is running at pretty much peak efficiency all of the time; and of course it being Atkinson-cycle rather than Otto-cycle, peak efficiency is higher than it would be on other engines.
The overall result is an end-to-end power-train efficiency under almost all circumstances of >30% where other cars will struggle to average 15% in mixed use.
I bought a BMW 330E for the low C02 because it meant it drastically reduced the company car tax I paid, no other reason.
But it's actually quite an impressive bit of tech, and I can drive to and from work every day 90% on electric.
Once its out of electric though it just a normal petrol car carrying a load of extra weight.
So if you do a commute more than 11 miles, it's a pointless car!
But it's actually quite an impressive bit of tech, and I can drive to and from work every day 90% on electric.
Once its out of electric though it just a normal petrol car carrying a load of extra weight.
So if you do a commute more than 11 miles, it's a pointless car!
buggalugs said:
Yeah that Porsche number makes no sense at all
Also why apply fairytale conversions to some of the cars but not others?
Re Porsche:Also why apply fairytale conversions to some of the cars but not others?
I agree, the quoted consumption for the porsche makes no sense, thats why I applied a conversion to get to a real world figure based on the electric-only range that previewers of the car have achieved, resulting in my estimate of 0.162 x 50/38 = 0.213 kWh/km
Re BMW i3:
The electrical consumption for this is based on EPA measurements, which I consider to be much closer to the real-world performance of the car, hence the absence of a fairytale-factor for this car. However the quoted EPA consumption is in kWh/mile which is misleading if compared directly with the Porsche, but the unit-equivalent is 0.181 kWh/km.
So the numbers suggest that the BMW is more efficient than the porsche, which common sense would suggest. The porsche is quite a lot heavier, but the beauty of energy recuperation in electric cars means that a heavier car is not penalised proportionately, depending of course on the driver behaviour and the terrain. Porsche sports cars are generally quite aero-efficient (for both Cd and A parameters) and so the CdA for the porsche is probably not drastically different from that of the BMW. The Porsche will of course probably suffer due to things like bigger tyres and internal friction losses.
I'm sure that my rough calcs are only good to about +/- 30% at best, but the point is that a car with electric propulsion makes a lot of sense in overall emission terms (either tailpipe or end-of-stack), even a hybrid Porsche with a big heavy engine. So if you really want to splash out on a new car and if you can accept the limitations of driving the car in full electric mode for most of the time then I would consider it to be a good compromise in environmental terms given current battery and recharging limitations (in short, Dan - you're wrong!)
Oh so wrong it's untrue. You hit the Outlander, we are on our second one. 12,000miles and an average in some months of 180mpg. Not bought just on emissions. Then Dan aligns it to diesels which are carcinogenic, a fact known even when the government was pushing it. Something you can't align to petrol hybrid.
The only future problem with electricity is the ability for our country to provide enough of it.
Not all hybrid sports cars have massive engines, and those using the technology responsible (BMW) are proving just that.
The only future problem with electricity is the ability for our country to provide enough of it.
Not all hybrid sports cars have massive engines, and those using the technology responsible (BMW) are proving just that.
peklim said:
I have a X5 PHEV & it has saved me a fortune in petrol. I buy petrol every couple of months now as opposed to at least weekly before, which admittedly was with a E61 M5.Buying a PHEV & not plugging it in,ideally at both ends of the journey,makes no sense.
I was appalled by the X5 PHEV it was terrible compared to my Outlander. I had the X5 for a week and used as much petrol in one week as my Outlander uses in one month.kambites said:
The mk4 Prius's drivetrain is enormously impressive; anyone with any interest in cars at a technical level should try to understand how it works.
Basically the engine runs constantly at WoT (I'm not even sure if the engine actually has a throttle?) regardless of load at the wheels; the drive-train then moves the RPM up and down the range and uses the motor/generator unit to brake/drive the system as required to give the correct power for the demand being placed on the overall system by the driver. This means that the engine is running at pretty much peak efficiency all of the time; and of course it being Atkinson-cycle rather than Otto-cycle, peak efficiency is higher than it would be on other engines.
The overall result is an end-to-end power-train efficiency under almost all circumstances of >30% where other cars will struggle to average 15% in mixed use.
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!Basically the engine runs constantly at WoT (I'm not even sure if the engine actually has a throttle?) regardless of load at the wheels; the drive-train then moves the RPM up and down the range and uses the motor/generator unit to brake/drive the system as required to give the correct power for the demand being placed on the overall system by the driver. This means that the engine is running at pretty much peak efficiency all of the time; and of course it being Atkinson-cycle rather than Otto-cycle, peak efficiency is higher than it would be on other engines.
The overall result is an end-to-end power-train efficiency under almost all circumstances of >30% where other cars will struggle to average 15% in mixed use.
amgmcqueen said:
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!
Who says it does 48mpg?http://www.honestjohn.co.uk/realmpg/toyota/prius-2...
Edited by Evanivitch on Thursday 23 March 22:25
Evanivitch said:
amgmcqueen said:
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!
Who says it does 48mph?http://www.honestjohn.co.uk/realmpg/toyota/prius-2...
AnotherClarkey said:
Evanivitch said:
amgmcqueen said:
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!
Who says it does 48mph?http://www.honestjohn.co.uk/realmpg/toyota/prius-2...
raspy said:
Same here. My last tank showed 66mpg on the dash, was actually 63mpg. I've never gotten lower than 55mpg average for a tank, even when it was cold this winter. Those running the car in hot climates are getting far more than those in Europe. Sounds to me like those that don't own a hybrid have misperceptions of what hybrids can and cannot do.
Even in the days of the Mk2 Prius the overall average economy equalled that of the contemporary Golf Bluemotion. I looked up Spritmonitor data for today's 1.6 Golf Bluemotion and the Mk4 Prius now seems to use about 18% less fuel overall (and burns a fuel that contains over 10% less energy in the first place). That seems like decent progress.liner33 said:
herewego said:
amgmcqueen said:
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!
Do you have a reference for this 48mpg?
liner33 said:
herewego said:
amgmcqueen said:
If that is the case why does it only average 48mpg? Let's not forget it also costs the best part of £30k!
Do you have a reference for this 48mpg? yourself...My next door neighbour has a gen 3 and is forever complaining about the poor consumption compared to my Golf. He actually gets more around 45mpg which I think is very poor.
As diesel will soon be on the way out I was intrigued to find out more about hybrids and see if they are a viable alternative?
This site also seems to confirm what he is saying:
http://www.fuelly.com/car/toyota/prius
Maybe the latest version is better but like I say considering it costs twice as much as a normal family car, how many miles would you need to cover to start seeing the benefits?
amgmcqueen said:
yourself...My next door neighbour has a gen 3 and is forever complaining about the poor consumption compared to my Golf. He actually gets more around 45mpg which I think is very poor.
As diesel will soon be on the way out I was intrigued to find out more about hybrids and see if they are a viable alternative?
This site also seems to confirm what he is saying:
http://www.fuelly.com/car/toyota/prius
Maybe the latest version is better but like I say considering it costs twice as much as a normal family car, how many miles would you need to cover to start seeing the benefits?
amgmcqueen said:
My next door neighbour has a gen 3
You've answered your own question then, the gen-3 has a completely different drivetrain. Although none of the owners I know get economy anywhere near that bad. By the way, fuelly is an American site so those figures are in US MPG by default. Alternatively compare it to diesels; even the gen-3 Prius comprehensively beats contemporary 2.0 diesel Golfs.
Edited by kambites on Friday 24th March 21:08
amgmcqueen said:
yourself...My next door neighbour has a gen 3 and is forever complaining about the poor consumption compared to my Golf. He actually gets more around 45mpg which I think is very poor.
As diesel will soon be on the way out I was intrigued to find out more about hybrids and see if they are a viable alternative?
This site also seems to confirm what he is saying:
http://www.fuelly.com/car/toyota/prius
Maybe the latest version is better but like I say considering it costs twice as much as a normal family car, how many miles would you need to cover to start seeing the benefits?
No diesel clatter
Big spacious well equipped car
Silent
Vaguely know someone who runs a local taxi company with ~300 self-employed taxis on the books. Having spoken with him socially a few times, he says almost all the local taxi drivers have shifted to the Prius in the past ~5 years. He reckons they save quite a bit of money on local pick-ups around town (5-10 miles), but make almost no difference on longer journeys between towns compared with good diesel or petrol cars (10-100 miles).
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