Cars engines that 'turn off' when in stationary traffic

Company fuel cards will waste more fuel than ‘Start Stop’ will ever save.
How do you work that out ?

Cos people aren’t paying for their fuel, they waste it by driving fast.

Re better mpg at higher speeds – I have heard it reported by owners of big petrol cars. The more you close the throttle on a petrol car the more inefficiency created by pumping loss. So if you have a big V8 and you want to drive at 60 you have to have a tiny throttle opening, the inefficiencies of which outweigh the extra drag of the extra speed.

My Passat seems to be worse on fuel or at least no better than 60mph if you drive below about 45mph which is below 1.5krpm in top I suppose. I’ve heard it said that the lower the revs the longer each combustion stroke holds hot gasses in the cylinder so the more heat is transferred to the cylinder walls and out the back door via the coolant. Dunno how slow that woul dhave to be though.

I had a hyundai like that , was most efficient at motorway speeds at 4100rpm 1.6 16v petrol

Happened to be about 78 on the speedo so probably 70 in real life.

All depends on the power and torque curves of the car.

**** rubber band powered car , my next car will sit on motor way at 3k or less

I’ve skim read some of this stuff.

I feel that Stop / Start has been rolled out to show that the industry is trying very hard to explore every possible avenue wrt fuel efficiency, reduction in emmisions, etc, etc.

My concern with S/S is with engine, lubricant and coolant temperatures and the effects on engine performance. But, as has already been pointed out, the OEMs have carried out all the analysis and testing needed to firstly ensure service life and reliability. So if you’re driving an S/S car, you should be fine.

OEMs don’t want loads of cars coming back to the dealer for warranty covered re-works of the stop / start on their cars. Not to mention the customer dissatisfaction that would errupt.
So, you have your stop / start tech now, it will filter down through the used car market and there will be many more of them, eventually.

I’d prefer not to have a car with this feature, but at worst, if I can deactivate it then its an acceptable compromise, in my view.

As for electric cars. Its a red herring, born of a bit of a Chicken and egg situation.
For years, OEMs looked to Governments for some indication of which auto-tech they wanted to see replace conventional petrol / diesel vehicles.
OEMs knew that if they played their cards right they might get a Gov to offer incentives to develop and sell cars powered by a particular technology / fuel source. You might argue that with Gov funding, you can probably make any fuel tech to work…

However, the Govs were looking at the OEMs, as experts in their industry, to advise the Government as for which alternative to conventional fuel, to advocate.

So, you had both sides looking at the other, for guidance on which fuel / technology to start throwing money at.

For now, we’ve kind of stumbled into the cul de sac of the electric powered car.
But imo, all electric powered cars do is relocate the emissions from the tail pipe, on the high street. To emissions from a power station, in some remote region of the country.
You may not burn as much petrol or diesel. But the chap in the power station is pumping much more gas, coal or radioactive material through that power station to meet increased demand for electricty to recharge ‘X’ millions of cars over night…

Honda have a hydrogen fuelled car on sale in the North American state of California. The Californians have / are investing in adding a hydrogen fuel distribution network within their state to facilitate refuelling of these hydrogen powered cars. However, as a global solution, I feel this is also a non-starter for reasons of cost.

However !, the fact that the hydrogen fuelled car can be driven 300 miles, refeulled in the same fashion as a conventional car, ie, in a few minutes at a refeulling pump. Then driven another 300 miles.
Is why it has been developed to the point of being sold to the public.
Its much easier and quicker to refuel compared to an EV. Making cars that are more difficult to and take longer to refuell. Is a step backwards.

My personal view is that fuel from GMOs processing conventional waste, will allow us to burn a fuel in our cars, which is a lot less harmful to the environment and will allow people to still use a personalized form of private transport such as conventionally fuelled cars provide for us today.

I believe work is already being carried out with GEN 2 GMOs for the specific purpose of producing fuel for vehicles. While cars have been running on methanol, for example, for many decades already.
I have also become aware of research which has demonstrated the capability to produce diesel from GMOs. But I’d rather see a more emissions friendly fuel being produced in this way.

As for fuel effeciency ?. Current cars could be more effecient. They could be adorned with Aero features which would enhance performance. But on the whole, make normal cars look ugly, imo.
Gearing would also play a part, but on current cars, is a compromise between fuel performance and dynamic performance. having to cater for those who want to tow a caravan, trailer or carry home from BnQ, umpteen bags of cement in the boot.
Theres also engine mapping. We’d all burn less fuel if the ECUs in our cars were mapped for maximum fuel effeciency, only. But that would probably mean like 0-60 in 22 secs, etc.

Modern cars are very much improved over cars from say, 25 years ago. Its good that we do not settle for what we currently have though and that we strive to improve the areas we think important. Safety, emissions, fuel economy and fuel type.
Pity though that, imo, we’ve lost time messing about with EVs.
But I have a feeling 😉 that things may have started to change.

Nothing to do with OP, but my 03 Ibiza is on 202k miles….original clutch, exhaust, dual mass flywheel, turbo, battery…
And I gave up on the 10k service intervals at about 115k miles. I now get it serviced every 15k miles.
Front discs & pads were first replaced at 119k miles so hoping to get to 240k on this set.

Not exactly disposable…

That’s because you obviously drive like my Grandmother.

Just to clarify, she is very dead.

But, as has already been pointed out, the OEMs have carried out all the analysis and testing needed to firstly ensure service life and reliability. So if you’re driving an S/S car, you should be fine.

OEMs don’t want loads of cars coming back to the dealer for warranty covered re-works of the stop / start on their cars. Not to mention the customer dissatisfaction that would erupt.

You seemingly have no idea of the sheer number of automotive recalls that occur, but then as most of these are done through routine servicing without the owner’s knowledge, why would you?

You seemingly have no idea of the sheer number of automotive recalls that occur, but then as most of these are done through routine servicing without the owner’s knowledge, why would you?

In the case of S/S, having a lot of cars that didn’t start again would see our roads littered with stranded drivers. So I’m fairly confident that S/S systems are quite well developed.

However, yes, I do have an idea about TSBs and other OEM re-works that filter down through to the dealer service network.

You see, I’ve spent 20 yrs designing cars for several OEMs. So, I’ve a fairly good idea of the development strategy and processes involved.
Thanks.
😉

Cos people aren’t paying for their fuel, they waste it by driving fast

bang on. Some companies send their staff on driving courses headlined as safety but with a very significant input on driving smoothly and efficiently. I commuted in a ‘job’ car for 2 years and got low 30’s mpg out of it, I eke high 40s out of my big lump of a diesel alhambra and drive like miss daisy. When its your credit card paying 90 quid a tank you notice!

there’s no such thing as “proper” driving

I deliberately used the quotation marks myself as I am referring to the police system of advanced driving, but I am aware that there are different approaches.

And if you really want to be an advanced police driver then it has flappy paddles for your corner-holding throttle situation.

…which was great as it gives the best of all worlds (proper throttle response and seamless gear changes) I was merely referring to my experience trying to “make progress” (another job euphemism) in full auto. I appreciate that’s not how the majority use it and for its intended purpose it makes driving easy.

sbob, are you 9?

And is your Dad the strongest Dad of all the kids in the playground?

If you were old enough to drive, I could just imagine you in the outside lane of the A14 during rush hour; accelerate, brake, accelerate, brake, accelerate, brake, accelerate, brake – three feet from the car in front getting nowhere fast but using loads more fuel & wearing your brakes while going the same overall speed as the grandmothers on the inside lane. Awesome driving…

Current cars could be more effecient. They could be adorned with Aero features which would enhance performance. But on the whole, make normal cars look ugly, imo.

If you go to the hypermiling forums (I think) they have a whole bunch of cars modded with fantastically ugly cardboard/perspex/estate agent board material, but they’re more efficient.

They could be adorned with Aero features which would enhance performance. But on the whole, make normal cars look ugly, imo.

It didn’t stop Toyota 🙂

Prius has the lowest drag coefficient of any production car. Someone has made a super streamlined blobby thing they are trying to get produced, pictures of it on youtube, but it’s a two seater and not much good for a family car.

You have to hand it to Toyota for raising the bar tbh. Very clever move, and bold investment, and it paid off. In the US, suddenly all manufacturers are forced to make cars that will do 50-60mpg, whereas previously 40 was considered excellent.

Grips.

Can’t say I agree on the Toyota thing. As before, an EV may remove pollution from the high street, but the energy has to come from somewhere.

Also, I remain sceptical about sitting in a tin box, in close proximity to power electric motors. TBF, there really are a lot of holes in the EV concept.

As for getting the U.S. to use fuel more responsibly, on the face of it, I can see how you came to that conclusion.

But as we’ve seen in the UK. Just increase the cost of fuel and the public will seek out more fuel efficient cars and not just because one manufacturer sells a hybrid. imo.

suddenly all manufacturers are forced to make cars that will do 50-60mpg, whereas previously 40 was considered excellent

OEMs were already making these cars, but they just weren’t sold in the US for various reasons. But you’re correct on the mpg thing. I’ve seen e-mails where the folk in the US are boasting about getting 23mpg from an SUV, like as if thats really good. Shocking really.

But imo, all electric powered cars do is relocate the emissions from the tail pipe, on the high street. To emissions from a power station, in some remote region of the country.
You may not burn as much petrol or diesel. But the chap in the power station is pumping much more gas, coal or radioactive material through that power station to meet increased demand for electricty to recharge ‘X’ millions of cars over night…

Honda have a hydrogen fuelled car

Where the hell do you think they get the hydorgen from? Hint… it either needs electricity or fossil fuels.

Where the hell do you think they get the hydorgen from? Hint… it either needs electricity or fossil fuels.

Nice, selective, quoting there Fletch….. 😉

Going a little OT by mentioning the Honda, I was merely pointing out that I do not believe Hydrogen fuel cell cars to be the future of motoring.
I was just expressing an opinion.
Calm down mate.

🙂

Can’t say I agree on the Toyota thing. As before, an EV may remove pollution from the high street, but the energy has to come from somewhere

Prius isn’t an EV though. It’s a normal car with much better FE than what was on the US market at the time. That’s what I meant by raising the bar.

But imo, all electric powered cars do is relocate the emissions from the tail pipe, on the high street.

Yes, but it’s more efficient to get energy from the grid, store it in a battery and then use it to power a car than it is to burn petrol in an IC engine. Equivalent CO2 with the current electricity generating mix in the UK is something like 30-40g/km CO2 afaik.

Of course, as we get more gas/renewables/nuclear that’ll come down.

Using power to generate hydrogen at the power station would remove grid and battery inefficiencies, so would probably be much more efficient again I’d think.

Prius isn’t an EV Its a Hybrid, employing an IC and an electric motor and battery pack. Even if you ran the IC on something such as Methanol, why have the electric motor but for urban emissions ?.
I am aware you are a Prius fan, and I’m not sure I have the time to explain to the degree that you would demand, why I think the Prius is a dead end. Sorry.
🙂

Yes, but it’s more efficient to get energy from the grid, store it in a battery and then use it to power a car than it is to burn petrol in an IC engine. Equivalent CO2 with the current electricity generating mix in the UK is something like 30-40g/km CO2 afaik.
Efficiency is a bit of a distraction. If the fuel is renewable an environmentally acceptable, then how much is used isn’t so much of an issue.

Of course, as we get more gas/renewables/nuclear that’ll come down.
Renewables was what I was referring to in my original post, when mentioning GMOs.
I’d hesitate to suggest the full term cost of using too much Nuclear power, as we have it currently.

Using power to generate hydrogen at the power station would remove grid and battery inefficiencies, so would probably be much more efficient again I’d think.

You’ve completely missed the issue. Please consider replacing every fuel pump on Earth, with one that handles liquid hydrogen. Every storage facility being stripped and re-fitted with the kit required to store liquid hydrogen and the list of infrastructure in place today to handle petrol / diesel having to be totally replaced, globally !.

Then consider the transportation of hydrogen, not to mention ramping up production of hydrogen to meet the demand of todays car useage.
Costs are prohibitive. Its not going to happen, imo.

Even if you ran the IC on something such as Methanol, why have the electric motor but for urban emissions ?

As I’m sure you know, two ways energy is wasted in a petrol car are pumping losses at the throttle body when cruising, and kinetic energy loss when braking. The parallel hybrid system can recover some of these losses by charging the battery under braking and also opening the throttle a bit more when cruising and siphoning of some energy for the battery. Then, when you have a full battery and you hit a traffic jam, you can use the battery to crawl along at 5mph with the engine off.

So it’s not a revolutionary concept, just a neat way of making a normal car more efficient. It’s always been considered a relatively small incremental improvement outside the marketing department.

You’ve completely missed the issue.

Well no, I’m not saying that hydrogen cars are the future at all. Someone else said that. I just said how it can be more efficient despite the fact that you still have to burn fossil fuels to get it.

If the fuel is renewable an environmentally acceptable, then how much is used isn’t so much of an issue

Well it is – renewables still have limited capacity, there is only so much wind/sunshine etc.

Sandwich – Member

We had an old (B Suffix) Polo that did this. Worked a treat, though it used to eat batteries in the winter.

VWs back to the 70’s had this – ‘Formula E’ it was called.

I agree with electronic hand brakes being gash.

Molgrips.
🙂

Well no, I’m not saying that hydrogen cars are the future at all. Someone else said that. I just said how it can be more efficient despite the fact that you still have to burn fossil fuels to get it.

Infrastructure and fuel handling is an major issue, I don’t think thats a point for debate. The cost to replace the global infrastructure currently in place to handle fossil fuels with an identical hydrogen handling infrastructure, whilst also considering also the carbon released and finance required to make all that kit, is prohibitively costly, financially and environmentally. I’d hardly describe this as a pathway to higher efficiency, especially when alternatives would be cheaper and easier to produce ?.

You also seem to be obsessed with efficiency, but having to produce and package an entire fuel cell in the trunk of a car, isn’t best use of package space within the vehicle. You need the fuel cell onboard and the fuel tank.

Well it is – renewables still have limited capacity, there is only so much wind/sunshine etc.

I didn’t write that it wasn’t an issue at all, just not as big an issue as being able to get off fossil fuels.

Grips, you know I work in this industry, as well as knowing that I can’t divulge specific details. If you want to keep believing in batteries and dreaming about electric cars, go ahead. Here.
😀

I’m not that comfortable with the whole stop/start thing. Nothing to do with any kind of informed opinion – I’ve just had too much experience of driving cars where you spend the entire journey fervently praying (to any divinity that might be passing) that the engine doesn’t cut out because there isn’t a hope in hell of getting the damn thing started again if it does.

You lot must have all had much better cars than me!

I find it strange that no one has mentioned the Nissan Leaf. Fully electric, very nice to drive, takes a family, has enough range for day to day use (100 miles ish) and made in Britain (soon!).

Grips, you know I work in this industry, as well as knowing that I can’t divulge specific details. If you want to keep believing in batteries and dreaming about electric cars

Wot? I don’t believe in them! I’ve said many times that I think the problems are too great.

Don’t get confused – I may point out the reasons or benefits of a particular idea, that doesn’t mean I think it’s the solution.

The solution to the world’s problems is far more complex than which fuel we use for our cars.

I find it strange that no one has mentioned the Nissan Leaf. Fully electric, very nice to drive, takes a family, has enough range for day to day use (100 miles ish) and made in Britain (soon!)

We’ve mentioned electric cars in general. The Leaf is a nice idea, but it’s a small local runabout, and costs almost £30k. Very few people are in the market for such a thing!

Solo – Member

In the case of S/S, having a lot of cars that didn’t start again would see our roads littered with stranded drivers. So I’m fairly confident that S/S systems are quite well developed.

However, yes, I do have an idea about TSBs and other OEM re-works that filter down through to the dealer service network.

You see, I’ve spent 20 yrs designing cars for several OEMs. So, I’ve a fairly good idea of the development strategy and processes involved.
Thanks.

I’m confused, are you saying that recalls don’t happen and that the manufacturers always get it right, or are you agreeing with me?
Thanks. 😉

stumpy01 – Member

sbob, are you 9?

And is your Dad the strongest Dad of all the kids in the playground?

If you were old enough to drive, I could just imagine you in the outside lane of the A14 during rush hour; accelerate, brake, accelerate, brake, accelerate, brake, accelerate, brake – three feet from the car in front getting nowhere fast but using loads more fuel & wearing your brakes while going the same overall speed as the grandmothers on the inside lane. Awesome driving…

Congratulations on having no sense of humour and a complete lack of comprehension. 🙂
Oh, and I’ll call bullshit on your pads lasting 120,000 miles.

Ps. try and avoid the A14 in rush hour. Then maybe you’ll be able to drive as efficiently as me. 💡

I agree with electronic hand brakes being gash.

Everyone says this, but no-one says why. I like mine.

And my car 55-plate car has just gone in for a service at 166k. It’s the 8th time it has been serviced, the oil doesn’t need topping up between services, it’s on the original clutch, and the only things that have gone wrong in that time are minor electricals (one of the heated seats, a door mirror heater).

I am happy with my electronic handbrake. It does a few useful things like if you open the door when the car’s in drive it applies it (my wife’s aunt saw some old biddy get dragged along the road and killed because she forgot to put the car in park before getting out, or it hadn’t fully engaged).

Also there’s more room for cups and storage etc in the centre console cos there’s no handbrake lever.

I think one reason people hate it in the Passat at least is that it’s meant to auto disengage when you drive off, which it does, but it takes a second. So what I do is either press the button myself or just tap the pedal before driving – that gives it time to disengage. Otherwise it gets a bit jerky. Second nature now though.

The big issue with the earlier ones is that they weren’t well weather sealed and failed a lot 🙁

sbob, call it what you like. I’m the one with the receipt for the service when the pads/discs were replaced. My mechanic was surprised too. They were done at 119k miles & I bought the car with 24k miles & fdsh. There had been no prior replacements. Car is now on 202k miles, so this set have done 83k miles.

With my job, A14 in rush hour is hard to avoid. But 60-64mpg when the traffic/weather doesn’t mess things up will do me.

Prius pads last for bloody ages, changed the rears at almost 90k, they were half gone. However the discs had corroded badly for the same reason the pads weren’t worn, so for the sake of a few quid I fitted new discs and pads all round.

That’s a car that needs stainless discs if there ever was one.

With the Pious, does the electric motor work as a brake, recovering energy to the battery and saving on pad/disc wear?

Yes.

Well, I’m going to find out soon enough whether this start/stop thing is any good; will be ordering a Skoda Fabia VRS some time this month…

Rachel

In the Pious (cough) all the power not used from the engine on braking charges up the battery, thats the only way the thing gets charged, you don’t plug it in the mains..

I’m not a fan of full electric cars, too limiting.

But BMW’s hybrids out next year could be worth looking at (but I’m now buying a CT200h) Look kinda smart and I think will kick start the looks department of cars for the future.

In the Pious (cough) all the power not used from the engine on braking charges up the battery, thats the only way the thing gets charged, you don’t plug it in the mains..

Kind of. The petrol engine stops whenever you lift off the throttle and is disengaged from the wheels altogether, and the computer dials in a little recharge too so it slows down slightly like a normal auto does.

If you are cruising at highway speed it’ll drag some energy from the petrol engine to put in the battery instead of using the throttle quite so much like a normal engine would. Until the battery gets full, then it just drives like a normal car but with really high gears

If you drive at say 30mph for more than a few minutes it’ll run on electric only mode for a couple of minutes then put the petrol engine back on for another couple of minutes and so on – again drawing energy from the engine to recharge the battery it used up when driving under electric mode. This is the most efficient cycle I think, you can get 85mpg ish easily enough, if you can find enough uninterrupted 30mph road 🙂 The Passat, by comparison, gets no better mpg doing 30mph in 4th as it does on the motorway.

And it does all that without any clutches or ocmplex gearboxes – just two electric motors and a planetary gear set. It’s really a fantastically clever bit of kit 🙂

My m3 has ‘brake energy regeneration’, sounds high tech, like some sort of F1 kers system for the road.

Its actually nothing of the sort, it just a system that disengages the alternator if you’re accelerating. BMW claim it improves fuel economy by 3%.

I only get an average of 20mpg overall, better fuel economy would be nice, but I dont want it if it comes at the expense of performance or throttle response.

I’ve moved from a 2.0 diesel Mondeo estate to a 1.6 diesel Focus estate with stop/start and have seemingly gone from around 40 mpg to 50 mpg.

The stop/start rarely gets used as I mostly drive on slow moving motorways and it only kicks in when you put it in neutral.

I see where Molgrips is coming from regarding fuel cards as if you pay for your private milage you pay a fixed amount based on engine size (I pay 12p per mile set by HMRC) so there is no motivation to drive economically if you pay the same at 40mph as at 80mph.