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TfL to possibly buy 200 extra New Bus for London
Recliner wrote:
It's only a matter of time before all cars are automatics: with more ratios, they're more fuel efficient and perform better than manual transmissions. In fact, many high performance and almost all Eco cars are now auto-only. The manual gearbox is going the way of the manual choke, carburettor, starting handle, etc. It's almost 30 years since I switched to automatics, and I wouldn't dream of going back. Finding a US rental car with a manual transmission in the US is near impossible outside of certain specialist vehicles. This also reflects the private vehicle market as even cars offered with supposed "manual" transmissions are really automatics with paddle shift switches. In the UK, it seems to be quite different and I'm not sure why. |
TfL to possibly buy 200 extra New Bus for London
On Sun, 26 Oct 2014 05:07:58 -0600, Arthur Conan Doyle
wrote: Recliner wrote: It's only a matter of time before all cars are automatics: with more ratios, they're more fuel efficient and perform better than manual transmissions. In fact, many high performance and almost all Eco cars are now auto-only. The manual gearbox is going the way of the manual choke, carburettor, starting handle, etc. It's almost 30 years since I switched to automatics, and I wouldn't dream of going back. Finding a US rental car with a manual transmission in the US is near impossible outside of certain specialist vehicles. This also reflects the private vehicle market as even cars offered with supposed "manual" transmissions are really automatics with paddle shift switches. Isn't it still possible to buy at least some sporty cars with traditional stick shifts in the US? But, certainly, the mainstream and rental markets abandoned the stick shift a long time ago. I wonder how many American drivers would be able to use a clutch pedal? In the UK, it seems to be quite different and I'm not sure why. Autos are usually more expensive, and traditionally had higher fuel consumption. As cars and fuel are already much more expensive in the UK than the US, I suppose this is a significant factor with the small cars that are more popular here than in the US. But with the pressure for cleaner, more economical cars, auto transmissions will become the norm here, too, as computers can control the (larger number of) ratios better. |
TfL to possibly buy 200 extra New Bus for London
On 26/10/2014 11:32, Recliner wrote: On Sun, 26 Oct 2014 05:07:58 -0600, Arthur Conan Doyle wrote: Recliner wrote: It's only a matter of time before all cars are automatics: with more ratios, they're more fuel efficient and perform better than manual transmissions. In fact, many high performance and almost all Eco cars are now auto-only. The manual gearbox is going the way of the manual choke, carburettor, starting handle, etc. It's almost 30 years since I switched to automatics, and I wouldn't dream of going back. Finding a US rental car with a manual transmission in the US is near impossible outside of certain specialist vehicles. This also reflects the private vehicle market as even cars offered with supposed "manual" transmissions are really automatics with paddle shift switches. Isn't it still possible to buy at least some sporty cars with traditional stick shifts in the US? But, certainly, the mainstream and rental markets abandoned the stick shift a long time ago. I wonder how many American drivers would be able to use a clutch pedal? In the UK, it seems to be quite different and I'm not sure why. Autos are usually more expensive, and traditionally had higher fuel consumption. As cars and fuel are already much more expensive in the UK than the US, I suppose this is a significant factor with the small cars that are more popular here than in the US. But with the pressure for cleaner, more economical cars, auto transmissions will become the norm here, too, as computers can control the (larger number of) ratios better. The issue highlighted upthread of the potentially astronomical cost of fixing an automatic if it goes wrong is also a consideration. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 11:07:58 +0000, Arthur Conan Doyle said:
In the UK, it seems to be quite different and I'm not sure why. Europe in general, not just the UK. I would think a few reasons... - Old style fluid-coupling slushboxes were less fuel efficient; fuel has always been expensive in the UK and Europe, while in the US it is fairly cheap. - Old style boxes were considered unreliable (and probably were). - Old style boxes were sometimes a little clunky and sapped power, an issue when for fuel consumption reasons we don't, unlike the US, put 4+ litre V8s in everything. None of these are really true now - modern boxes are efficient and reliable - and it's easier to build an automatic hybrid than a manual one (though there are a few manual parallel hybrids on the market). So I think we will increasingly see a move to automatics. There is the "with a manual you get better control" thing, but most drivers drive not for the experience but for getting from A to B, so that isn't a massive concern to them. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 11:32:55 +0000, Recliner said:
Autos are usually more expensive, and traditionally had higher fuel consumption. As cars and fuel are already much more expensive in the UK than the US, I suppose this is a significant factor with the small cars that are more popular here than in the US. But with the pressure for cleaner, more economical cars, auto transmissions will become the norm here, too, as computers can control the (larger number of) ratios better. TBH I think it will go one further than that - there will be a move to series hybrids, which have electric transmission just like a diesel-electric locomotive, with added regenerative braking to charge the batteries. No ratios at all needed then (other than one fixed one, obviously). Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 12:32:48 +0000, Mizter T said:
The issue highlighted upthread of the potentially astronomical cost of fixing an automatic if it goes wrong is also a consideration. True, though if a manual box goes wrong that's also pretty pricey these days. And some modern autos are closer in design to an H-gate box with automatic shifters and clutches. Certainly Stagecoach have this type on most of their newer coaches, as it is more fuel efficient than a fluid coupling. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
In message , at 13:15:22 on Sun, 26
Oct 2014, Neil Williams remarked: There is the "with a manual you get better control" thing, but most drivers drive not for the experience but for getting from A to B, so that isn't a massive concern to them. Unless it also has traction control I'd prefer a manual to an automatic in slippery (and icy) conditions. That's another cultural difference between the USA and elsewhere - they will buy a huge 4wd SUV as a family runabout without batting an eyelid. -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 13:15:22 on Sun, 26 Oct 2014, Neil Williams remarked: There is the "with a manual you get better control" thing, but most drivers drive not for the experience but for getting from A to B, so that isn't a massive concern to them. Unless it also has traction control I'd prefer a manual to an automatic in slippery (and icy) conditions. That's another cultural difference between the USA and elsewhere - they will buy a huge 4wd SUV as a family runabout without batting an eyelid. Don't all modern cars have traction control? I thought it was mandatory in the EU. |
TfL to possibly buy 200 extra New Bus for London
Recliner wrote:
Isn't it still possible to buy at least some sporty cars with traditional stick shifts in the US? But, certainly, the mainstream and rental markets abandoned the stick shift a long time ago. I wonder how many American drivers would be able to use a clutch pedal? I'm sure there are still some available, especially at the higher price ranges. Manual transmissions used to be standard on the lowest priced "econoboxes." Not at all today though. As you say - I doubt very many people in the US could drive a stick today outside someone who drove an HGV. |
TfL to possibly buy 200 extra New Bus for London
In message
, at 09:13:11 on Sun, 26 Oct 2014, Recliner remarked: There is the "with a manual you get better control" thing, but most drivers drive not for the experience but for getting from A to B, so that isn't a massive concern to them. Unless it also has traction control I'd prefer a manual to an automatic in slippery (and icy) conditions. That's another cultural difference between the USA and elsewhere - they will buy a huge 4wd SUV as a family runabout without batting an eyelid. Don't all modern cars have traction control? I thought it was mandatory in the EU. If it is, then it's passed me by. Seems a bit of an overkill for an entry-level Ford Focus. And of course we don't all buy new cars (my current one is an "R" reg). The best vehicle I ever had in snow had the opposite of traction control: A Series 2 SWB Landrover with the diff-locks on. That drove like it was on railway lines. Although once you got onto a less slippery road the lines went straight-ahead only! -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 14:13:11 +0000, Recliner said:
Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
In message , at 14:36:31 on Sun, 26
Oct 2014, Neil Williams remarked: Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
On 26/10/2014 14:36, Neil Williams wrote:
On 2014-10-26 14:13:11 +0000, Recliner said: Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. Neil Indeed - my 2009 Hyundai Coupe certainly doesn't have traction control. |
TfL to possibly buy 200 extra New Bus for London
Neil Williams wrote:
On 2014-10-26 14:13:11 +0000, Recliner said: Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. See http://www.cnet.com/uk/news/electron...n-new-eu-cars/ |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 09:13:11 on Sun, 26 Oct 2014, Recliner remarked: There is the "with a manual you get better control" thing, but most drivers drive not for the experience but for getting from A to B, so that isn't a massive concern to them. Unless it also has traction control I'd prefer a manual to an automatic in slippery (and icy) conditions. That's another cultural difference between the USA and elsewhere - they will buy a huge 4wd SUV as a family runabout without batting an eyelid. Don't all modern cars have traction control? I thought it was mandatory in the EU. If it is, then it's passed me by. Seems a bit of an overkill for an entry-level Ford Focus. And of course we don't all buy new cars (my current one is an "R" reg). Ok, I'm five days early: http://www.cnet.com/uk/news/electron...n-new-eu-cars/ |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 14:36:31 on Sun, 26 Oct 2014, Neil Williams remarked: Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? Yes, and they cut the power, too. See http://www.bbc.co.uk/news/business-13609388 |
TfL to possibly buy 200 extra New Bus for London
In message
, at 09:51:20 on Sun, 26 Oct 2014, Recliner remarked: Don't all modern cars have traction control? I thought it was mandatory in the EU. If it is, then it's passed me by. Seems a bit of an overkill for an entry-level Ford Focus. And of course we don't all buy new cars (my current one is an "R" reg). Ok, I'm five days early: http://www.cnet.com/uk/news/electron...n-new-eu-cars/ That's not traction control; it seems to be Nanny saying "don't go round a corner on opposite lock". Only applies to cars "launched", it says. So at least people can continue to make cars (launched previously) where a good driver can steer both ends (the front with the wheel, the back with the foot). How does this initiative affect Rally cars? -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
In message
, at 09:55:37 on Sun, 26 Oct 2014, Recliner remarked: Don't all modern cars have traction control? I thought it was mandatory in the EU. I don't think so, only ABS which has been mandatory since about 2002 I think. However if you fit one, the other is a very small change, mainly in software, as they both work by individually braking wheels. Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? Yes, and they cut the power, too. See http://www.bbc.co.uk/news/business-13609388 ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 14:45:21 +0000, Roland Perry said:
Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? Yes (and by doing so this uses the differential[1] to move some power to the other wheel from the spinning wheel, unless you brake that as well). Unless you had individual traction motors and electric transmission it would be horribly expensive to do otherwise. [1] With a non-locking differential of the type used on a car, if one wheel spins all power is lost. So you stop it spinning by braking it, and the power can go to the other wheel which isn't spinning. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 09:51:20 on Sun, 26 Oct 2014, Recliner remarked: Don't all modern cars have traction control? I thought it was mandatory in the EU. If it is, then it's passed me by. Seems a bit of an overkill for an entry-level Ford Focus. And of course we don't all buy new cars (my current one is an "R" reg). Ok, I'm five days early: http://www.cnet.com/uk/news/electron...n-new-eu-cars/ That's not traction control; it seems to be Nanny saying "don't go round a corner on opposite lock". ASC is a more sophisticated form of traction control: if a wheel starts to spin, it's braked. I can't remember when I first had it on my cars, but it was some time well before the end of the last century. Only applies to cars "launched", it says. So at least people can continue to make cars (launched previously) where a good driver can steer both ends (the front with the wheel, the back with the foot). No, it says it's mandatory on all new cars, even older designs, from this week: "All new car models launched from now on will have to be fitted with electronic stability control ( ESC ) as part of new European safety regulations. The technology, which prevents skidding during sudden manoeuvres, will become mandatory for existing model ranges in Europe from 31 October 2014." How does this initiative affect Rally cars? They're not standard cars. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 15:02:09 +0000, Roland Perry said:
Only applies to cars "launched", it says. So at least people can continue to make cars (launched previously) where a good driver can steer both ends (the front with the wheel, the back with the foot). Most drivers do not have that skill, so the overall effect will be beneficial. Same with ABS, because most drivers aren't quick enough with the pedal to do the same thing manually (and in any case no car has separate single wheel manual braking control, so ABS can pretty much always do it better). Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 15:06:25 +0000, Roland Perry said:
ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
Neil Williams wrote:
On 2014-10-26 15:02:09 +0000, Roland Perry said: Only applies to cars "launched", it says. So at least people can continue to make cars (launched previously) where a good driver can steer both ends (the front with the wheel, the back with the foot). Most drivers do not have that skill, so the overall effect will be beneficial. Same with ABS, because most drivers aren't quick enough with the pedal to do the same thing manually (and in any case no car has separate single wheel manual braking control, so ABS can pretty much always do it better). Most cars allow the ASC to be switched off, though some manufacturers still keep a milder version turned on in the background. My car has an ASC button next to the Sport button (used to change the Auto shift pattern and lock out sixth gear). By default, ASC is on and Sport off. But I don't think any cars allow ABS to be turned off. |
TfL to possibly buy 200 extra extremely fuel efficient New Bus for London
TBH I think it will go one further than that - there will be a move to
series hybrids, which have electric transmission just like a diesel-electric locomotive, with added regenerative braking to charge the batteries. The obvious approach would be to put motors in the wheels, like they do on electric streetcars. But apparently motors are heavy, and that would make the unsprung weight of the car undesirably high, so they'd have to put the motors in the body, with fiddly universal joints to connect them to the wheels. But unless they are a lot more fuel efficient than current hybrids I wouldn't bother. I have the US hybrid version of the Ford C-Max, which gets about 48 mi/G (imperial gallon), and the UK non-hybrid version is rated at 55. Do electric trolly buses have motors in the wheels like streetcars? I'd think that the greater overall weight would make the unsprung weight issue less important. |
TfL to possibly buy 200 extra New Bus for London
In message , at 15:22:25 on Sun, 26
Oct 2014, Neil Williams remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
In message
, at 10:19:53 on Sun, 26 Oct 2014, Recliner remarked: How does this initiative affect Rally cars? They're not standard cars. Do Homologation Specials no longer exist? -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
Isn't it still possible to buy at least some sporty cars with
traditional stick shifts in the US? But, certainly, the mainstream and rental markets abandoned the stick shift a long time ago. I wonder how many American drivers would be able to use a clutch pedal? Stick shifts are indeed rare in the US other than on some imports. Most drivers my age (60) and older can drive a stick, younger ones mostly can't. Of course, kids these days also have no idea what to do if confronted with a telephone with a mechanical rotary dial. R's, John |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 10:19:53 on Sun, 26 Oct 2014, Recliner remarked: How does this initiative affect Rally cars? They're not standard cars. Do Homologation Specials no longer exist? Even if they do, they'd just turn off the ASC, as you can in every performance car. Such cars wouldn't have a hidden, more subtle, ASC in the background, as many ordinary cars do. |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 15:22:25 on Sun, 26 Oct 2014, Neil Williams remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. If you had a car with independent direct power transmission to each wheel, your solution would work. But in the near 100% of cars with differentials, you just have to stop the wheel with no traction from spinning the power away from the other wheel that may have some limited traction. But the brake certainly won't be absorbing 100bhp: very little power is being transmitted when the wheels are spinning without traction. |
TfL to possibly buy 200 extra New Bus for London
In message
, at 11:38:16 on Sun, 26 Oct 2014, Recliner remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. If you had a car with independent direct power transmission to each wheel, your solution would work. But in the near 100% of cars with differentials, you just have to stop the wheel with no traction from spinning the power away from the other wheel that may have some limited traction. But the brake certainly won't be absorbing 100bhp: very little power is being transmitted when the wheels are spinning without traction. I'd do that by locking the differential, rather than braking the errant wheel, but I can see how the two activities could be conflated. -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 11:38:16 on Sun, 26 Oct 2014, Recliner remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. If you had a car with independent direct power transmission to each wheel, your solution would work. But in the near 100% of cars with differentials, you just have to stop the wheel with no traction from spinning the power away from the other wheel that may have some limited traction. But the brake certainly won't be absorbing 100bhp: very little power is being transmitted when the wheels are spinning without traction. I'd do that by locking the differential, rather than braking the errant wheel, but I can see how the two activities could be conflated. Independently and momentarily applying the individual brakes probably is more effective for regaining traction than locking the diff, not that many two-wheel drive cars have locking diffs. |
TfL to possibly buy 200 extra New Bus for London
"Recliner" wrote in message
... Roland Perry wrote: Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? Yes, and they cut the power, too. See http://www.bbc.co.uk/news/business-13609388 Slightly scary is that some systems will *apply* power to maintain directional control, even though the driver is requesting full braking. -- DAS |
TfL to possibly buy 200 extra New Bus for London
In message
, at 11:57:56 on Sun, 26 Oct 2014, Recliner remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. If you had a car with independent direct power transmission to each wheel, your solution would work. But in the near 100% of cars with differentials, you just have to stop the wheel with no traction from spinning the power away from the other wheel that may have some limited traction. But the brake certainly won't be absorbing 100bhp: very little power is being transmitted when the wheels are spinning without traction. I'd do that by locking the differential, rather than braking the errant wheel, but I can see how the two activities could be conflated. Independently and momentarily applying the individual brakes probably is more effective for regaining traction than locking the diff, not that many two-wheel drive cars have locking diffs. Not permanently locked ones, but a brake in the diff (rather that at the wheel). -- Roland Perry |
TfL to possibly buy 200 extra New Bus for London
In message , at 17:06:40 on Sun, 26 Oct
2014, D A Stocks remarked: Really? Traction control is all about putting the power down to the wheels with the best grip. Do cars really implement this by applying the brakes to those wheels which you don't want power transferred to? Yes, and they cut the power, too. See http://www.bbc.co.uk/news/business-13609388 Slightly scary is that some systems will *apply* power to maintain directional control, even though the driver is requesting full braking. One of the attractions of a high-end car is that the accelerator is a "speed pedal", but the quid pro quo is that the brake is a "stop pedal". -- Roland Perry |
TfL to possibly buy 200 extra extremely fuel efficient New Bus for London
On 2014-10-26 16:20:14 +0000, John Levine said:
The obvious approach would be to put motors in the wheels, like they do on electric streetcars. In the *wheels*? Never heard of that. They'd usually be on the bogie, surely? But apparently motors are heavy, and that would make the unsprung weight of the car undesirably high, so they'd have to put the motors in the body, with fiddly universal joints to connect them to the wheels. No more fiddly than the same universal joints/CV joints required to connect the internal combustion engine in a regular car to the wheels. But unless they are a lot more fuel efficient than current hybrids I wouldn't bother. The gains are different - lower complexity as there is no traditional gearbox, and a better ability to run electric-only for short periods e.g. when in and around a city, where avoiding pollution at the point of use is a key feature. Not necessarily raw MPG. Do electric trolly buses have motors in the wheels like streetcars? I'd expect body mounted and connected via a propshaft with a CV joint on each end. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 16:20:57 +0000, Roland Perry said:
I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. Your hope would be misplaced. But do some reading on how a differential works - it has exactly the same effect with a massive reduction in complexity over what you propose. Essentially the brake is not having to absorb anything. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 16:47:22 +0000, Roland Perry said:
I'd do that by locking the differential, rather than braking the errant wheel, but I can see how the two activities could be conflated. That's rather more expensive as it adds another component to the system (another thing to build, and another thing to break, as well as more weight added to the car) - all cars built since the early-mid 2000s have individually controllable brakes and all cars even older than that have a differential. All you need is a bit of software to make it work. The braking solution is incredibly elegant in its efficient and safe use of existing components. Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
On 2014-10-26 17:15:20 +0000, Roland Perry said:
Not permanently locked ones, but a brake in the diff (rather that at the wheel). What would be gained by duplicating the function? Neil -- Neil Williams Put my first name before the @ to reply. |
TfL to possibly buy 200 extra New Bus for London
Roland Perry wrote:
In message , at 11:57:56 on Sun, 26 Oct 2014, Recliner remarked: ABS-style braking is the opposite of traction control. The former automates the stopping of vehicles, that latter the acceleration. Yes, but they work in the same way using the same physical features of the car, taking advantage of how the differential works to deliver the former, which is why adding the latter is mainly a software thing. I would hope that proper traction control fed the power the most suitable wheels, without having to rely upon brakes on the least suitable wheels absorbing 100HP that the electronics says should be suppressed. If you had a car with independent direct power transmission to each wheel, your solution would work. But in the near 100% of cars with differentials, you just have to stop the wheel with no traction from spinning the power away from the other wheel that may have some limited traction. But the brake certainly won't be absorbing 100bhp: very little power is being transmitted when the wheels are spinning without traction. I'd do that by locking the differential, rather than braking the errant wheel, but I can see how the two activities could be conflated. Independently and momentarily applying the individual brakes probably is more effective for regaining traction than locking the diff, not that many two-wheel drive cars have locking diffs. Not permanently locked ones, but a brake in the diff (rather that at the wheel). A permanently locked differential isn't a differential at all, but a solid axle. A locking diff is one where there is resistance to the turning of one wheel vis a vis the other, which can be either mechanically or electrically controlled. But ASC (including traction control) are much more capable and sophisticated, which is one reason why so few two-wheel drive cars now have locking diffs. |
TfL to possibly buy 200 extra New Bus for London
In message , at 18:42:49 on Sun, 26
Oct 2014, Neil Williams remarked: Not permanently locked ones, but a brake in the diff (rather that at the wheel). What would be gained by duplicating the function? Braking a wheel isn't the same as locking a diff. Apart from anything else, the locked diff still powers both wheels. -- Roland Perry |
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