Hand Brake/parking Brake?

[Terry953]

Check this one out chaps, just stumbled across it.!

According to wikipedia: http://en.wikipedia.org/wiki/Parking_pawl

Quote:

Most vehicle manufacturers and auto mechanics do not recommend using the transmission's parking pawl as the sole means of securing a parked vehicle, instead recommending it should only be engaged after first applying the vehicle's parking brake. Constant use of only the parking pawl, especially when parking on a steep incline, means that driveline components, and transmission internals, are kept constantly under stress, and can cause wear and eventual failure of the parking pawl or transmission linkage. The pawl might also fail or break if the vehicle is pushed with sufficient force, if the parking brake is not firmly engaged. Replacement can be an expensive operation since it generally requires removing the transmission from the car.

It is highly inadvisable to use the parking pawl to stop a vehicle in motion. Modern parking pawls are connected to a safety mechanism that prevents the pawl from engaging unless the vehicle is stopped first. The pawl mechanism is generally not strong enough to stop a vehicle in motion, if it engages at all. Under that much stress, the pawl may simply break off in the transmission, leading to costly repairs.

[barrycoll]

this Post did start as the distinct Prius issue of not having an easy to use, and accessible hand brake...just how, and why, the foot operated parking brake (henceforth known as FOPB), evolved, by Toyota, out of a nicely positioned hand brake woould be an interesting topic, but maybe it was for the American market, and not Europe..

so many folks have figured out a 'work around' to reduce to need for star jumps with the left leg at every traffic light, and the P button offers that facility....but with many flaws, unfortunately...

Terry's parking pawl comments get to the nub of the situation

but just why the Germans can figure out a finger operated electric parking brake, that releases on first touch of the gas pedal, and the great Toyota company cannot do that, despite having Sony, Panasonic, Toshiba just up the road, is a mystery

cheers barrycoll

[Opifex]

One last question, why have a separate 'P' button anyway ? most of the types of mechanical autos have 'P' as just another position on the 'gear' selector along with D-N-R-D1..........

This bit of illogical design irks me as well. I drove a Yaris Hybrid last week and was pleased to find that it had the P as the end position on the gear lever.

Check this one out chaps, just stumbled across it.!

According to wikipedia: http://en.wikipedia.org/wiki/Parking_pawl

Quote:

Most vehicle manufacturers and auto mechanics do not recommend using the transmission's parking pawl as the sole means of securing a parked vehicle, instead recommending it should only be engaged after first applying the vehicle's parking brake. Constant use of only the parking pawl, especially when parking on a steep incline, means that driveline components, and transmission internals, are kept constantly under stress, and can cause wear and eventual failure of the parking pawl or transmission linkage. The pawl might also fail or break if the vehicle is pushed with sufficient force, if the parking brake is not firmly engaged. Replacement can be an expensive operation since it generally requires removing the transmission from the car.

It is highly inadvisable to use the parking pawl to stop a vehicle in motion. Modern parking pawls are connected to a safety mechanism that prevents the pawl from engaging unless the vehicle is stopped first. The pawl mechanism is generally not strong enough to stop a vehicle in motion, if it engages at all. Under that much stress, the pawl may simply break off in the transmission, leading to costly repairs.

Interesting post. Maybe I've got to mend my ways, but I do find the parking brake a bit tedious to use. Interestingly, I use the parking brake instead of P position when I am driving my wife's automatic Polo but that has a real handbrake so it feels more natural.

[Terry953]

Optiflex said :--

"This bit of illogical design irks me as well. I drove a Yaris Hybrid last week and was pleased to find that it had the P as the end position on the gear lever."

That's good news, Common Sense is creeping in, another of my irksome problems is the unergonomical directions you have to move the gear selector = Forward for Reverse travel and Backwards for Forwards travel , don't suppose they sorted that at the same time?

He also said :--

"Interestingly, I use the parking brake instead of P position when I am driving my wife's automatic Polo but that has a real handbrake so it feels more natural."

Which brings us back to barrycol's original topic - Apologies for trampling all over your topic mate.

I think this sop to American design tradition [the foot operated parking brake] is at the bottom of this dilemma.

Give drivers a proper HAND parking brake in the first place and most will adapt naturally to it from previous experience, and wouldn't even look for an easier option.

[Sagitar]

"I think this sop to American design tradition [the foot operated parking brake] is at the bottom of this dilemma.

Give drivers a proper HAND parking brake in the first place and most will adapt naturally to it from previous experience, and wouldn't even look for an easier option."

I agree that the American preference for a foot operated parking brake probably lies at the heart of Toyota design decision, but I think it is more than a sop.

I think Toyota sells about 25 hybrids in the 'States for every one that it sells in the UK so it is not surprising that it leans towards their preferences rather than ours.

Automatic gearboxes predominate in the US. I believe the ratio of autos to manuals sold is better than 10 to 1. The vast majority of autos sold have a foot operated parking brake and that brake is rarely used other than when the car is being parked and turned off. Short stops in traffic are achieved by using the brake (not the parking brake) and leaving the selector in "Drive". US drivers seem to be far less concerned about brake light glare than we are and I haven't been able to find legislation equivalent to the recommendation in our Highway Code in those States in which I have driven (I must admit I haven't looked very hard, having been much more concerned about the vagaries of things like turning right on red etc). I must also admit that I haven't driven in the 'States for some time so things may have changed; talking to my friends over there about it however does not give me that impression.

I would prefer a decent hand-brake personally, but I don't think I am going to get it, because Toyota knows on which side its bread is buttered. I suppose it would be possible to make a European version and a US version, but they would probably need to sell a lot more than they do now to make it worthwhile. It could be a different story with vehicles manufactured in Europe?

[barrycoll]

well after my third around London drive yesterday, I am starting to appreciate the "charms" of the F-O-P-Brake.....

with the seat set a bit further back, and the backrest a bit more upright, getting the left foot onto the FOPBrake was OK, especially as I didn't have to lift my knee so high, and after application, it was OK to rest the left leg on that pedal, until needed

I imagined that like the clutch pedal, one was obliged to NOT keep the pedal depressed, but as it holds its depressed ON position, it is not really a problem..............so the problem of High Intensity brake lights is solved for me, especially as slipping the car into N is dead easy too........phew!!

cheers bbarrycoll

[timberwolf]

Barry I'm glad you've found a solution to your problem and are happy with your car.

I've been driving automatics the way the rest of the world apparently drives them for a long time, and sorry if it upsets a few of you but I'm going to continue driving them that way.

I found it interesting that I can't find any other nation that complains about blinding glare from brake lights, it seems to be a UK thing only?

[Terry953]

I would prefer a decent hand-brake personally, but I don't think I am going to get it, because Toyota knows on which side its bread is buttered. I suppose it would be possible to make a European version and a US version, but they would probably need to sell a lot more than they do now to make it worthwhile. It could be a different story with vehicles manufactured in Europe?

Absolutely correct Sagitar, you ain't going to get one and Toyota are not about to male a european version.

This is where Honda HUM [Honda-UK-Manufacturing] came unstuck in UK, our Swindon factory only manufacture for the european market and that has gone dead flat, hence the lay-offs and reduced production.

[barrycoll]

hi timberwolf, please dont take the brake light thing personally, as we all have evolved our own methods....

but the consideration regarding brake lights showing while stationary goes back to the teaching at the Hendon Police Driving School that the IAM course is based on...

the standards taught in this country are very high in comparison to the US and Europe, and if you are at all interested in seeing what goes on, then your local library should/could/might have a copy of a DVD called Roadcraft, that follows a group of rooky coppers as they go through the course at the Hendon college....

it is very well done, a worth a view

I hadn't realised that the Prius is selling at a rate of 25 to 1, in relation to the States, so the FOPBrake explains itself, and as most big manufacturers cant even be bothered to change their handbrakes from the left to the right hand drive of the drive tunnel, it would be expecting to much to thing that Toy. would re-manufacture the brake itself for the Euro market...

cheers barrycoll

[kithmo]

Despite all this discussion on the difficulties of the "P", "FOPB" and hill starts, the (Gen 2) Prius was voted the easiest car to drive in the 2009 JD Power survey. :D

[johalareewi]

FWIW, the issue with the P button and the R N and D is also USA related.

"Vehicles conforming to US Government standards[2] must have the modes ordered P-R-N-D-L (left to right, top to bottom, or clockwise)."

http://en.wikipedia.org/wiki/Automatic_transmission#Automatic_transmission_modes

The Prius does conform to this layout but perversely the P is a separate button and lever doesn't move in R-N-D sequence like a traditional auto stick. Also, it doesn't have an L position, but has a B position instead.

It is worth mentioning that when the Prius (or other Toyota hybrid) is in N, the HV Battery cannot be charged. Which may be a consideration when using N while stationary and the HV Battery SOC is low.

[Sagitar]

Thanks johalareewi. I had thought to mention this in response to the post pointing out the oddity of moving the gear switch knob forward to reverse and backwards to go forward. I forgot. It is of course precisely what happens with a conventional auto box, but the Prius arrangement does somehow emphasise the counter intuitive aspect of it.

I also meant to mention that on Priuschat there are discussions about getting rid of the gear switch lever altogether and replacing it with a set of buttons. There are already components available to do this modification. It is not something that I would want to do, having driven auto boxes for more than thirty years, but those new to the experience might be interested. I will see if I can find the link.

Here we are

[Terry953]

johalawreei said :---

It is worth mentioning that when the Prius (or other Toyota hybrid) is in N, the HV Battery cannot be charged. Which may be a consideration when using N while stationary and the HV Battery SOC is low.

My experience in a mega traffic jam a couple of years ago was to creep forward - stop - apply H/brake - swith to 'N' and wait.

I kept an eagle eye on the HV Battery state, and of course it sunk down and down !! I decided to tough it out and see what happened.

All of a sudden [whilst still in 'N'] the electrics overrode the status quo and the engine started up and charged the HV battery.

When you think about it , Toyota R&D would have sussed this out ages ago.

If you doubt this try it for yourself then you can be reassured you won't get stranded in jams.

This was my MkI Auris HSD but I don't see any reason to modify the feature on later systems.

TerryB

[johalareewi]

All of a sudden [whilst still in 'N'] the electrics overrode the status quo and the engine started up and charged the HV battery.

When you think about it , Toyota R&D would have sussed this out ages ago.

It's good to know this.

With the fixed gear planetary system, and the HV Battery can still be charged by the ICE when in neutral, how exactly does neutral work? Time to look on google (other search engines are available).

[Terry953]

All of a sudden [whilst still in 'N'] the electrics overrode the status quo and the engine started up and charged the HV battery.

When you think about it , Toyota R&D would have sussed this out ages ago.

It's good to know this.

With the fixed gear planetary system, and the HV Battery can still be charged by the ICE when in neutral, how exactly does neutral work? Time to look on google (other search engines are available).

Just remembered another happening with my new Icon the other month in the cold weather.

I was sitting in the stationary car [obviously in 'P'] but electrics ON playing about with this wretched Toyota touch system radio Dab+AM+FM thingy trying to get the stations sorted out and tuned.

All of a sudden the touch screen went blank and a notice came up saying something like 'Engine starting to prevent Battery discharging" and without more ado it did.

After the initial shock it was actually an assett as the heater fired up and it became nice and warm as I battled with the thingy.

Initially In this instance I presumed the Battery it was referring to was the 12volt auxiliary battery, but thinking on further I seem to recall that the HV inverter system has a role in charging the auxiliary battery, anyway whatever the system is I have absolute confidence in Toyota R&D sorting out all possibilities of battery discharge and looking after us like guardian angels - apart that is, from punctures and spare wheels.

Cheers TerryB

[johalareewi]

...I seem to recall that the HV inverter system has a role in charging the auxiliary battery,

That is correct, the 12V Battery is charged by the HV Battery.

anyway whatever the system is I have absolute confidence in Toyota R&D sorting out all possibilities of battery discharge and looking after us like guardian angels

FWIW you also get a message like "shutting down to conserve battery" if you leave it in 'accessory' mode for too long.