“…going up a hill doesn’t decrease the amount of steam.”
Huh? As the engine slows down, the amount of steam is reduced proportionally. The pressure and thus the torque remains essentially constant, but since power is torque X rpm, power is also reduced proportionally.
@Whitey
I was reading an article about the amount of money made by a lot of service stations on brake jobs. It’s an absolutely huge money maker. Many newer hybrids that use regenerative braking, according to the article, have much lower brake costs. Electric cars and hybrids are not on the list of favorite cars for service stations. I would like to to think that when such brake systems become common place, where a motor does the lions share of the braking, hopefully electric, brake jobs will go the way of yearly exhaust system replacements. It’s one of those side effects of technology. What is good for the car owner, is not always good for “someone’s” economy. When i know people personally who jobs are affected by new technology negatively, regardless of how beneficial they are, it always gives me pause to think. Reeducation, job training and moving is always easy. Just the " wiener" in me.
I have heard reports of hydraulic energy recovery braking being developed for heavy garbage trucks, city busses, and other heavy vehicles that constantly have to stop.
This uses hydraulic motors acting as hydraulic pumps during braking pumping hydraulic oil into a pressurized accumulator, and then using that high pressure oil as hydraulic motors during acceleration. It’s supposed to have a higher percentage of energy return than electric motor/battery systems and hydraulic accumulators don’t have cycle and calendar life issues like batteries do.
So maybe a different type of hydraulic brake is in our future.
It should be noted that all the drive wheels of an old steam locomotive are locked together. If the steam cylinder on either side is turning its wheels, it’s transferring the power to all eight wheels. The axles are “locked” out of synch to prevent the engine from ever stopping at a point where both sides will be at their maximum extension (either end of the cylinder), which would render the steam engine impossible to again get rolling. There always needs to be one side at a point where the steam pressure will be able to sufficiently crank the system from a stop.
Some large locomotives, called “Big Boys” had two sets of eight drive wheels for a total of 16.
The ‘Big Boy’ was a specific Union Pacific articulated locomotive design. Many other railroads also has articulated locomotives with various configurations. They were most popular with the eastern coal hauling railroads, where they pulled very heavy trains at low speeds, and with western railroads, where both long trains and long, steep grades were common. These locomotives had lots of drivers (the driven wheels) of fairly small diameters.
In the flat parts of the country the typical road locomotives had fewer, but larger, drivers. In flat terrain it was easier to get a train moving with less tractive effort and those locomotives could run at higher speeds than the locomotives with more, but smaller drivers. In the hilly areas it just wasn’t possible (or safe) to operate trains at those speeds, so the locomotives had smaller drivers, for more tractive effort, but a lower top speed.
The "Shay"Locomotives were a bit different for steeper grades and the English had something a bit different-Kevin
@insightful
The steam pressure isn’t reduced and it’s the pressure that gives you the power, so at basically 0 rpms you have the most power you’re going to get from a steam engine.
The basic formula is PLAN/33000 which gives the theoretical horsepower, ignoring friction losses.
Where:
P=Mean Effective Pressure in Cylinder (MEP)
L=Length of Stroke in FEET (times 2 for Double acting engine)
A=Area of Piston in Inches
N=Revolutions per minute
So at 0 RPMs you technically have 0 hp, even though that’s when a steam engine is making the most power. The way an old timer explained it to me was toque was basically how much work you can do and hp is how fast. Yes I know it much more complex that that, given the relationship between the two, but when talking about steam think traction motor (electric) not ICE.
TT, there is absolutely nothing complicated, materials/parts intensive, or labor intensive about manufacturing and/or installing hydraulic brakes. It’s as basic and direct as possible. No electric system that I can envision could be more so.
Seriously?? How long do you think it takes a human to route and mount all of those lines? To connect them together and into all of the connecting blocks? Have you ever seen an ABS module with all the lines going into it? Have you priced an ABS module? How long do you think it takes them to bleed the brakes for the first time?
Now compare that to installing a single “caliper” onto the knuckle just like they do now and plugging in a wire harness. Yeah, no difference there.
I think you’re just being stubborn about it now. The labor difference seems quite obvious to me…
“So at 0 RPMs you technically have 0 hp, even though that’s when a steam engine is making the most power.”
Ah, I see the problem with this discussion…
… other than the fact that it’s drifted waaaaaaaaay off topic?
I doubt if we do away with Hydraulic brakes any time soon. However who knows what technology will come up with.
Dynamic brake assist forever-Kevin
@TwinTurbo
" How long do you think it takes a human to route and mount all of those lines? "
Not that long really when it’s going down an assembly line, same thing with the blocks. As to how it take to bleed brakes for the first time, a few minuets if you use the pressure method. Yea it a pain in the butt to replace brake line and that can take many hours, but how ofter is that really done? Or better yet when was the last time you replace your brake lines?
“Now compare that to installing a single “caliper” onto the knuckle just like they do now and plugging in a wire harness. Yeah, no difference there.”
And what do you think that “caliper” would cost? And you still need to run the wire that can handle the amount of power they will use, and attach connectors, etc. And if you have to replace a wire because of a short.
In the end it will cost more and you’re trading out one set of problem for another.
“Not really that long”
Sorry, that’s not a quantitative number that we can derive cost from. I can assure you that it isn’t inconsequential, especially when you factor in the cost of union labor. I have my own ideas on the labor content required to ensure leak free connections and proper placement and routing of all those lines…
“how often is it really done”
It done on every vehicle going down the line. We’re talking about initial manufacturing, not maintenance or repairs.
“what do you think that caliper would cost”
If you read my prior posts, you’ll get your answer. I’m not posting the same thing now three times.
“replace a wire because of a short”
Again, we’re discussing manufacturing costs. Harnesses are pre-tested after being built and a functional test is done on either system when assembled into the car. Here’s a difference, purely electrical systems can often be tested by automation. How do you suppose they test the “dumb” hydraulic brakes and check for leaks?? The good news is, it doesn’t take that long, right? 
Well, I had a few free minutes and decided to do a little looking around. It didn’t take much effort to find numerous manufacturers working on electronic brakes. Mercedes-Benz and Toyota have their own versions. Siemens appears to have the front runner in just about every aspect. If you bother to look, you can find plenty of information on them. The advantages I mentioned are all in there along with a few that weren’t as obvious.
Check out the Siemens VDO Electronic Wedge Brake, pretty impressive technology-
The VDO EWB system was being tested as early as 2005. Like it or not, they’re coming to a vehicle near you…likely sooner rather than later…
http://www.examiner.com/article/drive-by-wire-technology-cars-electric-brakes
Having worked on a lot of electrical systems, I find that opens are a lot more common than shorts.
@TwinTurbo
I’m willing to it’ll take about the same to to run the brake line as it does the cables for the electric brakes. It’s not like your going to get by with a small gauge wire. And yes I read your link,
“Around 100 times a second, a total of four sensors measure wheel rotation and therefore the speed of the vehicle, the forces on the brake and the position of the wedge. Whenever the driver presses the brake pedal, the system transmits the force electromechanically to the wheels, which are electronically networked with one another.”
and
“And if the vehicle’s entire power supply system failed, an emergency battery would ensure that all vital functions were maintained until the fault was remedied.”
Every time something new is introduced they almost always claimed it’s cheaper and better in most cases it’s not cheaper nor is it better. And I can see people after 4 or 5 years bitching that they have to replace this battery and that battery for the backup system, plus their regular battery. And I’m willing to bet you can’t just toss those battery out.
One last thing from your link
“If everything goes according to plan, the first vehicles fitted with the EWB as standard should hit the roads in 2009.”
2009 it’s now 2014 and I have yet to see it as an option an any car if it was so much cheaper and better why aren’t we seeing them?. Again I have no doubt that electric brakes are coming, but I’ll let you go first.
Every time something new is introduced they almost always claimed it's cheaper and better in most cases it's not cheaper nor is it better. And I can see people after 4 or 5 years bitching that they have to replace this battery and that battery for the backup system, plus their regular battery. And I'm willing to bet you can't just toss those battery out.
So lets get rid of airbags in cars because if you crash and deploy the bags it costs money to replace them. Lets all ride around in 1949 Volkswagen Beetles, cheaper you know…
So lets stop the madness and end this silly talk, its really all a bunch of nonsense since we are communicating on computers here, we like technology don’t we? Or should we go back to using an abacus because there was less to break on an abacus? After all Moses never had the hard drive fail on his abacus and it didn’t need batteries either.
If we had this sky will fall, woe is me attitude with everything we would never move forward with anything. Do you have a cell phone? Remember that was scary new technology at one time as well. Lets get on with it.
Abs, Supplemental restrain systems, fuel injection, crumple zones, and catalytic converters were all going to end the world as we knew it, yet they made the automotive world a better place just like electric braking systems will.
I think why we are afraid of new technology is because to many people drive problematic vehicles from GM. I mean GM can’t even make an ignition switch that will work reliably so they have no business messing with new cutting edge space age technologies like hybrids and electric brakes.
Lets leave the cutting edge stuff to Toyota, then GM can make an inferior copy of Toyotas technology all while building their junk in mexico and china all while we wave our flags and have illusions in our head about apple pie, baseball, and general motors. Its not the 1960’s anymore folks! Lets get with the times and quit being ignorant! Lets embrace electric brakes!
Ah many a car has been totaled because the airbag went off, minor damage but a totaled cars because replacing the airbags costs more than the car is worth.
While I’m generally an early adopter of new technology, when it comes to safety I tend wait until the bugs are worked out. Early airbags used compressed air but it was shown later in the 1960s showed that compressed air could not inflate an airbag fast enough for maximum safety. That is they had problems, same with all other systems, every system you listed had problems that generally major problems before they became useful.
Once they get the bugs out of the electric braking system then I’d be willing to buy a car with one, but I’m not willing to be one of the test subjects.
If you really wanted to make cars safer put a huge spike in the middle of the steering wheel where it would impale the driver in case of an accident. That would make drivers slow down and drive instead of talking on the phone etc.
Ah many a car has been totaled because the airbag went off, minor damage but a totaled cars because replacing the airbags costs more than the car is worth.
So airbags have no benefit? They have saved 30k plus lives since their introduction, not a big number unless your life was one of them. Of course drunks kill 10 to 20k people a year so maybe we need to deal with them first.
Once they get the bugs out of the electric braking system then I'd be willing to buy a car with one, but I'm not willing to be one of the test subjects.
You drive a GM vehicle don’t you. I have a Toyota Prius that has so much black magic technology it will make your head spin, and guess what, it works every single time, flawlessly. Fords Cmaxx hybrid? Not so much.
If you really wanted to make cars safer put a huge spike in the middle of the steering wheel where it would impale the driver in case of an accident. That would make drivers slow down and drive instead of talking on the phone etc.
If you get a DUI I think the airbag should be removed and a spike should be mandatory.