Originally Posted by Robin97396
Utah buses with retarders? They don't seem to have a great deal of buses at once but the sales seem pretty steady.
I had to look up retarders to understand what they were. Why don't those work like the dynamic braking systems that generate power instead of heat? Oh, probably not practical unless you've got a hybrid bus. Same principals though.
not only do you have to have an electric motor to turn into a generator, thus creating resistance, you also have to disperse that energy somewhere..
in my chevy volt if I ran it up a hill forced in gasoline mode wit ha full battery pack (no its not efficient.. just a demonstration)..
then when I went down the other side.. and switched to electric only at the top.. on a long hill the battery would full-charge and I would lose all dynamic braking.. the pedal would go down about halfway till i felt any braking.. which was then the normal friction brakes...
mechanical retarders use the high compression of a diesel engine to create the resistance against gravity.. thus helping the brakes..
many air-brake busses are All drums... Drums have more mass and can take longer before losing effectiveness than a disk brake.. however a disk brake will recover quicker than a drum brake....
using your retarder or jake-brake as much as possible helps to keep your brakes cool. I can always tell an inexperienced truck driver when going down the mountains because I will hear the jake brake only being used part of the time... those often are the ones I smell with hot brakes at the end of a hill...