I recently read some tips about how to P&G (Pulse and Glide). In those tips it suggested that when you are coming to a stop slowly that you should barely put your foot on the brake to create more energy to charge the battery. My question how of the braking is actually done in the engine? I've heard alot of different people say that alot of it is in the engine and that the brake pads are only used when braking abruptly. The reason I ask is because I don't want to prematurely wear down my brakes just to charge the battery faster when coming to a stop. Any ideas on this? Thanks, Dave
It's actually the MGs (motors/generators) that do the braking most of the time. When you brake normally, current is drawn from the MGs creating drag to slow down the car. This is called regenerative braking. You are not using the physical brake pads at all till you are down to ~7mph (or step on the brake pedal hard and fast). You will feel the difference in braking around 7mph, which is caused by switching from regen to physical brake.
In the Prius II a huge amount of the braking is done by the MG (not the Engine aka ICE) IF you don't brake too quickly or too hard and if you don't hit any bumps while braking. In brisk or emergency braking all the braking is done by the friction brakes. But, with practice, on routine stops you can brake solely with the regenerative braking via MG2 until your speed drops to 7mph.
Thanks! This answers my question, the brakes will not be worn by just barely tapping on the brakes. Great engineering on Toyota's part. Man I love this car.
Exactly. The pads and shoes may last the life of the car, barring wear caused by rusted rotors. Occasional brisk braking will clean the rotors. Remember to brake firmly in reverse every few months to allow the self-adjusters to adjust the rear brakes. (But if they don't wear, even this isn't an important step!) I've also heard that the brake computer tries to apply a bit more pressure to the rear drums, to balance wear. Front brakes always wear faster due to the weight shift during braking, so the computer even tries to help a bit there.
<div class='quotetop'>QUOTE(Rick Auricchio @ Jun 22 2006, 01:01 PM) [snapback]275297[/snapback]</div> Im curious about the rear brakes. Since they are drum brakes, the drums do not contact the inner surface of the brake drum unless there is pressure applied to the hydraulic system. With the regen system taking up 90% of the braking action, it seems to me that the rears never actually are engaged until you get down to 7 mph. This means that most of the time the car has 2 wheel braking, which in a normal car can result in front end dive when you hit the brakes. Obviously, the Prius doesn't do that, so what is going on? Sy Cohen
the vancover taxi Prius replaced its brakes at more than double the recommended mileage. that may not seem like a lot except that generally, taxi's replace their brakes at 60-75% recommended mileage because of the work they do.
<div class='quotetop'>QUOTE(hobbit @ Jun 22 2006, 10:28 PM) [snapback]275623[/snapback]</div> Sounds like something alot of Prius owners might be interested in. Might be useful to know if you are braking too hard (using the real brakes) vs. the MG doing the braking. I can see how this might help alot when you are in stop and go traffic during rush hour. There are alot of opportunities at that point to recharge your battery as you speed up and then instantly brake. Maybe Coastal could commercialize this?!
<div class='quotetop'>QUOTE(syclone @ Jun 23 2006, 01:20 AM) [snapback]275519[/snapback]</div> ohh Your rear breaks are drums brakes??? wow , i didnt know that ,, that a US thing right ? andreas :blink:
<div class='quotetop'>QUOTE(andreaswin @ Jun 23 2006, 04:33 PM) [snapback]275973[/snapback]</div> Yeah, the NA Prius gets drum rear brakes.... <_<
<div class='quotetop'>QUOTE(ScottY @ Jun 23 2006, 10:40 PM) [snapback]275978[/snapback]</div> hmm thats very close to insulting.......... :blink:
Heh. Coastal claimed they *were* going to commercialize the brake pressure indicator, and never did. I decided to go my own way. If they swipe the idea and make a ton of money off it and I never see a red cent of it for my contribution, it won't be a surprise given Coastal's track record. In the meantime, the electronics-handy can stop waiting for them. . _H*
