RX - 3rd Gen (2010-2015) Discussion topics related to the 2010 - 2015 RX350 and RX450H models

2012 RX 350 or RX450H

Thread Tools
 
Search this Thread
 
Old 08-13-17, 04:37 PM
  #16  
ukrkoz
Racer
 
ukrkoz's Avatar
 
Join Date: Mar 2011
Location: wa
Posts: 1,806
Received 228 Likes on 204 Posts
Default

OK, on Toyota hybrids brake system has no connection between brake pedal and brakes. You have brake pedal, it is connected to what is called brake stroke simulator, what gives you brake pedal feel. Thereafter, it all electric. COMPUTER decides how much hydraulic force to apply to the brakes via brake accumulator and actuator. You simply tell it if you want more or less stopping power, then ECM decides how to do it.
Hybrid brakes are tuned to utilize 80% of braking via regenerative - which is, basically, engine braking, sort off, when engine is used as counter mass for motor generator then operating as generator and any demand above that is then done by hydraulics. This is why some hybrids end with brake pads lasting so long. They are simply less used. Though not all, my rear pads on TCH had to be replaced at 45 000 miles. But shnookwhaler at TN still runs on original pads - and over 264 000 miles on odo.
Old 08-14-17, 01:50 PM
  #17  
riredale
Instructor
 
riredale's Avatar
 
Join Date: Oct 2016
Location: Oregon
Posts: 857
Likes: 0
Received 47 Likes on 36 Posts
Default

Can you provide a reference for this? This is not what I've read.

My understanding is that the braking system on my 2010 RX450h is utterly conventional except for the first 10% or so of pedal travel, where the computer uses the front and rear motor/generators as generators and the electricity generated goes into the hybrid battery.
Old 08-14-17, 02:01 PM
  #18  
vlad_a
Lexus Champion
 
vlad_a's Avatar
 
Join Date: Feb 2004
Location: Ohio
Posts: 1,973
Received 55 Likes on 53 Posts
Default

Brake pedal has to be a part of the physical hydraulic connection. Otherwise it wouldn't pass through federal safety requirements.

While moving at a safe location, press on the brake pedal and then put the gear lever into N position. Regen braking will disengage and you'll be left off with hydraulics only.
An old trick for the 1st Gen Honda Insight was to amplify the hydraulic pressure sensor reading to get more supplemented regen braking.
Old 08-15-17, 08:27 AM
  #19  
lexusrus
Pole Position
 
lexusrus's Avatar
 
Join Date: Aug 2013
Location: CA
Posts: 2,629
Likes: 0
Received 250 Likes on 228 Posts
Default

On my CT200h there is a "B" mode similar to the Toyo Pruis. I use it for extended down hill cruise as the "B" mode generates more electricity to recharge the hybrid batteries vs otherwise. I wished that is in the RX450h, but not there.

Still the brake pad wear is an indication of how that Hybrid car was driven. Early pad replacement = driven hard/abuse and if I were looking for a used Toyota/Lexus Hybrid, then I'll pass that one and keep looking.

Originally Posted by ukrkoz
OK, on Toyota hybrids brake system has no connection between brake pedal and brakes. You have brake pedal, it is connected to what is called brake stroke simulator, what gives you brake pedal feel. Thereafter, it all electric. COMPUTER decides how much hydraulic force to apply to the brakes via brake accumulator and actuator. You simply tell it if you want more or less stopping power, then ECM decides how to do it.
Hybrid brakes are tuned to utilize 80% of braking via regenerative - which is, basically, engine braking, sort off, when engine is used as counter mass for motor generator then operating as generator and any demand above that is then done by hydraulics. This is why some hybrids end with brake pads lasting so long. They are simply less used. Though not all, my rear pads on TCH had to be replaced at 45 000 miles. But shnookwhaler at TN still runs on original pads - and over 264 000 miles on odo.

Last edited by lexusrus; 08-15-17 at 08:31 AM.
Old 08-16-17, 12:47 PM
  #20  
roger5627
Driver School Candidate
Thread Starter
 
roger5627's Avatar
 
Join Date: Jul 2017
Location: MD
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the information. I wondered why some carfax reprots showed more brake pad changes for some hybrids as compared to other cars.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
North
Hybrid Technology
14
03-06-18 02:04 PM
RX300Crys
RX - 3rd Gen (2010-2015)
2
03-31-17 12:11 PM
daryll40
RX - 4th Gen (2016-2022)
5
03-06-17 06:50 AM
jtmoney528
RX - 3rd Gen (2010-2015)
13
05-10-15 07:07 PM
smd2972
RX - 3rd Gen (2010-2015)
10
10-16-12 03:13 AM



Quick Reply: 2012 RX 350 or RX450H



All times are GMT -7. The time now is 08:19 AM.