Regenerative Braking
08-21-17 | 10:50 AM
#16
Racer
Joined: Dec 2012
Posts: 1,718
Likes: 629
From: Toronto, ON
Both my Camry Hybrid and RX450h have the exact same symptoms. It is hybrid specific because when coming to a fairly normal/gradual stop regen is responsible for a majority of the braking, but as speed falls below ~5mph the system transitions to 100% mechanical braking, and this is the point at which the grab feeling occurs. After one or two initial grabs, it goes away. I'm not sure if its moisture, temperature, or perhaps even some system calibration on the fly, but I've personally considered it to be moisture, because I've felt similar grabs in other vehicles after a car wash or deep puddles.
08-21-17 | 12:18 PM
#17
Moderator
Joined: Apr 2001
Posts: 15,748
Likes: 1,133
From: Austin, TX
100% yes.
Both my Camry Hybrid and RX450h have the exact same symptoms. It is hybrid specific because when coming to a fairly normal/gradual stop regen is responsible for a majority of the braking, but as speed falls below ~5mph the system transitions to 100% mechanical braking, and this is the point at which the grab feeling occurs. After one or two initial grabs, it goes away. I'm not sure if its moisture, temperature, or perhaps even some system calibration on the fly, but I've personally considered it to be moisture, because I've felt similar grabs in other vehicles after a car wash or deep puddles.
Both my Camry Hybrid and RX450h have the exact same symptoms. It is hybrid specific because when coming to a fairly normal/gradual stop regen is responsible for a majority of the braking, but as speed falls below ~5mph the system transitions to 100% mechanical braking, and this is the point at which the grab feeling occurs. After one or two initial grabs, it goes away. I'm not sure if its moisture, temperature, or perhaps even some system calibration on the fly, but I've personally considered it to be moisture, because I've felt similar grabs in other vehicles after a car wash or deep puddles.
Salim
08-21-17 | 09:11 PM
#18
Racer
Joined: Mar 2011
Posts: 1,806
Likes: 228
From: wa
HSD is set up so that 80% of braking force is supplied by regenerative and if IT IS NOT ENOUGH to satisfy the demand for stopping, then hydraulic system is initiated. There is no difference in hydraulic system vs conventional vehicle. Unless it's an older car and does not have brake by wire feature. So brake pads can touch rotor at ANY speed based on parameters required. You will not have regen charging at low speeds though. That's why at low speed it is strictly hydraulic braking and feel different from higher speeds braking.
Don't complicate this. It is very simple. You have constantly spun MG as it is permanently coupled with drive axle. So as far as wheel rotates, MG rotates. Then you have sun gear connected to the ICE. ICE works as a stationary weight due to mass of pistons, crankshaft, etc, and force of friction. This causes ICE to act as stator and MG as rotor in generator. Electric cohesion between moving and stationary (relatively) masses creates braking force refereed to as regenerative braking. It is very simply engine braking using magnetic force.
Look at any generator. It has to be run by a motor to generate electricity, right? Rolling tires are acting as that motor in regen braking.
Don't complicate this. It is very simple. You have constantly spun MG as it is permanently coupled with drive axle. So as far as wheel rotates, MG rotates. Then you have sun gear connected to the ICE. ICE works as a stationary weight due to mass of pistons, crankshaft, etc, and force of friction. This causes ICE to act as stator and MG as rotor in generator. Electric cohesion between moving and stationary (relatively) masses creates braking force refereed to as regenerative braking. It is very simply engine braking using magnetic force.
Look at any generator. It has to be run by a motor to generate electricity, right? Rolling tires are acting as that motor in regen braking.
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