May I re-interate, and if you look closely at all the graphs and documentation, you wil see that re-gen braking is the recovery of kinetic energy by using the electric motor as a generator. This has NOTHING to do with the brakes. The brakes are purely mechanical (with assist). Regen happens when the motor changes to a generator and is controlled by the computer not by your foot on the brake pedal. Note that in most cases you have your foot off the accellerator pedal and on the brake (or vice versa), and never should you use both feet.

My simple experiment points out that if you trick the system with both feet, you will see that the brake pedal does not cause regen.

When you lift your foot off the accellerator/gas pedal, the computer thinks you wish to slow down, and switches the motor to generator mode.

If you are in the Glide state, the motor/gen is free wheeling (or stopped) and therefore no energy is being recovered, nor is any being used from the battery/ICE (Except for some accessories).

Marketing materials abound with false information, to help explain the technology to the average consumer.

 

Douglas, If you are saying regen starts with lifting your foot from the accelerator and has nothing to do with applying the brakes, then you would also be saying that when you do indeed apply the brakes that the rate of regen is the same, reguardless of pedal pressure on the brakes?

Is it not probable that pedal pressure on the brakes causes increased resistance in the generator, creating more current, and thus slows the car and that when additional braking is necessary then the hydraulic system is "kicked on" controlled by the computer.

 

Gents it seems we all know how the system works but are sticking on the term "brakes". Doug-dude is correct in saying that regen has nothing to to do with the friction brakes. At the same time everybody else is also correct that the brake PEDAL can/does increase regen. Truce?

 

and is controlled by the computer not by your foot on the brake pedal

Truce I guess, but I'm not talking about the "brakes" per say, but rather the use of the brake pedal to increase the rate of regen, which does indeed seem to be opposed to what Douglas is saying. Your foot on the brake seems to be what controls the computer.

I'm done

 

Douglas,

Are you familiar with "brake-by-wire" and ECB?
http://www.toyota.co.jp/en/tech/envi...hs2/power.html

The master cylinder does drive only a stroke simulator on the HSD system.
There is no mechanical path from the master cylinder to the wheels unless you see the power failure.
The brake signal on the stroke simulator goes to the skid controll computer, then the computer controls the regen and the mechanical brakes.


Ken@Japan

 

Yes, in essence. However the rate of regen is dependant on the speed of the motor/generator and the SOC [State of Charge] of the battery. A fully charged battery will not draw very much current from the generator, whereas a discharged battery will draw lots of current. The computer/controller limits this current (and voltage) to a safe level to prevent damage to the battery.

The only way you can increase the load on the generator is to add (electrical) resistance, or add more electrical load. Both would waste the engery as heat. As noted above if you have a fully recharged battery, regen will do little to add more energy to the battery, and at the same time will not slow you as quickly as when the battery is discharged.

Pressing the brake pedal engages the mechanical brakes only (in the Prius). And at one time US regulations required all cars to have a mechanical connection to the brakes, effectively outlawing electric brakes that were used on some cars like the old Citroen of the 60's era.

Cheers, Doug

 

Could be wrong but I don't think so Doug......

 

From:

http://www.4qd.co.uk/fea/regen.html

 

Douglas, you're pulling our legs on this one, I see that now... Everytime you post you're adding more and more truths to support a bit of false information just to see if we're paying attention. I have indeed enjoyed delving into this subject and all the excellent technical references people have come forth with. Good reading (if you saw my other recent post, you know I love reading about HSD). This post was better than a Google search!

And now for the next topic, if an HSD system powers up in the forest, does it make a noise?