2006 Honda Civic Hybrid's "S" Mode

It's not really higher-performance, it just uses the engine more and the electric motor less. It's ideal for going up long steep slopes without draining the battery.

 

Well, the "S" mode is an advantage in that you can drop it into S and know power is available. With the Prius, you just mash the gas and wait for the transmission to catch up. It does make a difference if you're trying to pass a truck or whatnot.

 

This seems contrary to what the Motortrend article is suggesting. It seems like they are suggesting that you don't actually gain any appriciable amount of power by switching into "S" mode. Are they wrong?

 

It's not going to make your 0-60 time any faster, no. It doesn't gain you any power.

It's more or less like downshifting from 5th into 4th. The engine is moving into the broader part of it's power range and giving you a bit of a boost. It's more or less giving you what it has as soon as you ask for it.

 

Unless Honda's current CVT has changed quite a bit from my experience, you still have to mash the pedal and wait for the engine to 'spool up' close into the redline range before the CVT kicks that power to the wheels in 'S' mode. It's still really fun to sit at the high VTEC whine range though once 'spooled up' because the engine is really really responsive at speed.

From my experience, the difference between the Honda CVT and the Toyota CVT is no parasitic HP loses at the high end and speeds due to the PSD meaning you get more of a kick in power/acceleration (and noise) at highway speeds in the Honda than the Toyota.

But of course, that could be misleading because people usually equate kick with power and constant acceleration (no kick), to be slow.

 

At highway speeds, HP matters more than torque since HP is a derivation of torque and RPM. Honda's engine specializes in HP with higher RPM limits versus Toyota's emphasis on torque with the HSD and its 5K RPM limit with some parasitic loss (28%) of spinning MG1.

So even looking at the Prius simulator, it seems the HSD would be spooling up MG1 instead of MG2 kicking in hard as you would expect by flooring it while 100% of Honda's engine power basically goes directly from engine to wheels.

From the green light, or low speeds, the HSD should cream most cars out there, including my friend's Mini as I did the other day.

 

Would you please post the reference pointer of the 28% loss?

Ken@Japan

 

It's not a loss as much as it doesn't directly go to the wheels. It goes through MG1 which can then send the charge to MG2 which would then drive to the wheels in that indirect way with associated losses.

http://www.ecrostech.com/prius/original/Un...SplitDevice.htm especially near the bottom.

We usually see this as a peach arrow from engine to generator, and then green arrow from generator to battery.

Of course when pushed, MG2 would get extra assist from the battery but maybe it's not programmed to be very aggressive.

I guess the only way to be really sure is to time acceleration time of N to M speeds between the two.

 

Thank you for your comments.

My understanding is different from yours.
At highway speeds, the ICE runs an ideal required power and the MG1/MG2 combination works like an electric torque converter.
The result will be at the minimum energy loss and the "tank-to-wheel" efficiency is 37% which is pretty good.

Ken@Japan
[Broken External Image]:http://www.toyota.co.jp/en/tech/environment/ths2/image/output_04.gif

 

"s" is like downshifting in the hch ii. additionally, it will force the batteries to recharge when you take your foot off the accelerator, even if the engine isn't warmed up. i use it all the time in the mornings to capture energy that would otherwise be lost to heat friction while the ice is warming up.