Hi All:

___I just gave this thread 5 Stars thanks to you two guys. Nice job indeed! Please do not forget to press up those tires before you even start them up in the morning!!!

___Elan C, any regen is wasteful when it’s not needed. Throwing out a boat anchor is my way of saying yes, it sucks and why in the hell is it there unless you use the ****ed brakes! Your Rav4EV was designed improperly as well …

___NASAgineer, try not to use assist for any acceleration if at all possible. It will lower the longevity of your pack and it will not give you the highest FE over a given distance. A 2 bar assist or EV mode is very low current flow, a 10 + bar of 20 (if that is what shows?) is a killer! I also have some more high speed experimentation for you to do once you get comfortable working into and out of all the modes and PRESSING UP THOSE TIRES!

___Good Luck

___Wayne R. Gerdes

 

No, I only get full regen when I take my foot off the gas if I'm going down a steep hill, or I put my foot on the brake firmly. If I understand what you are describing as a [B] gear, the 06 HCH has one built into the brake pedal! When you apply pressure to the brake pedal, the HCH figures out how much of the braking can be accomplished with regen, and only uses the hydraulic brakes to make up the difference. It depends on how hard you press the pedal. As you press harder, regen increases.

 

Try driving on the Bay Bridge from SF to Oakland. The final section is a straight decline about two miles long. In my EV I can coast the whole way at 70 MPH with zero energy consumption and zero regen. Basically it's like being in neutral. It's a good place to try various experiments with slight acceleration or deceleration.

 

Great! I was hoping it works that way.

What happens if you just take your foot off the gas pedal and don't touch the brakes? Does it coast as if it's in neutral or does it apply just enough regen to simulate the behavior of a regular gasoline powered Civic?

 

Yep, I did the same thing coming down 280 tonight (although at 60-65, not 70). Problem is I lose any gains I got when I go up the next hill My trip mileage from SF to SJ down 280 and 85 (~80 miles) was 54, almost all on cruise control at 60-65.

 

If it's flat, it just coasts. If it's downhill, it regens, the steeper the downhill, the more regen. I can cancel the regen if I want with slight throttle pressure without starting the ICE back up.

 

How so?

Just to clarify, the RAV4 EV has three modes. "Normal" driving is in [D]rive with EB (electrnic braking) on. Electronic braking applies enough regen when you take your foot off the pedal to simulate the deceleration of a conventional vehicle. It's a convenient mode because it doesn't require the driver to adapt his driving habits. Since I often alternate between my EV and my other car, I think this mode is useful and safe.

Another mode allows EB to be turned off. There is no regen when you take your foot off the pedal. The vehicle coasts as if it's in neutral.

The third mode is [B] as I described earlier. Higher regenrative power is applied when you take your foot off the pedal with the effect of slowing the vehicle down as if you were moderately pressing on the brake.

There is so much demand for these "improperly designed" cars that three year old used cars are selling for more than their original purchase price.

 

Wayne, could you summarize what tests you'd like me to try? Remember, I'm no hypermiler, so use english Like, what's DWL? I also don't have any experience with any of the previous HCH's (or any hybrids for that matter), so I can't compare behaviors.

 

Hi ElanC:

___Do you know how you sustain > 110 mpg from a Prius II when the Prius II commercials are telling us how great Regen is? You Do Not Use Any!

___The following should be enough …



___This is no regen (or as little as possible) with all the 5 minute bars maxxed at their 99.9 mpg limits. ICE braking is one of the biggest wastes of fuel in the US and the simulated ICE braking via Regen in an HEV/EV is another waste. Recovery is not 100% and the loss of momentum is a FE killer! That is why Regen is a mistake unless you actually do have to use the brakes? Your No EB mode is close but what happens when you do touch the brakes in the No EB Mode? Do you receive regen or not?
___You have no idea what I am talking about. If you want to see how a $23,000, semi-lux, non-hybrid sedan can achieve FE similar to that of a $27,000 Prius II, use some of my methods and you will see the hidden mistakes of the Prius II in great detail. The mistakes of all automobiles can be countered in some fashion including the non-hybrid Accord I drive but not without a lot of screwing around and not without losing something in the process. This includes your $42,000, 0 - 60 in 18 seconds, RAV4 EV from what you described?

___NASAgineer, DWL is “Driving w/ Load”. Assume your HCH only put out 25 HP at all times. As you are headed down the highway, you are WOT (Wide Open Throttle) and doing a max of 60 mph. Because you only have 25 HP, as you begin to climb an overpass, your speed droops. As you crest the overpass, you have reached a lower speed of let us say 54 mph. On the back side of the overpass, that same 25 HP at WOT accelerates you right back up to 60 mph. Since you obviously have way more HP then 25, your HCH will use more HP and Fuel to maintain 60 mph up the ascent on the front side (and burn gas like a SOB in doing so) and drop off the accelerator as you crest and drive down the ascent on the other. This is the worst way to drive over a hill. What you want to do is roller coaster it. Let us assume you hit the overpass at 60 mph and your instantaneous is sitting at 60 mpg. Instead of applying more accelerator to maintain 60 mph, lessen your accelerator pressure to maintain 60 mpg instead. At the peak, you should see your instantaneous still at 60 mpg but it should begin to climb. Add a slight bit of accelerator to maintain 60 mpg until you are again at 60 mph after descending the overpasses back side. This is DWL in a nut shell. You can actually do a bit better then this overall by letting the instantaneous peg on the back side and slowly accelerate back up to 60 mph after some distance past the bottom of the descent too. You will see this in action tomorrow morning.

___About the high speed technique. All I want you to do is perform a HS-P&G (High Speed Pulse and Glide) using your new found high speed Quasi-EV like mode. Accelerate without assist to 65 mph and EV/Glide back down to 45 mph. Repeat … Hopefully, your SoC will stabilize out at maybe 6 of 20 bars (I have no idea here?) and you can HS-P&G to your hearts content. Inside of heavier traffic, you can only HS-P&G between a much tighter range of course but you will get the hang of it and see what she is worth at various acceleration rates and speed ranges in very short order …

___I am really excited for the future HCH-II owners and what they may have available to them given what you have posted in the last 24 hours!

___Good Luck

___Wayne R. Gerdes

 

xcel, I agree completely with your sentiment on the regenerative braking. Here is how the '06 HCH works: At any speed, when you take your foot off the accelerator, gentle regenerative braking is applied. When you touch the accelerator pedal the braking is removed but the engine is turned on again. So even though much better FE could be achieved in a true coast, you are forced to keep the engine running unless on a downhill or you need to slow down anyway.

The regenerative braking is very gentle without the brake applied but there is some of it.