Last post on Nov 13, 2011 at 11:20 AM
You are in the Toyota Highlander Hybrid
What is this discussion about?
Toyota Highlander Hybrid, Hybrid Cars, SUV
#3698 of 4026 Re: Performance Hybrids [desertfox1]
Mar 26, 2007 (2:41 pm)
"#65 of 65 Re: Performance Hybrids [stevedebi] by desertfox1 Mar 26, 2007 (12:46 pm)
Replying to: stevedebi (Mar 08, 2007 10:11 am)
"The Nissan Altima hybrid does use Toyota HSD technology"
I was excited to hear Nissan was coming out with Hybrids, but I read that the Toyota HSD Technology they will be using is not the latest generation that Toyota will have in theirs. I suppose that makes sense from Toyotas standpoint."
I doubt if Toyota is still producing the first generation HSD components. I thought the Nissan used the Gen 2 stuff.
Does anyone have a URL for this issue?
#3699 of 4026 Re: Performance Hybrids [cdptrap]
Mar 28, 2007 (7:23 am)
I drove a 2008 model Ford Escape Hybrid last week. Wow what a vehicle. The ride was quiet and smooth and the climate system is much improved over the previous model. I was pleasantly surprised to find that dual zone automatic climate control was standard on the FEH. I also noticed that beyond the clutter of the new fuel economy sticker calculation method, Ford actually improved the fuel mileage. They list the new calculation method in big numbers, but the old method is still listed in small numbers under the big ones. 2007 model was rated at 36mpg city, but the 2008 is rated at 41mpg city. Fit and finish was also much improved for 2008 as the entire platform was revamped.
I'd been considering a Highlander, but after my experience with the Ford Escape Hybrid, I'll be back at the dealer with my wife to finalize the deal next week.
#3700 of 4026 Re: Performance Hybrids [bowman24]
Mar 28, 2007 (12:46 pm)
Good to hear about improvements in FEH. I just hope Ford keeps doing it at a more intense level. The more full-hybrids we have on the road, the better.
Mar 28, 2007 (12:57 pm)
Here is a crazy one.
1. Instead of CRUISE at set speed, have an option to CRUISE at set power. Just like flying , the HH cruises to that power level. I can adjust the speed on an as needed basis. This allows me to save gas without having to constantly adjust speed.
2. Now for some really cool advanced features:
a. Allow speed-limit dial-in.
b. Have a look-ahead CRUISE. This is already in Lexus.
c. Have a look-behind CRUISE.
WHen I CRUISE on set-power, the front detector adjusts speed and power to prevent collision and tailgating as it does today. The rear will detect fast approaching cars so it can warn me but more importantly, when my power is set so low that the car is moving below speed limit, the rear radar will work with the front radar to safely accelerate to safe speed (<= speed limit) if it detects traffic is approaching from the rear. With this system, I can just set a maximum speed and a desired power level and let the car drive itself . If we can do this for airplanes, no reason why we cannot do this for cars. Add plug-in to this mix, it may just eek out an extra 5-MPG or 10-MPG.
#3702 of 4026 Re: Performance Hybrids [bowman24]
Mar 28, 2007 (6:43 pm)
The other nice thing about the FEH/MMH is that you can have a mechanic remove one front halfshaft and "lock" the rear drive line and you have a RWD hybrid that is much SAFER than the FWD ones.
#3703 of 4026 Re: Performance Hybrids [wwest]
Mar 31, 2007 (7:51 am)
In what situation is RWD safer than FWD?
RWD if the drive wheels lose traction you'll have a tailspin. In FWD, lose of drive wheel traction = udersteer.
2. Acceleration from sleek road?
RWD, slower due to lighter rear weight resulting to less traction and more tendency to be immobilized, if both sides slips will result to tailspin again.
FWD, drive wheels has better traction due to engine and tranny weight and you can initiate side wall traction by turning the steering. Torque steer is controllable if you can control youself from pushing the gas pedal too far.
No difference among AWD, FWD, RWD. It is a function of the brahking system and not the drive system. Unless you are a rally or race driver who wants to take advantage engine braking to aid in slowing down and fine tune your power slides.
Maybe you can elaborate in which specific situation is RWD excels in safety compared to FWD.
#3704 of 4026 Re: Performance Hybrids [peralta]
Mar 31, 2007 (10:29 am)
Ford was actually awarded a patent, specific to the FEH/MMH or almost any FWD hybrid, that quite satisfactorily addresses this issue. Ford's patented technique is to significantly reduce the level of regenerative braking to be used if the OAT has declined to near or below freezing, and to INSTANTLY disable regenerative braking altogether if ABS activates while the brake pedal is depressed.
For almost ten years now the entire automotive industry has been going through an evolutionary change, trying to alleviate loss of control accidents caused by "inadvertent" engine compression braking while operating on a slippery roadbed.
Automatic transaxles are now being programmed to instantly UPSHIFT upon a full lift-throttle coastdown event. In most of these vehicles if you want a substantial level of engine braking you must manually downshift the transaxle.
You may notice that FWD vehicles equipped with manual transaxles are now seemingly going the way of the Dodo bird. One of the few left in the marketplace will actually rev-match the engine to roadspeed if you fully lift the throttle but fail to depress the clutch pedal.
Yes, the ability to have the "tail wag the dog" via too much "drive" to the rear is unique to RWD. But the nice thing about that is that with RWD you will still have directional control whereas with FWD you are now in God's hands.
#3705 of 4026 Re: Performance Hybrids [peralta]
Mar 31, 2007 (10:51 am)
An overstearing vehicle leaves the roadbed tail first, an understearing one head-on. Unless the driver of the RWD knows to counterstear with the wheels that are likely to still have traction.
"2. Acceleration from sleek road?"
FWD, hands down..!
Unless I have a 500 lbs of rocks in the rear of my 93 Ford Ranger PU giving it a definite rear weight bias.
But like with AWD/4WD/4X4 this often leads to over-confidence due to lack of "notice" of actual roadbed conditions.
RWD, hands down.
No engine compression braking on the front wheels, NONE, to interfere with the anti-lock system's ability to keep those front wheels rolling, even ever so slightly, and thereby allow the driver to maintain directional control right down to a full stop.
Think of this, stupid as it might be.
You're driving along in "cruise control" (mental or literal)and the climate is sub-zero. Suddenly you hit a bridge deck that is completely iced over. With RWD you INSTANTLY lose most roadbed traction at those rear wheels and now the tail begins to wag the dog. If the driver is quick enough, a recovery can be made by counter-stearing into the skid.
With FWD what would most drivers do?
Lift the gas pedal INSTINCTIVELY and thereby inadvertently apply engine braking to those front wheels.
And then HANG ON...?
Mar 31, 2007 (3:47 pm)
I think you should be aware that German engineers try hard to make there Mercedes and BMW to have minimal oversteer. In fact, some even dial an initial understeer.
The reason is they claim it is much more stable, predictable, and safer. With ovesteer, the car can easily turn around before the driver can catch it.
Wwest, that is not a theory, that is a fact and it is already an applied science.
To correct understeer, reduce power and the car will go back to it's lane.
To correct oversteer, reduce power, countersteer, if the tail wags to the opposite direction due to overcorrection, you countersteer again to the opposite side. Do the same sequence until the tail stops wagging, that is "if" you are still on the road.
Engine braking is almost non-existent in modern cars with automatic unless you shift to sport mode or do a manual downshift.
I want to know what kind of FWD car are you talking about that has engine braking when lifting the throttle. That is an interesting car you have there.
Compression braking intering braking system? What car are you driving?
#3707 of 4026 Re: WWest [peralta]
Mar 31, 2007 (6:36 pm)
"..To correct understear (steer is beef on the hoof), reduce power and the car will go back to it's lane.."
Understear is the result of the line of travel of the vehicle not following the direction set by the front, stearing, wheels.
That only happens when there is not enough roadbed traction for the front wheels to "force" lateral movement of the vehicle. And yes, you are correct in that you pointed out one of the most serious flaws of FWD vehicles:
"to correct understear, reduce power"
But only in the case where engine drive torque to the front wheels was a contributing factor in not having enough traction to sustain the lateral forces and the motive forces simultaneously.
"will go back to it's lane"
No, with a little luck it will begin following the path set by the stearing wheels. Staying in it's lane and NOT changing direction is the problem.
"Engine braking is almost non-existent..."
But apparently not quite non-existent enough so as to not interfere with the anti-lock feature's functionality.
About 8-10 years ago almost all automatic transaxles (FWD assumed) would downshift into first gear at about 5 MPH as you coasted down to/for a full stop. Nowadays many of them, Toyota and Lexus especially, upshift into a higher gear at 10-5 MPH as you coast down to a full stop and only downshift into first once the vehicle has fully stopped.
"What car are you driving?"
If you have ever driven on a slippery roadbed without ABS you know that it doesn't take much braking HP, application, to lock your front wheels and lose all directional control as a direct result.
The purpose of ABS, anti-lock braking, is to keep those front wheels rolling, even ever so slightly, all the way down to a final full stop, so you still have directional control.
Obviously if the roadbed is slippery enough even a slight level of engine compression braking will "BRAKE" the front wheels enough that ABS' releasing of hydraulic braking pressure will have no effect.
That's why the Ford technique warranted a patent grant.
I am driving, mostly, a 2001 AWD RX300 and I can attest to the fact that it upshifts during full lift throttle coastdown events at 40-30 MPH and at 10-5 MPH just as is designated in the Lexus shop/repair manuals.