Hybrids

[honda03842]

My goal is to explore the possibility of using a Hybrid as a tow vehicle.


First I have moved this to it's own thread. The thread started with my exploration of the possibility of towing with a hybrid. I have received two links to stories about hybrid towing and extended hybrid use as taxis. Both are interesting stories about the operation of these vehicles in tough environments. Both Links follow:


Escape Hybrid towing: http://www.starclass.org/artman/publish/article_357.shtml


Hybrid Taxis:
http://news.consumerreports.org/cars/2009/04/nyc-hybrid-taxis-prove-reliable-.html


I will say both of these links came via private emails because the source did not want to face the “fear mongering” that sometimes appears with “out of the box thinking”. This is not the topic but worth recognizing.


I'm not so interested in government behavior with respect to green subsidies. We can not change that environment. We can only live within it's confines. My singular interest is hybrids.

As I gather info on the subject my intent is to post it in this thread much as I have in Preparing a 1991 Scamp.

[David Tilston]

I look forward to your insites Norm.

[honda03842]

My introduction of the possibility of towing with a Hybrid was injected into the Thread in the title of this post. I had just looked at a 2013 Ford Escape and a Ford CMax hybrid at the dealer. Sorry Rick for interrupting your thread.

This is a response to Jim's comments on Keith's use of brakes in his hybrid (see link in previous post), to help establish how hybrid brakes function. People with more info please don't hesitate to add clarification.

Jim (CPAHarley) made the following comments about Keith's towing.
“That article' author amazed me with their cavalier attitude that towing 1500 lbs over her manufacturer's rating is acceptable, even pointing out that purposely avoiding using the brakes is beneficial to her driving experience and efficiency. Trying to eek out every advantage of energy conservation is commendable, but that type of driving and towing a trailer seem incongruous. Pulling a trailer is not energy conserving, you are towing another vehicle that is heavy and has it's own brakes which which must activated with your vehicle's brakes. Totally different style in driving habits and they indicate that the style is the same, towing or not. Your stopping distance is considerably greater and the wear and tear has to be more than non towing driving, but they indicates little change as they monitors their towing by For towing, I just keep my eye on the tachometer and MPG indicator to be sure I am not over-taxing the enginethis indicates they have little understanding of the effects towing has on her vehicle.

I do not know about them but I watch my engine temperature, my transmission temperature, the outside temperature, and my gas gauge when towing, my "MPG" is the last thing I'm interested in because I'm towing.”


Keith's comments about braking relates to how hybrids dissipate speed with out traditional brake pad/disc engagement. Instead of heating pads and discs, it converts energy to electricity, charging the battery and slowing the vehicle. If necessary the traditional brakes can be activated as in a normal vehicle. The simplest way to view hybrid braking, is it like down shifting, slowing the tow vehicle and trailer down, but in the hybrid case capturing electrical energy.


I believe the typical hybrid has the same braking ability as the traditional hybrid as well as the hybrid's unique braking, energy recovery system Though the braking maybe different, I don't think it's dangerous.


Keith also considered that the hybrid was the same vehicle as the gas powered version, same brakes, same chassis even an engine combo as powerful as the Escape's V6. He made an evaluation and choose to test his reasoning, a rather powerful view that he has shared with others after an extensive trial.

There is nothing in Keith's statement that he doesn't watch his gauges. I rather closely watch mine including trailer tire pressure but also watch mpg. As to mpg efficiency, it is to those of us spend 20 or 30,000 miles a year on the road. Cost of everyting is increasing and watching costs has become more necessary.


Based on the articles it seems that a used Escape Hybrid is a possibility or possibly a 2014 Escape Hybrid or maybe even one of the C-Maxs. My goal remains to contact Ford and read their response to my use of their hybrids to tow. I will post what I learn in this thread.


Towing my Scamp with a hybrid getting 27 mpg at 55 mph sounds great.

[Bobbie Mayer]

I have a concern/question about braking with the hybrid- I understand how that works, but if you downshift instead of activating the car brakes, you don't activate the trailer brakes. Doesn't this lead to the potential for the trailer to push the car or for problem handling on downhills?

Otherwise I'm impressed by the mileage he gets. I wonder how the Highlander does? I didn't think the hybrid had the same 3500 lb limit, though. Unless he just means he figures it is okay to go with the V6 limit instead of the hybrid limit.

[rabbit]

If the only issue was that regenerative engine braking doesn't activate electric trailer brakes, surge brakes or another system for activation of the magnets would be the answer. I'll bet there are larger issues of limited torque development by modestly sized electric motors and the reliability and efficiency of expanding sheave transmissions in many hybrids. Yeh, I know motors produce good torgue at low rpm. I don't happen to think a hybrid is designed, let alone optimized, for towing. If the engines and motors are used outside their design service, isn't their failure rate per mile going to increase?

jack

[rabbit]

The Highlander hybrid probably tows about like a non-hybrid Highlander. The batteries and motor are only in there to make a big six look more economical to operate. In other words, the Highlander gas mill wasn't optimized for mpg; it was supplemented by the electric to salve consciences.

jack

[Bobbie Mayer]

Well, I think the Highlander is rated for towing, but not high. Correction, just looked it up, and it is apparently rated for 3500 lbs but people say 2000 is more realistic.

But its gas mileage isn't that high. I looked at it compared to the Forester and thought the only advantage was a tiny bit more room inside, unless you do a whole lot of city driving where the electric is used more. Plus a much heftier price tag.

[Bobbie Mayer]

Originally Posted by rabbit

The Highlander hybrid probably tows about like a non-hybrid Highlander. The batteries and motor are only in there to make a big six look more economical to operate. In other words, the Highlander gas mill wasn't optimized for mpg; it was supplemented by the electric to salve consciences.

jack

That makes what I was typing at the same time make sense!

[Francesca Knowles]

Originally Posted by Bobbie Mayer

I have a concern/question about braking with the hybrid- I understand how that works, but if you downshift instead of activating the car brakes, you don't activate the trailer brakes.

Like Jack said, surge brakes are one possibility...but:

I think surge brakes an inferior substitute for electric unless fitted with an electric actuator for manual braking.

Don't know if this then overrides the "surge" function, in which case one would be right back at start in the case of this hybrid!

Francesca

[honda03842]

I'll ask the Ford expert about braking though I'm sure it's not an issue.

I have down shifted with no ill effect, not an uncommon tactic on a steep long down hill run instead of heating up the brakes. It is amazingly easy to overheat your brakes on a severe downhill run.

[David Tilston]

I come from an oil and gas background. Gas compressors are frequently powered by natural gas engines, big ones. They run at full output as much as possible. That's where they are most efficient. But also because they are producing more gas that way.
My point being, an undersized motor running at full output is more efficient then an oversized motor running at 30% of full output. Also, it is easier to tune an engine to produce more power and run efficiently in a small RPM range, which may not apply so much in this case.

[Brian B-P]

Originally Posted by Bobbie Mayer

I have a concern/question about braking with the hybrid- I understand how that works, but if you downshift instead of activating the car brakes, you don't activate the trailer brakes. Doesn't this lead to the potential for the trailer to push the car or for problem handling on downhills?

This is valid, but applies to engine braking in a non-hybrid as well, and is not a problem for moderate braking action. Engine (or regenerative) braking should always be used to maintain speed - to keep it from increasing - on extended descents; if you don't know that, you are a danger in mountainous areas, as you risk overheating the brakes dragging them down hills. Ask any qualified driver of a heavy truck rig: engine braking is necessary on some roads, and effective for appropriate use even away from the big grades.

When the brake pedal is pushed, the stop lamps go on and the trailer brakes are enabled, even in a hybrid using regenerative braking... the vehicle designers thought of that.

While surge brakes have advantages and are a great choice for some rigs, descending long grades is a bad situation for them. If the tug is braking to hold back the trailer (by any method) the trailer brakes will drag and could overheat.

Personally, I find that our Boler is more parachute than bullet, and the van+trailer rig rolls downhill more slowly than the van alone - the Boler acts like an anchor or drag chute and little braking (engine or otherwise) is needed except on the steepest downgrades or those requiring the lowest speeds due to curves.

[Brian B-P]

Originally Posted by honda03842

Hybrid Taxis:
http://news.consumerreports.org/cars/2009/04/nyc-hybrid-taxis-prove-reliable-.html

I will say both of these links came via private emails because the source did not want to face the “fear mongering” that sometimes appears with “out of the box thinking”. This is not the topic but worth recognizing.

I don't know what would be “out of the box thinking” about using a hybrid as a taxi: urban traffic is the operating environment for which they are best suited.

New York appears to be new to hybrids as taxis - they have been used for much longer in the Vancouver B.C. area, where the Prius is very common as a taxi due to high fuel prices, the roomier Prius V is almost the default choice, and these vehicles have proven over three vehicle generations to be solidly reliable. The Prius V is even becoming common in Calgary and Edmonton, where fuel is much less expensive (although still high by U.S. standards); previously, only a moderate number of Camry Hybrids were noticeable.

The NYC taxi rules include minimum interior room requirements, which may be why they don't use the Pris there, but I rode in a regular Prius taxi in Calgary, and found it roomier - at least in legroom and headroom - than the traditional Crown Victoria.

[Brian B-P]

Originally Posted by rabbit

I'll bet there are larger issues of ...
the reliability and efficiency of expanding sheave transmissions in many hybrids.

This is usually called a belt-type CVT, but yes this type does use expanding pulleys or sheaves.
The big player in hybrids is Toyota, which does not use a mechanical CVT of any kind in its hybrid system, called Synergy Hybrid Drive. Ford uses the same design as Toyota. GM and Dodge use another variation of Toyota's design (called Two Mode). That leaves only Honda and maybe Nissan or the Koreans using a belt-type CVT in a hybrid.

[dbailey]

I'm a newbie with respect to trailer brakes, so I'm likely wrong, but...

My understanding of proportional controllers (or so-called pendulum controllers, though I'd be surprised if any modern ones actually still used a pendulum) is that they apply power to your trailer brakes based on the tow vehicle deceleration, regardless of the source of that deceleration. If you hits the brakes, or down shift, or drag your feet Flintstones-style, doesn't matter -- your tow vehicle slows down so the controller senses the deceleration and thus sends power to your trailer brakes.

If this is all there is, it means that on a down grade, if you hit the brakes to slow down the trailer brakes will come on. But if you ride the brakes down the hill (yeah, bad driver) maintaining a constant speed, the brake controller won't detect deceleration, so won't apply the trailer brakes.

Now, I'm not sure if the brake controller *also* watches your tow vehicle brake lights and applies braking to the trailer every time you touch the brake pedal... If it does, then riding your tow vehicle brakes down a hill at constant speed will mean that your trailer brakes are also on...

Could any one clear up that point for me? Does a proportional brake controller watch the tow vehicle brake signal as well as watching deceleration?

[honda03842]

Brian the out of the box thinking I was refering to was Keith's considering the Escape Hybrid's heritage and realizing he could tow his 2500 lb boat with the Escape instead of simply reading the 1000 lb rating and not considering using it as a tow vehicle.

Another marvelous attribute of the Escape Hybrid is you can turn the key to the on position with the trailer hooked up and the Escape's DC-DC converter sends power from the big 330V battery to the 12 volt battery and charges the trailer's battery - without running the engine.

[Francesca Knowles]

Originally Posted by dbailey

Does a proportional brake controller watch the tow vehicle brake signal as well as watching deceleration?

It does neither- the brakes are only activated electrically by the controller, by way of either stepping on the brakes or using the manual activation knob..

Francesca

[honda03842]

Jack (Rabbit)

Most of the most popular hybrid vehicles including Toyota and Ford do not use sheaves, but rather a planetary gear system. Personally just beginning to understand it.

Honda uses a belt system.

Here's one of many links possible"


Toyota Prius - Power Split Device

[rabbit]

My wife has a 2010 Prius. I understand about the ICE, Norm. I think it's grand that it has more legroom than a Crown Vic, Brian. I'm sure it's a wonderful taxi. I'm also certain it would be an incredibly inadequate tow vehicle for a 1 ton trailer. But of course, no one is considering a Prius as a tow vehicle. I don't care about the bun one way of the other but there are meat and potatoes vehicles and others that aren't. And no free lunch.

jack

[Jared J]

The highlander could be promising, although some have mentioned low mpg and high price.

The escape doesn't look to promising with a 1,000 lb rating. They put it there for a reason, who knows why...