Best way to add regenerative braking to a Jeep?
I have a 1998 Jeep Cherokee 4x4 that I am trying to both modernize and make as efficient as possible. It's never going to be a prius but I know it can get better MPG than what the factory built.
With that said, I'm converting most of the accessories to electric power - cooling fans, water pump, air conditioning, power steering. Basically I'm going to eliminate everything on the belt system. The "alternator" will be a bank of rechargeable batteries so as not to add extra load to that. I will plug it in to recharge when it's parked. I'm going to set it up so I can kill the engine and coast as much as possible, also during stops instead of idling. I'd really, really love to have some kind of regenerative braking on this thing. The fewer batteries I can have, the better, obviously. Does anybody have any good ideas as to where I can add some sort of generator that would be activated with the brakes? I could add one to the engine pulley and use it like compression braking, but, the engine will still be wasting some of the power if I do that. It would need to be in gear while coasting. Is there a (relatively) easy way to add some kind of generator to the driveshaft? Something that would activate with the brakes and start generating power? It could go on either the front or rear driveshaft. Or maybe something that would attach to the transfer case? I know I've heard of hot rodders using an axle mounted alternator to clean up the engine bay, but I'm not sure how they attach it. Just looking for some input before I try and re-invent the wheel. Thanks for any info. |
Is your Cherokee an automatic? Most automatics can't handle engine-off coasting.
I want to do what you're suggesting on my Civic. I drive with the alternator belt off in the daytime and I'd love to get some charging down big hills. With a 4WD Jeep, you have a lot more places to drive an alternator. I'm guessing an axle-mounted alternator would be driven by a pulley sandwiched between the axle and driveshaft. Some trucks have a PTO output on the transmission and/or transfercase. That would be a really clever way of doing it if your drivetrain has a PTO output. |
I suggest leaving your alternator on the engine, but having a kill switch for it so you can turn it on when going down hills to capture some of that kinetic energy. I've been known to use the air conditioner like this too, since it's effectively free.
A free-spinning alternator not generating power has very little resistance and you'd probably not see any difference at the tank level vs taking the belt off. The advantage here would be that you would also be able to flip it on if you need to drive greater distances than the batteries can sustain. If you wanted to use some of that electricity for propulsion you could, I suppose, put another small motor on the belt system running off of the same 12v, but be aware that the net effect of the system will be near-negligible. Even on my Insight, where the car only weights ~1900lbs and the batteries can provide 100amps @ ~165v (16,500 watts), the energy captured by regenerative braking is relatively small, and though you can definitely feel the assist in propulsion, it saves relatively little gas overall; it's more a drivability aid for an undersized engine running lean, which is what really saves gas. With a 12v system you're not going to be capturing 1/50 of that, in a vehicle with more than twice as much mass. |
Is the purpose to recharge your 12v on-board battery? or to capture power to put back to the drive wheels when you take off?
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Wow, off-the-shelf differential mounted alternators! (of course overpriced)
https://www.summitracing.com/parts/p...eZORoCUeHw_wcB http://www.speedwaymotors.com/9-Inch...tem,27898.html http://www.ebay.com/itm/Powermaster-...-/330828187386 I've long wanted to do this with an AC drive motor such as the following to not only get significant boost, regen, and mpg, but also allow slow maneuvers without the engine running. Of course that is after the power steering goes electric. AC 2X Kits |
How will you convert the air conditioning to 12v electric?
Only like 3 people on here besided my self have even been able to go electric on power steering. I have an electronic water pump and I actually do not recommend them unless part of a coolant prewarming circulation setup. Unless you have some pretty incredible instrument controls and elecrtical knowledge, fabrication and design skills along with the tools to do make a regeneration hybrid it's not going to happen with out more money than it would take to buy a new hybrid SUV. |
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I'm not attempting to do any electric driving of the wheels, just every accessory. Also keep in mind my Jeep only weighs about 3,000lbs - only slightly more than a small economy car. Of course, more batteries means more weight, but more regenerative braking means less batteries. Quote:
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It really doesn't take a lot of controls for all the things I'm planning, certainly much less than it would take to install a large electric motor for propulsion. Simple thermostats and relays will do most of the work. |
I ran an electric cooling pump on my 5L Camaro ,suburban with a 454 and my 6.5L diesel.
I know pretty much all there is to know when it comes to electric cooling pump conversations. As far as I could tell the electric pump gave no measurable fuel economy important. All it does is use more power and make an alternator delete more difficult. The main benifit they give is being able to circulate coolant with the engine off. When I said I know know 3 people who have done electric power steering I was taking about members here. Cheap power inverters tend to destroy induction motors, a pure sine wave inverter should be used. There are no cheap pure sine wave inverters. |
Not all mods have to pay off or make any kind of financial sense though. Sometimes I like to tinker for the sake of tinkering. :p
I don't think regenerative braking is going to happen with bolt-ons, at least not in any meaningful way. Sure, there are hybrid conversions for sale on the market, but they're not remotely cheap and require some fabrication. And, unfortunately, most of the gains from hybridizing a vehicle are not from capturing braking energy, but from being able to use an undersized engine and/or run it lean and/or with the Atkinson cycle, and running that undersized and "detuned" engine as little as possible. I think the low-hanging fruit is going to be maximizing engine-off time in the Jeep, given how relatively inefficient and large the engine is. However, I'm under the impression that many automatic transmissions require the engine to be running for lubrication and cooling (? never owned an automatic) and that you run a very real risk of detonating it by coasting with the engine off. |
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