Quote:
Originally Posted by 48V
I really, really want a 1/2 ton plug-in hybrid pickup truck. First, I want all the engine accessories to be electric. No alternator, just a battery pack. Relatively simple to accomplish.
Second, I want the front wheels to be electrified. It doesn't need to go very fast, just for creeping along in traffic, parking lots, drive thrus, etc with the engine off. It could also provide regenerative braking at higher speeds.
If I start with a generic 1/2 ton 4WD truck (I'm not naming a brand on purpose) what would be the best way to try and accomplish this? I would like to get rid of the transfer case but keep the front axle.
What size motor would I need to do such a thing? Could I do something as simple as attaching a ~10hp electric motor to the front driveshaft, or directly on the differential? I'm not really sure how much power I would need, or what options are out there. I would prefer to keep the whole thing running on 48v if I can...
Thoughts?
|
Traction motor:
Motor size would depend on gear ratio and desired speed and acceleration. For creeping long in traffic you
could possibly get by with a 10hp motor connected to the front drive axle.
But you'd either need a way to disconnect it when going faster than a crawl or a bigger motor.
The thing is that in order to get enough torque you'd need to gear the 10hp motor down. But if it's constantly connected you would over-rev it and blow it up when going a faster speed. So you need a clutch to disconnect it. Of course if you use a clutch and disconnect it at higher speeds you wouldn't have any regenerative braking. So you need a motor that will rev up high enough and that's powerful enough so that the gearing (in the differential for an example) won't make it have so little torque it won't move the vehicle.
Motor type is also important. Series wound motors can have very high torque at low speeds and not have to be very powerful over all to do so. But it is very difficult (just consider it impossible unless you're an expert) to do regen in a series motor.
Accessories
Of course, for your accessories to be powered by electricity you'd need an electric motor that turns the accessories. But it would either have to match the voltage of the main motor, or you'd need separate batteries, one for the main plug-in hybrid, and one for the electric accesories.
If done right you wouldn't need an alternator (use the high voltage traction battery to power a DC to DC converter to charge the 12V system). So you could remove the alternator and put in place an electric motor that runs off the high voltage traction battery and route the accesory belt so it dpesn't connect to the crank pulley (or put a free wheeling pulley on the end of the crankshaft). That way it could run your A/C, power steering and water pump.
To make it even more efficient you'd hook up an electric motor to each of those separately, one for the A/C, one for the power steering and one for the water pump. That way, you only get power steering when you need power steering, or pump water only when you need to pump water to cool the enigne or heat the cabin, etc. Of course then you'd have to re-plumb things like the A/C compressor which needs high pressure tubing.
Quote:
Originally Posted by 48V
This is something I have been thinking about for a very long time. Technology is changing so fast it's kind of hard to keep up. Much of it is for convenience and reliability as much as it is for gas mileage. I want to be able to "idle" with the engine off. By that I mean heating or A/C, lighting, or creeping forward. I don't want any belt system on the engine, and it would be useful to be able to run electric water pump and fan with the engine off, or maybe a block heater depending on weather.
There will be an additional gas powered DC generator in the 3-4kw range installed in a toolbox in the bed. Obviously a battery pack, not huge, hopefully around 10kw, and it will also have a 10kw power inverter so it can be used as a mobile generator. With that I can also power 120v accessories like a block heater or air conditioning.
What kind of motors are available that mount to the trans tailshaft? If I did something like that I could simply use a lighter 2WD truck right? (I don't need to go off road) I will likely be using a 4L80E for a trans unless I decide I want more gears. I know GM did it like that but I figured they are kind of rare and hard to find parts, but maybe I'm wrong.
Basically I am building a "new" 20-ish year old truck because I absolutely hate all the new stuff. Maybe it would be easier to just get the factory GM hybrid and make it as nice as I can, but probably not easy to find. I do not want something that has rare and hard to replace components.
|
Question: What is the DC generator for?
My immediate thoughts (no offense) is that if you have regen and you already have a gasoline (or diesel?) engine you already have a way of charging the high voltage traction battery. If you're worried about running out of electricity and hurting your HV traction battery at a stop you could also put a generator on the engine and just start up and drive normally under gasoline (or diesel?) power. The generator would add more weight and could possibly be less efficient than the engine you already got.
Heating with the engine off (unless you just drove and are using residual engine heat for a short time) will use a lot of electricity, especially with the HV battery suffering the effects of the cold. One thing that can help is installing (if you don't have it already) and using heated seats. It's much more efficient to heat your body directly than the whole cabin. Of course that doesn't do much to defog the windshield.
A "10kW" battery is a measure of power. I'm not sure that would be enough power, even with a 10hp motor. Once you factor in some 3-5kW of heating the cabin or some 3kW to run the A/C you'd not have very much power left over, especially in the winter.
Maybe you meant "10kWh", a measure of energy. That sounds reasonable.
What motor? Well, this is where you kind of are on your own, because this kind of thing isn't done very often (you may be the first to do such a conversion, at least on the model of truck you're looking at). I'd suggest researching EV conversion stores. You'd need a custom made adapter to connect it to your drive shaft. So you'd need to higher a machine shop.
Most everything else can be done with off-the shelf parts. Battery cells, connected together with bus bars, cables, battery management system and motor controllers are all common off, the shelf parts. Remember to look for motors and motor controllers that have the same voltage ratings (that can handle the voltages of your battery) if you're hooking up motors for your accesories too.
I suppose you already know the basics of electricity. Each cell has an aceptable voltage range (e.g. 2.5-4.0V) and amount of current (e.g. 20A) If you add another cell in series you add the voltage (5-8V) but if you connect it in parallel you add the current (40A). Then multiply the voltage by the current and you get the wattage (6.5V x 40A = 260W) And ever 1000 watts or 1kW is equal to about 1.34hp. How long it will run at a certain power depends on the energy measured in watt-hours or kilowatt-hours.
Quote:
Originally Posted by 48V
Bull****. I've explained some things very clearly but let me be more blunt:
1. I am building a nice, expensive American pickup truck. I am not driving an embarrassing MPG mobile. Nor a wagon, or whatever other ridiculous stupid thing you dig up.
2. I've explained I absolutely do not want anything new. If you gave me a brand new truck, and paid the taxes for me, I would sell it and buy an old one.
3. I never said I wanted a full hybrid. The "mild hybrid" part is really easy. Electric fans/water pumps/AC is child's play in 2021. I can literally buy all this stuff straight out of a Summit catalog and it's designed to bolt up to my engine. And it cost almost nothing.
4. As far as movement is concerned, I want less than 10mph. That is not a big ask. There are many different ways this could be accomplished, I was simply curious if anybody else had done it. Obviously that takes very little HP, and thus, 48v would be absolutely fine. Maybe even 24.
5. I already explained I do not care about gas mileage. I want a truck that is functionally superior, I couldn't care less how much gas it uses. In fact, it will be getting a 100 gallon tank. Again, as I already said, this truck will be a mobile generator, and has features that are nicer than you will find in something from the factory. There are other reasons for hybridization beyond saving a few cents worth of gas.
6. I'm not poor. I could go to the dealership and take any car they have. Again, I have not seen any current models I want anything to do with. Thus, I make the car I want. Not my first rodeo.
I'm sure this conversation is over (to be fair it never started) so I won't bother checking this any further.
|
Hey! Nobody's forcing you to do anything. Nor can we read your mind and understand all of your goals here. I don't even know what exactly you mean by "functionally superior...
I do see problems using an automatic transmission. You don't want to just pop it in neutral and shut off the engine and use the EV motor to move the truck. You would soon ruin your transmission because it would be turning without any lubrication (pump would be off). You'd need to either install an electric hydraulic pump or have a way (transfer case?) of disconnecting it completely. Or go the stick shift route.