Diesel Hybrid '70 Charger Project
 

Howdy y'all.

My project: build a diesel electric hybrid system for my 1970 Dodge Charger. I know, it's not a great car for a conversion, however I already own the car and it's not something I've seen many people do (to classic muscle cars anyway). I have some mechanical skill (I built the engine in it, and it's not just a rebuild kit) and I have a good foundation in control systems (theory/math but not so much experience in practical application, other than with speakers/subwoofers).

More about the project. The car weighed in at ~3300lbs last time I weighed it (changes haven't been enough to really change it, and those changes happened primarily to the motor). I want to setup a serial system basically...a diesel engine drives a genny, but only enough for highway cruise power. Acceleration power will come from a battery bank. Nothing cosmic on that setup, it's been done before. However I want pretty good acceleration, this is a muscle car afterall...for planning purposes I've used 4sec 0-60mph as a goal.

Lately I've been looking at various AC motors and I've been looking closely at the Emrax motor (liquid cooled) from Enstroj (~100kW peak, ~40kW cont., 270Nm/120Nm peak/cont). I like it because of it's performance, it's size, and it's light weight, but of course these aren't the cheapest motors out there. Based on my planning accel. goal, I've come up with needing 3 of those motors all coupled together driving the input shaft of my transmission.

For the diesel generator setup, as an early thought, I came up with using 2 more of the same Emrax motors as the generator. This generator would be capable of producing a lot of electricity, way more than needed for cruising, so I would want to cap the power output to avoid overloading the diesel (assuming a small diesel only big enough to provide enough hp basically to propel the car at highway speed, plus all the losses and inefficiencies in the power transformations).

The biggest problem I'm running into in my plan right now is the controller. All of the AC controllers that are powerful enough to control an AC motor at these levels are about twice as expensive as the motors themselves. And I'd end up having to get one per motor since none of them seem large enough to control more than one of these. So I started looking into the DIY route for controllers. I like that route and I'm not afraid to jump right into something like that, however I had another thought: if the generator is matched to the motors (as in using the same type/model motor as the generator so the ouput would match the input of the drive motors) then a simplified controller would be all that was needed between the genny and the drive motors (ignoring the batteries at the moment). Basically a controller to convert the high volts/high amps (when needed) to the appropriate voltage/frequency/pwm and amps required based on throttle input. A simplified controller like this "seems" like it would eliminate at least some of the inefficiencies of converting AC output to DC then back to AC for the drive motors. The big problem is I know enough about controllers to design something like this. I don't even know if my logic is sound in this case.

I apollogize for the long post, the rest of my posts should be short & sweet. I hope. Anyway, I'd appreciate any and all feedback/suggestions/advice y'all can give. I'm still only in the planning stages and I'm not 100% set on anything, although I'd really like to stick with the diesel engine part...easy to make it run on bio!;) Thanks in advance for any and all help!

Doug

Interesting project Doug.

I'm not too familiar with AC setups, but I would highly recommend sticking with one electric motor if at all possible. I think you will just have too much added complexity and cost with multiple motors and controllers.

Have you looked at industrial AC motors? They're not as expensive since they're mass produced. Also, industrial VFDs aren't incredibly expensive. A local EV club member went this route with his car and is quite happy with it.

Daox, I would definitely prefer to stick with 1 motor, but I haven't been able to find something with enough output to achieve the performace goals I have with just one. I haven't looked into industrial motors much yet, not real sure where to look for something with about 800Nm of torque. If anyone has any suggestions for specific motors I could look at I'd welcome them. I definitely prefer simple! Thanks for the help!

Interesting project. What sort of diesel engine are you using?

I haven't settled on a particular diesel yet, but I found the VM Motori 2.8L diesel is a pretty good match...small, decent power (especially around the RPMs it would prob get used at), and pretty efficient (BSFC at peak torqe is about 200g/kWh...according to their documentation). Also, it can be found in some American vehicles (like the Jeep Liberty) so finding one salvage may not be impossible. I looked at compact diesels from Kubota and Kohler and Yanmar among some others, but they all tended to be heavier, bulkier, lower power, and/or less efficient than the VM engine. Still looking, and still open to other ideas.

I really wanted to use a Cummins small engine, but only because I love the Cummins in my truck!! ('05 Ram 3500 SRW...I've had a best of 24mpg from it on the hwy with 35" tires. It weighs 8000lbs.) But the small Cummins offerings are too bulky/heavy and just not realistic for this project...although I'm not really sure how realistic this project is as a whole to begin with, but it's something to work on.

Ok, so I forgot about something super simple that will REALLY help me out on this project. Something I've been planning on for a LONG time (ever since I got the car in fact) and yet forgot about it when I started planning this hybrid project. Changing the differential ratio. Yes, I know, dumb, rookie mistake. I need to replace the rearend anyway...it's a weak, base-model version that wouldn't hold up to much torque anyway! Now my motor options are wide open again! :)

Go ahead if you must and laugh at me, I'm a grown man, I can take it!

Is the primary focus going to be drag racing or highway cruising, or something else? Cuz I'm not seeing the benefit of what's basically an electric transmission, unless there's so much battery that it's more like an ICE augmented EV.

I agree, if it were me I would just find a 6.2, 5.7 or benz diesel with a matched FWD or RWD setup and matched MT and be done with it.

You couldn't drag race but if you are going for fuel economy why would you?

If he wants this to be a hybrid he will need FWD and not have a choice, otherwise you have the blasted inline motor problem.

Hi Doug,
What does this mean?
-m