TIGON Diesel Hybrid

[GreenHornet]

Originally Posted by cRiPpLe_rOoStEr

At least you managed to get a solution which is gonna lead to a minimum impact over the fuel efficiency...

Yes The EPS system will have less of an impact then if I would have tried to implement an hydraulic system.

The goal is to keep the diesel engine as free as possible of all parasitic devices.

So far I have eliminated the Starter, Alternator, and Water Pump from the diesel engine. This frees up the diesels full horsepower capability. Which in a 2 cylinder every bit of horsepower helps!

The diesel is a V twin, which will lend it self quite nice to twin turbos :-) So it will be interesting to see how much horsepower we can make out of that little 2 cylinder diesel. I will have to design my own water/methanol injection system for it, which will not be to difficult. The injection once its fine tuned should allow the diesel to handle the twin turbos just fine :-)

I think you will digg it when I am done Cripple Rooster :-)

GreenHornet

[cRiPpLe_rOoStEr]

Originally Posted by GreenHornet

So far I have eliminated the Starter, Alternator, and Water Pump from the diesel engine. This frees up the diesels full horsepower capability. Which in a 2 cylinder every bit of horsepower helps!

So, how are you gonna start it? Using the electric traction motor to also start the Diesel?

The diesel is a V twin, which will lend it self quite nice to twin turbos :-) So it will be interesting to see how much horsepower we can make out of that little 2 cylinder diesel. I will have to design my own water/methanol injection system for it, which will not be to difficult. The injection once its fine tuned should allow the diesel to handle the twin turbos just fine :-)

Honestly, I'd advice you to get a single turbo, preferably a twin-scroll. That would lead to a lighter setup and a single turbo seems to be gonna spool faster from lower revvings

[GreenHornet]

Yes the electric motor replaces the starter and alternator! This is one way how to setup a parallel hybrid vehicle. I used to work for GM and this is how they did it on there vehicles. The difference is they used a belt and pulley method and I will link directly to the drive shaft. Linking to the driveshaft is more efficient. This is how the Honda insight is configured they simply replace the flywheel with the electric motor.

The water pump is also electronic check it out = http://www.daviescraig.com.au/Electr...0-details.aspx

On the turbo design:

My thought was to use a parallel twin turbo setup with an IHI RHB31's. I would assign one turbo to each cylinder bank. This would provide good symmetry and also simplify the plumbing vs a single larger turbo design.

I don't think they make a twin-scroll turbo small enough for the 2 cylinder!

[GreenHornet]

Here is a little bit more info on the Electric water pump I will be using = Electric Water Pumps

This is in no way a cheap way to go they are expensive however they are far superior to our mechanical belt driven water pumps. They will last a long time, you will not need to be replacing these guys. Over time they will more than pay for themselves with efficiency and durability.

GreenHornet

[GreenHornet]

Today I want to talk a little bit about chassis selection, engine placement and hybrid design.

The plan thus far is to go with an RMR engine configuration. This for those of you who do not know what RMR is that stands for Rear Mid engine rear wheel drive. This is a pretty common engine configuration that you will see on sports cars. Mainly due to its favorable weight distribution and low moment of inertia characteristics. There are also Front mid engined designs but far less common.

The Tigon utilizes a Triumph GT6 chassis for part of its platform. The GT6 was a front engined rear wheel drive design. It employed a light backbone chassis very similar to other makes and models of its time. These designs were favorable for small 2 seat cars and can be seen today like in the Miatas for example. The backbone chassis is very strong for its size and works quite well with medium speed 2 seat cars. This was part of my reasoning for selecting this type of chassis. This style of chassis while not be the lightest or strongest represented but for me a good balance at an affordable cost. Not to mention for the prototype it presented a viable test platform that can be constructed quickly with little custom fabrication. This allows me to put more time into other areas of the build.

Moving forward if the Tigon ends up being what I imagine and is popular the need for a new improved chassis design will most likely be needed. Until that day if ever the GT6 and Spitfire chassis will work out great.

The chassis is set up quite nicely for a front engine placement. I thought about this a lot especially when considering the hybrid design layout. It would be extremely easy and favorable in many ways to go with a series hybrid layout with this vehicle.

The pros of this I listed:

#1. The front engine area could easily be adapted for a genset serial hybrid.
#2. Weight distribution would be favorable
#3. Would eliminate heavy drive axle
#4. Could locate diesel fuel tank behind seating compartment for max safety.
#5. More room in back for electric traction motor and other components

All of these advantages might lead one to wonder well why am I not going with this setup?

There are some key reasons why and I will explain them here. First of all while series hybrids can be designed for similar efficiency as a parallel design the majority of the time they are not. Some of the reasons include in the design itself. Series hybrids convert electric energy into mechanical and back again each time losing efficiency. Parallel hybrids do not suffer such penalties. The argument is a generator can be set to run in its most efficient operating range unlike a parallel layout, while this is true it is difficult to design a working model that creates enough energy to run the electric only traction motor all the time without the need to stop and charge up. The Tigon being light and aerodynamic would represent a perfect test subject for such a prototype as energy demands would be low and you could quite possibly achieve a vehicle that could run off the generator continuously without the need to stop and let the generator charge the batteries.

To achieve this it is more difficult and costly to put it simply. The series requires an extra electric motor and controller for best efficiency such as in a BLDC or PMAC electric motor designs. You typically also have to have a larger buffer in battery storage again increasing weight and cost. Batteries cost far more than diesel fuel for the amount of energy storage capabilities. So I decided to go with the least complicated, least weight, and least cost hybrid design I could and that led me to the parallel layout.

So why not use the parallel layout upfront instead of moving the engine location rear mid engined?

#1. You would need the heavy drive line unless you wanted to drop $1,000+ USD for a custom carbon fiber drive line. still adds complexity and weight!
#2. More exhaust piping and weight decreases aero potentially
#3. Less control of front air dam flow internally for aerodynamic purposes.
#4. Worse weight distribution.
#5. Less traction on rear tire not good in 3 wheel rear wheel drive design.
#6. Worse Polar Moment of Inertia

The main problem moving the hybrid drive train toward the rear was unlike in a 4 wheeled car weight distribution is much more critical. In a 3 wheeled reverse trike design you want to shoot for a 70-75% front weight distribution for best handling and safety characteristics. I needed to make sure that moving the drivetrain back would still allow me to get close to this appropriate ratios. Once I determined that I could still have a good ratio the decision was a no brainer. I still have some negatives with this layout nothing is a perfect world but the positives greatly out weight the few negatives. All in all I have much more advantages to this platform design than I would have if I would of went series hybrid and or kept the engine up front! Luckily for me my little diesel and electric motor are very light the Diesel weighing in at only 126lbs and the electric motor at 35lbs. Had I chose a bigger diesel and or larger motor most likely I would have had to have the hybrid drivetrain up front in the original engine location.

I am able to go with a smaller diesel engine due to the light weight and aerodynamic profile of the vehicle. If I would of done a straight conversion the increased weight and much worse aerodynamic profile of the GT6 would have made it impractical. The Urba Centurion made a solid attempt at fixing the GT6 aerodynamic flaws and weight penalty but still had much room for improvement. This improvement is what I am setting out to accomplish albeit at a larger expense but still in the realms of the average persons budget just not dirt cheap like the Urba Centurion. I am for the most part using upgraded parts that are much more costly than if I just used GT6 parts from the bone yards. I think the weight and overall quality is worth the added costs. We will see in the end if it was all really worth it I suppose.

I think now if you were able to read this post in its entirety you have a good idea of why I chose the parallel hybrid layout and why I chose the RMR engine layout. You will also have the reasons why I went with a backbone chassis as the donor of choice. As you can see there is so much to consider it is quite easy to get lost in all the questions.

My best advice and really my best allies are time and patients.

Take care gang,

GreenHornet

[GreenHornet]

I stumbled onto the NR1 vehicle today it boasts some pretty impressive figures. The engine it uses looks pretty revolutionary. Not sure where it is currently in the build process or other bureaucratic nightmares if anyone knows more about this vehicle and engine design feel free to chime in I would love to hear about it!

Vehicle website link = NR1
Engine and cycle link = About

[cRiPpLe_rOoStEr]

Originally Posted by GreenHornet

Yes the electric motor replaces the starter and alternator! This is one way how to setup a parallel hybrid vehicle. I used to work for GM and this is how they did it on there vehicles. The difference is they used a belt and pulley method and I will link directly to the drive shaft. Linking to the driveshaft is more efficient.

Not just more efficient, but also more reliable

I don't think they make a twin-scroll turbo small enough for the 2 cylinder!

It's not actually impossible to get a twin-scroll turbo small enough for the 2-cyl. Anyway, even if you'd get a regular turbo, I still believe a single is better to overcome the turbo-lag, unless you'd get a sequential turbocharging setup, with the smaller one to spool faster at lower RPMs and a bigger turbo as a 2nd stage

[GreenHornet]

Hey CR,

Twin scroll are very cool in deed and the sequential idea is awesome. I can tell you are a diesel guy which is good because so am I :-) Who knows maybe one of these days we can collaborate on a project. I have been itching to come down south anyways. It has been to long since I have been to your neck of the woods. South America is a beautiful land so much to see and do. I actually have family down there that would be great to visit.

Anyways my friend I hope Brazil is treating you well and I will talk to you soon

Take care and thanks for the ideas

GreenHornet

[cRiPpLe_rOoStEr]

There are too many dumb restrictions against Diesel engines in light-duty vehicles in Brazil

Someday I'll probably have to emigrate, I just need to get a college degree before. Currently attending to a college of Mechanical Engineering

[GreenHornet]

Hey guys,

I have not posted for a while been pretty busy with other things. I have for the most part been doing research on components and playing with TIGON drawings. I have started to read into 3D modeling as I think after I get my sketches a little more refined this will be the next step in the process.

Made some key changes to the original TIGON sketches. First I did away with the doors and opted for a single canopy like you would see in the XR3 or Tri Magnum. I decided on this do to the fact it would make getting in and out much easier. My original sketch had a height of 42" most likely I will try to reduce further to 40". Another change was in the windshield which originally used the GT6 glass. I decided to go with a custom formed Lexan front piece shaped more aerodynamically similar to what you might see on the Opel Eco-Speedster. Next I did away with the rear quarter panel side glass. I also did away with the side mirrors and opted for wide angle cameras similar to what you would see on the VW XL1. The rear canopy has glass and opens for easy access to the engine compartment.

On the TIGON top view I cleaned it up a bit added a single rear brake light shaded and centered as well as left and right turn signals. The vehicle will have a backup camera and audible sensors which will attach to an LCD monitor up front along with the side mirror cameras.

I will post some more sketches soon as I get them touched up a little better!