TIGON Diesel Hybrid

[GreenHornet]

I think I found the weight of the Panhard LM64 correct me if I am wrong because the site is in French and I am not so up to speed on that language but it stated a weight of 570kg or 1256lbs!

Here is the link to the page = Panhard CD LM 64 : LA ROUTE NOUS APPARTIENT!

With a weight of 1,256lbs and cd of 0.13 the Panhard is a pretty good representation of what I am aiming for with the Tigon. I am hoping with the Tigon I will be able to get to 1,000lbs which if I was going diesel only I definitely think I can get there but its going to be really tough in a hybrid version. I am all ready at 706lbs so there is not much wiggle room with the hybrid.

[GreenHornet]

I did some more digging on the Panhard and confirmed its light weight and cd. Here are the specs:

Weight = 560kg/1,234.59lbs
cd = 0.13
Height = 1.07m/42in
Length = 4.25m/167.28in
Width = 1.64m/64.56in

For comparison my rough specs on the Tigon:

Weight = 900lbs Diesel only and 1,250lbs hybrid
cd = 0.13
Height = 42in
Length = 172in
Width = 63in

My first sketch of the Tigon you can see I also have front and rear wheel well covers like the Panhard. The rough dimensions were also very similar and the Tigon also uses a 2 cylinder albeit diesel LOL! The diesel in the Tigon I am using could never compete with the Panhard 850cc 2 cylinder which could put out 60hp but if we used an electric motor in the right configuration with the diesel we just might be able to compete! I bet if you used a parallel configuration with the Smart .8L CDi you could do it! Which I almost did actually in the beginning. I could have bought the Smart CDi engine I still could in fact but at the end of the day this is not meant to be just a one off build. The Smart CDi can be chipped to produce 65hp but its a 3 cylinder so not as impressive as the Panhard 2 cylinder 850cc engines. For a diesel though the Smart .8L actually is not bad it would definitely have more low end torque than the Panhard!

I would need to figure out with a cd of 0.13 how much hp would be needed in the Tigon to maintain a 140mph cruise? from this I could then determine what size electric motor and battery bank size I would need along with all the rest.

That will have to wait for later because its time to scoot off.

Have a good day everyone,

GreenHornet

[NeilBlanchard]

Got it - I'm curious to see how the aero in the back works.

Edit: the site you linked to says the Cx (Cd) is 0.12, actually. I think the 0.13 is the accepted number though? Search EM for the Panhard LM64 and you will find lots of discussion and pictures.

[GreenHornet]

Due to the 3 wheel configuration the rear centered wheel would need to be wrapped and ground effects would have to be utilized. I am pretty sure the Aptera has a wrapped rear wheel but not absolutely sure on that.

This is my initial thought on how to deal with the centered rear wheel. As far as the teardrop sloping from front to back I will shape it much like the profile you see in the Fiat Turbina and CD-Panhard LM64. Only difference is I will only have 3 wheels vs 4. I will also not have the side wings or fins.

All of the sites I checked out except the one I provided a link for stated a 0.13 so maybe you are correct in that it is the accepted cd. Either way its still very impressive so again thanks for sharing. looking at the CD-Panhard really gives me hope for gain now. It is more similar in specs to the Tigon than that of the Turbina, even down to the weight. looking at it actually confirmed in my mind that I am not completely crazy LOL hahaha. What I am proposing is not all that far fetched as one might first conclude. It is not going to be a piece of cake from any stretch of the imagination, but if I take my time and stay disciplined I think I have a real shot at accomplishing my goals.

Talk to you later Niel,

GreenHornet

[NeilBlanchard]

Yes, the Aptera had a fully faired rear wheel. In the initial prototypes, it used a conventional swing arm, but it suffered from a lot a squatting under hard acceleration, so they had to engineer a more sophisticated arrangement.

[GreenHornet]

Today I was thinking about the weight distribution and how it relates to the center of gravity in a 3 wheeled design. Most all of my research concludes that in a 3 wheeled design you want to keep the cg as close as possible to the 2 side by side wheels and as low as possible. By doing so greatly reduces the risk of rollover and enhances overall stability.

Another very important aspect to this is sprung/unsprung weight in a light vehicle. You want to have as low an unsprung weight as possible especially in a low mass vehicle such as Tigon. With today's technology you can have larger wheels which are extremely light. This allows you to decrease unsprung weight and give better stability and handling characteristics. Larger wheels and tires will also help smooth out the ride in a low mass vehicle like Tigon.

When thinking about the Tigon hybrid design there will have to be many compromises made in order to get it completed in a practical time frame and on budget.

Today there are many different hybridization options available to the builder. We can go with a micro, mild, or full hybrid capable design. The cost and complexity go up as you get closer to the full hybridization model.

For the Tigon prototype my thought is to stay in the middle of the road so to speak. So I am adopting a more mild approach to the hybridization design. While I think it would be awesome to build a full hybrid, cost and complexity must be taken into careful consideration. I think currently the mild hybrid offers good benefits while still keeping the costs practical for the budget minded folks like myself. I think this is a good starting point and will allow me to get it up and going quicker. It also gives me a platform to test and build upon.

[GreenHornet]

Looking at the Urba Centurion it gets as high as 128mpg @ 35mph constant speed and as low as 65mpg in the urban traffic environment. The vehicle could do 85mpg at 55mph which is still very good considering no hybrid here in the states can pull that off.

Looking at the numbers to me it is still not really all that practical. I think by hybridizing the basic concept huge gains can be maid both in town and on the freeway. The main fuel loss for any ICE is during the initial starting acceleration. By hybridizing the ICE with the electric motor we can eliminate this disadvantage. The next big fuel loss for any ICE comes in at idle in the urban environment. By hybridizing it we also get rid of this parasitic loss.

The trick is to size and position the components properly for vehicle integration. Many things play into the overall fuel economy. One important factor is gearing the Urba Centurion had a final drive ratio of 3.89 and 4th gear overdrive of 0.84. By swapping gears one can easily increase cruise MPG as well as enhance low end acceleration. The Urba Centurion was limited by the Spitfire Transmission gear selection which was not very wide. However consider a full transmission swap such as a Tremec T5 and presto you have just gave yourself a world of gearing options as well as greater availability. The T5 has an overdrive available at .63 which would have made a good difference with the Urba Centurion. The rear differential of the Spitfires also had a 3.27 gear available. Swap that gear with the .63 overdrive of the T5 and MPG would have been much better even. Not to mention you could also have higher 1st and 2nd drive gears on the T5 for much better acceleration potential despite having a higher final drive ratio.

Look at the VW strategy for there 1L series of cars this is not much different really. VW uses there DSG tranny in there 1L series of cars. Proper gearing can have a big effect on MPG so this has to be chosen wisely.

While I am a big fan of the T5 for the Tigon prototype my thinking is going simple and even lighter than the T5. Despite the T5 being only 75lbs and having a virtually unlimited gearing selection and configuration, I decided to go with a simple CVT arrangement to start. The CVT I decided to go with is only 32lbs and has an acceptable gear spread for in town and freeway speeds. By hybridizing the Tigon you can do away with a gearbox altogether since you have the potential for electric reverse. The CVT can handle up to 60kw of power so more than enough for the Tigon design. 60kw puts us at 80hp which so far I have the Tigon at around 46hp combined. So there is still room there for experimentation such as adding a dual electric motor or turbocharging the diesel. Depending on how it works out or doesn't work out the T5 is an excellent backup choice. It is also a perfect choice for somebody down the road who would like to have the manual despite solid CVT performance. Some people just don't like the CVT and prefer a manual so why not be able to offer both as options. The T5 would also open the door for a Lemans style Tigon as they can routinely be built to withstand 500hp or more.

I would like to see the Tigon obtain a combined 100mpg. I don't know if its attainable but it is a great number to work toward and should keep me thinking hard.

[GreenHornet]

What have I been working on the past few days?

Mainly been cleaning up the front suspension pieces I will be keeping. The spindle, top & bottom wishbones, and anti roll bar (ARB) will be retained from the original GT6. Today I should be able to get some rust proofing primer on them. All of these parts will need new bushings and while I am at it I will most likely source all new bolts and nuts. The ARB itself was in good shape but everything else was shot so I will need a new overhaul kit for it. The overhaul kit is priced at $59.33 USD excluding shipping costs. This kit includes the end links, poly bushings, and all brackets nuts & bolts.

The shocks I am using are Spax while not the best in some peoples opinion they will more than get the job done and are ride and height adjustable. They have 28 stages of vehicle stiffness adjustment and are filled with krypton gas. Other options include GAZ and KONI shocks. GAZ being just a little less cost and KONI being the most expensive of the three.

These will be getting ordered up here real soon along with the rest of the front end parts. The majority of the stuff I am purchasing from outside the country mainly from Canley Classics and Rimmerbros so I will purchase them in bulk buys to save on shipping fees.

[GreenHornet]

Hey Everyone,

I started exploring my steering options today and any possible worth while upgrades that I could possibly do with the Triumph GT6 and Spitfire stock systems.

I found some upgrades that I will definitely be purchasing that I thought I would share. All of these upgrades are direct replacement so no need for any extra fabrication work.

#1. Quick Rack Assembly $202.37 USD
#2. Alloy Solid rack mount kit $29.22 USD
#3. Solid Heavy Duty Steering Coupling $57.71 USD
#4. Steering wheel $233.00 USD

Now there has been another upgrade that I have been working on as well. This one would require some thought and custom fabrication work on my part. However this upgrade would be well worth the extra effort. I am talking about an Electronic Power Steering (EPS) Assisted System.

Why would I would consider this upgrade?

First of all the Triumph GT6 and Spitfires had manual steering and while they were pretty light cars steering at low speed and during parking situations could be tiresome and problematic. Most people these days are use to the power steering so going from that to a manual steering would be tough I think. So in my mind if I am taking the time to upgrade the suspension and braking to a modern level I most definitely should do that with the steering as well. luckily for me there is a very cost effective solution to this upgrade and that is the Vauxhall Corsa C. This is a pretty popular and common car over seas and as such has readily available EPS systems for purchase over the internet all day long for under $100.00 USD. You would also need a controller for the unit which can also be picked up over the internet for a low cost.

From my preliminary research I have found this to be a very popular addition to several different Triumph cars including the Spitfires. Many conversions have all ready been performed so there is quit a bit of info available on how to go about doing it so this is good. Every thing that I have read thus far points in the direction that this can and would most definitely work trouble free. So I will be purchasing these parts and starting the customization soon.

Another benefit to this is the ability to upgrade the steering column to an adjustable unit which was not offered on the GT6 cars.

Adding the EPS with the Quick rack Assembly will give the GT6 a modern performance and feel while enhancing the driving experience. Another positive point that can and should not be over looked is it will improve the safety factor by a few degrees as well. So at the end of the day we get a very affordable, modern, light, and safe steering system for the Tigon.

[cRiPpLe_rOoStEr]

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