Class 8 Truck modifications
 

Hi all,
I am looking to enhance a fleet of Class 8 trucks. Predominantly these are 550-600HP cummins engined beasts, that do long distance line haulage towing single or B-Double reefers (Refrigerated box trailers)

I am looking to install fuel flow meters to obtain higher levels of accuracy in testing, however currently we have logs for trucks mileage. I will be testing each improvement with a weeks actual driving, with the same rig on the same route with the same driver..Currently we can measure our fuel burn to 2 decimal places, but with the fuel flow meter this will increase to 5 decimal places.

So far...
I am looking at

1. Supplementary gaseous injection (3 vendors all guaranteeing, with money back of a minimum of 15% fuel gain using their products)
--We have trialed propane (LPG) previously but too many negative effects occured *EGT increases, HP and torque increases, and resulted in a crank shaft failure and drivetrain issues from too much hp..*
--Vendor 1 is using HHO - have provided logs and references to other heavy fleet owners, guarantee with 100% money back a 15% gain, but historically have seen 25%+ with no tuning..With tuning gains up to 45% have been achieved.
-- Vendor 2 is using HHO and WI as a combined unit- I have received a guarantee of a free trial unit to put onto our truck, also guaranteeing 15%+ improvements or return the unit with no charge. This vendor I am not convinced is worthy to even test however, with some fairly vague sales pitches, and poor understandings of physics abounding on their web site..Their basic principles (Including "cracking" the water first (AFAIK simple ionising of the water to reduce the coherent bond..)) appear possible, but they come across as dodgy used car salespeople
-- Vendor 3 is using Stored Hydrogen - have logs across their own fleet of buses and other vehicles showing 20% plus improvements. Have also a newer technology for generating Hydrogen on demand from the exhaust gases using a catalyst. and plazma reformers. They are performing full dyno and onraod testing on their OWN fleet, and sharing full results, prior to us testing..they are also combining tuning, and water injection (As sub set results...so very interesting to see the stackability of the technology)..potentially someone actually doing Hydrogen injection to a diesel CORRECTLY and FULLY...

2. Tuning - I am looking at combining tuning with any gaseous attempt..it is pointless I believe adding a supplementary fuel (Or combustion enhancer) , without then reducing the baseline fuel being put into the engine..This tuning will take place on a dyno to ENSURE we do NOT gain any HP / Torque..Being in heavy trucking, with high hp trucks across the fleet, it is a negative effect to increase HP!. Obviously any maps that are created need to have the ability to default back to stock maps incase of supplementary failure. This will be recorded using fuel flow meters under static ramp loads.

3. Water fumigation / diesel emulsion - Looks very promising , and will be treated similar to the Gaseous supplementary above in point 1. It seems most of the aftermarket have very low quality kits available however, so we may need to create this inhouse to get some reliability in the product using quality stainless fittings etc.

4. Aerodynamics - obviously a critical component. Looking at aerotabs (Vortex generators), eco-flaps (Mudflaps), moon wheels, side farings (Fibreglass add ons to enclose sides of trailers, and also cover fuel tanks etc on the truck), Cheek Bones (For front side edges of trailers / cab over trucks),
--Also considering upgrading some of the older hoods on our fleet to reflect the newer more streamlined hoods and lights on later model trucks..still to find someone who has some "upgrade aero" hoods for sale..
-- Streamlining exhausts - removal of stacks infront /sides of cabs..to either behind the cab, or better exiting behind the wheels down low..
--removal of external air filters, relocating to under hood (Using ducting / airscoops to help funnel air to enhance ram-air effect to the 16 litre diesels..)
--Aero Mirrors to be installed / tested to see if much benefit..
--Possibly under trays to be installed..although this may not be possible.
--NB all trucks already have standard top of cab/sleeper farings etc installed.

5. Parasitic losses - removal of hydraulic engine fans, replacment with electric, power steering conversion to electric, airconditioning has already been transferred to the Aux power unit (Small genset instead of big engine),

6. Frictional losses - synthetic lubes in diffs / gearboxes already in use..marginal improvements. Considering using Super single tyres, but they may be too risky on our long haul routes


Open for any suggestions / thoughts...Please keep any negativity to HHO to a minimum, I am going to test 3 different types of Hydrogen to prove this / disprove this on our fleet at minimal cost/risk to ourselves..If it does work however, the unicorn corral will be upset lol

NB: I am a IT and project management specialist , I do NOT claim to be a mechanical engineer / chemist / biologist / rocket scientist / etc...I am pragmatic, and will chase fuel gains for the company.
Our trucks average around 1.95km/l currently, and I would like to push this to a minimum of 2.4km/l If I can obtain more than that I am very happy (My goal is 50% improvement..or around 3km/l......however all benefits must have a short ROI of less than 6 months to be considered worthwhile.

I am trying to keep costs under $30k per truck / trailer combination if at all possible..although ROI is the key..if it cuts enough fuel burn, we will spend to implement it.


.

Hi and welcome to the forum. I like that you are involved in improving fleet efficiency because it has the potential to make a big difference.

You probably already know this, but I'll state it for the benefit of anyone else that doesn't; heat is what powers an internal combustion engine. Burning fuel creates hot gases that want to expand, and this exerts pressure on the pistons to move.

1. HHO (2 hydrogen and 1 oxygen molecule burn to form heat and water) merely replaces some of the diesel that would be used to generate the heat needed to move the pistons. The reason this isn't efficient is because hydrogen costs more per BTU than diesel. In fact, commercial hydrogen is derived from petroleum products. In other words, to get hydrogen, you have to remove the carbon from petroleum, and that takes energy. What you are left with is less energy than if you had simply burned the petroleum in the first place.

I'll stop here and say go for it if there is little to no risk. I would caution that you should not rely on any measurement devices that the HHO suppliers might provide you. Do your own measurements with your own gauges and factor in all of the expenses to determine the true cost per km driven.

Natural gas is promising because it's the cheapest cost per BTU at the moment. It may even promote combustion efficiency when used in combination with diesel, however I'm no expert on the subject.

2. Unfortunately, improving engine efficiency often entails boosting top end power. As you point out, this means you must somehow limit output power, possibly through tuning, or risk placing undue stress on the drive-train. De-tuning may also undo any efficiency gains.

3. I don't know enough about water injection to have a strong opinion about it. It does seem there is potential for boosting efficiency, but then you have yet another tank to fill. BMW has implemented water injection, but the engine has to be designed for it. You can't just take a normal engine, inject water, and expect efficiency gains. The gains come from boosting effective compression ratio (either through a higher compression ratio, or from increasing turbo boost).

4. Aerodynamics will likely be the best bang for the buck. These improvements are a 1-time fixed cost. Everything you mention should help; some things more than others. Vortex generators likely won't be much help. They improve efficiency by keeping airflow laminar (attached to the surface). If you were to place a vortex generator at the very back of a trailer for instance, it would be pointless (and actually cause more drag) because there is nothing for the air to attach to beyond the end of the square trailer. It's no substitute for having the proper shape to begin with.

5. I'm not familiar with how hydraulic fans work, but electric fans are not very efficient. Electric fans require mechanical energy from the engine to turn an alternator to make electricity, which is then turned back into mechanical energy when the fan is on. It's not efficient to change forms of energy, so it's best to directly use mechanical energy to turn the mechanical fan. If the hydraulic fans are like power steering in that they always pump even when not needed, then maybe electric fans would be more efficient.

Power steering might benefit from not running the pump all the time. Steering is rarely needed, so eliminating a pump that is always running should improve efficiency.

I'm guessing the APU you're talking about is for the refer. Does that mean the cab gets cooled by the APU, which must run at all times anyhow? That sounds efficient, though negligible.

6. I have zero knowledge about the risk / reward of running super singles. My guess is that some routes with lower risk of blowouts, or lower costs when a blowout occurs, are worth running super singles. Risky routes, or those which have a high cost if a blowout occurs might not recover those costs in fuel savings. You'll probably need to trial this. Perhaps there is data available to help you make the decision?

Suggestions

Only test 1 modification at a time and record as many of the variables as possible. If more than 1 modification is done at once, there is a risk that 1 of the mods produces a large gain, and another mod causes a small loss. That loss would be masked by the larger gain of the other mod, and not only could you be getting better efficiency, but then you have the expense of implementing the mod that negatively affects economy.

Focus on aerodynamics, and then rolling resistance. The majority of fuel consumption is spent overcoming aerodynamic drag, so this should be the main focus, especially since buying a fairing is much cheaper than modifying an engine, supporting another fueling infrastructure, and maintaining all that equipment.

Now I'm curious, do they make TPMS (Tire pressure monitoring system) for tractor/trailers? It seems important for fuel efficiency, safety and avoiding blowouts. I would think they could have a decent ROI.

The best ROI might be in the driver. I've always wondered if there was some way to incentivise drivers to be efficient. It seems crazy to me that most drivers are paid by the distance they travel. This would give them incentive to drive faster but perhaps it's more profitable to have a faster turn around time? There has to be a trade-off between fuel consumption costs and being able to make more runs with a truck.

Great post, redpoint5.

The moon disc idea has me thinking -- one of the reasons just about all wheels have
"spokes" or other cutouts is to ventilate the brakes and prevent fade. Hypermilers can get away with covering up those slots with moon discs because we typically drive slower than average and leave lots of following distance, so maximum braking on already-hot parts is a very rare occurrence. For a semi-truck, there may be liability issues.

P.S. I remembered reading a little about super singles and other efficiency improvements on semis on Wayne's site a while back. I think these were the threads:
http://www.cleanmpg.com/community/in...threads/20739/
http://www.cleanmpg.com/community/in...threads/49495/

First post... Knows about the Unicorn Corral... You're off to a good start.

My plan for my own single vehicle is to gain 50% from the drivetrain and 50% from aero. In case he doesn't find the thread, look for a member called slowmover and look over his older posts. He's all about route planning and wheel alignment. Driving a straight line instead of weaving back and forth.

I am curious about the flow meter. My understanding is it is hard to measure small volume flows as in a fuel line. The best I found was a chamber with posts in it to generate a vortex street that was somehow measurable. What do you use?

Give incentives and training to the drivers, mainly let them know they can shut the dam thing off every time they exit the seat. Aero the trucks. I think Cummins already does everything possible within the law to keep efficiency on the cutting edge. I would bet any gains from other injection adds comes from leaning out the mixture and sending NOX emissions up. If your ok with that just gut the DPF filters and add an aftermarket tune and accomplish the same gains for much less.

Being in Australia we have some different regulations on emissions standards..I think with the Hydrogen (Especially using the Plazma Reformers) the emissions drop considerably..as the Plazma Reformer creates in effect 4 gasses to re-inject back into the engine..
These are primarily used to reduce emissions including Nox across different engines (A lot are designed for use in mining environments for obvious reasons).
Side effect is that with diesel from what I can find, injecting Hydrogen , and nitrogen into an engine allows for a change to the combustion ingredients, allowing for a shorter, quicker flame front to ignite the diesel more rapidly..with some timing changes to account for this, more power stroke is achieved relative to intake stroke ignition events (gasses expanding post TDC instead of some expanding prior..). Combining this with the ability to run much leaner due to ease of ignition on the diesel / gas fuel combination. I am hopeful to achieve up to 30% fuel improvement just with the gaseous implementation and tuning..(Of note, tuning on its own without the gaseous supplmentation, with emissions still retained has net very little gains..around 2-3% maximum...)
On a big rig this is a HUGE number..We have previously been spending 80k converting older rigs to the latest ISX Cummins engines to obtain 5-10% fuel savings as a comparison!.

Aero and Friction I think are going to provide comparable gains..The Director of Operations has been trialling adhoc aero pieces (EG moon wheels on otherwise poor aero trucks), and gaining inconsequential improvements. I believe this is a simple case of streamlining airflow over the wheels is useless if the air passing around the trailer before and after the wheels is turbulent already due to lack of sideskirts etc...
I think the only way to perform the aero is to complete one entire truck..from tractor to trailer..and compare it on before / after...I do not have a wind tunnel to measure each device individually so will instead focus on improving laminar airflow wherever i can (flares / skirts / ducts / cheek bones / vortex generators to create "air curtains" etc), and reduce frontal impact area with as much smoothing as possible (Different hoods, bumpers, trying to use vortex generators to "shape" the air between leading edge of bonnet and windscreen , same with leading edge to front wheel well..etc)

I forgot to list alignments for the wheels..this is a critical obviously..Thankyou for reminding me!!

The Power Steering and Engine Fans I actually "stole" the information from the super truck program on these..they are both hydraulic (Fan is a viscous mechanical fan powered by the ancillary drive belt on the engine..and the power steering pump is a huge device on the same belt)
Both of these use a LOT of power all the time...by using an electric fan the unit is not in use 95% of the time (Highway haulage)...and by using a smaller hydraulic unit, supplemented by an electric unit for the steering gains as much as 3% were realized in Kenworth testing (To be implemented on future models from what information I have discovered so far)

I agree with Driver training being a critical as well..a variance in industry monitoring of 30% exists between a good driver and a bad driver in the same rig..to this end I am setting up a few "carrot" style solutions..Drivers will be ranked using telemetry data focusing on good drivers at the top (braking events, harsh acceleration, fuel burn (from baseline on each vehicle), etc...). They will then be awarded prizes monthly for the top drivers...conversely we in the head office will know which are the bad drivers..and then can shift them to lower effective routes..
We are also implementing a full routing solution that optimises fleet mileage..so far the preliminary testing has achieved a net 5% reduction in miles required for our fleet (Minimal..but when you equate 35,000,000kms annually across the fleet..thats a LOT of savings)

Super Singles - I think with the enhanced risk of being stranded on our very poor Australian roads, that I will most likely have to shelve this idea for the time being..I am having the tyre suppliers return with pricing and gains, and have them advise on risks as well..but suspect they wont be allowed for safety and reliability issues..


Happy for any more feedback ..I am hoping to finalize my presentation and start the project inside of 2 months ..(I am also waiting on the primary vendor to complete their empirical testing of the entire solution (Plazma Hydrogen / Tuning / Water Injection) and provide their logs to me...they are stating up to 50% fuel gains with their solution in their preliminary testing on their test mules..I wont hold my breath..but promising to say the least!)

It sounds good but seems funny the guys who's job it is at Cummins to improve efficiency can't figure that stuff out.

Good luck with your economy project. Our 2015 600 hp Cummings visits the dealer more often than I would like. 60,000 miles and has been in 6 or 7 times all for emissions system failures. It has had oil changes every 10k miles and is never up to weight. 80k is where we have it licensed at.

If an engine manufacturer could deliver the most efficient engine taking into account a lot of external sources, and other pieces, forums such as this would NOT exist..

Every single engine ever made by a manufacturer can be improved upon with aftermarket parts and tuning available.

Pulling a Cummins apart, and rebuilding it to improve V.E. (Basic porting / balancing) will increase its fuel economy greatly, extra parts such as lighter pistons with shorter skirts, removal of parasitic external forces on the engine, transmission improvements, exhaust and inlet improvements all GREATLY enhance fuel economy and can at the same time REDUCE emissions...however, they are costly to perform in the factory, and even more costly in the aftermarket..
Bulk manufacturers are run by bean counters...NOT by the engineers and designers...
I guarantee Cummins could build a 20% more efficient engine without trying too hard...just the cost increases of 40-50% per engine would make that engine unjustifiable..And training the half educated mechanical geniuses in most facilities to service a much higher tech engine with tighter tolerances would be nigh on impossible.

I am looking at simply changing some bolt on equipment, introducing an extra fuel/combustion enhancement (Water in its own right acts in this area!, but is not commercially viable to sell as most fleets are not interested in the training required to give to the drivers).
I am hopeful after introduction of the engine enhancements and tuning, that we may be able to do away with the DPF and Add Blue (Urea) components as well, and still pass the ADR mandated emissions tests...this would further free up more hp..and thus with some potential detuning (RPM limitation or fuel reduction or simple boost reduction (Might have a negative effect on VE reducing boost however)) we should gain significant fuel economy.

However, before I get ahead of myself or ahead of empirical testing results, I am here on a forum like this to obtain as many more ideas as possible, and to ensure I dont go off on any tangents (EG chasing the proverbial Unicorn due to a good sales pitch from some internet savvy salesperson!)

I apologize if I come across harshly, but I know many others get frustrated by naysayers who believe manufacturers are the only people on the world who can improve mileage..and I am VERY surprised to find such a person on a forum such as this.

How large is your fleet?

Long ago I was involved with servicing of diesel trucks and was astounded at the lack of fuel mileage. Fuel was cheap and management did not seem to care as it was part of the cost of doing business. Today with fuel costs once again on the rise, increasing big rig fuel efficiency has got to offer some serious rewards if executed well across a large fleet.

One thing not mentioned was the application of smaller high efficiency alternators. Another item was the ceramic coating of wheel bearings. Another item of interest might be the special coatings applied to the transmission and differential gears to make them far more slippery. That combined with the synthetic lubricants might make for some nice improvements.

Best of luck with your fuel savings program and keep us informed as to what you do and how well it works.

I for one don't understand people who insist on driving something completely stock. Like they are the specific demographic the whole thing was tuned to. Here's a few more things to think about. First this:

http://ecomodder.com/forum/member-fr...dynamics-c.jpg

A long box van is a special case aerodynamically. The length allows turbulent air to reattach to the skin. This is called fineness ratio. Find a member called aerohead and look at his posts or albums. There is a lot on cab-van spacing, buses drafting each other, etc. Also there is a member named Sheperd777 that is building the AirFlow Truck Company StarShip

The other thing is some work by Robt. Englar that came out Georgia Tech:

https://www.osti.gov/scitech/servlets/purl/770965
https://books.google.com/books?id=yN...umatic&f=false
https://www.gtri.gatech.edu/casestud...uel-efficiency
I'm not selling anything, I just want you to be happy. :)

Helpful info. Your on the right track
 

https://cumminsengines.com/uploads/d...whitepaper.pdf
This info from Cummins backs up many of your theories.

~150 trucks, plus a number of other vehicles.

Read this one a few times :) Some nice easy to understand information in there!

I say no way. They would take a 20% improvement if it doubled or tripled the price of the motor. Fleets just like you would scarf them up by the thousands over their competitors at International or Volvo or whoever. I also say any increase in economy is going to put NOx emissions over what the government will allow. I personally don't think that's a problem, but that is what is holding the manufacturers back. If you are willing to throw NOx to the wind then you can accomplish whatever HHO (which just never is going to make scientific sense) would do with simple tuning and deleting emissions. If HHO is actually doing anything anywhere it is only because it is fooling the tune and changing power and emissions not efficiency.

I do say try it on a couple of trucks with long established routes and drivers. Don't tell the drivers anything is changed and see what you get if they will give you your money back.

Not a bad paper..

https://www.tc.gc.ca/media/documents...T-MAY_2012.pdf

I wonder how hard it would be to make an accordion connection between the cab and trailer, like you see in articulated buses. Even though the airflow would still be pretty dirty around those folds, the majority of it would have to flow around the whole thing as a unit rather than detaching and swirling around before hitting the square front edge of the trailer.

If there's one thing I've learned on EcoModder, it's that even when a vehicle company tries to make something reasonably aerodynamic, there are still lots of opportunities if you're willing to put some work into it. :thumbup:

There are some adjustable gap devices out there, but most seem prone to failure fairly quickly..especially when you change trailers frequently..you never know what the next trailer will be exactly..

Further, with refrigerated trailers, you need to feed the fridge motor some air..

I am studying as much as I can on the Vortex generators (twin closed vortex scrolls style.. (Kinda of a V shaped bit of plastic).) not sold on them 100%, however we have some in use already and they definitely keep the rear doors cleaner on the trailers their installed on currently.

We have not put them on the rear of the truck, or on the gap between trailers yet...merely on the back of the last trailer..I am now looking to get some of these at a reasonable price instead of the absolute rip off $5+ each they charge us from the suppliers currently!. As I will need around 18000 of them, thats a considerable chunk of change, so will approach some manufacturers to reproduce at a more realistic price..
They are on the market from multiple vendors, and are all basically identical (Small size changes, some have a strip with 4-5 of them, instead of single units etc..). Having had some car parts produced previously myself (Predominantly carbon fibre air intake systems for a sports car..and engine mounts for the same sports car) I am not worried in contacting people to get mass production at a reasonable price..
5 cents worth of plastic and glue should NOT be sold for $5...

If you're installing 18,000 of them; it might be worth investing in some Computational
Fluid Dynamic simulations.

Vg's havs a local air flow directional dependency(can be as much as90° difference from 1 to the next)tuft testing is needed for proper application. VG will allow steeper change of angle with out loosing attached flow. Consider a 3D Printer to produce in house. (I see a short ROIwith the volume of VG'S needed as well as the capability to produce scale models for testing)
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Are you running Road Trains? Single 53'? Triple 20' ? I assume you have many configurations.
----
The Canadian artical is interesting, I am still reading it (120pg).

This paper shows the vortex generators hurt but they don't look the same as the littles ones I have seen.
https://www.google.com/url?sa=t&sour...Qs3Wg-JJm7lr0w

The VG on top(1"x1"x1/8"x1'-1.5'aluminum angle) have a blunt front and rear (rectangular). There orientation is in the direction of travel. Travel and air flow direction seldom match at the rear especially at corners.

The fronts should be curved from bace up and back. Parallelogram with curved leading and trailing edges. Not like the side VGs.(trapezoid)
This is a poor example with witch to condemn all VGs. Poor fit and finish .In my opinion.

They did have to make thier own on the fly but that was because none of the actual makers of the vortex generators for sale at the time wanted to supply their product to be tested in an actual wind tunnel on an actual truck. That sort of raises a red flag to me but it was back in 2006.

I see you have all the scientific links already. There are two links from my bookmarks (i am not affiliated with any of the companies, i just somehow like the product although i have never seen it in reality (central Europe is quite different place for big trucks, than Australia or America)

https://www.youtube.com/watch?v=jc8jUXfQnPM ( homepage)

https://www.youtube.com/watch?v=aGF_UcBdZ5I (homepage)

-they are probably much more expensive than home-built variant, but its insdustry delivered proven solution with all insurance etc.

Thanks for adding the wheel cover story. I'd thought of it but hadn't added it to the thread.

If we get off vortex generators maybe the OP will come back?

I'm a little skeptical of their "proprietary speed-sensing radar technology" -- seems more like it's held closed by a weak spring that gets defeated by a strong enough wake. ;)

We have the moon wheels already under trial.... Results are minimal at best on our current rigs... But that may be due to not enough supporting aero...

The trailers boat tails we can't use in Australia as we go over length by adding it on unfortunately :(

In relation vortex generators... Most of the vortex strikes seem to be a thing of the past.. With products causing twin closed vortices being used now... Eg airtab is one brand... We have them in use and can notice some mileage saving just when installed on last trailer... But I am still to trial on all the locations on the tractor and between trailer gaps etc... Once I find a decent supplier we will progress.

Other aero like replacement hoods to upgrade old poor aero designs from the manufacturer.. Aero mirrors.. Etc.. Still to be actioned as well.

Parasitic losses to the engine I am also starting to investigate... Things like the mechanically driven fan... And other things need to be rectified.. But it's a big work in progress...

I am also investigating tilting the radiator back with a electric fan behind it to reshape the aero of the front...

We can't use undertrays due to amount of wildlife.. (damn kangaroo's) so I can rule that out as well...

You know, it's not exactly lying, its marketing . :-)

(Reality agent: "Calm place close to countryside.", English translation: "Seven miles to the closest grocery store". No one will buy "horse ****s", but "environment friendly, biodegradable fertilizer")

OTOH it is proprietary and speed sensing so it's 66% true. ;-). Their PR did good job.

I was under the impression that foldable design had exception and the length restriction doesn't apply. Therefore it opens at speeds over city speed limit.

EDIT: I have checked. They claim they have "EXEMPT from U.S. DOT length restrictions" on their webpage. I know nothing about Australia though. But if it proves worth, maybe you can persuade them to get australian DOT approval too.

https://lh3.googleusercontent.com/-X...0/IMG_4388.jpg
http://www.mgexp.com/phorum/read.php?1,1956757

Vee radiators were popular in the Brass Era, and lately with Porsche.

http://www.skylersrants.com/Porsche/...r/P0001081.jpg
Accessing the Radiators

I wouldn't want to tilt a radiator unless it was designed to be installed at that angle. In other words, the fins are lined up to pass air straight through at the installed angle. Otherwise, the fins are not at optimal angle, not cooling as efficiently as they could, and creating higher air pressure in front of the radiator. In Australia, I would think it is important to get full cooling capacity out of the radiator.

Issue would be more with the space if installing a V radiator...I can not really extend forward more than around 4-5 inches (Maybe not even that much..I may have to stay behind the bumper line..still trying to decipher the ADR (Australian design Regulations) in relation this..)

The old brass era setup looks sexy though! Disparaging to think in the 1910's they had more conceptual understanding of aerodynamics than a brand new truck manufacturer delivering forward glorified house bricks in 2017!!

Lean the radiator or go costom.
 

Look into a dual pass radiator. Referenced in this article. Aero-tuning the Championship-Winning NASCAR Dodge Trucks
They reference a shop in the US But any reputable Australian shop should be able to do the work .
For you its more about being able to pack as much cooling into the least space(less air doing the same job=less drag) = the most body mod with out compromised cooling. The custom aero hood has more freedom to take the best shape possible to get more productive results ,less cd.
--
redpoint5
The US Army HMMWV has a tilted 45° radiator with conventional core.
Air passes through the radiator because of pressure differential, not ram force. Ram can be counter productive. Diverging/Converging Radiator Ducting - Why?
The sudden change of direction increasing pressure in front and decreases pressure behind resulting in a larger pressure differential.
A neet aerodynamic trick would be to duct the energized air into a low pressure zone behind the wheels, brake of the hood.

http://ecomodder.com/forum/showthrea...e-29689-2.html
A link from that thread I found interesting from FSAE.COM.
Diverging/Converging Radiator Ducting - Why?

I've heard great things about Humvee efficiency. :p

I would like to second (or third) driver training and incentives.

There is a company in Europe (Germany IIRC) who have focussed primarly on the drivers and have had huge savings.

The other thing would be considering setting a company speed limit, the company who I last drove for had a company speed limit of 80 km/h instead of 90 km/h, that saved them fuel and it was marketed as being for safety, there are numerous companies who have done the same.

Not sure how your company runs, but try and branch out and if your wagons return empty, try and find 'return loads', it wont be a fuel saving but if you have a truck going empty from A to B, and can get a return load, it helps the bank balance. Just make sure that it is a good simple run.

Longer term, consider buying low rolling resistant tyres. Super singles help but as you said conditions may not be right.

Longer term there are (at least in Europe) axels that have been designed with efficiency in mind.

Again longer term - investigate the posibilities of teardrop bodies here is an English company who produce them Aerodynamic Teardrop Trailer

And another long term consider the purchase of alternative trucks, many of the European brands are keen to get out into the rest of the world, and presumably offer a good deals.

experience with V-spoilers vortex generators
 

To your point on aero dynamics we too have fitted Vortex Generators on both our trucks and trailers, and we have good experience with them (around 100 vehicles). The brand is V-Spoilers and we mainly use their panels (on few of the trucks we had to use their single units due to curves and rivets on some of our tractors). They are cheap.

And wheel covers we are considering Flow Below (The V-Spoilers guy suggested that also)

Hi Trucker John,
What kind of gains are you measuring with the VG's?

Are you fitting them to all the places on the trucks recommended? (IE trailer rear, trailer gaps between trailers if B-Double, Rear of the cab / sleeper unit...on top and sides for all those..and then also fitting prior to front wheels, rear of any toolboxes, and on the bonnet(Hood) around 1/3rd in to deflect over the windscreen?)

Hi Craysus,
Hard to give precise info on the fuel saving as it various a lot. But somewhere between 2-4%. They are very efficient on stability, less spray and dirt at the rears. Even on 2 tankers that we have. There are some independant road tests on V-Spoilers web page, including one from Australia.
We fit the panels on mostly at the end of each trailer (also double trailers). Also on all the tractors, that helps a lot in strong cross wind. Sometimes the panels don't fit, so we switch to their single units (but takes longer to mount). We dont fit in other locations, as we dont like how it then would look.

Have contacted a radiator specialist to see what can be done..I believe a dual pass radiator approximately 40cm shorter than the original should suffice..we can increase the capacity by encroaching on the space originally used by the mechanical fan, and possibly even increase the volume of the radiator (Along with using a dual pass with the "relocated" capacity pre cooling the hot coolant prior to passing to the front of the radiator)

With twin electric fans behind this should create more than enough cooling..

Of note, this would allow a huge height reduction in the front leading edge of the hood..possibly to only around 7.5cm (3 inches) above the standard fender height on the leading edge.....(Similar to the "airflow bullet truck" if you were to remove the front nosecone..)
We can not emulate the bullet trucks aero shape 100%, but some of the other aero he has used can be replicated on our vehicles fairly readily..such as the flat side panels (We have 50mm clearance to hit maximum width..meaning just over 1" clearance over the tyres is possible). I will be looking to use a hinged design to allow easy changing of tyres.
Side skirts on the trailers are definately a requirement, and i think with using some vortex generators, relocating exhaust stacks (To underneath the truck), aero mirrors, and a few other things we should be able to get a very decent improvement in airflow and therefore mileage..

Who knows...the Airflow Bullet truck with mainly aero and some friction reduction has gone from 5mpg to 13.4mpg...if I emulate 80% of that kit, and then also apply engine improvements..we may end up with very similar improvement levels...