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Old 01-09-2017, 12:01 AM   #1 (permalink)
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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.


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Old 01-09-2017, 03:16 AM   #2 (permalink)
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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?


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.
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Old 01-09-2017, 11:17 AM   #3 (permalink)
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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:

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Old 01-09-2017, 12:35 PM   #4 (permalink)
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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?
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Old 01-09-2017, 12:47 PM   #5 (permalink)
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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.
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Old 01-09-2017, 08:34 PM   #6 (permalink)
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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!)
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Old 01-09-2017, 09:32 PM   #7 (permalink)
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It sounds good but seems funny the guys who's job it is at Cummins to improve efficiency can't figure that stuff out.
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Old 01-09-2017, 10:18 PM   #8 (permalink)
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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.
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Old 01-09-2017, 11:02 PM   #9 (permalink)
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Originally Posted by Hersbird View Post
It sounds good but seems funny the guys who's job it is at Cummins to improve efficiency can't figure that stuff out.
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.

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Old 01-09-2017, 11:29 PM   #10 (permalink)
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How large is your fleet?

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