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November 10, 2010  |   Comments (14)   |   Post a comment

Propane injection system ‘greens’ buses, saves money

The Powershot 2000 Diesel Propane Injection System can be retrofitted onto a bus’ engine without any modifications to the engine. When installed on a School District of Westfield bus, it helped to decrease exhaust emissions by 60 percent, according to Transportation Director Scott Peterson.

The Powershot 2000 Diesel Propane Injection System can be retrofitted onto a bus’ engine without any modifications to the engine. When installed on a School District of Westfield bus, it helped to decrease exhaust emissions by 60 percent, according to Transportation Director Scott Peterson.

A system by Diesel Performance Products that has been tested by pupil transportation operations in Arizona and Wisconsin can reportedly help increase school buses’ torque and horsepower while decreasing fuel consumption and emissions output.

The Powershot 2000 Diesel Propane Injection System can be retrofitted onto a bus’ engine without any modifications to the engine. It injects propane in increasing amounts into the engine’s air intake system as the boost pressure level of the engine increases.

The system, which is available for all vehicles with a turbo diesel-powered engine, is controlled by an illuminated on/off switch located inside the bus’ cab. A propane tank that will accommodate at least 25 percent of the vehicle’s fuel capacity is required. (Tanks are sold separately.)

Keith Long of Diesel Performance Products told SBF that in addition to improving a bus’ power, performance and drivability, the Powershot 2000 is a convenient alternative to running a bus solely on propane because if the bus runs out of propane, it can continue to operate on diesel.

“Many districts cannot afford to purchase new or alternative-fueled buses without bond money or government incentives, so they are unable to ‘green’ their fleets and save on fuel costs. The Powershot can offer a return on investment usually in one school year depending on the cost of both fuels and the mileage increases achieved,” Long added, noting that the Powershot 2000 retails for between $1,500 and $2,000.

A propane tank that will accommodate at least 25 percent of the bus’ fuel capacity is required for operating the Powershot 2000. John Bedway, transportation director at Concho Elementary School District #6, said the system gave this bus more power.

For John Bedway, transportation director at Concho (Ariz.) Elementary School District #6, the Powershot 2000 gave one of his 1997 Amtran school buses 10 to 15 percent more power.

“The bus was really underpowered and almost unusable, but now it’s working great for routes and field trips,” Bedway told SBF in mid-October. In addition to the increase in power, Bedway said the bus is getting about 21 percent better fuel mileage. Prior to installing the Powershot 2000, the bus was getting 6.32 miles per gallon (mpg), and it is now getting 8.04 mpg. Moreover, he noted that using the system has yielded a cost-savings of $.042 per mile (diesel and propane included), so he is saving $840 every 20,000 miles.

“It really cleaned the bus up — you don’t see any black smoke coming out of the bus,” Bedway added.

After seeing the benefits of the Powershot 2000 on the older bus, the district purchased another system, which Bedway would like to install on one of his 2006 or 2007 model year buses.

“I’m hoping that the propane will help me run the bus a little cleaner and give me more life out of it,” he said.

The School District of Westfield in Wisconsin also tested the Powershot 2000 on one of its older buses. Transportation Director Scott Peterson told SBF that the system provided the bus with 25 to 30 percent more horsepower and helped to decrease exhaust emissions by 60 percent.

He used the Powershot 2000 on the bus when it was fueled with a 50-50 blend of biodiesel and diesel, and when it was fueled by 100 percent biodiesel.

“When we ran the Powershot with 100 percent biodiesel, the bus had just as much power, if not more than when it was fueled by regular diesel without the Powershot,” Peterson said.

He also said that the bus’ mpg increased. “When we used the system while running the bus on diesel, it went from 7.36 to 9.83 mpg, which is very good for an older school bus,” Peterson said.

He added that if he did not have buses powered by biodiesel, he would invest in a Powershot 2000 system for all of his buses because the cost-savings is so significant: He estimated that the system would have reduced fuel costs by $30,000 per school year.

“With our biodiesel manufacturing nearly the same price as liquid propane, I am unable to use the system in our entire fleet,” Peterson explained. “If anything were to happen to our biodiesel program, I would not hesitate to install the Powershot 2000 on all of our diesel buses and vehicles.”

For more information about the Powershot 2000, visit or e-mail Long at [email protected].

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If anyone is interested the actual case studies of reduce emmissions with propane injection can be found here:

Jim    |    Mar 27, 2012 08:05 AM

in some instances exceeded the necessary requirements. I can only point to over ten years of safe, effective and proven results on every type diesel engine, that this is not an "unproven concept". The nOx reductions are real, we are the only system to have obtained, emissions certifications and have passed to ADR79/00 standards in Australia and New Zealand and are currently testing in Finland to Euro 5/6 standards. The mileage gains, are "net" gains, acheiving cost per mile reductions, even when using two fuels. Please contact me and I will be happy provide you with addtiional information and documentation. I understand and appreciate your concerns. Keith

Keith Long    |    Jan 14, 2011 07:41 PM

I am the designer and manufactuer of the Powershot system featured in the article. I would be happy to address any questions or concerns anyone has regarding the system or the safety of the installations. Please feel free to contact me at [email protected] or at 800-606-0858. Briefly, The U.S. National Highway Traffic Safety Administration (NHTSA) publishes the Federal Motor Vehicle Safety Standards (FMVSS) that manufacturers must meet in order for their vehicles to be legally sold in the United States. 301 pertains to fuel system integrity and 303 pertains to CNG fuel systems specifically. The majority of the current US regulations pertain to the construction of the fuel tanks. LP-gas tanks are built to the specifications of either the ASME Boiler and Pressure Vessel Code or DOT Hazardous Materials Regulations. These tanks are 3 steel walled thick and all LP tanks are equipped with "auto shut off " valves, so that if the tank or any component there of is compromised, the flow is shut off immediately. Propane vehicles(conversions) and injection systems such as the Powershot, must adhere to different standards than vehicle manufacturers do, (FMVSS) as they are considered "retro fit, or add on parts" , however, they can not compromise or affect the original integrity of the fuel system, or cause them to be non compliant. Injection type systems such as the Powershot, do not alter or interfere with the original fuel supply system , they are simply an additional source. The propane does not enter the factory fuel system or injectors and at no time does the vehicle run(or is propelled) by anything other than diesel fuel. The Powershot system complies fully with NPGA 58 and CSA -B149.5-05 and is UL/ANSI and ASME approved. These codes apply to the installation, servicing, and repair of propane fuel system components and tanks on highway vehicles for the provision of motive power. The installations on both districts met and

Keith Long    |    Jan 14, 2011 07:34 PM

Tom, if you're still there reading this. First of all my lengthy response was in three parts because of the limitation on text quantity presented by this site. I'm disturbed by this story because these cash strapped school districts are experimenting with unproven concepts based on claims and promises and no hard information. I'm sorry to have to say this, but the depth of their understanding is exemplified by the installation of the fuel supply system without regard to the requirements of FMVSS 301 and 303. I'm confident that if tested to the requirements of those standards they would fail. And on and on. There's no point in repeating what's already said. I'm not going to invest time in "researching" so-called development projects for factual data; let those who are making the sales claims present that information - if it exists.

Dan Herman    |    Dec 09, 2010 06:31 PM

With all due respect sir, I do not understand why these two districts trying out cost saving and emission reduction technology that they can afford, disturbs you to the point of preparing a three part rebuttal. This article is simply offered as "informative" news of what some people are trying. The questions and concerns you raise, could be addressed to the people mentioned in the article or one of the many manufacturers of these type systems. I am sure the districts researched the technology before hand and could provide you with the facts and answers to your issues with their projects. Also many technical colleges now provide NAFTC (National Alternative Fuels Training Consortium)certifications in alternative fuel systems and emissions where many of these new ideas and technolgies are investigated and researched, including propane, CNG and Hydrogen diesel injection who you could contact as well for "factual" evidence. Or simply research it on the web...? I personally think it's great to see new technology in action and these districts seem genuinely pleased with the performance and savings.

Tom    |    Nov 27, 2010 04:36 PM

Part three, start with part one two comments below. when the product has been so obviously altered. Also, I have difficulty understanding how a simple change in fuel supply can extend the life of the engine/bus. There are many factors besides the engine that influence the useful life of a bus. By the way, Doctor Diesel ran his engine on coal dust injected with compressed air. He ran his first engine in 1893 and LPG was developed in 1910. Still looking for facts.

Dan Herman    |    Nov 18, 2010 03:13 PM

Part two, read part one below. The entry has a size limit. no acceleration loads. Worst operating conditions include cold starts, transient speeds, acceleration, full load operation and lots of idle time. The latter sounds like a school bus. Comparing pumping engines to bus engines is not valid. "Visible reduction in smoke" Subjective, no test numbers. "Soot (a simplified term for particulate matter- PM) reduced and likely NOx" If you were to ask any legitimate emissions development engineer he/she would tell you that prior to the advent of EGR and exhaust after treatment particulate filters they had to deal with behavior called the "NOx/Particulate Tradeoff". Any control measure designed to reduce NOx would result in an increase in particulates and vice-versa. So, your statement is not only wishful thinking its dead wrong. "More complete combustion would reduce emissions." Begging the question. What data is presented that proves "more complete combustion" and how is it a truism that this relationship exists? In fact, more complete combustion would be a step in reducing smoke (burn all the carbon particles) and result in an increase in NOx. You attempted to explain how the system works and i explained that in my first post. You didn't answer my question on MPG claim. Even if I give you the reduction in cost per mile it still doesn't address the miles per gallon issue. Is it miles per gallon of diesel only or miles per total gallons of diesel and LPG? It's likely the latter will be a reduction in total MPG because propane has only 60% of the heat content of diesel and more gallons are needed to make up for the unused diesel fuel to develop equal or more power. I have trouble deciphering the sentence "As long as the power . . . should not be a warranty issue" , but don't see how you can make this "don't worry" statement when you don't know what is the power increase. Further, the various manufacturers can be rather "difficult"l about warranty coverage when the product

Dan Herman    |    Nov 18, 2010 03:08 PM

Ray is right! This fuel supply installation has a slim-to-none chance of meeting Federal safety requirements. FMVSS 301 and 303 do not specifically call for a cage around the fuel tank, but state that the bus must endure a crash test with a moving barrier (battering ram) with a specified and severely limited amount of fuel leakage afterward. The test is so severe that all bus mfrs. use a protective cage. Tom says it's mounted same as a motor home. So? A motor home is not a school bus and does not have the crash test requirements of a school bus. Relying on the DOT/ASME pressure vessel certification is false security. The FMVSS addresses not just the tank, but the fuel delivery system. If this unprotected installation were impacted and resulted in a fracture of the delivery pipe, a fitting, or the fill valve you would have a pressurized leak that would make a dandy torch. I know of a specific situation where a fitting cracked in a liquid fuel system test and was declared a failure to comply. I would not want to defend this installation in a court case. Tom, can't decide whether you are an observer or a representative of the seller of this system; assuming the latter. Your responses are filled with generalities, speculation and non-documented statements. "Study showed no increase in temperatures . . " What temperatures? I'm most concerned about the increase in total fuel flow (increased power claim) rejecting more heat to the cooling system. Did you run a cooling test? Do you know what a cooling test is? The increased fuel/heat rejection could easily exceed the design limit of the cooling system when new and even more so in an older deteriorated system resulting in overheated vehicles, especially in places like the mountains of Arizona. Yes, generator and pipeline pump engines do live a long time. Primarily because of the mode of operation; continuous running, no cold start-warmup-cool down conditions, continuous moderate speed part load operation, no acceleration l

Dan Herman    |    Nov 18, 2010 02:24 PM

The system looks promising. The youtube is confusing to watch. My first concern is the mounting of the propane tank in regards to safety. CNG tanks (on school buses) are usually mounted between frame rails for safety. Can the tank be refueled easily while being mounted in a location such as this? Would the heat from the engine influence any changes to the propane system over the long term? Also, would the system work well on a 2 stroke engine such as a 71 series detroit? We still have many of those here in Ca; some with turbos and some without. It might be a nice alternative for the many small companies who do not have the funding to purchase newer equipment, but want to run cleaner.

Brian    |    Nov 15, 2010 08:59 AM

The study showed no increase in temperatures with this method, other designs can raise EGT's and actually no signs of any excessive wear, long term. (Not sure how long term the study was though) Propane/Diesel generators run 24/7 for months at a time, and when overhauled, are so clean, they look almost new. This is not a new technology, has been around for a long time. The way this is done, is unique, and apparently shows promise!

Tom    |    Nov 12, 2010 12:04 PM

The tank is mounted the same as it would be in a motor home. It has to be DOT/ASME certified, and is also safer than the diesel fuel tank in construction. (3 steel wall thickness for example) The same tank, albeit it a bit smaller, is used in the propane powered Visions but those are mounted in place of the diesel tanks. They stated a "visible" reduction in the amount of black smoke. This would tell you that soot (and most likely nOX )is being reduced. Maybe perception, maybe tested. Either way, more complete combustion would reduce emissions. It doesn't even add any propane until a certain boost is reached, and then it increases with load, and appears the amount is controlled by turbo pressures. Seems like both districts are liking it. Just had a course on alternative fueling, very interesting and very promising way to introduce not only propane but natural gas, while still running on the original fuel, but using less of it. The cost effectiveness (cost per mile reduction)included both fuels in both test cases. (even was tested with bio diesel) This after all is not a conversion or even a dual fuel set up where any diesel fuel is dialed back, or any changes made. It is all mechanical,and no modifications to the bus, which would affect reliability and function were made. It is not introducing propane through the fuel system either. It says introduced into the air intake. The engine always runs on diesel, and the propane is simply fumigated in, just as Rudolph Diesel envisioned in the beginning. As long as the power increase is up to but not over the gross mfg rating, which is less, than what the vehicle certifies to, there should not be a warranty issue. These two districts did not seem to experience any drive ability issues or concerns. These buses were out of warranty, and this has given them a few more years of service.

Tom    |    Nov 12, 2010 11:57 AM

Would this increase in cylinder temperature? Could this possibly burn exhaust valves? My question is what would something like this do in the long run? It seems like this would not have a good effect on engine wear. I'd have to see a long term study first.

D    |    Nov 12, 2010 11:14 AM

There is no way the bus shown above with the propane tank mounted in a side compartment would or should pass safety standards for a school bus. What are they thinking ??!!

Ray    |    Nov 12, 2010 05:16 AM

First an observation, then a few questions. This is not rocket science. If you spill fuel into the intake system of a diesel engine you will increase the power output. More fuel (heat content) in the combustion chamber means more firing pressure and more power. You could get the same power effect by injecting gasoline in the intake system. Or grain alcohol or bourbon whiskey for that matter. If you add fuel content in this manner at full load (acceleration, hill climbing) the diesel injection system will deliver full fuel and the added intake fuel will mean more total power output. At part load the diesel injection system will dial back, reducing the diesel consumption and the intake fuel will supplement the diesel rate to provide the road load power needed. Simple. How was the power increase measured? Seat of the pants evaluation or chassis dynamometer? The former speaks for itself and the latter is highly variable and inaccurate. The only correct measure of power output is to mount the engine (and the trick fuel system) on a laboratory dynamometer. How was the emissions improvement measured? Vehicle at rest, engine at no load and advanced idle speed and a tail pipe sniff of hydrocarbons and CO? Highly variable and inaccurate, no relation to real world operation and especially not relatable to the EPA Transient Emissions Dynamometer evaluation that all production engines are required to meet. The claimed reduction in fuel consumption. Was that the reduction in diesel consumption only? Sure it would be reduced because at part load (most of the operation of the bus) the diesel rate is dialed back as discussed above. Does the mpg figure include the gallons of propane used? Oh, and what does Allison say about the impact of the increased power output on the life of their transmission which was designed and matched to the original power and torque output of the production engine? If I had a bus still under warranty on the transmission I wouldn't want to present a fa

Dan Herman    |    Nov 11, 2010 04:02 PM

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