Why Diesel is Cleaner and Greener Than You Think… And Still the Best Option for Heavy Duty Trucking
Is the transportation industry’s use of diesel fuel environmentally sustainable? When truck owners and operators are asked this question, they can honestly say “certainly, and it’s getting better every year.”
This answer may surprise you but consider this. What do we mean by the word “sustainable?” Simply stated, it means meeting our needs today without compromising the ability of future generations to meet their needs.
For the trucking industry, today’s “needs” include transporting and delivering over 80% of the freight in the U.S. For most freight haulers, that means using diesel engines for one primary reason: diesel engines, fueled by liquid D2 diesel, are the most powerful and efficient means of delivering freight vs. any other fuel source or engine design available today.
Truckers proved how essential they are to the U.S. economy during the COVID-19 pandemic and did so in heroic fashion. Now, it’s up to the trucking industry to adopt new tools and technologies to make their jobs easier, more satisfying, and more sustainable “over the long-haul.” Contrary to popular belief, this does not mean abandoning diesel in favor of the latest and greatest alternative energy sources. Diesel remains the best option for heavy duty trucking, now and for many years to come.
Diesel engines are primarily energized by fossil fuels, which means that their carbon and oxides of nitrogen (NOx) footprints are and have been of concern for decades, resulting in increasing limits on their emissions from motive power sources. Motive power refers to the harnessed energy or force that is used to power a mechanical device or system. The word motive is derived from “motion” and led to the standardized expression of engine motive power as horsepower.
In order to accomplish an immediate and major impact on diesel engine emissions from motive power (and thereby maximize the sustainability of the trucking industry) we need a flexible, economical, and immediately available means to reduce fuel consumption, while also reducing CO2, NOx, and carbon soot particles. The initial focus needs to be on Class 8 trucks, which burn a higher percentage of diesel fuel than any other freight delivery vehicle.

In order to validate the sustainability of diesel fuel, we need to consider the chemistry and thermodynamic properties of alternative energy sources, specifically the fuels being studied and adapted to providing motive power. That means we need to know the Energy Density of our fuel choices. The U.S. Department of Energy (DOE) has done that for us.

The DOE has proven that there is NO alternative fuel that can match the energy availability of D2 diesel. For example, natural gas and hydrogen are 400% lower in energy density. Now, how do we unlock and harness that potential more efficiently to perform useful work while meeting the environmental requirements of our nation and the world? We do it by going back to the process of combustion in diesel engines that is the most practical and efficient source of road and rail motive power.

The current “aftertreatment” systems on modern diesels employ three chambers containing catalysts whose purpose is to eliminate the exhaust pollutants shown here in the DOC, DPF and SCR systems. However, in doing so, they also release oxygen (O2), water (H2O), and other chemicals, all of which are valuable in diesel combustion, and which are currently wasted into the atmosphere. The immediate practical approach is to stop the waste, which is also a feature of sustainable practices.
SPI.Systems Corporation has just released a system that does just that. We call it SPI Exhaust Reaction, or SPIER for short, pronounced like “SPEAR”.
The sustainable accomplishments to date, proven over two years of nationwide freight delivery by Class 8 trucks, include:
a. Reduction in fuel usage of 15-25%.
b. Parallel reduction in greenhouse gases, called CO2E, of over 18%.
c. Reduction in oxides of nitrogen, called NOx, of 10-30% at engine-out, which saves maintenance caused by various emission control systems, such as Exhaust Gas Recirculation (EGR).
d. Near elimination of poisonous fine particle emissions that even penetrate respirators and reside in the atmosphere.
e. Power improvements of 4-8%, better ability to climb hills, which also means faster, less costly deliveries and less frustration and annoyance for drivers.
SPIER is available immediately as a retrofit to any catalyzed diesel as an upfit, with no interaction with or alteration of OEM systems.
If organizations are going to take major, effective and immediate action to improve the environment in a sustainable manner, the trucking industry is certainly dedicated to that goal. However, it must do so in a manner that is effective and practical for the millions of diesel-powered vehicles on the road. Now it has a powerful tool to do exactly that.