You’ve been exposed to all the headlines. Battery electric vehicles (BEVs) have made an entrance. Diesel is considered obsolete….However, hold your horses. Judging by all significant indicators that take into account the future of the automotive industry, it is evident that diesel systems will persist for a minimum of another decade, and maybe even a full twenty-five years. This is particularly true in the heavy-duty pickup truck category, where traversing mountains while towing a 20,000-pound trailer is a common scenario. In this domain, electric technology has much more ground to cover compared to the everyday commuting vehicle sector. But why exactly will diesel engines continue to be the leading force in this specific niche of the automotive realm?
To comprehend how diesel will endure the BEV surge, let’s commence from the start and progress forward. From an environmental perspective, the diesel internal combustion engine (ICE) has greatly improved its performance. As the regulations on nitrogen oxide (NOx) become more stringent, diesel engines will become even more environmentally friendly in the upcoming years—all while generating substantial torque figures. In the next five to seven years, anticipate Ford’s Power Stroke, Ram’s Cummins, and potentially even GM’s Duramax to produce 1,300 to 1,400 lb-ft of torque directly from the showroom floor. Ahead, we’ll unveil the reasons behind our expectation of The Big Three achieving this milestone.
How It Commenced
Because the design of every ICE is aimed at reducing emissions, it is crucial to start from there. When diesel engines made their debut in the ¾-ton and larger pickup truck sector through GM’s 130 hp, 240 lb-ft torque 6.2L V8 in 1982, there were hardly any nitrogen oxide (NOx) or particulate matter (PM) standards in place. Consequently, those engines—along with Ford’s 170 hp, 310 lb-ft International Harvester 6.9L V8 introduced in 1983—could easily be deemed as “polluting.” By 1985, the initial NOx standard of 10.7 g/bhp-hr was enforced, and a 0.60 g/bhp-hr PM regulation became effective in 1988—coinciding with the launch of the revolutionary, turbocharged, direct injection, and 400 lb-ft 5.9L Cummins inline-six in Dodge trucks.
How It Progresses
It should not be underestimated that as NOx and PM emissions standards became more stringent, not only did The Big Three comply with the heightened emissions standards, but they also succeeded in producing more potent engines. For example, Ford’s truck range starting from F-250 and beyond has evolved from offering engines that were not subject to NOx or PM standards to the current 6.7L Power Stroke in its Super Duty lineup, which manages to meet a NOx standard of 0.20 g/bhp-hr as well as a PM standard of 0.01 g/bhp-hr (compared to the 10.7 g/bhp-hr and 0.60 g/bhp-hr levels of 30 years earlier). Moreover, Ford’s current premium diesel engine produces an outstanding 500 hp and 1,200 lb-ft of torque. The 2023 F-450 XL model presented above comes equipped with this powerhouse and can tow up to 40,000 pounds.
Future Emission Compliance
While the present lineup of Power Stroke, Cummins, and Duramax diesels is the cleanest (and most robust) versions ever introduced, they will soon need to meet even more stringent emission standards. By 2027, a new ultra-low NOx standard of 0.020 g/bhp-hr (as opposed to the current 0.20 g/bhp-hr) will be enforced. The approach used by Ford, Cummins, and GM to ensure their engines comply with the new regulation is yet to be determined, but we anticipate that future iterations of the Power Stroke, Cummins, and Duramax will utilize advanced exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) technologies to meet the requirements.
Current Challenge: Transmission Durability
With the aid of high-pressure common-rail injection, variable geometry turbochargers, and modern electronics, diesel engine manufacturers face no obstacles in creating engines capable of generating substantial horsepower and torque. However, downstream of these numbers, there often lies an automatic transmission teetering at the edge of its torque-handling limits, even in factory form. GM’s 10L1000 Allison, Ram’s 68RFE, the Aisin AS69RC in high-output Ram models, and Ford’s 10R140 all have significant weak points. To further the torque rivalry, or to even elevate it, the introduction of more robust transmissions to the market is imperative.
Why BEV Technology Will Not Eradicate Diesel Power
Even though there have been advancements in the commercial BEV sector (consider Tesla’s regional haul “Semi”), BEVs are yet to demonstrate they can even remotely rival diesel’s supremacy in the pickup truck field. Much of this centers around range. When pulling at the maximum gross combined weight rating (GCWR) of a modern diesel truck, it’s possible to achieve between nine and 12 mpg—or a range of about 350 miles, depending on the tank size (which varies slightly across brands). Based on our observations in half-ton BEV testing, only half of that range (at most) would be attainable in a ¾-ton or larger truck. Diesel continues to offer exceptional range under heavy workloads, while, for now at least, battery-electric vehicles in this vehicle category do not.
Detroit Continues to Invest in Diesel
The mere fact that The Big Three are still pouring resources into the diesel ICE indicates everything you need to know about the future decade or more of heavy-duty pickup trucks. For instance, General Motors wouldn’t have recently injected nearly $1 billion into its DMAX engine operation if it didn’t plan to offer a Duramax diesel-powered HD truck well into the future. The automaker’s engine component plant for the current 6.6L Duramax will be expanded fourfold, from 250,000 square feet to 1.1 million, when all is said and done. This represents a significant investment and underscores that GM is taking a long-term approach with its key HD pickup engine.
If The Duramax Is Here to Stay…
Then similarly, Ford’s 6.7L Power Stroke or the 6.7L Cummins choice in Ram heavy-duty vehicles are also not going away. For instance, in 2019, Ram unveiled a brand-new, high-output 6.7L Cummins for its fifth-gen trucks, featuring a compacted graphite iron block. In 2020, Ford introduced the revamped 6.7L Power Stroke V8—an engine that now boasts steel pistons akin to those in Class 8 vehicles. Since then, both engines have seen substantial increases in torque, with Ford’s ’23 model year H.O. Power Stroke delivering an unprecedented 1,200 lb-ft. If OEMs, who plan years ahead, felt pessimistic about the diesel future, they wouldn’t have introduced these engines.
Anticipating the Next 5 to 7 Years
So, what does the diesel outlook hold for the next five years? We anticipate that, along with more robust transmissions, Ford’s 1,200 lb-ft torque rating will be challenged and even exceeded by competitors. It might seem ambitious, but a breach of the 1,300 lb-ft mark is probable—and maybe even reaching 1,400 lb-ft. Achieving this could involve a variety of factors, but we suspect high injection pressure and steel pistons could play a role in the engine designs. When it comes to meeting stricter emissions regulations, we believe the OEMs have strategies in place as well. As we mentioned earlier, there is room for enhancing existing EGR and SCR systems.
Image Source: Jonathan Weiss / Shutterstock