Hybrids Are Having a Moment

Hybridization can prolong the relevance of ICEs, and it appears to be growing in favor for certain off-highway and heavy-duty vehicle applications.

August 1, 2024

Ryan Gehm

John Deere expanded its hybrid machine offerings with two new production-class E-Drive wheel loaders: the 744 (shown) and 824 X-Tier models. (John Deere)

Manufacturers at the forefront of sustainability efforts and intent on electrifying commercial trucks and off-highway machines still see the necessity to include internal combustion engines in their future product plans. Take Volvo, for example. At the 2024 Advanced Clean Transportation (ACT) Expo in Las Vegas, the company reaffirmed its goal of reaching net-zero carbon emissions with a 100% fossil-free fleet of vehicles by 2040. And ICE will remain a staple.

Deere’s electric variable transmission (EVT) E-Drive system, shown at CONEXPO 2023, delivers up to 25% reduced fuel consumption. (SAE/Ryan Gehm)

“The internal combustion engine will continue to exist in the future – after 2040, after 2050. Then we can ask ourselves, what kind of fuel do we use, to what extent are we able to use fossil-free fuels like HVO,” Peter Voorhoeve, president of Volvo Trucks North America, said at ACT Expo during a CEO Roundtable on Scaling Vehicle Electrification. “The internal combustion engine will [celebrate] its 200th birthday in my opinion.”

Hybridization is another strategy that can prolong the relevance of ICEs – and appears to be growing in favor for certain applications. In the first quarter of 2024, Caterpillar began developing a hydrogen-hybrid powertrain for off-highway vehicles that’s built on its new C13D engine platform. Partially funded by the U.S. DOE, the project will demonstrate how the latest control systems and electric-hybrid components can help hydrogen-fueled engines meet or exceed the power density and transient performance of traditional diesel engines, while lowering CO₂ emissions.

The internal combustion engine will continue to exist after 2050, according to Peter Voorhoeve, president of Volvo Trucks North America. “Then we can ask ourselves, what kind of fuel do we use, to what extent are we able to use fossil-free fuels like HVO.” (SAE/Ryan Gehm)

John Deere continues to expand its hybrid machine offerings, launching last month two new production-class E-Drive wheel loaders: the 744 and 824 X-Tier models. Rather than overtly calling the machines “hybrids,” Deere uses the X-Tier badge with E-Drive, or “electric drive system,” to signal that its electric variable transmission is on board. Paired with a JD9 diesel engine, the EVT replaces the torque converter and traditional transmission and provides instant power.

The hybrid machines’ default Standard Mode for operation delivers up to 25% reduced fuel consumption; a Performance Mode increases performance by 5% while still reducing fuel consumption by 15%. Up to a 7% total cost of ownership (TCO) lifecycle advantage is possible versus conventional drive systems, Deere claims.

“There’s some areas where pure battery-electric may not be feasible, may not be ready in its current state, but hybridization will be a great solution in those situations,” Grant Van Tine, product manager, electric vehicles, John Deere, said at ACT Expo. Van Tine is participating in SAE Media Group’s August 22 webinar on “The Future Role of Hybrids in Off-Highway Vehicles.”

Cummins has commissioned a diesel-battery solution in partnership with the Chinese manufacturer North Hauler Joint Stock Co., Ltd. (NHL). The hybrid NHL NTH260 mining truck has a 220 metric ton payload. (NHL-Cummins)

Heavy mining trucks are one of those applications in which a hybrid powertrain could be preferable to battery-electric, given the substantial expense and weight of the batteries required to fully electrify such vehicles. One notable example: Cummins has commissioned a diesel-battery solution in partnership with the Chinese manufacturer North Hauler Joint Stock Co., Ltd. (NHL). The hybrid NHL NTH260 mining truck has a 220 metric ton payload and is being field tested at the Baiyun Iron Mine of Baogang Group.

Cummins optimized the hybrid system to enable engine downsizing from the previous 2,500-hp QSK60 to the current 2,000-hp two-stage QSK50. The truck is expected to provide a leading TCO, the companies claim, based on initial cost advantages, fuel efficiency and extended service life of the engine. Advanced hybrids have the potential to improve fuel efficiency up to 30%, according to Cummins, depending on the mine profile and advanced battery technology and controls integration.

Cummins optimized the hybrid system to enable engine downsizing from the previous 2,500-hp QSK60 to the current 2,000-hp two-stage QSK50 (shown). (Cummins)

A couple of on-highway hybrid applications have been detailed recently on www.sae.org/news . Hexagon Agility and Brudeli Green Mobility are working together to electrify existing CNG/RNG trucks by integrating Brudeli’s plug-in PowerHybrid system. And Kenworth’s chief engineer Joe Adams discussed the truck maker’s plans for hybrid technology in meeting stricter emissions standards.

Hybrid electric drives may be considered an interim solution or “bridge” technology, but it’s likely to be a long bridge.