Spawning an All-New Gasoline Engine, Stellantis’ Hurricane Is Coming
A powerful and efficient inline 6-cylinder will propel the company’s most-crucial models during the next phase of internal-combustion’s narrative.
Although Stellantis has announced its intent to have EVs account for at least 50% of its sales mix by 2030, this week the company’s Head of Propulsion Systems Micky Bly revealed an all-new 3.0L inline six-cylinder engine dubbed Hurricane. “Internal-combustion engines will play a key role in our portfolio for years to come,” Bly declared, “and we owe it to our customers and the environment to provide the cleanest, most-efficient propulsion possible.”
He said the twin-turbocharged Hurricane I-6 is a “clean-sheet” design that at once will outperform larger-displacement engines (read: the V8s American customers revere in pickup trucks and SUVs) while offering better fuel economy and reduced emissions. The inline 6-cylinder layout has long been a favorite of engine developers because of its inherent balance and superior NVH qualities, but Bly noted another factor: “It sounds wonderful.”
Initially, the 3.0L Hurricane, developed in SO (standard output) and HO (high-output) variants, will be built at Stellantis’ engine plant in Saltillo, Mexico, but Bly confirmed there is potential to add Hurricane production at a company engine-building site in the U.S. Currently installed capacity at the Saltillo plant is approximately 250,000 units.
Bly said the Hurricane will be available in some Stellantis models this year. Although he would not be specific about vehicle applications, he noted that the new inline 6-cyl. engine is intended only for vehicles with longitudinal engine placement. “It fits in any [longitudinal-engine] vehicle that has a V6 or V8 today,” he said. More specifically, “The Hurricane twin-turbo I-6 is the primary internal combustion powerplant of the future in North America for vehicles using the STLA Large and STLA Frame platforms,” said the company’s release detailing the new engine.
Although Bly would not confirm it, the Hurricane engines likely will immediately displace at least some volume of the company’s celebrated “Hemi” V8 – not to mention the 3.6L V6 also used in many truck, SUV and passenger-car models – as the company seeks to address increasing regulatory pressure to reduce greenhouse-gas emissions. Stellantis recently seems to have been deemphasizing Hemi branding in vehicle engine bays and the Hurricane SO out-powers the Hemi 5.7L V8, which currently generates 395 hp and 410 lb-ft (556 Nm) in the Ram 1500, for example.
The Hurricane moniker is not new for the company. The former Chrysler Corp. used the name in the 1950s through the early 1970s for a 4-cyl. engine used in various Jeep CJ models and Willys-brand trucks and sedans.
Power or efficiency paths
The company said that the SO variant of the Hurricane I-6 is “optimized for efficiency,” but at an SAE-certified estimated 400-plus hp (Stellantis said final horsepower and torque figures will vary based on model application), it generates a minimum of 133 hp/L, a power density that Bly said places the engine “at the leading edge of horsepower per liter.” The Hurricane SO will be rated for a minimum of 450 lb-ft (610 Nm).
Bly said 90% of peak torque is available over a 4000-rpm range. The engine’s redline is a comparatively unstressed 5800 rpm and the company said the engine is up to 15% more efficient than larger engines. The Hurricane HO 3.0L is SAE-rated at a minimum of 500 hp and 475 lb-ft (644 Nm). Its redline is 6100 rpm. Total engine weight is about 441 lbs. (220 kg), or around 11 lbs. (5 kg) more than the Hurricane SO.
Some 3 lbs. (1.4 kg) per engine is saved via the use of plasma transfer-wire arc (PTWA) coating of the cylinder bores instead of fitting iron liners. The low-friction coating, used by Ford, Porsche and other automakers, also is 10 times more wear-resistant than an iron liner, Bly said. The Hurricane uses a deep-skirt aluminum block and structural aluminum oil pan topped by DOHC cylinder heads. Variable valve timing imparts 60 deg. of crankshaft authority on the intake valves and 55 deg. on the exhaust side. The Hurricane is fitted with a forged-steel crankshaft and connecting rods.
The new Hurricane design shares bore (84 mm/3.31 in.) and stroke (90 mm/3.54 in.) dimensions – as well as bore spacing – with Stellantis’ global 4-cyl. engine family. The “common-cylinder” format – also used by other global automakers – could “maybe lead to other future spinoffs,” Bly allowed, although he suggested a 3-cyl. variant is unlikely, given the existing strength of the 3-cyl. family from the PSA Peugeot-Citroen side of the Stellantis propulsion portfolio.
Bly said the two Hurricane variants share about 96 common parts. The differences in output between the SO and HO effectively define the variant-specific components. The twin turbochargers of the Hurricane SO operate at a peak 22.4 psi (1.5 bar) versus the 26 psi (1.8 bar) of the HO. The Hurricane SO operates at a 10.4:1 compression ratio compared to the 9.5:1 compression ratio for the HO variant. At a sensitive time for gasoline prices, Bly confirmed that for the Hurricane SO, premium unleaded gasoline is recommended but not required – for the HO, premium unleaded is a requirement.
The two engines also have different thermal-management and fuel-injection systems. The engine-mounted water-to-air intake-charge cooler has a single inlet for Hurricane SO and dual inlets for the HO variant. Meanwhile, the 350-bar (5075-psi) direct-injection system has a single pump for the SO and dual pumps for the HO; a separate chain-driven shaft energizes the pumps.
For now, the new engine is fitted with a stop-start system centered on a “robust starter motor for quick restarts.” But Bly said the new Hurricane is “fully capable to work with an electrification system” for future hybridization.