Kenworth’s hybrid vigour
Hybrid engines maintain presence in electric future
THE Australian Kenworth T610, in its two versions with new roomy cabs and plethora of revolutionary technical innovations (for Yankee iron), has gobsmacked both industry and tyre kickers since its launch in 2017.
But in the States, the T680 is already marching down the highways and the new aerodynamic day cab is running in trials in California as Paccar pushes its conservative envelope into what the company sees as a changing future.
Supported by financial investment from state and federal governments, prototype versions of the T680s are powered by a range of trial power sources using hybrid combinations of fuel cells and natural gas, putting traction to the rubber through electric power.
These Kenworth hybrid solutions are being trialled in the most emission-critical state in the US, predominantly on short-haul work.
The development of the 2017/18 prototypes was helped along with multimillion dollar support of the US Department of Energy (DOE) and the office of Energy Efficiency and Renewable Energy (EERE), the funding channelled through southern California’s South Coast Air Quality Management District (SCAQMD).
Hybridisation seems to be the preferred path for Paccar’s attempt to meet future emission standards.
“Within the next decade, hybrid electric power trains are expected to be required to satisfy emissions regulations in most US metropolitan areas,” says Kenworth’s chief engineer, Patrick Dean.
The development of the Californian prototypes is proceeding in three stages. In 2017 a fuel cell powered electric truck and a hybrid using the Cummins Westport ISL G compressed natural gas (CNG) engine were built for initial testing.
This year the first of four Westport CNG / electro hybrids will be built for real world testing out of Californian ports.
The first zero emissions T680 built sources its energy from fuel cells, using compressed hydrogen as the fuel.
Part of the government grants awarded in 2016 went towards this prototype Class 8 hydrogen fuel cell prime mover providing true zero emissions operation.
The fuel cell technology was provided by Ballard Power Systems to recharge the lithium-ion on-board batteries.
A true zero emission solution, the only to come from the truck is water out of the exhaust pipe.
The fuel cell T680 is powered by a dual rotor electric motor driving the rear tandem axle through a four-speed automated transmission.
Fuel cell technology has advanced over the decades and relies on hydrogen as fuel combining with oxygen from the atmosphere being fed into a layered stack of Polymer Electrolyte Membranes (PEM) where a chemical process takes place through the membranes to produce electrical energy and water.
The process is not dissimilar to combustion but rather than heat, electric energy is output through conductive membranes.
One fuel cell produces 1.16 volts so to obtain the energy to power heavy machinery, the cells are stacked in large batteries.
While the emissions of fuel cell technology at the truck are zero, the downside of this method is that the manufacture of hydrogen comes from natural gas at a processing plant and the major by products of carbon monoxide and carbon dioxide are not greenhouse friendly.
But Paccar is not the only one to experiment with hydrogen fuel cells.
Toyota has developed a concept hydrogen fuel cell truck that is currently doing short-haul port work in California with average daily running of about 300 km.
The Toyota engineers have been reported as saying as the truck proves itself on the shorter hauls, they will be extended to medium haulage.
Toyota claims the 80,000 lb GVM concept truck generates more than 670 hp from two Mirai fuel cell stacks.
The futuristic trucks from Nikola Motors are powered by fuel cells but the improvement of all-electric trucks and battery technology has seen the machines be overshadowed by high profile all-electrics such as the Tesla Semi.
Perhaps emissions coming from hydrogen production was part of the reason why Paccar moved the technology of the second T680 prototype to what is essentially a conventional internal combustion engine driving a generator to recharge the on-board battery and supply electrical energy to the electric motor for tractive power.
The second prototype uses the Cummins Westport ISL G Near Zero NOx engine fuelled by compressed natural gas (CNG) to generate the electrical energy.
All the Kenworth prototypes carry lithium-ion batteries and the electric-only range of these trucks is just under 50 km, but as a hybrid they are capable of operating a full day’s work with the hybrid source of power.
With data collected trialling will enter the real world this year with the project receiving an additional $4.8 million in funding from the Californian Air Resources Board.
The two original prototypes are identical other than their respective power generation systems (fuel cell vs internal combustion with CNG fuel).
Kenworth is building an additional four hybrid electric T680 Day Cabs equipped with the Cummins Westport ISL G Near Zero NOx engine operating on compressed natural gas to go into customer vocations for field testing in southern California.
This year’s real world trialling will give Kenworth engineers the data and efficiency profiles to make design and system refinements to the T680 and perhaps lift the curtain on Kenworth’s future.
❝trial The T680s taking part in the are Kenworth’s new ultra aerodynamic day cabs, the product of sophisticated air tunnel modelling.
FUELLING THE FUTURE: The Kenworth T680 Zero Emissions Cargo Transport (ZECT) hydrogen-electric.