Kenworth in the USA has announced it is focusing a large part of its research and development on figuring out how make cost-effective trucks that can use less-polluting alternative fuels to haul freight.
Kenworth said it wants to match or exceed the performance of diesel-powered trucks without the pollution.
Brian Lindgren, Kenworth’s R&D director, has spelled out some of the challenges facing truck makers such as Kenworth in trying to meet the growing regulatory demand for zero-emission freight trucks.
Lindgren says that alternative power is a large part of Kenworth’s current R&D efforts and specifically says they’re working to develop trucks that have the capability to haul freight while producing zero emissions.
“We believe that zero-emission trucks will be required for operation in certain areas, first in California, then elsewhere,” said Lindgren.
“We need to be ready with competent, commercially viable trucks that will be good business tools for our customers but we also know it will take years to achieve our durability, reliability and cost targets, and we’re already making good progress,” he added.
“These trucks rely on electric power, regardless whether that power comes from the grid, an on-board generator, a fuel cell or a battery, so we’re developing electrified powertrains that are agnostic to the source of the electricity,” Lindgren emphasised.
The R&D director went on to say that by doing the integration of these systems in-house, Kenworth is learning all the details that it will have to understand before it can build such trucks in production quantities.
Lindgren said that the company’s T680 hydrogen fuel cell truck will begin testing with Total Transportation Services in Southern California ports soon and the company will be working withTTSI to evaluate the results.
“Having TTSI run the Kenworth T680 Zero Emission Cargo Transport (ZECT) truck in real commercial operations will be hugely beneficial,” he said.
“The truck is fitted with telematics, so we can examine data on all aspects of the truck, from driver requests for more power to shift quality, to details on what is happening inside each of the cooling systems. We can simulate much of this on our computers and at the test track, but it’s imperative that we have real-world conditions to validate our models,” he added.
Lindgren said it was important to note that the Kenworth ZECTtruck project was funded in part by the US Office of Energy Efficiency and Renewable Energy, the U.S. Department of Energy and the South Coast Air Quality Management District.
Lindgren also addressed the fear that some drivers have thathydrogen tanks might explode in a crash.
“Hydrogen is generally considered to be as safe or even safer than other flammable fuels, any compressed fluid, even air, requires precautions to ensure safety,” said Lindgren.
“We use tanks that are wound with carbon fiber for high strength and durability and our current on-board fuel storage system uses six tanks and if any one of them loses pressure unexpectedly that tank is instantly isolated from the rest of the system, so only that one tank’s fuel is lost,” Lindgren said.
“If a tank were to be punctured somehow, any hydrogen that leaks out will disperse very rapidly unlike gasoline, which can pool on the ground as a liquid and then turn to vapor at temperatures as low as 40 degrees below zero and can ignite at 500 degrees, hydrogen just wants to get up and away fast,” Lindgren said.
“Hydrogen is 13 times lighter than air, so it races up into the atmosphere away from the scene of the accident the auto-ignition temperature is more than 900 degrees so it’s harder to ignite than gasoline,” he added.
In terms of processing hydrogen as fuel Lindgren says the Kenworth system communicates between the truck and the fueling equipment to ensure that all connections are secure before starting the flow of hydrogen into the tanks and then it monitors the pressure in the truck’s tanks during the entire fueling process.
“The fuel system isn’t the only area where we’re taking precautions, our batteries and our traction motors run at 650 volts so our battery sub-packs each have their own enclosure,” he said.
“We then place these inside another enclosure and position them away from likely impact,” he added.
“We have even taken care to locate all of the battery electrical connection facing inboard inside the enclosure to minimise damage, accidental impact or unintentional disconnection and we’ve incorporated interlock loops in the high-voltage circuits that power down the high-voltage system if a connector is unplugged or damaged, or if a cable is severed,” said Lindgren.
Addressing the challenge of volume production of hydrogen fuel cell and alternative fuel trucks Lindgren said that Kenworth has shown that it can make these trucks work but that the company now has a lot of work to do before it can take these concepts into series production.
“Diesel powertrains, along with the accessories such as engine-driven air compressors and power steering pumps, have had decades of continuous improvement to reach their current status,” said Lindgren.
“Electric ones are still in their infancy though so there is still is a lot of work to be done to develop, integrate, tool and validate truck-specific components that can achieve the reliability, durability and cost expectations of our customers,” Lindgren added.
Lingren says that while the fuel cell system produces plenty of acceleration and hill-climbing capability the real impact to performance is in payload capacity, saying that a tonne dded to the tare weight means a tonne of cargo you can’t carry.
“We’re working with the fuel cell suppliers to increase the power capability, which means we’ll be able to reduce the battery size,” he said.
“ ZECT is our first fuel cell truck as a proof-of-concept prototype and it’s probably over-built, so there are opportunities to reduce weight as we improve our power electronics, accessory drives and cooling systems,” Lindgren added.
Asked what is next for Kenworth’s R&D efforts Lindgren said the company alreadyhas funding approved to develop four more CNG powered hybrid electric trucks which are zero-emission capable for 50 to 70 km and run at near-zero emissions beyond that.
“This project allows us to take our electrified powertrain and accessories one step closer to production design,” he added.
“We’re putting together a project which if approved and funded, would build a small fleet of hydrogen fuel cell trucks capable of regional haul applications in addition to port cartage.”
Lindgren went on to say that the company continues to work on advanced driver assistance systems projects as well as working on improving its diesel-powered products through advanced controls and aerodynamic improvements.