If not for the word “mucosalivary,” the following analysis could have come from a combustion-engine technical paper: “Recent work has demonstrated that exhalations, sneezes, and coughs not only consist of mucosalivary droplets following short-range semi-ballistic emission trajectories but, importantly, are primarily made of a multiphase turbulent gas – (a puff) cloud that entrains ambient air and traps and carries within it clusters of droplets with a continuum of droplet sizes.”
Its author, Lydia Bourouiba, Ph.D, is an associate professor at the Massachusetts Institute of Technology, specializing in fluid dynamics. The gas turbulence and “coughs” she refers to, however, aren’t dyno-room observations. They’re part of Dr. Bourouiba’s expert studies of how SARS-CoV-2, the coronavirus that causes the disease COVID-19, can be disbursed from human carriers – through laughing, yelling, sneezing and simply talking – into the atmosphere. A sneeze can unleash a turbulent cloud of micron-sized droplets at velocities of 100 ft/sec. The pathogen-laden cloud then can travel up to 27 feet (8 m) before landing, while still an active threat, on contact surfaces.
Invisible clouds of even smaller aerosol contagions can remain suspended in the air for hours, depending on wind currents. Such viral clouds are menacing in the open air and dangerous in closed spaces. Their impact on vehicle occupant health and safety is a growing concern of both consumers and vehicle developers – particularly in the ride-share, public transit and autonomous sector. With increased urgency, engineers and scientists are developing solutions for maintaining cabin air quality and keeping interior surfaces sanitary, according to Neil Boehm, chief technology officer at Gentex Corp., a Tier 1 specializing in microelectronics, safety-related sensing and electro-optical technologies.
“It started with driver-monitoring systems to ensure the driver is paying attention when the vehicle is in a semi-autonomous or autonomous state,” he told SAE International. “That technology has increased the awareness of the state of the overall vehicle interior, and it’s been heightened with the pandemic and interest in sensing the actual virus itself. The concern can be as simple as getting a rental car and wondering how clean it is.”
The materials matrices that comprise vehicle interiors present a challenge to those seeking solutions, along with the unknowns related to COVID-19 pathology. A study released in March 2020 from the National Institutes of Health, Center for Disease Control, UCLA and Princeton University scientists, published in The New England Journal of Medicine, reported that SARS-CoV-2 was detectable for up to three days on plastic surfaces. A virus can live for up to four days on glass, depending on location and temperature, noted a January 2020 study by the Journal of Hospital Infection.
To tackle these issues, Gentex is creating technology paths based around the company’s core capabilities. Their development “tool box” includes smoke-detection solutions that use optical electronics to look for particulates; Gentex-designed-and-built cameras; light sensors; nanomaterials capable of sensing health threats to driver and/or passengers that could be residing in a vehicle and, increasingly, artificial intelligence.
“In the world of autonomous and even [SAE] Level 3 and 4 automated vehicles, we see a lot of use cases for different sensing systems including bio- and chemical hazards, and even explosives,” he said. “There is a need to provide the ability to know what’s in the vehicle that shouldn’t be there or could be causing health concerns – whether it’s being driven by a human or not.
Designing around variables
Boehm acknowledges that the road to vehicle autonomy will require a long transition. He explains that the technologies Gentex is investigating for next-generation sensing systems are intended to span human driving – involving not only air quality but also occupant position and driver monitoring. There’s also commercial delivery. “One of the scenarios we talk about a lot, related to autonomous fleet vehicles such as shuttles, is concerns about people smoking in them. Or leaving trash behind,” he said. “Fleet operators need all vehicles to be clean because they’re in use as close to 24/7 as possible.”
When an AV drops off one rider and picks up another, how do you identify who was smoking in it? Such issues might cause the vehicle to be pulled out of service. “Some of our sensing systems are being developed around understanding that environment – air quality, surface cleanliness, and even content left behind by passengers,” Boehm said.
Monitoring the cabin and cargo spaces and designing systems that can disinfect the cabin air and surfaces and alert the fleet operator of an airborne or onboard hazard is no easy task. “It’s incredibly complex, with almost infinite variables,” he noted. “But if you can identify the variables you can drive to a solution.” The dynamic behavior of aerosols, now known to linger in air for longer than was previously understood, is one example.
Among the priorities in creating bio-safe (and cost-effective) vehicle interiors is the process of thermally checking the occupants – both in the vehicle and those about to enter. “Just taking the body temperatures of people is a challenge in itself,” Boehm explained. “Normal” temperatures vary among individuals. And depending where the thermal sensor contacts the forehead can result in a reading that varies by as much as plus/minus 2%.
“What accuracy levels are required – and how accurate can we get the systems?” he asked. “The challenge is in being non-invasive so there is no surface contact required of the consumer, then ensuring the technology is consistent and reliable.” He said increasingly, the accuracy of sensing systems improves with use, as the vehicle “learns” an occupant’s baseline temperature – it may be a “normal” 98.6 degrees on one individual and 99 degrees on another.
“As you understand the variables, you can then design systems around them,” Boehm stated. “For example, airborne health threats can get into the HVAC system. We have the ability to use filtering and extensive airflow to help clean that. If it’s something on a surface in the vehicle, now we need to be working on UVC systems to clean the interior surfaces.”
UVC is ultraviolet light with wavelengths between 200 – 280 nanometers. Light in the UVC wavelength has germicidal qualities. It can be used for sterilizing surfaces and destroying harmful airborne micro-organisms. It has proven highly effective at eradicating viruses in medical use. But for use in vehicles, interior materials will need to be more robust in color and durability to survive the wavelength and intensity of light. Surfaces also can be coated or processed in a way that makes them anti-bacterial or anti-viral.
“Those subjects get us excited and their use cases create opportunities to utilize technologies we have in our chemistries and coatings, or materials-based background, in concert with our sensor designs and engineering,” Boehm said. “There is great potential to bring these systems together, but there are a lot of variables involved. I don’t know that covering every scenario is achievable in the near term. I think we start with the goal of achieving a better interior environment, working on air quality, then start adding the other technologies to it for further improvements.”
He expects artificial intelligence and edge computing to enable more processing at the sensing component, versus downstream, so engineers can cover more areas faster. “There is a lot of interest in how these technology pieces can come together for use on future platforms, to create a safer environment for passengers,” he asserted. “I think that once COVID slows down, the focus will continue – on influenza, for example.”
Bridging automotive and medical
A tenet of Gentex’s product-development process is spreading core technologies across multiple vertical markets where they can be applied. Capability to sense a virus or chemical in a ground vehicle, for example, might apply to the aerospace or medical environments. The company also has realized the need for more bio-medical inputs and expertise for its development and engineering team, for which it has thus far taken two paths.
“We’re expanding our internal skillsets. We don’t have a big bio-medical group here, but as this [the pandemic] changes the environment, it’s something we’ve been investigating and getting deeper in,” Boehm reported. “The automotive and medical, verticals are bridging each other. People want information on the driver’s health. Is there an issue developing where the vehicle will need to take control? There is still a question on whether the consumer wants that information given, however, but that’s a privacy discussion.”
The second path is collaboration. In October Gentex announced a partnership with RetiSpec, an AI-proficient medical imaging company that is developing a tool for the early detection of disease biomarkers in the eye. Gentex will engineer, manufacture and commercialize technology for the early detection of Alzheimer's disease. And at CES 2020 Gentex showed its collaborative project, done with the Mayo Clinic, for medical operating-room lighting of the future.
“It’s a bit strange for auto guys getting involved with an operating room, but the collaboration was driven by our camera and lighting-control technology,” Boehm said. “We took some of the baseline technology used in our SmartBeam [automotive high-beam control] product, added to it, and came up with solutions for future ‘smart’ OR lighting that would be controlled and focused by surgeons in different situations. Importantly, we learned a lot from the feedback provided by 75 doctors and nurses. So, as we look at other opportunities, we have a real strong research pool to help us determine if a technology makes sense for a given application.”Continue reading »