What Hasn't Worked: PM Filters, Alternative Fuels....
Current approaches to particulate filters, after-treatments, and combustion tuning have not prevented the emissions health crisis we are now experiencing in major cities worldwide. The reason for this is simple. None of these technologies addresses the fundamental cause of these emissions: incomplete combustion.
diesel Particulate filters cannot solve the problem
of poor combustion
Particulate filters capture the bulk of large-molecule combustion waste products but do not eliminate them. The most dangerous ultrafine particles are a very difficult technological problem. Any filter fine enough to capture nano-particulate matter would restrict airflow to a degree inconsistent with fuel efficiency. Combustion tuning to reduce NOx also sacrifices efficiency. More fuel burnt, higher costs, and more greenhouse gasses.
Complete combustion is the solution: eliminate toxic byproducts of hydrocarbon combustion through converting all of the fuel's hydrogen and carbon into heat, carbon dioxide, and water. HMWPIB is the only technology we currently have that can substantially improve combustion without producing NOx and with no compromise in fuel efficiency.
Why Not GDI and GPF?
Deadly Emissions
Already, more than half of the light-duty vehicles sold in the U.S. have a gas direct-injection (GDI) option—and the number of GDI-equipped models is rapidly increasing. There is ample evidence that engines equipped with GDI emit ultrafine particulates (UFPs) and particulate matter (PM) that is comparable to the emissions of diesel engines that do not use diesel particulate filters (DPFs).
Gasoline direct injection engines use less fuel, but produce more of the most dangerous emissions — 10 times more, according to a 2016 University of Toronto study reported in the American Chemical Society journal, Environmental Science and Technology.
Unlike laboratory GDI testing, the Toronto study evaluated performance on the road, collecting air samples in real conditions over several seasons. What they found was alarming: 10 times more fine particulate matter on the road than in the lab in the same engine designs.
As US EPA Tier 3 emission standards go into effect, we need thorough data collection and assessment of PM/UFP emissions from GDI in real-world operating conditions. It is of urgent importance to employ technologies that reduce emissions (such as HMWPIB). Capturing PM with technologies, such as gasoline particulate filter (GPF) increase fuel use, NOx, and CO2, while failing to protect the public from ultra-fine particulate matter.
Millions Are Exposed to Deadly Pollution Despite EU Emission-Control Measures (WHO 2020)
Share of the EU urban population exposed to air pollutant concentrations above EU standards and WHO guidelines in 2020
Barriers to Use of Other Fuel Alternatives
Many alternative fuel sources have been proposed to reduce urban air pollution from diesel vehicles. They all have pros and cons. None come close to HMWPIB for reduction of PM, NOx, and O3 emissions and increased fuel efficiency. And, importantly, ALL require expensive infrastructure investments that would take years to complete. HMWPIB can be used cheaply in existing engines and distributed with minimal fueling, supply chain, or storage modifications.
Natural gas — Although it is cleaner than gasoline or diesel, burning natural gas does produce nitrogen oxides (NOx), which are precursors to smog. In addition to NOx, natural gas drilling, extraction, and transport releases methane, an extremely damaging greenhouse gas (30-80 times more heat-trapping than CO2). Natural gas for vehicles has been around for many years, both in compressed form (CNG) and liquefied form (LNG). Using it in heavy engines requires modifications that reduce engine performance (i.e. adding spark plugs). Cost and safety have also been issues (very high pressure refueling and storage/cryogenic chilling). Expensive supply infrastructure would be required (estimated US $2 million/filling station). Threats to public health from methane leaks that we see in existing natural gas supply chain would have to be addressed.
Battery Electric Vehicles (BEV) — BEVs generate no emissions themselves, although their true impact must include sources of battery power, which can be coal, diesel, and other emissions-generating technologies.
To date, the challenge for BEVs has been high cost, low energy density, significant weight, and lengthy recharging requirements. Battery energy density appears to be reaching a limit, suggesting that battery power alone will not be able to provide sufficient energy for long-range or heavy-duty applications, such as trucking.
Hydrogen fuel cells — Refueling and storage requirements for hydrogen are so demanding and expensive (the pressures and temperatures involved are even more extreme than for natural gas). No cost-effective plan for large-scale hydrogen refueling infrastructure has been articulated to date.
LPG — Unlike natural gas and hydrogen, LPG is cheap, easy, and safe to dispense and store as a liquid, with moderate pressure demands. However, LPG is not a suitable replacement fuel for diesel engines. At best, it can supplement diesel in specially modified trucks. Application is currently limited to passenger cars that have been modified for its use.
DME — The big advantage of dimethyl ether (DME) is that it does not generate particulate matter. However, it can only be used in specially designed engines, where it is about 10% less efficient than standard diesel. And, while it generates no PM emissions, DME produces methane, a greenhouse gas. Even worse, DME creates transient spikes of NOx, CO, and unburned hydrocarbons that exceed standard diesel emissions and current US and EU air quality limits. NOx emissions following ignition three-fold higher than standard diesel have been measured in testing.