Technology Comparison

Purify Solutions is the only technology that reduces both NOx and particulate-matter emissions. Compared to competitive technologies/products, Purify Solutions is superior in several dimensions, including cost, maintenance, weight and layout impact, emissions reduction, and fuel savings. In order to achieve the required emissions reductions, other solutions must combine a NOx-reduction technology with a particulate-matter-reduction technology. So, in the chart below, competing solutions must combine either a catalytic converter, exhaust gas recirculation, or selective catalytic reduction technology, with a particulate filter technology.

Technology Descriptions

The current technology for reducing oxides of nitrogen (NOx), carbon monoxide (CO), and hydrocarbons (HC) is the catalytic converter. The introduction of the catalytic converter in the 1970s caused a great deal of consumer backlash at the time because of the large amount of backpressure it placed on the engine, robbing it of significant power. In addition, chemicals in common fuels, such as lead and sulphur, can poison a catalytic converter over time, rendering it useless. This led to the introduction of lead-free gasoline in the United States for the automotive market.

Hence, the recent introduction of ultra-low sulphur diesel fuel has paved the way for catalytic converters in diesel engines. Compared to gasoline engines, diesels run hotter, which makes them more efficient, but also causes them to produce more NOx.

The technology behind the Combustion Purifier™ reduces NOx, carbon monoxide, and hydrocarbons without the use of a catalytic converter, although the integration of catalytic materials into the Combustion Purifier™ can provide addition reductions, if needed, under special circumstances. Since the Combustion Purifier™ avoids the use of catalytic materials in a catalytic converter, typically the rare and extremely expensive metals platinum or rhodium, the Combustion Purifier™ is less expensive to manufacture.

Also, because the Combustion Purifier™ does not have to put the exhaust flow in close contact with the catalytic material, the resulting backpressure is avoided, restoring the power that catalytic converters are known to rob.

There are several other technologies that have also been proposed to cut down on particulate emissions. These include particulate traps, filters, and exhaust gas-recycling systems.

Particulate traps separate particulate matter from the exhaust stream by forcing the gas to make very tight, quick turns. During these turns, the denser particulates get thrown to the outside, where they then get caught in gas flow eddies. The particulates then settle into a catch chamber or trap. Particulate traps cause massive amounts of backpressure on the engine, driving down fuel mileage, and require periodic maintenance to clean out the trap. They are also extremely expensive and significantly increase the volume needed for the exhaust system due to their size.

Particulate filters force the exhaust stream to pass through a filter, much like intake air is passed through an air filter. Some particulate filters are periodically manually cleaned, and tend to be quite large because of the large amounts of particles they need to trap without clogging. Other particulate filters periodically clean themselves by heating up like a light bulb and burning off the particles. These filter systems tend to be smaller, since they can clean themselves more frequently. The cleaning mechanism works reasonably well until the filter fatigues and breaks (like the filament of a light bulb). When this happens, the filter clogs up very quickly because of its small size, causing the vehicle to stall out on the highway.

Exhaust gas recycling systems take exhaust air and mix it with intake air, under the assumption that the particulates will burn out after being passed back through the engine combustion chambers. This system looks good on paper and on the test bed, but breaks down when applied to a real vehicle. The recycled gas dilutes the intake air, reducing its proportion of needed oxygen, which in turn leads to requiring a larger engine to handle the increased engine airflow needed to get the necessary oxygen for combustion. This recycled exhaust gas is a burden to the underlying combustion cycle, driving down fuel efficiency. The system allows for minor reductions in exhaust particulates, but becomes impractical at higher reduction values. If exhaust gas recycling was attempted in order to achieve the Combustion Purifiers 95%+ reduction levels, a truck’s 400 hp engine would end up growing to the size of an 8,000 hp “locomotive” engine. This is obviously an impractical solution.