FIRST PERSON/OPINION:

By Jay Sherritt

Fellow Riders,

At the end of July, EPA Chief Christie Whitman, while out championing the cause of motorcycle emissions regulations, said “a typical motorcycle still emits about 20 times more pollution per mile than a new car.”

So how accurate is her representation? Does it truly reflect the impact of motorcycles on significant air quality issues?

I can’t help but remember Whitman’s lockstep with the EPA’s agenda promoting automotive emissions inspection when she was Governor of New Jersey. The EPA touted their MobileX emissions modeling software, and corresponding “credits,” as supposedly based on “best available science.” Governor Whitman vigorously defended the validity of the MobileX results.

So let’s use the EPA’s current version, Mobile6, as a truth meter for Whitman’s statement.

While accepting standard, default values for most inputs (I do use Colorado temperature, altitude and fuel volatility and oxygenate content parameters, as this is where I live), I submitted a Mobile6 run for a scenario evaluating carbon monoxide, hydrocarbons as VOC, and oxides of nitrogen for January, 2002.

Low and behold, the emissions in grams per mile traveled are computed to be 22.73 (CO), 2.61 (VOC) and 1.07 (NOx) for motorcycles. For “Light Duty Gas Vehicles” (passenger cars), the values are 17.57 (CO), 1.158 (VOC) and 1.027 (NOx).

Hmmm. Perhaps Christie is mistaken. Did she mean 29% higher? That is a long way from 20 times higher. Maybe most cars pollute 15 times more than Christie’s cars?

The truth meter flashes red, buzzes loudly, and the needle quivers in the middle of the “Deception” zone. A victim of her own devices.

What is really going on here? A classical EPA (mis)information campaign. The weasel words included in her quote were “new car.” Certified emissions for new cars are quite low, especially until they hit the real world. This is a common EPA trick – compare something in the real world that they don’t like with something in their own fantasy world that they do like. (They are pretty proud of certified emissions, even if they are contrived to make them look good at the expense of real-world durability and function).

The EPA did the same thing in their anti-snowmobile crusade. They took the researcher’s data that showed snowmobiles to be, say, two to three times as dirty as automobiles, and then substituted automobiles that were twenty times as clean as real-world automobiles into the comparison, and voila – the snowmobiles in Yellowstone were 60 times dirtier than cars.

The EPA’s interpretation of the “Clean Air Act” involves adopting regulations that address all internal combustion engines, even down to model airplane engines. (I’m not kidding!) Somehow, they find it essential to offer dramatic justification, even when the regulations have no effect on the real world.

Let’s toss the EPA nonsense and look at things from a real perspective.

The emissions components that motorcycles tend to produce at a greater rate than automobiles are carbon monoxide and hydrocarbons.

First, let’s look at carbon monoxide (CO). This product of combustion only becomes a hazard in high concentrations, typified by traffic jams with atmospheric circulation trapped by a thermal inversion. (Not exactly great riding conditions). Once diluted, it eventually fully oxidizes in the atmosphere, with a half life of somewhere around one to three weeks. It is invisible and odorless, and is not considered a significant participant in the formation of smog.

CO is generated when there is insufficient oxygen in the combustion chamber to fully oxidize all of the fuel. In the past twenty five years, automobiles have dramatically reduced their CO emissions due to the incorporation of a component that measures the oxygen content of the exhaust, and uses this to iterate on an air-fuel mixture that is on the threshold of oxygen presence. At the resulting air/fuel mixture, there is very little carbon monoxide produced. The component, referred to as an oxygen sensor or lambda sensor, produces a voltage as a result of imbalances of gas-phase O2 molecules imparted on zirconium. This technology provides a method for dynamically adjusting mixture based upon the results of combustion, commonly described as “closed loop” operation.

Within the last few years, oxygen sensors have been appearing on production motorcycles – partly in response to the market force that demands crisp throttle response without having to “re-jet” carburetors for temperature, humidity and altitude. Many of us have seen oxygen sensor displays on race motorcycles in order to provide better carburetor jetting feedback to the operator.

As oxygen-sensor-based fuel injection systems overtake the market (as they are doing rapidly now), CO emissions from new on-road motorcycles will approach or diminish to less than those of new real-world automobiles, whether or not the EPA takes action.

Mobile6 was written before the current wave of closed loop, oxygen-sensor-based fuel injection systems became common on production motorcycles. It is likely that it does not accurately reflect actual recent trends in motorcycle emissions. We could already be at the point where real-world motorcycles are cleaner than real-world automobiles with respect to CO. Even as things are today, we could turn the tables on the EPA and correctly argue that (real world) automobiles produce much higher emissions than new motorcycles. (Hey, they started it. They compared apples with oranges, so why can’t I compare oranges with apples? Buzz. Flash. Quiver.)

As for hydrocarbons, they have a minor point.

Hydrocarbons are allowed to pass through to the exhaust generally when combustion does not occur (due to misfires, or sometimes compression braking), when the incoming charge blows through the combustion chamber and out the exhaust port before the exhaust valve or port closes for compression (port or cam overlap), and as a result of the flame being unable to propagate too close to the metal surfaces of the combustion chamber (quenching). Hydrocarbons released into the atmosphere are associated with the formation of smog.

The performance oriented motorcycle market prefers more cam overlap than would be used to minimize hydrocarbon emissions. You could argue that there is a tradeoff here – either adopt catalyzers or less cam overlap, but neither would produce a measurable benefit to ambient air quality. The default travel fraction from Mobile6 for motorcycles is only .006, while cars and SUVs make up .769. Closed-loop fuel injection technology probably reduces hydrocarbons significantly beyond the assumptions of Mobile6, as do other fuel injection elements. Even without the benefit of these considerations, automobiles still produce forty times more hydrocarbons emissions than motorcycles on a fleet basis. How meaningful is it to further reduce the contribution of motorcycles? Do we get a gold star if we cut it to a hundredth, or a thousandth? (Not difficult to attain. All we have to do is surrender some of our freedom, and rewrite the next-to-the-last line of the national anthem).

Catalyzers can reduce CO and HC emissions to near zero in some cases (also NOx), but are much more effective in extinguishing emissions in the EPA testing procedures than they are in the real world. In practice, the extremely wide dynamic range of operation of motorcycle engines makes it difficult to design a catalyzer that works under all load conditions. (My FZR1000 is great at low throttle, fifth gear, and 2000 rpm. It is also great under full throttle at 11,500 rpm). The same applies to automobiles, but to a lesser degree.

So what is wrong with the EPA’s proposed regulations if the industry is wandering that direction anyway?

The devil is in the details. In addition to federal anti-tampering laws, most states have laws on the books that prohibit tampering with emissions control devices. If cams, cylinder heads, fuel tanks and intake and exhaust systems become “emissions control devices,” then much of the freedom that we exercise in customizing, modifying and tuning arguably becomes tampering. Those of us with riding experience know that some law enforcement personnel in some jurisdictions take a great deal of liberty in interpreting these laws when it suits their mood. Whether or not they buy the “Honest, officer. The California Air Resources Board issued a letter of exemption.” in Peoria is not a matter that is addressed in the proposed regulation. Visualize customs agents seizing your Italian titanium exhaust system.

The right thing to do would be for the EPA to monitor the sales of on-road motorcycles that do not employ closed loop fuel injection for the next five years, and compare the real-world emissions of motorcycles with those of automobiles before they propose similar regulations. And make their press releases informative instead of inflammatory.