Posted on Monday, January 13, 2003

No quick fix to problem of tricycle emissions

By Dave L. Llorito, Research Head

If the government really wants to rid the streets of harm­ful emissions from noisy, clunky tricycles, it should clear the atmosphere first of misconceptions about the “poor man’s taxi.”

The most blatant myths floating around are the follo­wing: a) two-stroke motorcycles are inherently dirty; b) four-strokers are inherently clean; and c) “alternative” fuels are inherently clean.

According to Dr. Brian Wilson, professor and research director of Engines and Energy Conversion Laboratory of the Department of Mechanical Engineering (Colorado State University), these assumptions are false. With current technological breakthroughs some types of two-strokes are clean and that four-strokes and “alternative fuels” like natural gas or liquefied petroleum gas or LPG are not necessarily cleaner.

Different bikes, different strokes

Motorcycle engines are either two-stroke (manufactured by Suzuki, Yamaha and Kawasaki) or four-stroke (manufactured by Honda). About a third of total motorcycle sales is accounted for by Honda; the rest are shared by the three other brands.

All over the country, there are about a million motorcycles and tricycles. In Metro Manila alone, there are 162,000 tricycles confined mostly to secondary streets. Most, if not all, are two-strokers because Honda does not encourage the conversion of its four-stroke bikes into tricycles.

There are several factors why two-strokers are generally dirty (See Table 1 on effects of motorcycle and tricycle emissions). According to Wilson, one is that it uses a “waste lubrication system.”  

In his paper entitled Direct Injection as a Retrofit Strategy for Reducing Emissions from Two-Stroke Cycle Engines in Asia, Wilson explains: “In small two-stroke engines, the oil mixed with the fuel during the refueling … Some of the oil is deposited on the appropriate components (crank bearings, rod bearings, cylinder walls) while the mixture is in the crankcase. The remaining oil then travels with the air/fuel mixture into the cylinder where it is either short-circuited or trapped in the cylinder. This short-circuited oil contributes to hydrocarbon emissions. Those trapped oil does not burn readily and becomes a major source of visible smoke (coming off the tailpipes).”

In short, two-strokers have low fuel inefficiency, compared with four strokers, with 15-40 percent of the air/fuel mixture escaping into the air. It is also noisy and gives off high particulate matter and hydrocarbon emissions.

But tricycle drivers prefer two-stroke bikes because they have excellent torque or power; fewer moving parts and thus easy to maintain; lighter and smaller engines; greater operating smoothness; and lower nitrogen oxide emissions.

“Tricycle drivers feel it’s more macho because it gives them power on demand,” says Archie H. Diaz, program officer of the Clean Air Project of the Swiss Contact, a foundation implementing clean air projects in the Philippines funded by the Swiss government. “Magaling humarurot.”

Four-strokers are thought to be cleaner because of their much-improved fuel economy and they give off less particulate matter and hydrocarbons. And compared to two-strokers, four-strokers purr like a kitten. Hence, many environmentalists and experts think the only way to meet the standards of Clean Air Act is to convert to four-strokers. That is why some environmentalists are campaigning for a ban on two-strokers.

It is not as simple as that, says Wilson. One, not all two-strokers are dirty. There already are “clean” two-strokers with direct-fuel injection and catalytic converters that are as clean or even cleaner and cheaper than four-strokers.

“In direct injection two-stroke engines, the fuel is injected into the cylinder after the piston has closed the exhaust ports … The combustion chamber is scavenged by air only,” says Wilson. This results in 90- percent reduction in unburned hydrocarbon emissions. With catalytic converters, the reduction in hydrocarbons and carbon monoxide could reach 99 percent. Bikes equipped with converters give off virtually no smoke.

The problem, however, is that the technological breakthroughs in two-strokers have largely been proven in the advanced countries. The challenge is adapting them to Philippine conditions. Wilson has started crunching numbers and the results are promising: retrofitting two-stroke tricycles that are already in use would cost P10,000 each. With appropriate micro-financing, tricycle drivers and operators could pay off their loans in two years without losing the shirt off their backs. This is particularly attractive because one need not scrap the existing tricycles compared to other options like shifting to four strokes or the use of compressed natural gas and LPG.

Dirty four strokes?

Contrary to common belief, not all four-strokers are squeaky clean.

“Replacing two-stroke engines with four-strokes … would significantly reduce hydrocarbon and particulate emissions, say experts like Masami Kojima, Carter Brandon and Jitendra Shah in a paper entitled Improving Urban Air Quality in South Asia by Reducing Emissions from Two-Stroke Engine Vehicles. “[However]…emissions of nitrogen oxides would increase.” Thus, scrapping two-strokers and switching to four-strokes is just like doing away with one type of poison and getting greater doses of another type.

Some groups insist four-strokes are definitely one of the best options, especially for brand-new tricycles. This is attractive because of significant reduction in particulate matter and hydrocarbons. That means there is no black smoke blowing out of tailpipes. There are remaining emissions to worry though – nitrogen oxides and carbon monoxide – that are not seen by the naked eye. But one could get philosophical about them: one problem at a time.

The main drawback to the four-stroke option, however, is cost. The current talk about “converting” to four-strokers actually means retiring two-strokers and buying a brand-new four-stroke bike to be fitted to the sidecar. That means each tricycle owner has to spend at least P65,000. With incomes of at least P200 per operating day, they could hardly afford the upgrade.

Besides, driving tricycles is physically exhausting; most drivers don’t drive seven days a week. Either they alternate with other drivers or drive only during peak hours. That means reduced average daily incomes. Hence, there is truth to the tricycle drivers’ claim that the Clean Air Act could destroy their livelihood.

What to do with the junked two-strokers — many of them are probably new – is another problem. Sell them to the junk shops? When these two-strokers are scrapped, they might just end up in some parts of the country where local governments and the LTO are lax in implementing the Clean Air Act, thus merely shifting the problem from Metro Manila to the countryside.

Alternative dirt?

So what are the other options? Many earth lovers easily suggest tricycles fuelled by natural gas or LPG. According to the Dr. Carl Vergel de Dios, faculty of the National Center for Transportation Studies based in the University of the Philippines, it is a viable option. But that is still a long way off considering many technical barriers.

LPGs are stored in large cylinders; that means they are going to occupy a lot of space in the tricycles. Safety concerns would deter its immediate adoption. These days, many could not still imagine a tricycle weaving in and out of crowded alleys and subdivisions carrying a bulky LPG tank. The design of tricycles in the country involving lots of moving parts (since motorcycles and the sidecar are designed separately) could be dangerous. Potential leaks and constant friction of parts could cause sparks that may ignite a fire. Still, it holds promise, considering that LPG has been successfully used to fuel “tuk-tuks” in Thailand.

Natural gas is also promising but its containers are equally bulky. Besides, supply of the commodity as alternative fuel from Malampaya is not yet available.

And, contrary to common notion, “alternative fuels” are not necessarily cleaner. “Unless the vehicles are maintained properly, compressed natural gas could actually result in higher emission of methane, another pollutant,” says Joji Manalaysay, director of the Partnership for Clean Air, a coalition of NGOs, environmentalists, and transport groups financed by the Asian Development Bank. “What is more urgent is to develop that culture of proper maintenance among drivers.”

Behavioral problem

So the more basic issue is not the complete or abrupt shift to four-strokers or alternative fuels. It is first and foremost behavioral: proper and regular vehicle maintenance. By addressing these behavioral factors, it is possible that two-strokers could be less dirty.

What makes two-strokers dirty are the misconceptions of tricycle drivers themselves. One is that if one’s tricycle does not give off smoke, it does not have power. So what they do is put more 2T oil in the gas tank to produce more powerful smoke bursts.

Or they might just be ignorant of the right mixture. Brand-new tricycles come with autolube to guide them of the right 2T oil-gasoline mix. According to De Dios of NCTS, when the autolube is damaged, drivers don’t bother to buy a new one. What they do is approximate the mix, resulting to the abuse of the 2T oil. He says that the ratio is about 1:20 or 1:40, depending on the motorcycle brand and make, but the NCTS survey indicates that the average ratio employed by tricycle drivers is 1:10. The problem is aggravated by the proliferation of cheap, possibly adulterated, 2T oils that are sold in the streets and some gasoline stations. In some cases, tricycle drivers don’t bother to go to gasoline stations but instead buy potentially adulterated fuel from small street-side “entrepreneurs.” Wilson says these factors explain why the emission of one tricycle in the Philippines is equivalent to that of 50 cars!

Short-term fix

Manalaysay says one way to address the abuse of 2T oil and adulterated fuel is to require gas stations to sell “premixed” fuel for tricycles. This is to avoid the problem of tricycle drivers worrying whether or not they fed the right mix of fuel into the tricycle. And with proper maintenance — regular tune-up, cleaning of carburetor, cleaning and adjusting the ignition system, timely replacement of spark plugs and air filters, among others — two-stroke engines might just pass the Clean Air Act standards. Hence, there might not be any need to scrap two-strokers that could disrupt the livelihood of about half-a-million tricycle drivers in Metro Manila.

Recently, the Metropolitan Manila Development Authority issued a resolution requiring tricycle drivers to take mandatory emission testing before they can be registered with the Land Transportation Office. After the drivers protested, the MMDA gave them a month’s reprieve, after which only those that pass the test will be allowed on the streets. What will happen after a month?

What adds to the confusion is the fact that the Clean Air Act does not actually have any standards for tricycles. It does have “approval-type” standards for motorcycles but the law does not contain “in-use standards.” Approval-type standards are those that govern new models about to be introduced in the market. These are essentially emission-control regulations through vehicle design.

In-use standards are for those motorcycles that are currently being used. In effect, there are no standards with which to base the mandatory emissions testing for tricycles as required by MMDA. Currently, the technical working group created by the government to handle this issue is rushing the drafting of the new standards, hoping it can finish it in January so that by February, LGUs can start with the mandatory emission testing for tricycles. So far, the TWG is bogged down by what standards for hydrocarbons should apply.

Uncertain future

Come February, will the tricycle drivers pass the standards? Manalaysay hopes so because otherwise, thousands of families would lose their means of livelihood. Realistically, however, there seems to be less room for optimism. For one, not all drivers are possibly aware of the new regulations. Hence, the mandatory emission testing that will be enforced by MMDA will come as a surprise to many of them.

Second, the emission standards for tricycles will probably follow “international standards” owing to pressure from environmentalists. De Dios is less optimistic that a “properly maintained” two-stroker of current make will pass the standards, given the nature of the technology itself. He says that NCTS has made a study on the emissions of existing tricycles. “The results show that the likelihood that they will fail is very high,” he says.

What De Dios implies is that solution to the tricycle problem could not come in a matter of months as what the MMDA resolution requires. It would require gradual, long-term process.

One possible medium- or long-term solution is the shift to the “multicab,” a small Ford Fiera-type Asian utility vehicle common in the Visayas and Mindanao. Multicabs have already replaced some tricycle fleets in some Mindanao cities. Equipped with the right engine, a multicab could be a lot cleaner and more efficient than tricycles. Its price, however, is almost double that of a tricycle. Social acceptability is probably a problem and NCTS is still conducting “willingness to pay” studies to determine their applicability in Metro Manila.

Two-strokers with direct injection, four-strokers, tricycles with alternative fuels and multicabs are all viable solutions, provided they are equipped with catalytic converters and properly maintained. But it may take several years of research and testing before they can be made to work in real-world conditions in the Philippines. For instance, setting up refueling stations for alternative fuels will take time.

According to Diaz, the technologies that will prevail will be determined by factors like cost-effectiveness, practicality, and reliability. As a policy, therefore, he thinks what is needed are clear emission standards that do not specify what technologies are allowed or banned.

Meanwhile, tricycle drivers are wondering what’s in store for them come 
February.

Conclusion