Emissions From Snowmobile Engines Using Bio-based Fuels And Lubricants
Jeff J. White and James N. Carroll
Southwest Research Institute
Howard E. Haines
Montana Department of Environmental Quality
ABSTRACT
Snowmobile engine emissions are of concern in environmentally sensitive areas, such as Yellowstone National Park (YNP). A program was undertaken to determine potential emission benefits of use of bio-based fuels and lubricants in snowmobile engines. Candidate fuels and lubricants were evaluated using a fan-cooled 488 cc Polaris engine, and a water-cooled 440 cc Arctco engine. Fuels tested include a reference gasoline, gasohol (10% ethanol), and an aliphatic gasoline. Lubricants evaluated include a bio-based lubricant, a fully synthetic lubricant, a high polyisobutylene (PIB) lubricant, as well as a conventional, mineral-based lubricant. Emissions and fuel consumption were measured using a five-mode test cycle that was developed from analysis of snowmobile field operating data. Emissions measured include total hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NOx), carbon dioxide (CO2), particulate matter (PM), polycyclic aromatic hydrocarbons (PAH), both particulate bound and vapor-phase, and individual hydrocarbon species (C1-C12). Emissions and fuel consumption using bio-based fuels and lubricants were compared to results using a conventional fuel and lubricant. Promising candidates were identified and recommended for further study in a field demonstration in Yellowstone National Park.
INTRODUCTION
Government officials in the Yellowstone National Park region face concerns about health and environmental impacts of emissions from winter transportation, especially snowmobiles operating in stagnant air conditions. Snowmobiles are powered by two-stroke engines that have high emissions of hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM), compared to four-stroke engines. A partnership of public, private, national, and local organizations developed this study to quantify impacts, and determine how they might be reduced with commercially-available products. Benefits observed in the laboratory study will be demonstrated this winter in and around Yellowstone National Park. These results will help set policy on the fuel, lubricant, and type of equipment that should be operated in Yellowstone, and in other environmentally-sensitive areas including national parks and forests.
TEST ENGINES
Program fuels and lubricants were tested with two engines to evaluate emission effects with both air- and water-cooled designs. Engines were selected that were considered most representative of the snowmobile population in the Yellowstone area. According to a usage survey conducted by the State of Montana Department of Environmental Quality, Polaris and Arctco snowmobiles accounted for approximately 81 percent of the 1,400 sled rental fleet in West Yellowstone, Montana (1995/6 season), and the Polaris 488 cc fan-cooled engine was the engine most used in YNP.(1) Engines are described in Table 1.
Both engines are carbureted and employ oil injection. Lubrication is provided by a crankshaft driven pump at a rate that is a function of engine speed and throttle position. Mode 1 (WOT) observed power was 45 kW at 7000 rpm for the Polaris, and 42 kW at 8000 rpm for the Arctco.
TEST PROGRAM
The test program was designed to evaluate the effects of alternative, bio-based fuels and lubricants on snowmobile engine emissions, power, and fuel consumption. Fuels evaluated included a reference, certification-grade gasoline (EEE Clear), gasohol, which was 10 volume percent ethanol splash-blended with the reference gasoline, and an aliphatic fuel (Alkylate) purchased from Aspen Petroleum.
Oxygenated fuels have been determined to provide significant reductions in ambient carbon monoxide (CO) concentrations in cities participating in the oxyfuel program.(2) Missoula, Montana has reduced measured ambient CO by 24.3 percent on average, since introducing oxygenated fuels.(3) Even greater reductions were observed during stagnant air conditions. Gasohol was included in this program to determine whether similar emission reductions could be achieved with snowmobile engines.
Aliphatic fuels have minimal amounts of olefinic and aromatic hydrocarbons, and are used in specialized applications where concern exists about the toxicity of benzene in conventional gasolines. Aliphatic fuels have been found to substantially reduce the ozone formation potential of exhaust organics from both 2- and 4-stroke small engines.(4,5) Alkylate was included in this program to evaluate this benefit in snowmobile engines. Fuel inspection data are presented in Table 2.
Because fuel and lubricant are combusted together in conventional 2-stroke engines, lubricants contribute to engine emissions. An aerosol of uncombusted lubricant is the primary source of 2-stroke engine particulate emissions, as measured gravimetrically from diluted exhaust gas. Lubricants would also be expected to contribute to heavier exhaust hydrocarbons in both solid and vapor phases.
Lubricants evaluated included a baseline, manufacturer recommend lubricant (ARCTIC Extreme), as well as three alternative lubricants, CONOCO Biosynthetic, CASTROL XPS, and TORCO Smokeless. The CONOCO Biosynthetic is a biomass-based, 100 percent synthetic, biodegradable lubricant. The CASTROL XPS is a fully synthetic, low-ash 2-stroke lubricant that also claims to be highly biodegradable. The TORCO Smokeless material is a high PIB (~38% polyisobutylene) content lubricant. Lubricant analyses are shown in Table 3.
The test matrix is shown in Table 4. Most tests utilized a 5-mode snowmobile engine test cycle developed for the International Snowmobile Manufacturers Association (ISMA) by Southwest Research Institute (SwRI). Tests A11-3 and 4 established baseline emissions on the Polaris engine with reference gasoline and the manufacturer recommended lubricant (ARCTIC Extreme). Test A12 evaluated the CONOCO Biosynthetic lubricant with reference gasoline. The RICH test was run with a size 240 jet (210 jet used in other tests), to examine changes in emissions due to richer operation. This test simulates the situation one would have if a snowmobile jetted for lower altitude operation were run at a higher altitude (lower air density), resulting in richer operation. This provides a rough indication of the emissions increases which could result from operating a lower altitude sled in YNP, which has roadside elevations ranging from 5,300 to 8,800 feet. Tests A21 and A22-1 evaluated emissions with gasohol and two different lubricants. Tests A31-1 and 2 were run with the aliphatic fuel and reference lubricant. Tests A22-2, A23, and A24 were back-to-back, mode 1 only tests of the three alternative lubricants with the lowest emissions fuel (gasohol). Tests W11-1 and 2 and W21 repeat selected combinations on the Arctco liquid-cooled engine.
EMISSIONS MEASUREMENT
A wide range of emissions measurements were made to thoroughly characterize fuel and lubricant effects. Regulated emissions including total hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), and carbon dioxide (CO2), were measured from diluted exhaust in every test. Instrumentation used included a heated flame ionization analyzer (HFIA) for THC, non-dispersive infrared analyzers for CO and CO2, and a chemiluminescent analyzer for NOx. Particulate was measured using 90 mm Pallflex filtration of double diluted exhaust gas following 40 CFR Part 86, Subpart N protocols. Hydrocarbon speciation was also performed on selected proportional bag samples of diluted exhaust using the three GC Auto/Oil procedure, which quantifies C1 to C12 hydrocarbons, including aldehydes, ketones, and alcohols.
Additional analyses were performed on selected tests. Particulate phase polycyclic aromatic hydrocarbons (PAH) were determined by analysis of extracts of particulate collected on 20x20-inch Pallflex filters. Gas phase PAH compounds were determined from samples collected on polyurethane foam (PUF) filters. PAH species were identified and quantified using a quadrupole GC/MS operated in selected ion monitoring mode. PAH results were not available in time for publication, and will be reported in a future paper.
TEST PROCEDURE
Emissions were measured using a 5-mode snowmobile engine test cycle that was developed for ISMA by SwRI. Real time operating data were collected on four instrumented snowmobiles operated over various on- and off-trail segments representing five driving styles. These data were statistically analyzed to determine steady-state modes representative of real in-use operation. This cycle is described in Table 5.
Modes are run in order from highest to lowest speed. One hundred percent engine speed is the speed declared by the snowmobile manufacturer as representative of the maximum steady engine speed in snowmobile operation. Torque values are specified as a percent of the maximum (WOT) torque observed at 100 percent speed in Mode 1.
TEST FACILITY
Snowmobile engines were tested in SwRI's nonroad engine test cell. Each engine was mounted on a bed plate using jack stands, and connected to a dynamometer using an appropriate coupling. A high speed, water-brake dynamometer was used for the Polaris engine. The Arctco engine was tested with an eddy-current dynamometer using a toothed belt, speed reduction system. Engines were instrumented for measurement of various temperatures and pressures. Fuel and lubricant consumption were determined as mass delivered from precision balances. The Polaris engine is shown in Figure 1.
Engines were operated using stock intake air boxes and exhaust systems to ensure correct operation. All engine exhaust was collected without physical connection to the exhaust system, and conveyed to a 0.457 m (18 in.) diameter dilution tunnel. Total dilute flow was maintained at approximately 16.0 scmm (565 scfm). Proportional bag samples of diluted exhaust were collected for CO and CO2 analysis and HC speciation. Separate continuous samples were analyzed to determine THC and NOx. A portion of the diluted exhaust stream was further diluted in a secondary dilution tunnel for particulate measurement, as shown in Figure 2.
RESULTS AND DISCUSSION
REGULATED EMISSIONS - Five-mode cycle emissions and fuel consumption from the Polaris engine are shown in Table 6. HC, CO, and PM emissions are high, and NOx emissions are low, as is typical of 2-stroke engines. Emissions are comparable to previously reported results with allowance for differences in engine operation and test procedure.(6,7)
The RICH test generated significantly higher HC, CO, and PM emissions (20%, 14%, and 28%, respectively), than the mean gasoline baseline result. Fuel consumption also increased by 13 percent, and Mode 1 (WOT) power decreased by 14 percent. This test was run with a richer than specification main jet to simulate the effect of operating a snowmobile at a higher altitude than originally calibrated for. The difference between the normal (210) and richer (240) jet corresponds roughly to an 1800 m (5906 ft.) altitude difference, and confirms that incorrect jetting significantly increases snowmobile engine emissions.
Test A12 examined emissions with the CONOCO Biosynthetic lubricant and reference gasoline. Results were similar to those generated with the reference lubricant (ARCTIC Extreme), except for particulate matter, which increased 66 percent. This may be related to the lower front end volatility of the CONOCO lubricant compared to the reference lubricant as observed in the distillation results in Table 3.
The gasohol results indicate substantial emission benefits may be obtained using an oxygenated fuel in snowmobiles. Test A21 (gasohol with reference lubricant) produced 16 percent less HC, nine percent less CO, and 24 percent less PM than the mean gasoline baseline result. Specific fuel consumption was also reduced, and Mode 1 power was maintained or possibly slightly increased, from base gasoline levels. The gasohol test run with the CONOCO lubricant (A22-1) resulted in 64 percent more PM than Test A21 with the reference lubricant, confirming the increased PM observed in Test A12. The gasohol/CONOCO test also produced less HC and CO than the gasohol/ARCTIC Extreme test, however it is unlikely that this was due to a lubricant change. HC and CO reductions were not observed in the gasoline-based comparison between these lubricants, and it is more likely that these emissions differences reflect engine drift between tests.
Aliphatic fuel results reflected increased HC and PM results (33% and 47%, respectively), compared to the mean gasoline baseline result. Fuel consumption also increased, and Mode 1 power was reduced about 5 percent.
Engine emissions were not as repeatable as we would have liked. Steep engine power output characteristics, coupled with the less precise control of the waterbrake dynamometer made if difficult to achieve precise control of modal setpoints. To try to obtain a more accurate comparison of lubricant effects, three lubricants were run back-to-back in Mode 1 (WOT) operation without shutting the engine off or making any adjustments. After switching lubricants, the engine was operated for a sufficient length of time to flush the injection system with the new lubricant prior to taking emission data. Gasohol was selected as the fuel for this comparison because it provided lower emissions than the reference gasoline. Results are summarized in Table 7.
Differences in HC, CO, and NOx emissions are small, and likely not significant. These results are consistent with 5-mode results which showed significantly higher PM emissions with the CONOCO lubricant. As a point of reference, Mode 1 PM emissions in the gasohol/ARCTIC Extreme test (A21) were 0.27 g/kW-h, similar to results observed with the CASTROL lubricant. The TORCO Smokeless lubricant emitted 43 percent less PM than the CASTROL, which suggests that the use of this material could decrease the visible haze associated with snowmobile engine operation.
Five-mode cycle test results with the Arctco engine are presented in Table 8. To obtain better engine control, an eddy-current dynamometer, fitted with a belt-driven speed reduction system, was used for this engine. See Figure 3. This approach provided much better control than the water-brake dynamometer used with the Polaris engine. Speed and load setpoints were maintained typically within a few percent of set value. In spite of this, variability between repeat Arctco tests W11-1 and 2 was not substantially decreased compared to Polaris results. This may be due to the type of carburetion employed with these engines, which uses three different circuits to control fuel delivery. Emission rates appear to be highly sensitive to small changes in engine operation, particularly at the more heavily weighted part-throttle modes.
The water-cooled Arctco engine also showed reduced emissions using gasohol, although it was less sensitive to fuel differences than the Polaris engine. With gasohol, HC, CO, and PM were reduced 7 percent, 6 percent, and 3 percent, respectively. Oxides of nitrogen emissions increased 6 percent, and specific fuel consumption was reduced 3 percent. Mode 1 WOT power with gasohol was equivalent to or slightly greater than with gasoline. Improvements in power and fuel economy are due to the rich base calibration established for gasoline. Enleanment provided by the oxygenated fuel appears to improve the quality of combustion in these engines, yielding reduced emissions and increased power at equivalent fuel flows.
Emission rates of HC, CO, and NOx were fairly similar for the two engines tested. Particulate emission rates however, were much higher with the Arctco engine. An examination of lubrication rates (fuel/oil ratio) (Table 9) showed that the Arctco engine ran 3 to 18 percent more oil rich than the Polaris engine, except in Mode 5 (idle) where the Arctco engine lubrication rate was over three times that of the Polaris engine. These differences, however, are insufficient to account for the magnitude of the PM difference. Further investigation suggested an additional factor. Spark plug seat temperature data showed that there were large differences in cylinder temperatures between air-cooled (Polaris) and water-cooled (Arctco) designs. Polaris spark plug seat temperatures were typically 180 C higher in Mode 1, than those with the Arctco engine, and it is likely that these higher cylinder temperatures promote more complete volatilization of injected lubricant, resulting in lower PM emissions.
SPECIATED EMISSIONS - Hydrocarbon speciation was performed on selected tests using the three GC Auto/Oil procedure, which identifies and quantifies 223 individual C1-C12 hydrocarbons. Results may be analyzed in a variety of ways depending on specific properties of interest. Organic gases may be classified according to hydrocarbon type, such as paraffin, olefin, aromatic, carbonyl, and other. Toxic or other target species emissions rates can be examined. Since the regulation of organic gas emissions is due to their role in ozone formation, speciation results are often analyzed to determine ozone formation potential, based on application of species-specific Maximum Incremental Reactivity (MIR) values. Selected Polaris engine speciation results are presented in Table 10. Total speciated hydrocarbons are compared to THC levels determined by FID. Agreement between the two methods is quite good with GC levels ranging from 90 to 101 percent of FID HC levels.
Four organic gases have been classified by EPA as toxic species - 1,3-butadiene, benzene, formaldehyde, and acetaldehyde, and these are also shown in Table 10. Emission rates of 1,3-butadiene are fairly similar among the different fuel/lubricant combinations. Benzene emissions were considerably less with the aliphatic fuel, as would be expected with its low level of aromatics. It appears that some benzene is being produced in the combustion of this aliphatic fuel, perhaps through thermal cracking and reformation. Formaldehyde emissions are slightly higher with both gasohol and aliphatic fuel than with gasoline. Acetaldehyde emissions are also increased with the ethanol containing fuel, as expected, since the ethyl group is a direct precursor of acetaldehyde, and may be readily converted to acetaldehyde through partial oxidation.
Overall, toxic species appear to be present in similar proportions to those observed from other sources. For example, 1,3-butadiene, benzene, formaldehyde, and acetaldehyde were present in gasoline-fueled Polaris engine exhaust at levels of 0.14, 0.80, 0.64, and 0.10 percent, respectively of total hydrocarbon emissions. These levels are similar, percentage wise, to those observed in older catalyst and non-catalyst equipped passenger cars.(8)
Ozone formation potential was reduced 15 percent with gasohol, compared to gasoline results. The aliphatic fuel provided an even greater reduction (22%) in spite of its higher total hydrocarbon emissions. This is due to the lower composite reactivity of species emitted. Fuel characteristics may also be viewed in terms of specific reactivity, which is equivalent to total ozone formation potential divided by total hydrocarbon levels. Specific reactivities for gasohol tests were 3 percent higher than with gasoline. With aliphatic fuel, specific reactivity was 25 percent less than with gasoline. These values reflect a slightly higher composite exhaust reactivity with an ethanol-containing fuel, and a significantly lower composite reactivity with the aliphatic fuel. While these data suggest some important benefits which could be provided by aliphatic fuels, ozone formation potential is likely of less concern than CO (and HC) emissions in a winter-use scenario.
SUMMARY AND CONCLUSIONS
Alternative fuels and lubricants were tested in both fan-cooled and water-cooled snowmobile engines to determine effects on emissions, fuel consumption, and power. The following observations were made:
- Gasohol reduced HC, CO, and PM emissions, and slightly increased NOx emissions, while maintaining equivalent engine power, as compared to results with reference gasoline.
- The aliphatic fuel, while increasing total hydrocarbon emissions, yielded the lowest ozone formation potential of the three fuels tested due to its low specific reactivity.
- Lubricant formulation affects PM emission rates. The high PIB TOROCO Smokeless lubricant created significantly less PM than the three other lubricants tested.
- Particulate emission levels are influenced by lubrication rate, and may also be influenced by engine design. The fan-cooled engine had significantly higher spark plug seat temperatures and, by inference, cylinder temperatures, and substantially lower PM emissions, than the liquid-cooled engine.
- Toxic hydrocarbon species are present in similar proportions in snowmobile engine exhaust to those observed from other sources such as passenger cars.
- Benzene emissions were considerably reduced with the aliphatic fuel.
Promising candidates are being recommended to the National Park Service for further evaluation in a field demonstration to be conducted this winter in Yellowstone National Park.
| Snowmobile Manufacturer | Polaris | Arctco |
|---|---|---|
| Snowmobile Model | 1997 Indy Trail | 1995 Panther |
| Engine Manufacturer | Fuji HI | Suzuki |
| Engine Model | EC50PM04 | H44-690033 |
| Operating Cycle | 2-stroke | 2-stroke |
| Displacement, cc | 488 | 440 |
| Cylinders | 2 | 2 |
| Cooling | Fan Air | Liquid |
| Carburetion | 2-Mikuni VM3455 | 2-Mikuni VM34 |
| Main Jet Size | 210 | 240 |
| Ignition System | CDI | CDI |
| Spark Plug | BPR8ES | BPR9ES |
| Lubrication | Oil injection | Oil injection |
Fuel Property |
Method |
Reference Gasoline | Gasohol |
Aliphatic Gasoline |
|---|---|---|---|---|
| Specific Gravity | ASTM D-4052 | 0.7433 | 0.7485 | 0.6961 |
| RVP, psi | ASTM D-5191 | 8.88 | 9.69 | 9.36 |
| Aromatics Olefins Saturates |
ASTM D-1319(Total) | 27.3 0.6 72.1 |
25.7 0.5 64.8 |
1.6 0.2 98.2 |
| Carbon, wt. % Hydrogen, wt. % |
ASTM D-5291 | 86.39 12.92 |
83.11 13.19 |
84.42 16.21 |
| EtOH, vol. % Oxygen, wt. % |
ASTM D-4815 | N/A N/A |
9.31 3.43 |
N/A N/A |
| Sulfur, wt. % | ASTM D-2622 | 0.001 | 0.001 | 0.001 |
| Benzene, vol. % | ASTM D-3606 | 0.14 | 0.17 | 0.00 |
| Lead, g/gal U.S. | ASTM D-3237 | <0.001 | <0.001 | <0.001 |
| Phosphorus, g/gal U.S. | ASTM D-3231 | <0.001 | <0.001 | <0.001 |
| RON | SwRI | 97.5 | 101.7 | 96.4 |
| MON | SwRI | 89.6 | 90.6 | 94.6 |
| Distillation, °C IBP 5% 10% 20% 50% 80% 90% 95% EP |
ASTM D-86 | 31 42 50 65 105 124 152 172 199 |
35 47 52 58 99 124 156 171 198 |
32 48 66 91 104 110 122 143 194 |
| Recovery, % Residue, % Loss, % |
97.5 0.5 2.0 |
98.0 0.5 1.5 |
96.0 1.0 3.0 |
Property |
Method |
ARCTIC Extreme | CONOCO Biosynthetic | CASTROL XPS |
TORCO Smokeless |
|---|---|---|---|---|---|
| Specific Gravity | ASTM D-4052 | 0.8676 | 0.9265 | 0.8958 | 0.8598 |
| Viscosity @ 40°C, cSt | ASTM D-445 | 24.16 | 55.62 | 41.23 | 43.24 |
| Viscosity @ 100°C, cSt | ASTM D-445 | 5.01 | 9.05 | 8.78 | 7.22 |
| Flash Point, °C | ASTM D-92 | 80 | 244 | 104 | 80 |
| Total Base Number | ASTM D-4739 | 6.40 | 1.18 | 2.99 | 0.86 |
| Total Acid Number | ASTM D-664 | 0.71 | 0.68 | 0.64 | 0.25 |
| Carbon, wt. % Hydrogen, wt. % |
ASTM D-5291 | 84.88 13.63 |
75.52 12.13 |
80.32 12.86 |
86.11 14.20 |
| Nitrogen, wt. % | ASTM D-5291 | 0.620 | 0.245 | 0.253 | 0.034 |
| Ba, ppm Ca, ppm Mg, ppm Mn, ppm Na, ppm P, ppm An, ppm |
<1 7 <1 <1 4 3 3 |
1 2 <1 <1 3 186 1 |
2 588 4 <1 1 68 1 |
<1 304 8 <1 10 9 9 |
|
| Distillation by GC, °C IBP 5% 10% 20% 50% 80% 90% 95% FBP |
ASTM D-2887 | 141 189 211 250 410 521 648 691 724 |
318 400 469 484 492 605 618 692 728 |
174 194 207 431 561 581 640 673 727 |
140 184 210 250 418 641 684 698 724 |
| Test ID | Fuel | Lubricant |
|---|---|---|
| Polaris Fan-Cooled Engine | ||
| A11-3 | Ref. Gasoline | ARCTIC Extreme |
| A11-4 | Ref. Gasoline | ARCTIC Extreme |
| A12 | Ref. Gasoline | CONOCO Bio-Synthetic |
| RICH | Ref. Gasoline | ARCTIC Extreme |
| A21 | Gasohol | ARCTIC Extreme |
| A22-1 | Gasohol | CONOCO Bio-Synthetic |
| A31-1 | Aliphatic | ARCTIC Extreme |
| A31-2 | Aliphatic | ARCTIC Extreme |
| A22-2 | Gasohol | CONOCO Bio-Synthetic |
| A23 | Gasohol | CASTROL XPS |
| A24 | Gasohol | TORCO Smokeless |
| Arctco Liquid-Cooled Engine | ||
| W11-1 | Ref. Gasoline | ARCTIC Extreme |
| W11-2 | Ref. Gasoline | ARCTIC Extreme |
| W21 | Gasohol | ARCTIC Extreme |
| Mode | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Speed, % | 100 | 85 | 75 | 65 | Idle |
| Torque, % | 100 | 51 | 33 | 19 | 0 |
| Wt. Factor, % | 12 | 27 | 25 | 31 | 5 |
| Fuel | Lubricant | Test ID | Emissions, g/kW-h | BSFC | Mode 1 | |||
|---|---|---|---|---|---|---|---|---|
| BSHC | BSCO | BSNOx | BSPM | kg/kW-h | kW | |||
| Gasoline | ARCTIC | A11-3 | 223 | 589 | 0.61 | 2.13 | 0.68 | 43.8 |
| Gasoline | ARCTIC | A11-4 | 180 | 526 | 0.56 | 1.49 | 0.60 | 46.2 |
| Baseline Gasoline (mean) | 202 | 558 | 0.58 | 1.81 | 0.64 | 45.0 | ||
| Gasoline | ARCTIC | RICH | 241 | 635 | 0.42 | 2.31 | 0.72 | 38.9 |
| RICH/Baseline | 120% | 114% | 72% | 128% | 113% | 86% | ||
| Gasoline | CONOCO | A12 | 199 | 537 | 0.57 | 3.01 | 0.62 | 45.9 |
| A12/Baseline | 99% | 96% | 97% | 166% | 97% | 102% | ||
| Gasohol | ARCTIC | A21 | 170 | 506 | 0.59 | 1.38 | 0.60 | 46.1 |
| A21/Baseline | 84% | 91% | 101% | 76% | 93% | 102% | ||
| Gasohol | CONOCO | A22-1 | 140 | 445 | 0.59 | 2.26 | 0.54 | 46.9 |
| Aliphatic | ARCTIC | A31-1 | 245 | 552 | 0.63 | 2.53 | 0.70 | 42.1 |
| Aliphatic | ARCTIC | A31-2 | 292 | 586 | 0.68 | 2.80 | 0.76 | 43.4 |
| Mean Aliphatic | 268 | 569 | 0.66 | 2.66 | 0.73 | 42.8 | ||
| Aliphatic/Baseline | 133% | 102% | 112% | 147% | 113% | 95% | ||
| Fuel | Lubricant | Test ID | Mode 1 Emissions, g/kW-h | |||
|---|---|---|---|---|---|---|
| BSHC | BSCO | BSNOx | BSPM | |||
| Gasohol | CASTROL | A23 | 91 | 387 | 0.74 | 0.21 |
| Gasohol | TORCO | A24 | 97 | 381 | 0.80 | 0.12 |
| Gasohol | CONOCO | A22-2 | 91 | 372 | 0.83 | 0.64 |
| TORCO/CASTROL | 108% | 98% | 109% | 57% | ||
| CONOCO/CASTROL | 101% | 96% | 112% | 310% | ||
| Fuel | Lubricant | Test ID | Emissions, g/kW-h | BSFC | Mode 1 | |||
|---|---|---|---|---|---|---|---|---|
| BSHC | BSCO | BSNOx | BSPM | kg/kW-h | kW | |||
| Gasoline | ARCTIC | W11-1 | 199 | 468 | 0.68 | 4.14 | 0.66 | 42.5 |
| Gasoline | ARCTIC | W11-2 | 237 | 505 | 0.64 | 5.11 | 0.72 | 42.3 |
| Baseline Gasoline (mean) | 218 | 487 | 0.66 | 4.63 | 0.69 | 42.4 | ||
| Gasohol | ARCTIC | W12 | 203 | 459 | 0.70 | 4.51 | 0.67 | 43.0 |
| Gasohol/Gasoline | 93% | 94% | 106% | 97% | 97% | 101% | ||
| Engine - Measured Fuel/Oil Ratio | Mode 1 | Mode 2 | Mode 3 | Mode 4 | Mode 5 |
|---|---|---|---|---|---|
| Polaris | 30 | 43 | 46 | 44 | 90 |
| Arctco | 29 | 37 | 38 | 38 | 24 |
| Engine - Spark Plug Seat Temperature °C | Mode 1 | Mode 2 | Mode 3 | Mode 4 | Mode 5 |
|---|---|---|---|---|---|
| Polaris | 251 | 166 | 139 | 113 | 70 |
| Arctco | 71 | 66 | 64 | 60 | 54 |
| Polaris data - mean values of A11-3&4 Arctco data - mean values of W11-1&2 |
|||||
Fuel |
Lubricant |
Test ID |
Emissions g/kW-h |
Ozone Potential |
Specific Reactivity |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| BSHC (FID) | BSHC (GC) | 1,3- Buta- | Benzene |
Formald. |
Acetald. |
g/kW-h |
g O3/g HC |
|||
| Gasoline | ARCTIC | A11-3 | 223 | 210 | 0.29 | 1.69 | 1.35 | 0.20 | 629 | 3.00 |
| Gasoline | CONOCO | A12 | 199 | 188 | 0.30 | 1.49 | 1.01 | 0.12 | 568 | 3.02 |
| Gasohol | ARCTIC | A21 | 170 | 172 | 0.31 | 1.52 | 1.58 | 1.11 | 532 | 3.09 |
| Gasohol/Gasoline (A21/A11-3) | 85% | 103% | ||||||||
| Gasohol | CONOCO | A22-1 | 140 | 142 | 0.28 | 1.25 | 1.50 | 0.59 | 438 | 3.08 |
| Aliphatic | ARCTIC | A31-1 | 245 | 220 | 0.38 | 0.46 | 1.86 | 0.26 | 493 | 2.24 |
| Aliphatic/Gasoline | 78% | 75% | ||||||||
REFERENCES
- State of Montana Department of Environmental Quality telephone survey, letter to Jeff White from Howard Haines, May 8, 1996.
- "Regression Modeling of Oxyfuel Effects on Ambient CO Concentrations," Systems Applications International, Inc., January 8, 1997.
- State of Montana Air Quality Control Implementation Plan, Vol. III, Chapter 32, December 9, 1996.
- Hare, C.T. and White, J.J., "Toward the Environmentally-Friendly Small Engine: Fuel, Lubricant, and Emission Measurement Issues," JSAE Paper 911222, Yokahama, Hamamatsu, Japan, October 1991.
- Hare, C.T., Carroll, J.N., Latusek, J.P., and Burrahm, R.W., "Speciation of Organic Emissions to Study Fuel Dependence of Small Engine Exhaust Photochemical Reactivity," Final Report to Advisory Committee for Research, Southwest Research Institute, July 1993.
- White, J.J., Carroll, J.N., Lourenco, J.G., and Downing-Iaali, A., "Baseline and Controlled Exhaust Emissions From Off-Highway Vehicle Engines," SAE Paper 931541, Pisa, Italy, December 1993.
- Hare, C.T. and Springer, K.J., "Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using Internal Combustion Engines, Final Report - Part 7, Snowmobiles," by Southwest Research Institute under Contract EHC 70-108 to U.S. EPA, April 1974.
- Warner-Selph, M.A., and Smith, L.R., "Assessment of Unregulated Emissions from Gasoline Oxygenated Blends," Final Report EPA 460/3-91-002 to EPA, Contract No. 68-C9-0004, March 1991.
