Status and Prospects for Two-Stroke Engines Used in Off-Road Recreational Vehicles
John Williford
Chrysalis Technology Group, Ltd.
April 30, 2001
REVIEW OF TWO-STROKE APPLICATIONS
Substantial numbers of two-stroke engines are used in chainsaws, lawn mowers and small tools. These make significant contributions to smog and air pollution in some urban localities3.
In the United States, emission standards for road vehicles have led to the replacement of two-stroke engines with four-stroke engines in road motorcycles and scooters. However, the two-cycle engine still dominates for scooters in Asia.
For purposes of this report, our attention is focused on recreational or off-road applications of larger, two-cycle engines. These are primarily found in personal watercraft and snowmobiles, as well as all-terrain vehicles. Conventional outboard motors for recreational boats also remain two-stroke engines.
The U.S. snowmobile market is dominated by four industry leaders, listed in Table 1, below.
| Site | Description | URL |
|---|---|---|
| Arctic Cat | Home Page | http://www.arctic-cat.com/snowmobiles/index.asp |
| Polaris | Home Page | http://www.polarisindustries.com |
| Ski-Doo | US Home Page | http://www.ski-doo.com/home.htm?langCode=US |
| Yamaha Motor Corp | Home Page | http://www.yamaha-motor.com/ |
The magnitude of snowmobile use is indicated by the state-by-state list of registrations for the year 2000, provided in Table 2.
State |
# Registered Snowmobiles |
|---|---|
| Alaska | 19,508 |
| Arizona | na |
| California | 15,888 |
| Colorado | 30,000 |
| Idaho | 40,000 |
| Illinois | 60,000 |
| Indiana | 16,877 |
| Iowa | 33,600 |
| Maine | 85,680 |
| Massachusetts | 13,000 |
| Michigan | 357,033 |
| Minnesota | 282,153 |
| Montana | 22,653 |
| Nebraska | 1,075 |
| New Hampshire | 66,000 |
| New York | 126,041 |
| North Dakota | 17,470 |
| Ohio | 22,331 |
| Oregon | 17,093 |
| Pennsylvania | 39,400 |
| South Dakota | 10,000 |
| Utah | 22,543 |
| Vermont | 32,500 |
| Virginia | na |
| Washington | 32,247 |
| Wisconsin | 223,665 |
| Wyoming | 18,571 |
| Total | 1,605,328 |
Source: ISMA
Yearly sale information in terms of numbers of units and dollar value of sales is provided in Tables 3 and 4, respectively. These data are from the International Snowmobile Manufacturers Association:
| Year | Units |
|---|---|
| 2000 | 136,601 |
| 1999 | 147,867 |
| 1998 | 162,826 |
| 1997 | 170,325 |
| 1996 | 168,509 |
| 1995 | 148,207 |
| 1994 | 114,057 |
| 1993 | 87,809 |
| 1992 | 81,946 |
Source: ISMA
| Year | Dollars |
|---|---|
| 2000 | $821,000,000 |
| 1999 | $882,766,000 |
| 1998 | $975,147,000 |
| 1997 | $1,005,790,000 |
| 1996 | $905,194,000 |
| 1995 | $791,277,000 |
| 1994 | $556,879,000 |
| 1993 | $403,921,000 |
| 1992 | $356,000,000 |
Source: ISMA
Tables 3 and 4, taken together, show a peak sales year occurred in 1997, when about 170,000 snowmobiles were sold, for about $1 billion. This indicates an average unit price of about $5,900.
Personal watercraft have user numbers approximating those of snowmobiles, based an AP news item that describes banning of Jet Ski watercraft from all national parks. An estimated 1.2 million personal watercraft owners are in the U.S., and the average price of this product appears to be $7,0004.
Thus, between snowmobiles and personal watercraft, two-cycle engines are used in about three million existing vehicles. Provided that a retrofit solution could be found for these existing machines, which could be made available at a cost of $1,000, the economic impact of retrofitting all of these machines would be about $3 billion.
The personal watercraft industry appears to be slightly ahead of the snowmobile industry on provision of electronic fuel injection and other refinements to reduce hydrocarbon emissions (by 75%) and noise (by 70%)5.
The research directions to achieve these sorts of improvements are discussed in the next section.