Search Results

Recent legislation including the California Clean Air Act of 1988 and the Federal Clean Air Act Amendment of 1990 will regulate exhaust emissions from small utility, lawn, and garden equipment engines. In an attempt to gain as much understanding as possible in a short time, SwRI has conducted a series of tests to investigate the effectiveness of late 1960's automotive emission reduction technology on small engines. Experiments were conducted utilizing air injection into the exhaust, exhaust gas recirculation (EGR), and ignition timing changes. The test engine was a 4 stroke generator set engine rated 5.88 Kw at 3600 rpm. Results show these technologies to be very effective in reducing hydrocarbons (HC), oxides of nitrogen (NOx), and carbon monoxide (C0).

Recent legislation, including the California Clean Air Act of 1988 and the Federal Clean Air Act Amendment of 1990, includes off-road engines, equipment, and vehicles as targets for new exhaust emissions regulations. The Santa Barbara County Air Pollution Control District in cooperation with EXXON USA is conducting a major Low NOx Demonstration Program including mobile sources, construction equipment, and offshore equipment. As a part of this program, an existing backhoe has been retrofitted with a low NOx engine and demonstrated in the field. This paper discusses the work performed to allow Case model 580 backhoes to be retrofitted with Cummins 4BTAA3.9 on-highway turbocharged diesel engines. A standard production conversion kit can be used to mount the new engines in place of the older existing JI Case engines in some models while other newer models already have 4B3.9 engines. In addition, an air-to-air aftercooler and associated plumbing was designed and installed.

Small utility engines have been targeted with new exhaust emissions regulations by both the United States Environmental Protection Agency (EPA) and the California Air Resources Board (CARB). CARB emissions standards are already in place, as shown in Table 1, while EPA is still considering legislation. Overhead valve (OHV) engines and those near the upper end of the power limit for small engines, 18.6 kW (25 horsepower), will be able to meet these new regulations much easier than the lower power engines and those of side valve design. Side valve, or L-head engines, have relatively higher emissions levels and will require a greater effort to meet regulations. One of the reasons that L-head engines produce higher levels of exhaust emissions is due to relatively high combustion chamber surface-to-volume ratios compared to OHV engine combustion chambers.