Technical Innovations
SwRI prototype propane engine
 Engineers at Southwest Research Institute (SwRI) developed a low-emissions propane engine that can be modified for other naturally aspirated off-highway vehicles used by the agricultural, construction, and power-generation industries.  |
Engineers at the Southwest Research Institute (SwRI) developed a propane engine to replace a 60-kW (80-hp) diesel engine in a John Deere 5410 tractor. The prototype "demonstrates that a clean, efficient alternative to diesel-powered tractors and other off-road equipment is feasible," said John T. Kubesh, an engineer in the SwRI Engine and Vehicle Research Division, adding that the engine would be particularly practical in emissions non-attainment areas.
Emissions reduction in off-highway vehicles can be particularly challenging because the vehicles come in a broad range of engine sizes and are used in a vast array of applications and operating environments, including environments with excessive heat, dust, and moisture. In addition, these engines are typically naturally aspirated designs, and solutions to the emissions problem used in the on-highway vehicle market are not always practical.
The propane engine features a lean-burn combustion system and electronic controls to deliver 55 kW (74 hp). It has a full-load thermal efficiency of 34.8%, which is nearly on par with the 35.4% efficiency of the diesel engine and provides a 7-dB reduction in noise over the diesel, according to SwRI. The tractor features conformable fuel storage, "a first" for an off-road vehicle. The new storage system enables higher fuel capacity and convenient, single-point refueling.
The propane engine produces "significantly lower" emissions than a diesel, meeting the EPA Tier 3 standards scheduled to go into effect in 2008, which limit emissions to 4.7 g/kW•h of oxides of nitrogen (NOx) plus nonmethane hydrocarbon (NMHC). SwRI quotes that current diesels emit 9.5 g/kW•hr of NOx + NMHC, while its propane engine emits 3.95 g/kW•h. Similarly, a diesel emits 0.23 g/kW•h of particulate matter (PM), while the propane engine emits 0.05 g/kW•h. Tier 3 currently calls for PM levels of 0.4 g/kW•h, a carryover of the Tier 2 levels. However, SwRI claims that future reductions in PM standards are expected. Because the propane engine is a lean-burn engine that also uses an oxidation catalyst, carbon monoxide (CO) emissions already are well below Tier 3 standards.
 The 55-kW (74-hp) propane engine features a lean-burn combustion system and electronic controls to deliver EPA Tier 3 emissions levels, rivaling the performance and fuel economy of a diesel engine, according to SwRI. |
"We used existing CNG (compressed natural gas) and diesel engine hardware to the extent possible for this engine to help minimize costs," said Kubesh. "Should market demand ever lead to the propane engine being placed in production, the use of common diesel and automotive components will help keep costs low."
This engine development program was funded by the Propane Education and Research Council (PERC), Texas Alternative Fuels Council, and the John Deere Product Engineering Center. The initial concept and support for this project was generated by the Alternative Fuels Research and Education Division of the Texas Railroad Commission.
- Jean L. Broge
Natural gas genset from Ballard
The Ecostar is a high-speed, natural gas fueled genset from Ballard Power Systems' Electric Drives & Power Conversion division that is capable of producing 80 kW for standby and back-up power applications. The genset is based on the 4.2-L Ford V6 natural gas engine and operates at double the speed of conventional gensets to produce nearly twice the power, claims Ballard.
The ES080-42N-S genset is the result of a collaboration between Ford and Ballard to increase the speed and endurance of the Ford engine, which Ballard integrated with its generator, electronics, and control systems. Ballard cites the inherent efficiency (32%) of the Ford engine and its engine-performance module, which controls and optimizes engine performance, as combining to provide the "highest fuel-to-wire efficiency and lowest emissions of any genset."
The brushless synchronous generator used in the genset can be configured to deliver three phase voltages, up to 480 V, or single phase voltages up to 240 V. Eight distinct configurations enable the genset to serve both 60 and 50 Hz applications at the above voltages. The genset is available with a modem or full communications and diagnostics.
- Jean L. Broge
Stanadyne's fuel-filtration system
 Finland-based Sisu Diesel uses Stanadyne's Fuel Manager diesel fuel filter and water separation units for the engines it supplies to companies that include Valtra, Case, Steyr, and Massey Ferguson. |
Since the introduction of its Fuel Manager diesel fuel filter and water separator system in the early 1990s, Stanadyne Corp. claims it has become the "leading North American manufacturer" of such systems for agricultural and industrial engines under 300 hp (224 kW). One of the benefits the company cites for its system is that it integrates all necessary filtration and separation functions in one unit. In addition to the company's filtration/separation media—which it claims is over 99% efficient at 2µ—the fuel-management components include electronic lift and purge pumps, in-line fuel heaters, electronic water-in-fuel sensors, see-through water bowls, and hand primers.
Sisu Diesel of Finland uses Stanadyne's Fuel Manager diesel fuel filter and water separation units for both the pre- and final- diesel fuel-filtration systems on its Tier II engines. Sisu Diesel supplies engines primarily for the agricultural sector to customers such as Valtra, Case, Steyr, and Massey Ferguson tractors and MF combine harvesters, as well as to portions of the forestry sector and other off-road applications. Stanadyne cites other customers as including Mitsubishi Engines North America, UK-based TransBus International, Perkins, General Motors, Deere, New Holland, and Caterpillar.
Sisu recently extended its use of the Fuel Manager to its final filtration application needs after having used the system several years for pre-filtration. All future Sisu diesel engines will be fitted with both pre- and final filter Fuel Manager units. Stanadyne also supplies Sisu with injectors, injection sensors, diagnostic equipment, and injection pumps for Tier I applications.
The final filtration unit for the Sisu Tier II diesel engines consists of an assembly with a 5µ final filter—6-in (152-mm) type—with no optional features other than constant air bleed (CAB), which is integrated into the filter header. The CAB permanently purges air back to the fuel tank, allowing a quick and automatic purge of the low-pressure fuel circuit when servicing the filter elements on both pre- and final filter units.
The various pre-filter assembly configurations always include a long, 30-µ water separator pre-filter elements of the range—5.1-in (129-mm) type—to meet servicing interval requirements, as well as additional modules or options to meet specific application and the final customer requirements. Some of these options include a transparent bowl or a "water-in-fuel" electronic control feature to monitor water separated from the fuel by the filter element's high-performance water separation, an integrated electric lift pump with auto-regulation of the outlet pressure to supply the injection pump with a controlled inlet fuel pressure, and four-port filter headers that allow Sisu to simply install the same filter and pre-filter units in different ways to meet various engine layout configurations and room availability.
- Jean L. Broge