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Fuel injectors capable of rapidly electrically heating ethanol for cold starts below ethanol's flash point temperature have been developed for the Brazilian transportation market. These injectors also enable the enleanment of 20°C cold start fueling, which has shown to reduce FTP bag emissions. Initial E-100 vehicular emission test results were published in SAE paper 2009-01-0615 and presented during the 2009 SAE Congress. Further development has shown that heated injector systems can enable emission reductions with a variety of automotive fuels. Engine control strategies which make use of heated injector systems, along with corresponding test results, are presented and discussed.

Ethanol is commonly employed as a transportation fuel in Brazil. However, since pure ethanol’s flash point is 12°C, flex-fuel vehicles marketed in Brazil are currently equipped with a redundant fuel system which delivers gasoline during cold starts below [typically] 18°C. Since these low temperatures are infrequently experienced in Brazil, gasoline in the auxiliary fuel tank may evaporate and/or varnish during extended dormant periods, resulting in poor quality or no-starts. It is therefore desirable to eliminate the gasoline system by vaporizing a sufficient quantity of ethanol to enable cold starts at low ambient temperatures. A port fuel injector capable of rapidly heating ethanol above its flash point has been developed which eliminates the need for the redundant fuel system. During cold-start conditions, the vehicle’s controller commands power to an electrical heater contained within each injector.

Compressed Natural Gas (CNG) is gaining popularity as a viable alternate transportation fuel in many regions of the world. Injectors capable of delivering pressurized gaseous fuels have been developed for this emerging vehicular market segment. CNG fuel injectors must be designed to be compatible and durable with a very low lubricity gaseous fuel to meet automotive OEM life expectancy standards. Traditional gasoline injectors utilize a “hard/hard” sealing configuration, in which both the valve and seat are constructed out of hard metals. When properly lubricated with liquid fuels, these valves can meet vehicular injector leak and flow durability requirements. However, metal valves operating without lubrication can experience excessive wear, which leads to unacceptable levels of gas leakage and flow shifts. The use of elastomer-to-metal sealing surfaces minimizes leakage, but may cause cold ambient operation challenges.

LEV-3 regulation changes require 100% SULEV30 fleet average by 2025. While present applications meeting SULEV30 are predominately small displacement 4-cylinder engines, LEV-3 standards will require larger displacement engines to also meet SULEV30. One concept previously investigated to reduce the cold start engine-out HC emissions was to heat the fuel injected during the cold start and initial engine idle period. Improved atomization and increased vaporization of heated fuel decreased wall wetting and unburned fuel. This resulted in more fuel available to take part in combustion, thus reducing the required injected fuel mass and HC emissions. Single cylinder engine testing with experimental heated Gasoline Direct Injection (GDi) injectors was conducted at 40°C engine coolant and oil temperature conditions. The operating mode simulated cold start idle operating conditions, with split injection for improved Catalyst Light-Off (CATLO) times.