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Page 2 of 2 Flex-fuel vehicles
As of 2006, most every vehicle maker has a flex-fuel, or E85-capable, vehicle for sale in North America. As an example, for 2006, General Motors vehicles equipped with a 5300 V8 engine are designed as flex-fuel vehicles.
Driveability
Regardless of the vehicle maker, the use of ethanol-blended fuels can cause driveability issues from using ethanol-based fuels with ethanol concentrations above 10% in non flex-fuel vehicles, or from a condition called “phase separation.” Phase separation occurs when water saturation occurs to ethanol-blended fuel.
Using fuel in vehicles that are not capable of handling ethanol ratios above 10% can damage parts from the fuel pump to the engine. Depending on the age of the vehicle and the vehicle maker, flex-fuel-specific parts can include the fuel tank, fuel pump, fuel sending unit, non-metallic fuel lines and hoses, fuel filter, fuel injectors, and parts of the exhaust system.
Phase separation
When water is absorbed by the ethanol, the alcohol in the fuel begins to be removed, therefore reducing the octane rating of the fuel. When enough moisture is absorbed into ethanol-based fuels (one gallon of ethanol fuel can absorb 3.8 teaspoons of water), beyond 3.8 teaspoons of water, the fuel can no longer absorb water and the extra water separates and settles to the bottom of the fuel tank.
What occurs as a result is poor driving conditions, such as knocking, pinging, sluggish performance, or a hard or no-start condition. From the effect of the alcohol being removed, the air-to-fuel ratio becomes lean and combustion chamber temperatures increase. Increased combustion chamber temperatures will lead to premature wear.
With ethanol fuels being used more in North America, the opportunity for water entering an open fuel system may become a concern for repair facilities. Water contamination of a fuel system may become a problem for vehicles that are stored for extended periods of time in environmental conditions that are humid or wet.
Visit www.e85fuel.com to view a listing of E85-capable vehicles.
Conclusion
With the ever-changing design of motor fuels, and the evolution of vehicles that are capable of burning different types of fuel, there could be a diagnostic challenge for collision facilities today and in the future. Filling a vehicle with the wrong fuel can lead to driveability problems not commonly seen by most technicians.
With these many options available to the consumer, there are also opportunities for a repair facility to become exposed to different types of vehicle fuel systems. The two most recent fuel system introductions are the gasoline-electric hybrid and vehicles capable of burning ethanol-blended fuels, E85 being the most common (see Figure 1).
This Advantage Online article first appeared in the I-CAR e-newsletter, which is published and distributed free of charge. I-CAR, the Inter-Industry Conference on Auto Collision Repair, is a not-for-profit international training organization that researches and develops quality technical education programs related to collision repair. To learn more about I-CAR, and to subscribe to the free e-newsletter, visit http://www.i-car.com.
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