Is this a good methodology for accurately measuring fuel economy? | TopGear.com.ph
Quote:
The technical committee discussed different approaches to fuel testing. The possibility of draining the fuel systems completely both before and after the test carried the greatest potential for accuracy, but also had the potential for damaging high-pressure fuel pumps and injectors. Fuel cells were nixed as they're too expensive, and further required the partial dismantling of each vehicle's fuel system.
Then the committee turned to the applicability of weight measurement of fuel as opposed to volume. By measuring fuel consumption by weight, you eliminate the need to fill each tank completely, and any change of volume due to temperature would not affect the weight of the fuel.
Measuring the total weight of the vehicle both before and after each test also ensured that "hidden" fuel stored in the fuel rail, filter and return lines was also taken into account. Chevron/Caltex provided tables to convert kilograms of fuel into liters, based on ambient temperature.
Several further challenges were identified, but they were not viewed as insurmountable. Test runs were set at 100km to minimize rounding errors at the scales. A course was mapped out to provide a wide variety of running speeds and running conditions, and the course was marked out to ensure consistent driving and lap times. Motorsports-grade scales with an accuracy of 0.01% were sourced for these tests, and validation tests were carried out to the satisfaction of the committee.
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Just wondering what everyone thinks.
The background... it was an economy test of around two dozen vehicles (only 19 showed up, but, whatevs). Previous testing had the technical crew spend two days filling the car before the test, just to make sure it was completely topped off.
Due to time constraints, this is what was done, instead.
Sounds stupid. Worked. I think. But still, a lot of questions.
