The fuel economy test results confirmed 1.2% improved fuel economy for this design level of system as compared to the stock system. The similar warm-up rate and steady state operating temperature data (see figure 1) confirmed the integrity of this fuel economy results comparison without adjusting the operating control temperature. The coolant temperature, coolant flow and pump power consumption during the driving cycle is plotted on figure 1.

From that data, the average power and efficiency calculated for the driving cycle simply illustrates the source of the fuel savings contribution of the controllable variable flow system (figure 2).

In summary, the average parasitic mechanical power reduction for this city driving cycle is about 85% (figure 1) which resulted in 1.2% fuel saving when the prototype vehicle was tested by a certified fuel economy and emissions testing laboratory. The same tests yielded total hydrocarbons reduction of 8 % and carbon monoxide reduction of 23% over the US FTP 75 driving cycle.

The vehicle-level fuel economy tests (see US EPA75 driving cycle, figure 3), were conducted in a modern climate-controlled chassis roll emissions test facility.