sample_car_engine_RSM

# sample_car_engine_RSM - 0.25-5.49 2.49-5.49 2.49 X Variable...

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Class Example - car engine RSM calculations J. M. Cimbala Given: a = spark plug gap, in inches b = spark plug timing before TDC, in degrees c = fuel:air mixture set screw, in number of turns of the screw P = power in horsepower from the engine To do: Calculate the direction of steepest ascent. Solution: Physical variables Result Coded variables current condition: 0.03 10 0 156 0 0 0 0.03 9 0 162 -1 -1 0 0.03 11 0.25 159 -1 1 1 0.03 11 -0.25 154 1 1 -1 0.03 10 0.25 158 1 0 1 0.03 9 -0.25 160 0 -1 -1 minimum 0.03 9 -0.25 -1 -1 -1 maximum 0.03 11 0.25 1 1 1 range 0 2 0.5 2 2 2 mid value 0.03 10 0 0 0 0 Now perform a regression analysis on these normalized coded variables: SUMMARY OUTPUT Regression Statistics Multiple R 0.93 R Square 0.86 Adjusted R Square 0.65 Standard Error 1.69 Observations 6 ANOVA df SS MS F Significance F Regression 3 35.1 11.7 4.08 0.2 Residual 2 5.73 2.87 Total 5 40.83 Coefficientstandard Err t Stat P-value Lower 95%Upper 95% ower 95.0pper 95.0% Intercept 158.17 0.69 228.82 0 155.19 161.14 155.19 161.14 X Variable 1 -1.5 0.93 -1.62

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Unformatted text preview: 0.25-5.49 2.49-5.49 2.49 X Variable 2-2.1 0.93-2.26 0.15-6.09 1.89-6.09 1.89 X Variable 3 0.9 0.93 0.97 0.43-3.09 4.89-3.09 4.89-1 (unitless) We calculate the increments of the other two coded variables, based on the direction of steepest ascent.-0.71 0.43 Now convert back to the physical variables: 0 (inches of spark plug gap) a (in) b (deg.) c (turns) P (hp) x a x b x c Since coded variable x 2 has the maximum absolute value of slope, we choose parameter x 2 as the one for which to choose the increment. ∆ x 2 = ∆ x 1 = ∆ x 3 = ∆ a = -1 (degrees before TDC) 0.11 (turns of the screw) Final result: March in direction of steepest ascent, i.e. delta a = 0 (inches of spark plug gap) delta b = -1 (degrees before TDC) delta c = 0.11 (turns of the screw) ∆ b = ∆ c =...
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sample_car_engine_RSM - 0.25-5.49 2.49-5.49 2.49 X Variable...

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