'Is this table suitable?'
Fuel pressure analog signal from sensor is calculated with:
Vout=(c1*Pabs+C0)*Us
- Vout = signal output voltage in V
- Vs = supply voltage in V
- Pabs = absolute pressure in kPa
- C0 = -5/350
- C1 = 0.8/350 kPa ^-1
With Vsupply at nominal 5V this means
- Vout min = 0.500V = Devision 0
- Vout max = 4.500V = Devision 255
With the req_fuel calculated at 255 kPa Fuelpressure the original PW is altered by 1/1 at Vsens_out = 2.843V
Gives the following look-up table:
\n
# kPa Vout devision multiplier 45.8 0.452 0 0.179607843 47.2 0.468 1 0.185098039 48.6 0.484 2 0.190588235 50 0.5 3 0.196078431 51.4 0.516 4 0.201568627 52.8 0.532 5 0.207058824 54.2 0.548 6 0.21254902 55.6 0.564 7 0.218039216 57 0.58 8 0.223529412 58.4 0.596 9 0.229019608 59.8 0.612 10 0.234509804 61.2 0.628 11 0.24 62.6 0.644 12 0.245490196 64 0.66 13 0.250980392 65.4 0.676 14 0.256470588 66.8 0.692 15 0.261960784 68.2 0.708 16 0.26745098 69.6 0.724 17 0.272941176 71 0.74 18 0.278431373 72.4 0.756 19 0.283921569 73.8 0.772 20 0.289411765 75.2 0.788 21 0.294901961 76.6 0.804 22 0.300392157 78 0.82 23 0.305882353 79.4 0.836 24 0.311372549 80.8 0.852 25 0.316862745 82.2 0.868 26 0.322352941 83.6 0.884 27 0.327843137 85 0.9 28 0.333333333 86.4 0.916 29 0.338823529 87.8 0.932 30 0.344313725 89.2 0.948 31 0.349803922 90.6 0.964 32 0.355294118 92 0.98 33 0.360784314 93.4 0.996 34 0.36627451 94.8 1.012 35 0.371764706 96.2 1.028 36 0.377254902 97.6 1.044 37 0.382745098 99 1.06 38 0.388235294 100.4 1.076 39 0.39372549 101.8 1.092 40 0.399215686 103.2 1.108 41 0.404705882 104.6 1.124 42 0.410196078 106 1.14 43 0.415686275 107.4 1.156 44 0.421176471 108.8 1.172 45 0.426666667 110.2 1.188 46 0.432156863 111.6 1.204 47 0.437647059 113 1.22 48 0.443137255 114.4 1.236 49 0.448627451 115.8 1.252 50 0.454117647 117.2 1.268 51 0.459607843 118.6 1.284 52 0.465098039 120 1.3 53 0.470588235 121.4 1.316 54 0.476078431 122.8 1.332 55 0.481568627 124.2 1.348 56 0.487058824 125.6 1.364 57 0.49254902 127 1.38 58 0.498039216 128.4 1.396 59 0.503529412 129.8 1.412 60 0.509019608 131.2 1.428 61 0.514509804 132.6 1.444 62 0.52 134 1.46 63 0.525490196 135.4 1.476 64 0.530980392 136.8 1.492 65 0.536470588 138.2 1.508 66 0.541960784 139.6 1.524 67 0.54745098 141 1.54 68 0.552941176 142.4 1.556 69 0.558431373 143.8 1.572 70 0.563921569 145.2 1.588 71 0.569411765 146.6 1.604 72 0.574901961 148 1.62 73 0.580392157 149.4 1.636 74 0.585882353 150.8 1.652 75 0.591372549 152.2 1.668 76 0.596862745 153.6 1.684 77 0.602352941 155 1.7 78 0.607843137 156.4 1.716 79 0.613333333 157.8 1.732 80 0.618823529 159.2 1.748 81 0.624313725 160.6 1.764 82 0.629803922 162 1.78 83 0.635294118 163.4 1.796 84 0.640784314 164.8 1.812 85 0.64627451 166.2 1.828 86 0.651764706 167.6 1.844 87 0.657254902 169 1.86 88 0.662745098 170.4 1.876 89 0.668235294 171.8 1.892 90 0.67372549 173.2 1.908 91 0.679215686 174.6 1.924 92 0.684705882 176 1.94 93 0.690196078 177.4 1.956 94 0.695686275 178.8 1.972 95 0.701176471 180.2 1.988 96 0.706666667 181.6 2.004 97 0.712156863 183 2.02 98 0.717647059 184.4 2.036 99 0.723137255 185.8 2.052 100 0.728627451 187.2 2.068 101 0.734117647 188.6 2.084 102 0.739607843 190 2.1 103 0.745098039 191.4 2.116 104 0.750588235 192.8 2.132 105 0.756078431 194.2 2.148 106 0.761568627 195.6 2.164 107 0.767058824 197 2.18 108 0.77254902 198.4 2.196 109 0.778039216 199.8 2.212 110 0.783529412 201.2 2.228 111 0.789019608 202.6 2.244 112 0.794509804 204 2.26 113 0.8 205.4 2.276 114 0.805490196 206.8 2.292 115 0.810980392 208.2 2.308 116 0.816470588 209.6 2.324 117 0.821960784 211 2.34 118 0.82745098 212.4 2.356 119 0.832941176 213.8 2.372 120 0.838431373 215.2 2.388 121 0.843921569 216.6 2.404 122 0.849411765 218 2.42 123 0.854901961 219.4 2.436 124 0.860392157 220.8 2.452 125 0.865882353 222.2 2.468 126 0.871372549 223.6 2.484 127 0.876862745 225 2.5 128 0.882352941 226.4 2.516 129 0.887843137 227.8 2.532 130 0.893333333 229.2 2.548 131 0.898823529 230.6 2.564 132 0.904313725 232 2.58 133 0.909803922 233.4 2.596 134 0.915294118 234.8 2.612 135 0.920784314 236.2 2.628 136 0.92627451 237.6 2.644 137 0.931764706 239 2.66 138 0.937254902 240.4 2.676 139 0.942745098 241.8 2.692 140 0.948235294 243.2 2.708 141 0.95372549 244.6 2.724 142 0.959215686 246 2.74 143 0.964705882 247.4 2.756 144 0.970196078 248.8 2.772 145 0.975686275 250.2 2.788 146 0.981176471 251.6 2.804 147 0.986666667 253 2.82 148 0.992156863 254.4 2.836 149 0.997647059 255.8 2.852 150 1.003137255 257.2 2.868 151 1.008627451 258.6 2.884 152 1.014117647 260 2.9 153 1.019607843 261.4 2.916 154 1.025098039 262.8 2.932 155 1.030588235 264.2 2.948 156 1.036078431 265.6 2.964 157 1.041568627 267 2.98 158 1.047058824 268.4 2.996 159 1.05254902 269.8 3.012 160 1.058039216 271.2 3.028 161 1.063529412 272.6 3.044 162 1.069019608 274 3.06 163 1.074509804 275.4 3.076 164 1.08 276.8 3.092 165 1.085490196 278.2 3.108 166 1.090980392 279.6 3.124 167 1.096470588 281 3.14 168 1.101960784 282.4 3.156 169 1.10745098 283.8 3.172 170 1.112941176 285.2 3.188 171 1.118431373 286.6 3.204 172 1.123921569 288 3.22 173 1.129411765 289.4 3.236 174 1.134901961 290.8 3.252 175 1.140392157 292.2 3.268 176 1.145882353 293.6 3.284 177 1.151372549 295 3.3 178 1.156862745 296.4 3.316 179 1.162352941 297.8 3.332 180 1.167843137 299.2 3.348 181 1.173333333 300.6 3.364 182 1.178823529 302 3.38 183 1.184313725 303.4 3.396 184 1.189803922 304.8 3.412 185 1.195294118 306.2 3.428 186 1.200784314 307.6 3.444 187 1.20627451 309 3.46 188 1.211764706 310.4 3.476 189 1.217254902 311.8 3.492 190 1.222745098 313.2 3.508 191 1.228235294 314.6 3.524 192 1.23372549 316 3.54 193 1.239215686 317.4 3.556 194 1.244705882 318.8 3.572 195 1.250196078 320.2 3.588 196 1.255686275 321.6 3.604 197 1.261176471 323 3.62 198 1.266666667 324.4 3.636 199 1.272156863 325.8 3.652 200 1.277647059 327.2 3.668 201 1.283137255 328.6 3.684 202 1.288627451 330 3.7 203 1.294117647 331.4 3.716 204 1.299607843 332.8 3.732 205 1.305098039 334.2 3.748 206 1.310588235 335.6 3.764 207 1.316078431 337 3.78 208 1.321568627 338.4 3.796 209 1.327058824 339.8 3.812 210 1.33254902 341.2 3.828 211 1.338039216 342.6 3.844 212 1.343529412 344 3.86 213 1.349019608 345.4 3.876 214 1.354509804 346.8 3.892 215 1.36 348.2 3.908 216 1.365490196 349.6 3.924 217 1.370980392 351 3.94 218 1.376470588 352.4 3.956 219 1.381960784 353.8 3.972 220 1.38745098 355.2 3.988 221 1.392941176 356.6 4.004 222 1.398431373 358 4.02 223 1.403921569 359.4 4.036 224 1.409411765 360.8 4.052 225 1.414901961 362.2 4.068 226 1.420392157 363.6 4.084 227 1.425882353 365 4.1 228 1.431372549 366.4 4.116 229 1.436862745 367.8 4.132 230 1.442352941 369.2 4.148 231 1.447843137 370.6 4.164 232 1.453333333 372 4.18 233 1.458823529 373.4 4.196 234 1.464313725 374.8 4.212 235 1.469803922 376.2 4.228 236 1.475294118 377.6 4.244 237 1.480784314 379 4.26 238 1.48627451 380.4 4.276 239 1.491764706 381.8 4.292 240 1.497254902 383.2 4.308 241 1.502745098 384.6 4.324 242 1.508235294 386 4.34 243 1.51372549 387.4 4.356 244 1.519215686 388.8 4.372 245 1.524705882 390.2 4.388 246 1.530196078 391.6 4.404 247 1.535686275 393 4.42 248 1.541176471 394.4 4.436 249 1.546666667 395.8 4.452 250 1.552156863 397.2 4.468 251 1.557647059 398.6 4.484 252 1.563137255 400 4.5 253 1.568627451 401.4 4.516 254 1.574117647 402.8 4.532 255 1.579607843
Plotting the above with gnuplot\n
plot 'pres.dat' using 3:4 with lines title 'multiplier', 'pres.dat' using 3:($1/100) with lines title '*100 kPa', 'pres.dat' using 3:2 with lines title 'Vout'
shows that it's all linear. (note that pressure was plotted in bar using 1/100 so all curves fit on same graph, same y axis range).
Why do we need the lookup than? Simple slope and offset can be used the same way as for MAP kpafac and kpaoffs.