2004 Saab 9-3 Owner's Manual - Page 173

2004 Saab 9-3 Manual

Get 2004 Saab 9-3 PDF manuals and user guides View all 2004 Saab 9-3 manuals

Page 173 highlights

Starting and driving 173 Economical driving Factors affecting fuel consumption The fuel consumption of a car is greatly affected by driving conditions, climate, road conditions, speed, driving technique, and so on. Breaking-in Fuel consumption may be somewhat higher during the break-in period (the first 3,000-4,000 miles (5,000-7,000 km)). Weather conditions Summer temperatures give better fuel economy than winter ones. The difference can be as much as about 10%. Consumption increases in cold weather because the engine takes longer to reach its normal operating temperature. The transmission and wheel bearings also take longer to warm up. Even distance affects consumption: short journeys of 3-5 miles (5-8 km) do not give the engine enough time to reach its optimum temperature. Wind conditions also have a marked effect on fuel consumption. How to read the diagram: If fuel consumption with the engine at normal temperature is 28 mpg (10 l/ 100 km), the actual fuel consumption 3 miles (5 km) after the engine has started from cold will be: - 23.5 mpg (12 l/100 km) at outside temp. of 68°F (+20°C) (increase of 20%). - 17.7 mpg (16 l/100 km) at outside temp. of 32°F (0°C) (increase of 60%). - 14 mpg (20 l/100 km) at outside temp. of -4°F (-20°C) (increase of 100%). It is clear from the diagram that both distance driven and outside temperature have a significant impact on fuel consumption, after a cold start. If the car is normally driven on short journeys, 3-5 miles (5-8 km), for example to and from work, the average consumption will be 60-80% above the normal level. Percentage increase in fuel consumption of engine starting from cold compared to engine at normal temperature. Driving techniques • To obtain the best running economy, with regard to fuel consumption and general wear, the car must be serviced regularly. • High speed, unnecessary acceleration, frequent braking and much changing down all give higher fuel consumption. • Frequent gear changing in traffic, starting in cold weather, the use of studded tires and roof racks, and towing a caravan all increase fuel consumption. • Do not warm up the engine while the car is stationary. If idling, the engine will take much longer to reach its optimum temperature, and

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
  • 226
  • 227
  • 228
  • 229
  • 230
  • 231
  • 232
  • 233
  • 234
  • 235
  • 236
  • 237
  • 238
  • 239
  • 240
  • 241
  • 242
  • 243
  • 244
  • 245
  • 246
  • 247
  • 248
  • 249
  • 250
  • 251
  • 252
  • 253
  • 254
  • 255
  • 256
  • 257
  • 258
  • 259
  • 260
  • 261
  • 262
  • 263
  • 264
  • 265
  • 266
  • 267
  • 268
  • 269
  • 270
  • 271
  • 272
  • 273
  • 274
  • 275
  • 276
  • 277
  • 278
  • 279
  • 280
  • 281
  • 282
  • 283
  • 284
  • 285
  • 286
  • 287
  • 288
173
Starting and driving
Economical driving
Factors affecting fuel consumption
The fuel consumption of a car is greatly
affected by driving conditions, climate, road
conditions, speed, driving technique, and
so on.
Breaking-in
Fuel consumption may be somewhat
higher during the break-in period (the
first 3,000–4,000 miles (5,000–7,000 km)).
Weather conditions
Summer temperatures give better fuel
economy than winter ones. The difference
can be as much as about 10%. Consump-
tion increases in cold weather because the
engine takes longer to reach its normal
operating temperature. The transmission
and wheel bearings also take longer to
warm up. Even distance affects consump-
tion: short journeys of 3–5 miles (5–8 km)
do not give the engine enough time to
reach its optimum temperature. Wind con-
ditions also have a marked effect on fuel
consumption.
How to read the diagram:
If fuel consumption with the engine at
normal temperature is 28 mpg (10 l/
100 km), the actual fuel consumption
3 miles (5 km) after the engine has started
from cold will be:
–
23.5 mpg (12 l/100 km) at outside temp.
of 68°F (+20°C) (increase of 20%).
–
17.7 mpg (16 l/100 km) at outside temp.
of 32°F (0°C) (increase of 60%).
–
14 mpg (20 l/100 km) at outside temp.
of –4°F (–20°C) (increase of 100%).
It is clear from the diagram that both dis-
tance driven and outside temperature have
a significant impact on fuel consumption,
after a cold start.
If the car is normally driven on short jour-
neys, 3–5 miles (5–8 km), for example to
and from work, the average consumption
will be 60–80% above the normal level.
Driving techniques
•
To obtain the best running economy, with
regard to fuel consumption and general
wear, the car must be serviced regularly.
•
High speed, unnecessary acceleration,
frequent braking and much changing
down all give higher fuel consumption.
•
Frequent gear changing in traffic, starting
in cold weather, the use of studded tires
and roof racks, and towing a caravan all
increase fuel consumption.
•
Do not warm up the engine while the car
is stationary.
If idling, the engine will take much longer
to reach its optimum temperature, and
Percentage increase in fuel consumption
of engine starting from cold compared to
engine at normal temperature.