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 
Sonia backs EGR for Euro-4
Page 12
If you've noticed an error in this article please click here to report it so we can fix it.
Scania has come out fighting on Euro-4, with its money still on exhaust gas recirculation (EGR) as the more reliable technology. Andy Salter reports.
SCANIA HAS blasted back in the battle for technical superiority ahead of the Euro-4 emissions deadline in 2006.
The Swedish truck and engine builder will meet the new law with exhaust gas recirculation (EGR) on its 9,11 and 12-litre engines, claiming that EGR will be just as, if not more, efficient than the rival selec tive catalytic reduction (SCR). Congestion To date SCR, set to be offered by Mercedes, Iveco, Volvo and Dathad widely been thought of as the superior technology with the alternative exhaust gas recircula tion (EGR) regarded as low-tech.
"A lot of the competitors are claiming fuel efficiency improvements with their SCR technology over EGR," says Hasse Johansson, head of research and development at Scania. "That may be so, but in terms of operational costs there are many unknown factors which will impact on the costs to users.
"I think people need to be careful with some of the public claims which are being made. We don't know yet whether the urea infrastructure will be fully in place The cost of the liquid is unclear and there is a question mark over the in-service reliability of SCR in a range of operating conditions."
Scania has joined MAN in offering EGR, though it will opt for SCR on its V8 motor."This is due to cooling constraints," says Urban Johansson, head of Scania's powertrain division.
"It does, however, mean we have a lot of experience with SCR and surely the fact that we have opted for EGR given this experience tells you something about the relative merits of the two solutions," he adds.
• For more on Euro-4 engine technology, see page 58.