Page 19 - issue-78

Road test
and TGX sold included Ef cientCruise 2, this included 47% of all TGXs. MAN suggest it might become a standard tment in the future.
So far so good... But while Ef cientCruise 2 is growing in popularity with the bosses there isn’t much they can do if the driver decides to ignore it and use the traditional cruise control instead. Cruise control works on the spot; it changes down the gearbox when it thinks more revs are required and moves up when the roads ats out.
The test
Over two days, the TGX 26.500 XXL using the Tipmatic 12-speed transmission with Ef cientCruise 2 and freighted to 44
tonnes GVW was driven over two sections of motorway. Travelling at a set speed of 85km/h, the truck was set to Level 4 of Ef cientCruise 2; the maximum setting overrun and underrun. The cruise control was set at 4km/h overrun, its maximum setting. The truck made all the decisions in Ef cientCruise 2 and cruise control and fuel consumption and time was measured.
The rst part was the M6, starting from J37 for Kendal and Sedbergh in Cumbria. This
is 233m above sea level (MAMSL). Heading north it passes Tebay at J38, 180MAMSL
then up to J39 at Shap. Just before the junction it reaches 320MAMSL, second highest point on the UK motorway network after the M62 at Saddleworth Moor.
At J40 for Penrith, 140MAMSL, the truck returned on the southbound to J37. This is a total of 48 miles, with each section was driven twice; once using Ef cientCruise 2 and once using cruise control.
This route is tough at the best of times and 4°, driving rain and a 25mph south- westerly didn’t help. The route is de ned by the climb to Shap which is in the middle of two descents. Southbound is the opposite, two climbs separated by a long and steep descent towards Tebay.
The M56 is less arduous. From J3A at Wythenshawe, Cheshire, which is 50MAMSL, it progresses west past J10 south of Warrington, the highest point at 80MAMSL, before dropping gradually, via several;
undulating sections to the run into J14 at Ellesmere Port, which is 9MAMSL.
The truck used the roundabout at J14 to start the return leg. This is 51 miles, again driven twice, once with Ef cientCruise 2 and then with cruise control. The weather was 9° and there was little wind.
In conclusion
MAN claimed Ef cientCruise 2 can achieve up to 9% fuel saving, so the manufacturer
is right. Overall the results show a total fuel saving is 8.2% over the 99 miles covered. In any context that is a signi cant saving. What is more, it shaved a minute off the combined journey times using Ef cientCruise 2 compared to cruise control.
Looking at the results in closer detail,
it shows where the bulk of the 8.2% was achieved, and that is on the undulating M56 heading westbound that gradually descends to J14. Ef cientRoll was activated ve times through this section. The longest point
where Ef cientRoll was active was a 2.0km section progressing to and over J12, the Mersey Gateway Bridge. That remarkable 15.6% improvement was tempered slightly by the return leg, which produced 7.1%. That is a remarkable improvement in its own right considering the route is a gradual climb back to the starting point at J3A.
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