Stihl presented a real firecracker at the autumn press conference: The Stihl MS 500i will be the first chainsaw with electronically controlled injection.
The technical specifications of the prototype are impressive:
- 5 kW (6.8 PS) from 80cm³
- Empty weight 6.2 kg
- Power-to-weight ratio 1.24 kg/kW
- Chain acceleration 0-100km/h: 0,25 sec
Especially the last two values are absolutely world records for a serial saw. So far, no saw has managed to get below the magic limit of 1.3 kg/kW and the peak values for acceleration are otherwise around 0.3 sec. In other words, the saw is almost as strong as an MS 661 (5.4 kW) with a weight just above the MS 462 (6.0 kg). And Formula 1 drivers can only dream of the sprint time.
While the previous M-Tronic could only adjust the ignition timing, the electronics here also regulate the optimum injection timing and duration, depending on the outside temperature and machine condition. Incidentally, we don’t inject into the combustion chamber, as you might think, but into the crankcase – the two-stroke engine still needs lubrication there as well.
It cannot be taken for granted that the saw also became lighter at the same time. After all, a generator, the control unit and the injection valve are added as components.
On the other hand, you save the carburetor and the ignition system on the fan wheel. This also improves the flow conditions there, so that it can get smaller. So the bottom line is a weight saving.
A good ten years ago there was already a saw with injection, the Oleo-Mac PS 400, identical in construction to the Efco MT 4000. The comparatively simple technology reduced fuel consumption and pollutant emissions enormously for the conditions at the time, but it was not able to assert itself. Stihl is still quite modest about fuel consumption and exhaust emission values at the moment. These values are at the level of very good conventional saws, but not significantly better yet.
On the other hand, some experience has already been gained with electronic injection, namely in the TS 500i cut-off grinder, which has been in existence for four years. So it won’t be long before the injection saw comes onto the market. At Christmas 2018 at the latest, we can wish them all the best for the Christkind… At what price did the Stihler not want to reveal yet, but the difference between the cut-off grinders and the normal ones is minimal.