Sigma Power

1996 Sigma Power milestones

Valtra history

1994 Sisu ownership
1994 1997 1 Read more

In February 1988 Valmet’s chief design engineer Hannu Niskanen met his childhood friend, Heikki Eskola, a livestock farmer and contractor in Nivala, Finland. Auto­control had just been introduced, and Hannu praised the advantages of electronics in such tasks as ploughing, for example. Heikki replied, “I can manage my ploughing in a couple of days, but I have to run a forage harvester the entire summer. What would be great is extra power from the PTO.”

This got me thinking, and an idea occurred to me a few days later. The engine is the power source for three different functions: for the transmission to the wheels, for hydraulic power, and for the mechanical PTO. If a certain amount of power is transferred through the wheels, it would be possible to run more engine power through the PTO. A patent was duly applied for, and the idea was tested by the Norwegian ITF research institute with positive results. Pekka Huuskonen completed the design.

In 1992–1993, the global tractor industry was in crisis, Valmet included. Just one sector was growing: peat for energy. In response, Valmet introduced its “Peat Special” – an 8400 with a turbocharged 6.6-litre Valmet engine producing 140 horsepower, a three-speed Delta Powershift and a heavy-duty 1,000 rpm PTO transmission using a large dia­meter 45 mm PTO shaft. This model proved to be a success among customers.

The introduction of a new long-stroke 7.4-litre Valmet engine together with the reinforced transmission and heavy-duty PTO meant that all the pieces were in place for Sigma Power. The Mega 50 Series was duly launched in France in the spring of 1996. The flagship was the Valmet Mega 8750 Sigma Power that had a nominal output of 160 horsepower when only the driving transmission was used. However, when the torque exceeded 250 Nm, the injection pump increased the maximum power to 190 horsepower. The control system was based on the torsion of the long shaft between the engine and PTO mechanism.

In 1997, Sigma Power was awarded the Gold Medal at the Agritechnica fair. Since then, more than 10,000 Valmet/Valtra tractors have been manufactured utilising the Sigma Power principle. With the introduction of electronically controlled common rail technology, it became easier to manipulate the power and torque curves, and new terms appeared such as transport boost and PTO boost. But Sigma Power was the pioneer.

Today, Sigma Power PTO boost is available on all new S Series models, as well as on the T213, T203, T183 and N163 models.

Read more:

New Sigma Power

Sigma Power - a milestone in agricultural engineering

In 2013 German DLV named Valtra Sigma Power an influential milestone of agricultural technology.

In 2013 German DLV named Valtra Sigma Power an influential milestone of agricultural technology.

Chairman of DLG Philip von Bussche awards Valtra’s CEO Jouko Tukiainen with a gold medal at Agritechnica 1997.

Chairman of DLG Philip von Bussche awards Valtra’s CEO Jouko Tukiainen with a gold medal at Agritechnica 1997.

Valtra Sigma Power ststem...

The Sigma Power system...

... extremely useful in PTO work.

... extremely useful in PTO work