New C Series - Valtra

More reliable engines and transmissions
Tractor pulling important for product development
Together with the Valtra tractor pulling
team, the Herlevi family has won the
Euro pean Championships in the Pro Stock
class for the past four years in a row.
Valtra has chosen to compete in Pro Stock
class, as it allows for the maximum use
of standard tractor components.
One of the biggest challenges for effective prod-
uct development is getting suffi ciently fast feed-
back about reliability and durability, as in nor-
mal use tractors would not accumulate enough
driving hours to provide this kind of informa-
tion. Competing in tractor pulling events is
thus an ideal way to test engines and tractors,
as it offers fast and valuable data for product
development. For example, based on informa-
tion accumulated from tractor pulling competi-
Today’s valve rockers are much stronger than
before thanks to tractor pulling experience.
This ensures that fuel enters the cylinders at the
correct rate, even at the highest engine speeds.
30
tions, Valtra has been able to make substantial
improvements to its diesel engines and elec-
tronically managed HiTech transmissions.
Competition tractors and engines are
subjected to loads that are around ten times
greater than ordinary loads. In addition, engine
speeds are approximately three times higher
than ordinary use, creating around 2 000 horse-
power at 6 000 rpm. The rear wheels can spin
up to 100 km/h in competition pulls lasting from
10–14 seconds. Such considerable loads quickly
point out the weak points in engines and trac-
tors. Over the years these areas are strength-
ened and improved, which in turn allows for
higher speeds and output.
The following are just some examples of
improvements that have been made and tested
in tractor pulling competitions:
Transmissions
Tractor pulling competitions have been espe-
cially benefi cial for the development and testing
of Valtra’s Powershift technology. Competition
tractors use a similar Powershift module to that
used in normal Valtra tractors (DPS).
In developing pulling tractors, Valtra has
sought to minimise power losses at high engine
speeds. This has been done by minimising drag
between the clutch brakes and eliminating
the adverse effects of centrifugal force on the
clutch cylinders.
Massive power outputs also highlight the
effi ciency of lubrication systems. According-
ly, the lubrication of the planetary gear was
improved by redesigning the oil channels.
Pulling tractors are indeed subject to much
The slide bearing used in Valtra tractors now
has a fl at surface. Tractor pulling experience
showed that the oil fl ows more smoothly
if there is no separate oil channel along the
surface of the bearing.
higher power outputs than normal tractors. By
increasing the pressure level of the low-pres-
sure circuit, the lifespan of the piston rings has
also been tested and extended. The results of
improvements in these areas can already be
seen in today’s HiTech transmissions as well as
in Valtra’s ongoing transmission development
projects.
Engines
The lifespan of main bearings used to be very
short. Apparently, the lubrication channel at the
centre of the bearing split the supporting oil
fi lm into two parts. A new bearing whose low-
er lubrication channel had been removed was
tested during tractor pulling competitions. As a
result, the lifespan of the bearing was doubled.
Moreover, the new technology did not increase
the price of the bearing; in fact, it even lowered