UniAir Fully-variable Valve Control System [608133]

UniAir Fully-variable Valve Control System
Environmentally-friendly and powerful

UniAir is the world’s first electro-hydraulic system for fully-variable control of intake
valves per cylinder and according to requirements in gasoline and diesel engines.
This means the engine is always operated at optimal efficiency. UniAir reduces fuel
consumption by up to 10 %, increases power by 10 % and torque by up to 15 % in the
lower speed range – and these improvements are achieved while complying with the
requirements of emission standards Euro 5 and 6.
How does UniAir work?
In a conventional valve control system, the cams of the rotating intake camshaft
ensure the valves open and close. The air required for the combustion process is
controlled by the position of a throttle valve. One of the disadvantages of this tech-
nology is reduced efficiency due to pumping losses incurred in the throttle valve.
In the UniAir system, the intake valves are not controlled directly by the
intake camshaft, but indirectly via intermediate hydraulic chambers.
These chambers open the valves by means of oil pressure.
If this pressure is discharged by a controlled solenoid valve, the intake valve will not open
even if the cam is in the lift phase.Flexible intake control with UniAir …Valve Control System
UniAir – was developed in conjunction with Fiat Powertrain and is
produced in volume by Schaeffler Automotive under the INA brand

… reduces fuel consumption and CO₂ emissions
Valve lash can be adjusted to meet
changing performance requirements with
the UniAir system. The supplied fuel
mixture is controlled solely by the valves.
Four operating modes for increased
environmental compatibility
➀ Full load describes an operating
mode in which the valves are fully
opened and closed as during normal
control by the camshaft.
➁ The Late Intake Valve Opening mode
(LIVO) is activated when starting the
engine and during idling. This means
the opening of the intake valves is delayed and they open for a shorter period and not so wide. Only a small amount of cold air enters the cylinder
during cold starting of the engine – the
engine starts more easily as a result.
➂ The operating mode EIVC, E arly Intake
Valve Closing, is activated during low to medium engine speeds and lower
levels of cylinder charging. This
reduces pumping losses, increases the
engine output per liter and prevents
an undesirable backflow of the fuel
mixture into the intake ports.
➃ The only difference between the
partial load mode and the EIVC mode
is wider opening and later closing of
the valves. Charge cycle losses and
back flows of the fuel mixture are
prevented, while power is increased.
In addition, the UniAir system is able to
completely deactivate individual cylinders
in the partial load range. This saves fuel and reduces CO₂ emissions. ➀ Full load: if full power is required
➁ LIVO – for reliable cold starting and increased
fuel economy during idling
➂ EIVC – early closing of the intake valves for lower emissions
➃ Economical driving during partial load operation

Every care has been taken to ensure the
correctness of the information contained in this publication but no liability can be
accepted for any errors or omissions.
We reserve the right to make technical changes.
© Schaeffler Technologies GmbH & Co. KG
Issued: 2011, September
This publication or parts thereof may not be reproduced without our permission.MATNR 036926450-0000 / PUA / US-D / 2011091 / Printed in Germany by mandelkowSchaeffler Technologies
GmbH & Co. KG
Industriestrasse 1–3
91074 Herzogenaurach Germany
Internet www.ina.com
E-Mail info@schaeffler.com
In Germany: Phone 0180 5003872
Fax 0180 5003873
From other countries: Phone +49 9132 82-0
Fax +49 9132 82-4950