18 June 2007.
With its newly developed variable
valve lift mechanism, Toyota goes a step further in the
evolution of its Variable Valve Timing-intelligent
(VVT-i ) system.
Called Valvematic, the new variable
valve lift mechanism combines the advantages of the
VVT-i technology (it controls the timing of
intake valve opening/closing) with a new mechanism that
can also control the intake valve lift volume.
In other words, VVT-i controls the timing
(duration of the opening) while the new mechanism will
also control the distance of the opening (lift).
Conventional engines control air
intake (outside air is filtered then directed to the
combustion chambers, naturally or compressed by a direct
compressor or a turbocompressor) using a throttle valve.
With Valvematic, the volume of air taken in is adjusted
by continuously controlling the intake valve lift volume
and timing of valve opening and closing, bringing
optimal performance based on the engine’s operational
condition, combining high fuel efficiency with dynamic
The first application of Valvematic
will arrive in a new 2.0-litre engine to be introduced
soon. This new system further evolves the Toyota petrol
engine and improves fuel efficiency by between 5 and 10
per cent (depending on driving conditions), reduces CO2
emissions, boosts power output by at least 10 per cent
and enhances throttle response.
As a part of its efforts to reduce CO2
emissions through high fuel efficiency and to achieve
cleaner exhaust emissions, Toyota Motor Corporation
(TMC) plans to completely revamp its petrol engine and
transmission lineup by 2010.