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 performance.
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.
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Toyota has something new up it’s sleeves - Valvematic, an evolution of the VVT-i mechanism which now incorporates continuous valve lift control together with VVT-i’s existing valve timing control. Valvematic also eliminates the need for a throttle valve, instead controlling the volume of intake air using valve lift instead.
According to Toyota, an improvement of 5% to 10% can be seen with fuel efficiency, as well as an improvement of 10% with the power output on a similiar engine displacement comparison. Toyota also mentions reduced CO2 emission as well as improved acceleration responsiveness.
The first Valvematic-equipped engine will be a 2.0 liter model, most likely a replacement for the 145 horsepower 1AZ-FE engine which has been pretty much slotted with different tune levels into all Toyota cars in the C-segment and above. The trademark “Valvematic” was registered by Toyota a few months ago, so alot of people have been expecting this. One of the first few cars to get the new Valvematic 2.0 liter engine are the 2.0 liter versions of the recently launched twin sedans Toyota Allion and Toyota Premio. The 2.0 liter variants are set to debut in Winter 2007.
The new Toyota Valvematic 2.0 liter engine will most likely be christened the 3ZR-FAE, and will put out 158hp at 6,200rpm and 196Nm at 4,400rpm. Being part of the new ZR engine family, variable valve timing features will be the same as the 2ZR-FE’s Dual VVT-i system - valve timing on both intake and exhaust valves.
Honda also recently announced an engine with continuous valve lift control combined with variable valve timing, a technology it calls AVTEC.
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