Toyota recently released details of its new Valvematic variable-valve timing technology for improving the efficiency and performance of its gasoline internal-combustion engines, according to a recent WardsAuto.com article. In addition to employing elements of its existing VVT-i (Variable Valve Timing-intelligent) technology, Valvematic uses a new mechanism to control the volume of air entering the engine by precisely metering the opening/closing of the intake valves.

This development, Toyota says, improves performance by allowing the engine to operate without the use of a conventional throttle valve, or "butterfly." Benefits of the new technology include up to 10% gains in engine efficiency and power output, as well as reduced carbon-dioxide emissions and improved vehicle acceleration.

Toyota says a 2.0L four cylinder will be the first engine to feature Valvematic, with the first applications reportedly including the new Toyota Allion and Premio sedans, which go on sale in Japan this winter, slotting in between the Corolla and Camry.

Meanwhile, Honda is also working on advanced valvetrain systems and plans to release the next generation of its VTEC (Variable Valve Timing Electronic Control) technology in 2009 in an Accord-class vehicle. Honda currently is demonstrating the system on a 2.4L four cylinder, which it says is getting approximately 13% better fuel economy than its existing i-VTEC engines.

Although Toyota plans to continue refining its hybrid-electric powertrain technology, the automaker says Valvematic will add to its environmental-preservation efforts as it moves to revamp its entire IC engine and transmission lineup by 2010.

Source: Sutton, Mike. (June 20, 2007). "Toyota Introduces Throttle-Less Valve Control." WardsAuto.com. Retrieved June 20, 2007, from www.wardsauto.com.