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Non-equilibrium all-atom MD simulations are used to study the traction properties of hydrocarbon fluids. A fluid layer is confined between two solid Fe plates under the constant normal force of 1.0 GPa. Traction simulations are performed by applying a relative sliding motion to the Fe plates. Shear behaviors of nine hydrocarbon fluids are simulated on a sufficiently large film thickness of 6.7 nm, and succeeded in reproducing the order of the experimental traction coefficients. The dynamic mechanism of the momentum transfer on layers of fluid molecules are analyzed focusing on the intermolecular interactions (density profile, orientation factor, pair-correlation function) and intramolecular interactions (intramolecular interaction energy, conformation change of alicyclic ring). In contrast to the case of n-hexane, which shows low traction due to a fragile chain-like interaction, other mechanisms are obtained in the high traction molecules of cyclohexane, dicyclohexyl and santotrac 50.

The NOx emission of the TOYOTA LEAN BURN ENGINE is lower than that of a conventional engine due to the presence of a prechamber called a “Turbulence Generating Pot”. The mechanism of this NOx reduction was analyzed experimentally and theoretically. The results showed that large-scale mixing motions of burned gases were caused in the post flame region as a result of the jet flow from the prechamber. It was concluded that the reduction of NOx emission was due to the decrease of temperature gradient and lowered mean temperature of burned gases caused by these motions.

This engine has been developed to achieve lean combustion. A prechamber which is named as the Turbulence Generating Pot (TGP) was developed to extend the lean misfire limit and also to increase flame propagation velocity. The lean misfire limit and the combustion velocity depend on the configuration of the TGP and also on the spark plug location. The jet flame from the TGP creates a strong turbulence in the main combustion chamber resulting in a high velocity propagation of the flame. NOx emission is reduced to a minimal level due to the strong turbulence generated by the TGP.