E-TVCS Technology Drastically Reduced NOx Emission
    1. Shape of the combustion chamber inlet
2. Combustion chamber
3. Three vortex
4. Injection nozzle
5. Combustion chamber
6. Glow plug
7. Fan-shaped concave
8. Valve recess
9. Piston
  By offsetting the direction of fuel injection into the swirl chamber, and designing the throat of the swirl chamber to match the concave recess on the piston head, E-TVCS produces far less NOx than the D.I. (direct injection) system. In order to lower NOx emission even more, the injection pump and nozzle designs are optimized to match the combustion chamber. The volume of fuel injection per crank angle (fuel injection rate) and its pattern are controlled by an optimum matching of the fuel cam profile, Bosch-type injection pump with damping valve, and the double throttle nozzle with flat cuts. The increased compression ratio and the modified injection nozzle angle not only improved normal starting without the aid of any special warm-up device, but also improved low temperature start ups with a glow plug and a considerable reduction of toxic blue-white smoke emission. In short, the E-Series is a well balanced engine series with improved power output, fuel economy, engine start up, reduced noise and cleaner emission.   Kubota's proprietary TVCS (Three Vortex Combustion System) obtains optimum air/fuel mixture by generating three intense swirling air flow (vortexes) within the spherical-combustion (swirl) chamber. The New TVCS added a special concave recess on the piston head to force compression air in the swirl chamber and to smooth combustion gas discharging. The E-TVCS, based on New TVCS, is aimed at drastic emission reduction.

The "E" in E-TVCS and those following the model numbers stand for "Ecology," "Environment," and "Earth," from Kubota's environmental protection campaign slogan, "Loving and Caring for our Earth."