NOx Reduction is Compatible with Fuel Economy Through Toyota’s Lean Combustion System

T-LCS (TOYOTA LEAN COMBUSTION SYSTEM ) has made the engine possible to be operated with very lean mixture over 22 of air-fuel ratio, and achieved the NOx reduction and the improvement of fuel economy.

This system has two features, one of which is the feed-back control of lean mixture strength using the LEAN MIXTURE SENSOR that has been newly developed.

The other feature is the improved combustion through the SWIRL CONTROL VALVE and individual timing control of fuel injection for each cylinder.

The influence of the test patterns, the vehicle weight and the air-fuel ratio on the exhaust emissions of lean combustion system has been examined and the results are reported in this paper.