The problem of fuel economy as well as reducing emissions ideally leads to the complete combustion problem. In our view it has at least four complementary dimensions as the following; FUEL ADDITIVES: To enhance the engine operation and reduce hazardous emissions. This is the field of chemical engineers. IR LASER INITIATED COMBUSTION: By using the heating effects of Laser as well as the infrared absorption, and choosing the frequency of Laser around the “resonance” of the air-fuel mixture, we can initiate a very turbulent fast burning with super high initial temperature, which is a step toward perfect combustion. This is the subject of our other paper, PARTICLE BEAM: High energy particles such as UV-Laser and hot electron beams can break the “unwanted” chemical bounds. The research for construction of commercial electron guns is under progress. OPTIMUM ATOMIZER AND ALLOWABLE DELAY TIME: This kind of optimization improves combustion too. In this approach, as a sample calculation, we choose an optimum pneumatic nozzle design with the shape that follows the optimum size distribution, the Nukiyama-Tanasawa distribution with q = 2. Then using the relation between average size and the nozzle diameter, we determine the diameter of the nozzle as well as air velocity. Nucleation and formation of big droplets have detrimental effects on perfect combustion. In order to minimize the nucleation, we determine an upper limit for allowable delay, between injection and initiation of the combustion (by IR Laser).