Fig. 1. Schematic diagram of optical engine test^[11]

Fig. 2. Schematic of structure and view field of the combustion chamber

Fig. 3. Effect of high and low sensitivity (S=0, 6) fuel on in-cylinder pressure, heat release rate and flame development at -25°CA ATDC injection
(a): Cylinder pressure heat release rate curve at -25°CA ATDC injection; (b): S=0; (c): S=6

Fig. 4. Effect of high and low sensitivity (S=0, 6) fuel on in-cylinder pressure, heat release rate and flame development at -15°CA ATDC fuel injection
(a) In-cylinder pressure and heat release rate curve During Fuel Injection at -15°CA ATDC; (b): S=0; (c): S=6

Fig. 5. Effect of high and low sensitivity (S=0, 6) fuel on in-cylinder pressure, heat release rate and flame development at -5°CA ATDC injection
(a): In-cylinder pressure and heat release rate curve at -5°CA ATDC fuel injection; (b): S=0; (c): S=6

Fig. 6. Self-luminescence spectrum of high and low sensitivity fuels at -25°CA ATDC injection
(a): S=0; (b): S=6

Fig. 7. Pseudo-color diagram of high and low sensitivity fuel intensity at -25°CA ATDC injection
(a): S=0; (b): S=6

Fig. 8. Self-luminescence spectrum of high and low sensitivity fuels at -15°CA ATDC injection
(a): S=0; (b): S=6

Fig. 9. Pseudo-color diagram of high and low sensitivity fuel intensity at -15°CA ATDC injection
(a): S=0; (b): S=6

Fig. 10. Self-luminescence spectrum of high and low sensitivity fuels at -5°CA ATDC injection
(a): S=0; (b): S=6

Fig. 11. Pseudo-color diagram of high and low sensitivity fuel intensity at -5°CA ATDC injection
(a): S=0; (b): S=6