Valve timing diagram for 4-s CI engine is shown in Figure 6.14 and timings are tabulated in Table 6.5.
Figure 6.14 Valve Timing Diagram for Four Strokes CI Engines
The timings for valves for 4-s CI engines is summarized in Table 6.5.
Table 6.5 Valve Timing for Four Strokes CI Engines
| Valve activity | Theoretical timing | Actual timing |
|---|---|---|
| Inlet valve opens | TDC | 30° before TDC |
| Inlet valve closes | BDC | 50° after BDC |
| Inlet valve is open for | 180° | 260° |
| Exhaust valve opens | BDC | 45° before BDC |
| Exhaust valve closes | TDC | 30° after TDC |
| Exhaust valve is open for | 180° | 255° |
| Valve overlap | NIL | 60° |
| Injection | TDC | 15° before TDC |
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