🔍 Key Concepts

• On an indicator diagram, maximum rise in pressure means the steepest upward slope of the pressure curve, not the highest pressure point • The diagram’s horizontal axis is crank angle around TDC (top dead center); the vertical is pressure in the cylinder • Each labeled period (G, H, J, K) represents a crank-angle range between two vertical reference lines

💭 Think About

• Look carefully at where the solid pressure curve climbs the fastest just before and after TDC—during which labeled interval is that steepest part located? • Compare how much the pressure increases over the same crank-angle width in each labeled period: where does the curve go from low to high pressure over the shortest angle? • Is the maximum rate of rise likely to be in the early combustion (right after ignition delay) or in the later, more gradual expansion portion of the stroke?

✅ Before You Answer

• Be sure you are focusing on slope (rate of change), not on the highest point of the curve • Verify exactly which vertical lines define each label (G, H, J, K) on the horizontal axis • Confirm that the chosen period corresponds to the part of the curve where pressure is increasing most sharply just before or near TDC