The heat flowing through the positon head h may be

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: the piston head in °C. The temperature difference (TC – TE) may be taken as 220°C for cast iron and 75°C for aluminium. The heat flowing through the positon head (H) may be deternined by the following expression, i.e., H = C × HCV × m × B.P. (in kW) where C = Constant representing that portion of the heat supplied to the engine which is absorbed by the piston. Its value is usually taken as 0.05. HCV = Higher calorific value of the fuel in kJ/kg. It may be taken as 45 × 103 kJ/kg for diesel and 47 × 103 kJ/ kg for petrol, m = Mass of the fuel used in kg per brake power per second, and B.P. = Brake power of the engine per cylinder Notes : 1. The thickness of the piston head (tH) is calculated by using equations (i) and (ii) and larger of the two values obtained should be adopted. 2. When tH is 6 mm or less, then no ribs are required to strengthen the piston head against gas loads. But when tH is greater then 6 mm, then a suitable number of ribs at the centre line of the boss extending ar...
View Full Document

Ask a homework question - tutors are online