Question

An ideal Diesel Engine has a diameter of 150mm and stroke 200 mm. The clearance volume is 10% of the swept volume. Determine the compression ratio and the air standard efficiency of the engine if the cut-off takes place at 6 percent of the stroke​

Answer 1

Answer:

efficiency is 57.52% and cut off ratio is 1.6 swept volume is 3534cm^3

Answer 2

Answer:

The compression ratio is 1.6 and the efficiency is 57.52%.

Explanation:

Given:

Diameter(D)= 150mm = 15cm

Stroke(L) = 200mm = 20cm

Vc = 10% Vs

To find:

Compression ratio(ρ) and efficiency(η)

Step 1:

Vs = (πD²L)/4

Vs = (3.14×15²×20)/4

Vs = 3533cm³

Vc = 10% × 3533

Vc = 353.3cm³

Step 2:

n = (Vs + Vc)/Vc

n = (3533+353.3)/353.3

n = 3886.3/353.3

n = 11

Step 3:

ρ = V₃/V₂

ρ = (V₂ + 0.06V₃)/V₂

ρ = (353.3 + 0.06×3533)/353.3

ρ = 565.28/353.3

ρ = 1.6

Step 4:

η = 1 - [(ρⁿ-1)/n(ρ-1)][1/n^(γ-1)]

Substituting the given values, we get

η = $1 - [\frac{1.6^{1.4}-1}{1.4(1.6-1)}][\frac{1}{11^{1.4-1}}]$

η = 57.52%

Therefore, the compression ratio and the air standard efficiency of the engine is 1.6 and 57.52% respectively.

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