In a single cylinder, four stroke, single acting gas engine, the cylinder diameter is 180 mm and the stroke is 350 mm . When running at 250 rpm , the mean area of the indicator diagram taken off the engine is 355 mm² , length of diagram 75 mm , scale of the indicator spring 90 kN/m sq per mm , and the number of explosions was counted to be 114 per minute. Calculate the indicated power. so i have already asked this question and got a good answer, however on step 4, i dont understand how they reached 18.43 KW. When i do the math provided, i get the answer 7195.566. Where am i going wrong? thanks StepsTo clarify how we determined the Indicated Power, I'll go over each step in detail. Step 1: Comprehending the Provided Information - Cylinder diameter (in meters) = 180 mm = 0.18 m - Stroke length (in meters) = 350 mm = 0.35 m - Engine speed = 250 rpm -Indicator diagram mean area = 355 mm² The diagram's length is 75 mm; its spring scale is 90 kN/m² per mm, or 90,000 N/m² per mm; and there are 114 explosions each minute. Step 2: Determine the Cylinder Area Using the Formula: Area = (3.14159 × 0.0324)/4-Area = 0.0254 m²-Area = (π × D²)/4-Substituting D = 0.18 m-Area = (π × 0.18²)/4 Step 3: Determine the MEP (mean effective pressure). The formula is MEP = (mean area × spring scale)/diagram length.355 mm2 is the mean area.Scale of spring = 90,000 N/m² per millimeterThe diagram is 75 mm long.(355 × 90,000)/75= MEP.31,950,000/75= MEP = 426,000 N/m² is the MEP calculated as Step 4: Indicated Power (IP) calculation is step four. IP = (MEP × L × A × n)/60 is the formula for a 4-stroke engine.Location:426,000 N/m² is MEP (from step 3).L is the stroke length (0.35).The cylinder area from step 2 is A = 0.0254 m².114 (explosions per minute) is n. These figures can be substituted: IP = (426,000 × 0.35 × 0.0254 × 114)/60 IP = 18.43 kW Since power is measured in kilowatts (kW), which is a measurement in a second, we divide by 60 to translate from per minute to per second.Since one explosion happens every two revolutions in a 4-stroke engine and the actual observed explosions provide more accurate data for power computation, the number of explosions (114) is utilized instead of engine speed (250 rpm).
In a single cylinder, four stroke, single acting gas engine, the cylinder diameter is 180 mm and the stroke is 350 mm . When running at 250 rpm , the mean area of the indicator diagram taken off the engine is 355 mm² , length of diagram 75 mm , scale of the indicator spring 90 kN/m sq per mm , and the number of explosions was counted to be 114 per minute. Calculate the indicated power.
so i have already asked this question and got a good answer, however on step 4, i dont understand how they reached 18.43 KW. When i do the math provided, i get the answer 7195.566. Where am i going wrong? thanks
Steps
To clarify how we determined the Indicated Power, I'll go over each step in detail.
Step 1: Comprehending the Provided Information
- Cylinder diameter (in meters) = 180 mm = 0.18 m
- Stroke length (in meters) = 350 mm = 0.35 m
- Engine speed = 250 rpm
-Indicator diagram mean area = 355 mm²
The diagram's length is 75 mm; its spring scale is 90 kN/m² per mm, or 90,000 N/m² per mm; and there are 114 explosions each minute.
Step 2: Determine the Cylinder Area Using the Formula: Area = (3.14159 × 0.0324)/4
-Area = 0.0254 m²
-Area = (π × D²)/4
-Substituting D = 0.18 m
-Area = (π × 0.18²)/4
Step 3: Determine the MEP (mean effective pressure).
The formula is MEP = (mean area × spring scale)/diagram length.
355 mm2 is the mean area.
Scale of spring = 90,000 N/m² per millimeter
The diagram is 75 mm long.
(355 × 90,000)/75= MEP.
31,950,000/75= MEP = 426,000 N/m² is the MEP calculated as
Step 4: Indicated Power (IP) calculation is step four.
IP = (MEP × L × A × n)/60 is the formula for a 4-stroke engine.
Location:
426,000 N/m² is MEP (from step 3).
L is the stroke length (0.35).
The cylinder area from step 2 is A = 0.0254 m².
114 (explosions per minute) is n.
These figures can be substituted: IP = (426,000 × 0.35 × 0.0254 × 114)/60 IP = 18.43 kW
Since power is measured in kilowatts (kW), which is a measurement in a second, we divide by 60 to translate from per minute to per second.
Since one explosion happens every two revolutions in a 4-stroke engine and the actual observed explosions provide more accurate data for power computation, the number of explosions (114) is utilized instead of engine speed (250 rpm).
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