Indicated power of a 4-stroke engine is equal to

We are often asked why the Doctor system shows higher power figures than are seen on the output board of an electric generator or a torque meter on a propeller shaft. The difference is due to losses in the engine and transmission system. This note explains these losses that reduce efficiency, often referred to as the difference between indicated power and shaft power. Indicated Power is what we measure with the Doctor system. This is the actual power produced in the cylinders. However, some of this power is used by the engine itself in driving pumps and cams. Additionally, power is lost due to friction within the engine, together with heat losses. The power produced at the shaft, known as Shaft Power, is therefore reduced. To put some approximate numbers to these losses, the most efficient 4‐stroke engines can be expected to show about 12.5% loss, and usually the loss is higher than that. On a 2‐stroke a figure of 7% is what might be expected but at lower loads you will lose more. However, modern common rail engines are showing improvements in efficiency and, when new, can be as low as 4.5 to 5%. The MCR (Maximum Continuous Rating) figure quoted for an engine is the power that the engine can produce continuously, and so equates to shaft power. Icon’s version 6 software allows engine losses to be entered into the engine parameter definitions, so the relationship between MCR and Maximum Indicated Rated Power can be adjusted. The differences between MCR and Max Indicated Powe...

This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core concepts. See Answer See Answer See Answer done loading Question:A 4-stroke four cylinders square gasoline engine operating at 6105 rpm has an indicated power of 113.2 kW. The cylinder bore is equal to 81 mm and the connecting rod length is 16 cm. The compression ratio of the engine is 9 and the brake mean effective pressure is 1083.8 kPa. The mechanical efficiency is: Select one: O a. 92.18% b.72.77 % C. 81.31 % O d. A 4-stroke four cylinders square gasoline engine operating at 6105 rpm has an indicated power of 113.2 kW. The cylinder bore is equal to 81 mm and the connecting rod length is 16 cm. The compression ratio of the engine is 9 and the brake mean effective pressure is 1083.8 kPa. The mechanical efficiency is: Select one: O a. 92.18% b.72.77 % C. 81.31 % O d. 87,42% Previous question Next question

Concept: Indicated Power for four-stroke engine is given by, \(I.P.~=~\frac\) whereη m= mechanical efficiency, B.P. = brake power, I.P. = Indicated power

IC Engines Multiple Choice Questions on “Engine Performance Parameters”. 1. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called ___________ a) net efficiency b) efficiency ratio c) relative efficiency d) overall efficiency Answer: c Clarification: Relative efficiency is defined as the ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency. 2. Compression ratio of I.C. engine is ___________ a) the ratio of volumes of air in cylinder before compression stroke and after compression stroke b) volume displaced by piston per stroke and clearance volume in cylinder c) ratio of pressure after compression and before compression d) swept volume/cylinder volume Answer: a Clarification: None. 3. The air standard efficiency of an otto cycle compared to a diesel cycle for the given compression ratio is? a) same b) less c) more d) more or less depending on power rating Answer: c Clarification: None. 4. The calorific value of gaseous fuels is expressed in terms of ___________ a) Kcal b) Kcal/kg c) Kcal/m 2 d) Kcal/m 3 Answer: d Clarification: None. 5. Indicated power of a 4-stroke engine is equal to ___________ a) pLAN b) 2pLAN c) pLAN/2 d) 4pLAN Answer: c Clarification: Indicated power of a 4-stroke engine is equal to pLAN/2. where p = mean effective pressure, L = stroke A = area of piston and N = rpm of engine. 6. If the intake air temperature of I.C. engine increases its efficiency will ___________ a) ...

Table of Contents • • • • • Introduction The Mean Effective Pressure (MEP) is a theoretical parameter used to measure the performance of an The cylinder pressure in an ICE is continuously changing during the combustion cycle. For a better understanding of the pressure variation within the cylinder, read the article Formula The mean effective pressure can be regarded as an average pressure in the cylinder for a complete (6) As you can see, from expression (6), the mean effective pressure is not influenced by the engine speed. Also, since the torque is divided by the engine capacity, the mean effective pressure parameter can be used to compare For an engine with multiple cylinders we have to take into account the total volumetric capacity. For n c being the number of cylinders, the expression of mean effective pressure becomes: (7) Types Mean effective pressure is used for initial engine design calculations, with engine torque and MEP as inputs, the engine designer can calculate what is the required There are different “flavors” of mean effective pressure: • indicated mean effective pressure (IMEP) • brake mean effective pressure (BMEP) • friction mean effective pressure (FMEP) Indicated mean effective pressure (IMEP) is the mean effective pressure calculated with indicated power (work). This parameter does not take into account the efficiency of the engine. Brake mean effective pressure (BMEP) is the mean effective pressure calculated from the dynamometer power (torque). Th...

Mean Effective Pressure The mean effective pressure (MEP) is defined as the average pressure required to act on the piston as it moves one displacement to give the work W. In our case From: Advances in Energy Systems and Technology, Volume 4, 1983 Related terms: • Cylinder • Friction • Biodiesel • Exhaust Gas Recirculation • Diesel Engine • Compression Ratio • Specific Fuel Consumption • Engine Speed Exhaust Emissions and Control Doug Woodyard, in Pounder's Marine Diesel Engines and Gas Turbines (Ninth Edition), 2009 Fuel Nozzles Different fuel nozzle types and designs have a significant impact on NOx formation, and the intensity of the fuel injection also has an influence. The increased mean effective pressure ratings of modern engines require increased flow areas throughout the fuel valve, which, in turn, leads to increased sac volumes in the fuel nozzle itself and a higher risk of after-dripping. Consequently, more fuel from the sac volume may enter the combustion chamber and contribute to the emission of smoke and unburnt HC as well as to increased deposits in the combustion chamber. The relatively large sac volume in a standard design fuel nozzle thus has a negative influence on the formation of soot particles and HC. The so-called ‘mini-sac’ fuel valve introduced by MAN Diesel incorporates a conventional conical spindle seat as well as a slide inside the fuel nozzle. The mini-sac leaves the flow conditions in the vicinity of the nozzle holes similar to the flow condi...

Four Stroke Engine A four-stroke engine is an internal combustion engine that utilises four distinct piston strokes (intake, compression, power, and exhaust) to complete one operating cycle. A complete operation in a four-stroke engine requires two revolutions (720 0) of the crankshaft. In this article, let’s study the four-stroke engine. Table of Contents • • • • Parts of a Four Stroke Engine Piston In an engine, a piston transfers the expanding forces of gas to the mechanical rotation of the crankshaft through a connecting rod. Crankshaft A crankshaft is a part that converts the reciprocating motion to rotational motion. Connecting Rod It transfers motion from a piston to a crankshaft, acting as a lever arm Flywheel The flywheel is a rotating mechanical device that is used to store energy. Inlet and Outlet Valves It allows us to enter fresh air with fuel & to exit the spent air-fuel mixture from the cylinder. Spark Plug It is a device that delivers electric current to the combustion chamber, which ignites the air-fuel mixture leading to the abrupt gas expansion. Four Stroke Engine Cycle The four strokes of the engine go by the following names: Suction/Intake Stroke Intake stroke occurs when the air-fuel mixture is introduced to the combustion chamber. In this stroke, the piston moves from TDC (Top Dead Center – the farthest position of the piston to the crankshaft) to BDC (Bottom Dead Center – the nearest position of the piston to the crankshaft.) The movement of the p...