Search results
Results from the WOW.Com Content Network
p–V diagram for the ideal Diesel cycle.The cycle follows the numbers 1–4 in clockwise direction. The image shows a p–V diagram for the ideal Diesel cycle; where is pressure and V the volume or the specific volume if the process is placed on a unit mass basis.
A PV diagram plots the change in pressure P with respect to volume V for some process or processes. Typically in thermodynamics, the set of processes forms a cycle, so that upon completion of the cycle there has been no net change in state of the system; i.e. the device returns to the starting pressure and volume.
Four-stroke cycle used in gasoline/petrol engines: intake (1), compression (2), power (3), and exhaust (4). The right blue side is the intake port and the left brown side is the exhaust port. The cylinder wall is a thin sleeve surrounding the piston head which creates a space for the combustion of fuel and the genesis of mechanical energy.
The first person to build a working four-stroke engine, a stationary engine using a coal gas-air mixture for fuel (a gas engine), was German engineer Nicolaus Otto. [4] This is why the four-stroke principle today is commonly known as the Otto cycle and four-stroke engines using spark plugs often are called Otto engines.
Because the net variation in state properties during a thermodynamic cycle is zero, it forms a closed loop on a P-V diagram. A P-V diagram's abscissa, Y axis, shows pressure (P) and ordinate, X axis, shows volume (V). The area enclosed by the loop is the net work done by the processes, i.e. the cycle:
IMEP may be determined by planimetering the area in an engine's pV-diagram. Since naturally aspirated four-stroke engines must perform pumping work to suck the charge into the cylinder, and to remove the exhaust from the cylinder, IMEP may be split into the high-pressure, gross mean effective pressure (GMEP, p m g {\displaystyle p_{mg}} ) and ...
The pressure–volume diagram (pV) diagram is a simplified and idealised representation of the events involved in a diesel engine cycle, arranged to illustrate the similarity with a Carnot cycle. Starting at 1, the piston is at bottom dead centre and both valves are closed at the start of the compression stroke; the cylinder contains air at ...
Carnot engine diagram (modern) - where an amount of heat Q H flows from a high temperature T H furnace through the fluid of the "working body" (working substance) and the remaining heat Q C flows into the cold sink T C, thus forcing the working substance to do mechanical work W on the surroundings, via cycles of contractions and expansions.