Internal Combustion Engines

(The Closed Cycle daemons build upon the closed-process daemons. Visit Closed Process pages first.

States	Closed Process	Closed Steady	Open Steady
Open Process		Open Cycles	States-II
HVAC	Combustion	Equilibrium	Gas Dynamics

(Each section above is divided into two sub-sections - Manual and Applications.)
	Applications

(This page is yet to be complete)

Daemons>Closed Cycle> Manual

A Closed Cycle Daemon handle reciprocating engines.

A Closed Cycle is made up of
a series of closed processes forming a loop.

a. Closed-Process Cycles: The air-standard cycles such as the Otto cycle or the Diesel cycle used for modeling reciprocating engines (spark ignition or compression ignition) comprise of a series of closed processes and are tackled by the Closed-Process Cycles daemons in TEST. These cycle daemons build upon the Closed Process daemons to individually analyze each stroke of a cycle and combine these processes to extract cycle variables such as the thermal efficiency or mean effective pressure etc.. However, if the details of the constituent processes are unimportant, the overall cycle quantitites can be obtained using the simpler Closed Steady daemons.

As with most other daemons, the choice of working fluid is the last step in launching such daemons, which reside on the Closed Process, Specific branch.

The building block of the Closed Cycle daemon is the Closed Process daemon (discussed in the Tutorial>Daemons> ClosedProcess>Manual chapter).

b. The Process Analysis Panel: The Process Analysis panel for the cycle daemon is shown in Fig. 1. Except for the schematic of the system, the equations and process variables are almost identical to the ones found in a Closed Process daemon. The only other difference is having the boundary work W_B as the only means of work transfer for the processes making up the cycle. The States panel is exactly identical to the panel found on a Volume State daemon (discussed in the Tutorial>Daemons> States>Manual chapter).

After having the anchor states for each constituent process evaluated, the processes are analyzed one by one (discussion can be found in the Tutorial>Daemons>ClosedProcess>Manual chapter).

Fig. 1 Image of the Process panel in a Closed Cycle daemon.

Processes are automatically imported to the cycle panel.

c. The Cycle Analysis Panel: Once all the processes making up the cyles have been analyzed, all one has to do to calculate the cycle quantities is to switch the view to the Cycle panel (see Fig. 2.) and click the Calculate button. The daemon check for the series of stored processes forming a loop and then calculates all the relevant cycle variables.

In case of regenerative cycles such as the Starling cycle or the Ericson Cycle, choose the donor and receiver processes to specify the regeneration direction.

The only variables that can be specified in this panel, are N, the number of cycles per sec, and Wdot, the total power produced by the cycle.

Fig. 2 Image of the Cycle panel in a Closed Cycle daemon.

Change a variable, Calculate and Super-Calculate

d. Parametric Studies: Once a Closed Cycle has been set up, it is relatively simple to evaluate the effect of changing one or more variables on the problem. Simply change the independent variable, say the compression ratio, to a new value, Calculate and Super-Calculate . The States, Processes and the Cycle are all re-calculated with a detailed report, spreadsheet friendly table and TEST-Codes generated on the I/O panel.

You will find a number of closed cycle examples on the Applications page, Slide Show and the Archive .

Applications