% Verbal description for system Cycle (Cycle_desc.tex)
% Generated by MTT on Thu Dec 4 15:59:55 GMT 1997.

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% Revision 1.1  1997/12/08  09:37:04  peterg
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   The acausal bond graph of system \textbf{Cycle} is
   displayed in Figure \Ref{Cycle_abg} and its label
   file is listed in Section \Ref{sec:Cycle_lbl}.
   The subsystems are listed in Section \Ref{sec:Cycle_sub}.
The system has two heat engine ports: 
\begin{enumerate}
\item \textbf{[Heat]} and
\item \textbf{[Work]}
\end{enumerate}
By convention, energy flows in to the \textbf{[Heat]} port and out of
the \textbf{[Work]} port. Both ports are true energy ports.


The subsystem \textbf{CU} (Section \Ref{sec:CU}) is a two-port
component describing an ideal gas. It has two energy ports which, with
integral causality correspond to
\begin{enumerate}
\item Entropy flow in; temperature out
\item Volume rate of change in; pressure out
\end{enumerate}

Four \textbf{SS} components are set up as sensors to measure the
important quantities pertaining to the cycle:
\begin{enumerate}
\item \textbf{S} to measure the integrated entropy flow
\item \textbf{T} to measure the (absolute) temperature
\item \textbf{V} to measure the integrated volume change
\item \textbf{P} to measure the pressure
\end{enumerate}

   \begin{table}[htbp]
     \begin{center}
       \leavevmode
       \begin{tabular}{|l|l|l|l|l|}
         \hline
         Cycle & Compression & Heating & Expansion & Cooling \\
         \hline
         Otto & II & II & II & II \\
         Carnot & II & DI & II & DI \\
         Diesel & II & ID & II & II \\
         Joule & II & ID & II & ID \\
         \hline
       \end{tabular}
       \caption{Cycles and their causality}
       \label{tab:cycles}
     \end{center}
   \end{table}
   
   A number of cycles can be built depending on the causality of the
   two ports \textbf{[Heat]} and \textbf{[Work]} of \textbf{Cycle}
   Some possible cycles listed in Tables \Ref{tab:cycles} where each
   table entry gives the causality on the heat and work ports
   respectively.