Cycle

Figure 13.3: System Cycle: acausal bond graph

The acausal bond graph of system Cycle is displayed in Figure 13.3 (on page ) and its label file is listed in Section 13.1.4 (on page ). The subsystems are listed in Section 13.1.4 (on page ).

The system has two heat engine ports:

1. [Heat] and
2. [Work]

By convention, energy flows in to the [Heat] port and out of the [Work] port. Both ports are true energy ports.

The subsystem CU (Section 13.1.3 (on page )) is a two-port component describing an ideal gas. It has two energy ports which, with integral causality correspond to

1. Entropy flow in; temperature out
2. Volume rate of change in; pressure out

Four SS components are set up as sensors to measure the important quantities pertaining to the cycle:

1. S to measure the integrated entropy flow
2. T to measure the (absolute) temperature
3. V to measure the integrated volume change
4. P to measure the pressure

Table 13.1: Cycles and their causality

Cycle	Compression	Heating	Expansion	Cooling
Otto	II	II	II	II
Carnot	II	DI	II	DI
Diesel	II	ID	II	II
Joule	II	ID	II	ID

A number of cycles can be built depending on the causality of the two ports [Heat] and [Work] of Cycle Some possible cycles listed in Tables 13.1 (on page ) where each table entry gives the causality on the heat and work ports respectively.