880

The predicted results were obtained by inputting actual heat release data (as measured from cylinder pressure data) into the IRIS engine model. The first two columns in Table 4 Show a comparison between the SwRI measured results and the IRIS predicted results for the baseline metal enginei The measured and predicted results show good agreement in indicated horsepower (IHP), indicated thermal efficiency (ITÉ), top ring reversal temperature (TRR), and firedeck temperature. The percent heat transfer (%HT) was calculated by the engine model and corresponds to thé percent of fuel energy transferred to the coolant by the combustion chamber surfaces. The third and fourth columns in Table 4 correspond to the hot ceramic engine test. Again there

The IRIS model also predicted a 30 percent reduction in heat transfer to the coolant for the hot ceramic engine compared to the baseline metal engine. The baseline heat release was then input into the insulated engine model to simulate hot ceramic engine performance with no degradation in combustion, as shown in the last column of Table 4. The result was a predicted increase in ITE of 0.9 percentage points, with a reduction in heat transfer to the coolant equivalent to 3.6 percent of fuel energy.

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