# Chapter 19 - Exercises and Problems - Page 351: 58

The diesel engine is more efficient.

#### Work Step by Step

We know that the value of $\gamma$ in air is 1.4. We use the efficiency of the gas engine found in problem 55: $e=1-r^{1-\gamma}$ $e=1-8.3^{1-1.4}=.57$ In problem 57, we found that the efficiency of the diesel engine is given by: $e_{diesel}=1-\frac{r^{1-\gamma}(\alpha^{\gamma}-1)}{(\alpha-1)\gamma}$ Thus, we find: $e_{diesel}=1-\frac{19^{1-1.4}(2.4^{1.4}-1)}{(2.4-1)(1.4)}=.62$ The diesel engine is more efficient.

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