3. An inventor has designed a promising spark-ignition engine where the expansion ratio is greater than the compression ratio. The compression process 1-2 can be modeled as isentropic, with a compression ratio rc. The heat addition process 2-3 can modeled as constant volume. The expansion process 3-4 is isentropic, and such that the final pressure p4 is equal to pi at the start of the cycle. Thus, the heat rejection process 4-1 is at constant pressure. (a) Draw the cycle on a p-V and a T-s diagram, clearly showing all the states. Also, superpose on these diagrams a conventional Otto cycle where the heat rejection occurs at constant volume. (b) Show that the thermal efficiency of the cycle is nth 1 - y-1 [a-1] -1 where =p3/p2 (c) Compare the gross indicated work and thermal efficiency of the new cycle against the standard Otto cycle (make the comparison by using the p-V and T-s diagram).