(Solved): An air standard Otto cycle:- 1. Draws air from the environment at \\( 95 \\mathrm{kPa} \\) and \\( ...

An air standard Otto cycle:- 1. Draws air from the environment at \\( 95 \\mathrm{kPa} \\) and \\( 21^{\\circ} \\mathrm{C} \\). 2. The cycle has a compression ratio of \\( 9.5: 1 \\). 3. Heat: \\( 850 \\mathrm{~kJ} / \\mathrm{kg} \\) is added to the compressed gases at constant volume. 4. The working fluid is air, a perfect gas with ratio of specific heats \\( Y=1.4 \\) and gas constant \\( R=287 \\mathrm{~J} / \\mathrm{kgK} \\). Follow the instructions below: a) Describe each of the four processes from the thermodynamic point of view. [2 marks] b) Sketch the \\( P-V \\) and T-S plots for this cycle. Add labels starting as air intake at (1). [2 marks] c) Calculate the peak in cylinder pressure. [3 marks] d) Calculate the thermal efficiency of the cycle [2 marks] e) Evaluate the Brake Mean Effective Pressure [1 mark]\r\nOtto Cycle (Unseen Part of Q2) f) \\[ \\eta_{\\text {thotto }}=1-\\frac{1}{r_{v}^{y-1}} \\] Above is the well-known expression for the thermal efficiency of an air standard Otto cycle in terms of its compression ratio \\( r_{v} \\) and the ratio of specific heats \\( \\gamma \\). Derive the equation. [5 marks] g) Use your answer to f) above to calculate the overall efficiency of the engine in the Bookwork part: compare it to your result. [1 mark] h) Using your result of f) state how the Otto thermal efficiency varies with the ratio of specific heats. [2 marks] 1) If we try and increase the thermal efficiency by changing the compression ratio what unfortunate behaviour can occur and what effect might this have on the engine? [2 marks]