Working Fluid Constituents

Differentiate between constant volume combustion and constant pressure combustion processes. Give examples.

How combustion efficiency of an IC engine is defined? Show the effect of fuel-air equivalence ratio ($\phi$) on spark ignition combustion efficiency.

Calculate the higher heating value of $CH_4(g)$. Consider bomb calorimeter is used. Given standard enthalpies of formation of $CH_4(g)$, $CO_2(g)$, $H_2O(g)$ and $H_2O(l)$ are $-74.87 \text{ MJ/kmol}$, $-393.52 \text{ MJ/kmol}$, $-241.83 \text{ MJ/kmol}$ and $-285.84 \text{ MJ/kmol}$, respectively. Given $T_o = 298.15 \text{ K}$ and $\bar{R} = 8314.3 \text{ J/kmol.K}$

What is the difference between scavenging and supercharging?

Why actual cycle is different from fuel-air cycle?

Calculate the higher heating value of $\text{CH}_4$. Assume the fuel is fully vaporized and bomb calorimeter is used. Standard enthalpies of formation of $\text{CH}_4(\text{g})$, $\text{CO}_2(\text{g})$, $\text{H}_2\text{O}(\text{g})$ and $\text{H}_2\text{O}(\text{l})$ are -74.87 MJ/kmol, -393.52 MJ/kmol, -241.83 MJ/kmol and -285.84 MJ/kmol respectively. Datum temperature $= 25^{\circ}\text{C}$, $\bar{R} = 8314.3 \text{ J/kmol.K}$.

Why actual cycle is different from fuel-air cycle?

What is combustion efficiency? How equivalence fuel-air ration affects diesel engine combustion efficiency?

Calculate the lower heating value of $\text{CH}_4$. Assume the fuel is fully vaporized and $\text{CH}_4$ is burned in a constant pressure process. Consider standard enthalpies of formation (at $25^\circ\text{C}$) of $\text{CH}_4(\text{g})$, $\text{CO}_2(\text{g})$, $\text{H}_2\text{O}(\text{g})$, $\text{H}_2\text{O}(\text{l})$ are $-74.87 \text{ MJ/kmol}$, $-393.52 \text{ MJ/kmol}$, $-241.83 \text{ MJ/kmol}$, $-285.84 \text{ MJ/kmol}$ respectively.

Why fuel-air cycle is different from actual cycle?

How does equivalence fuel/air ratio affect engine combustion efficiency?

Calculate the HHV of $CH_4$ considering the fuel is fully vaporized and bomb calorimeter is used. Standard formation of enthalpies for $CH_4$, $CO_2$, $H_2O(g)$ and $H_2O(l)$ are $-74.85$, $-393.5$, $241.82$ and $285.85$ kJ/mmol respectively. $R = 8.3143$ kJ/kmol-K.

Explain intake process of internal combustion engine for unthrottled operation ($P_i = P_e$), throttled operation ($P_i < P_e$) and supercharged operation ($P_i > P_e$).

Calculate the lower heating value of $\text{CH}_4\text{(gas)}$ when it is burned in a bomb calorimeter with air. The standard enthalpies of formation of $\text{CH}_4\text{(g)}$, $\text{CO}_2\text{(g)}$, $\text{H}_2\text{O(g)}$ and $\text{H}_2\text{O(l)}$ are $-74.87$ MJ/Kmol, $-393.52$ MJ/Kmol, $-241.83$ MJ/Kmol and $-285.84$ MJ/Kmol respectively. $\bar{R} = 8314.3\text{ J/Kmol.K}$, $T_0 = 298.15\text{ K}$