Two automobile engines have the same total displacement volume and the same total power produced within the cylinders. List the possible advantages of V6 over a straight line (in line).

What is the friction power for IC engine? How this power can be reduced?

In a test of single cylinder engine with bore $30 \text{ cm}$, stroke $45 \text{ cm}$ and working on 4-stroke cycle, the following observations were made:
Duration of trial $= 1 \text{ hour}$, total fuel consumption $= 8 \text{ kg}$, heating value of fuel $= 45000 \text{ kJ/kg}$, total revolutions made $= 12000$, indicated mean effective pressure $= 6 \text{ bar}$, brake load $= 1500 \text{ N}$, torque arm $= 92 \text{ cm}$. Find, indicated power, brake power, mechanical efficiency, thermal efficiency.

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 $\bar{R} = 8314.3 \text{ J/kmol.K}$

Explain the knocking phenomena in SI engine and CI engine.

Explain the different combustion stages of CI engine.

Why lowering the compression ratio in CI engine increases the knock tendency?

A 4-stroke cycle engine may or may not have a pressure boost (supercharger, turbocharger) in the intake system. Why must a 2-stroke cycle engine always have an intake pressure boost?

Explain the effect of delayed charging on IC engine volumetric efficiency.

A diesel engine operating on the 4-stroke cycle is to be designed to operate with the following characteristics where the mean conditions are: $1 \text{ bar}$ and $25^\circ\text{C}$, brake power $= 254 \text{ kW}$, volumetric efficiency $= 0.79$, brake specific fuel consumption $= 0.27 \text{ kg/kW.hr}$, air-fuel ratio $= 17:1$, speed $= 1525 \text{ rpm}$. Calculate the required engine capacity and brake mean effective pressure. Heat of combustion of diesel fuel $= 43000 \text{ kJ/kg}$, $R_a = 287 \text{ J/kg.K}$.

Why the cooling of IC engine is necessary? Explain how cylinder size affects engine heat transfer?

Explain the effects of load on $NO_x$ emission from CI engine.

Estimate heat loss of 12 cylinder gasoline engine operating at $590 \text{ kW}$, fuel-air ratio $= 0.08$, inlet air temperature $= 27^\circ\text{C}$, gas temperature $= 400^\circ\text{C}$. The engine is of $145 \text{ mm}$ bore and $145 \text{ mm}$ stroke, brake thermal efficiency $= 0.25$. Calculate heat loss per unit piston area, ratio of heat loss to heat of combustion. Heat of combustion of gasoline fuel $= 42 \text{ MJ/kg}$, $\mu_g = 32.5 \times 10^{-6} \text{ kg/m-s}$ and $k_g = 0.12 \text{ kW/m-K}$.

Explain briefly the difference between direct and indirect cycle for gas turbine. Derive a relation between compressor and turbine outlet temperature for getting maximum specific power.

A gas turbine inlet receives air at $1 \text{ bar}$ and $300 \text{ K}$ and compresses it adiabatically to $6 \text{ bar}$. The compressor efficiency is $90$ where the fuel has heating value of $44000 \text{ kJ/kg}$ and fuel-air ratio is $0.017$. The turbine efficiency is $92$. Calculate the work of the turbine and compressor and also find the thermal efficiency. For air $c_p = 1.005 \text{ kJ/kg-K}$, $\gamma = 1.4$. For products of combustion, $c_p = 1.47 \text{ kJ/kg-K}$, $\gamma = 1.33$.

What is photovoltaic device? Explain P-type silicon and N-type silicon and working principle of photovoltaic device.

What is fuel cell? Explain working principle of $H_2 - O_2$ fuel cell.

How turbofan engines are aerodynamically more efficient than turbo propeller engine? How energy produced from turbines is distributed in these engines?

Differentiate between ramjet and rocket. Enlist the advantages of ramjet.

A turbojet engine flying at a speed of $850 \text{ km/hr}$ consumes air at the rate of $46 \text{ kg/sec}$. Calculate (i) jet exit velocity, the enthalpy for the nozzle is $190 \text{ kJ/kg}$, (ii) flow rate of fuel, assuming air-fuel ratio is 82, (iii) thermal efficiency of the plant, (iv) propulsive power and thrust power, heating value of fuel is $44000 \text{ kJ/kg}$. Assume any data required.