(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In many spark-ignition engines, liquid fuel is added to the inlet air upstream of the inlet manifold above the throttle. The inlet manifold is heated to ensure that under steady-state conditions the fuel is vaporized before the mixture enters the cylinder.

At normal wide-open throttle operating conditions, in a four-stroke cycle 1.6 L (Vd) displacement four-cylinder engine, at 2500 rpm (N), the temperature of the air entering the carburetor is 40C. The heat of vaporization of the fuel in 350 kJ/kg and the rate of heat transfer to the intake mixture is 1.4 kW. Estimate the temperature of the inlet mixture as it passes through the inlet valve, assuming that the fuel is fully vaporized. The volumetric efficiency is 0.85. The air density is 1.06 kg/m^3 and cp for air is 1 kJ/kgK. You may neglect the effects of the heat capacity of the liquid and vapor fuel.

2. Relevant equations

Volumetric Efficiency: Ratio of the mass of air inducted into the cylinders to the mass of ambient air

[itex]\eta_v =\frac{m_a}{\rho_a V_d}=\frac{2 \dot{m_a}}{\rho_a V_d N}[/itex]

Rate of Heat Transfer

[itex]\dot{Q} = \dot{m} c \Delta T[/itex]

3. The attempt at a solution

Not 100% sure where to start.

Calculating the mass of air inducted into the cylinders is straightforward... I'm just not sure how to tie it all together.

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# Homework Help: Calculating Temperature of Fuel-Air Mixture

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