- #1

syt0x

- 5

- 0

## Homework Statement

An automobile has a 2.5-litre, four-cylinder, homogeneously charged, direct injected, four-stroke diesel engine. The maximum power output of this naturally aspirated engine is 200 HP at 4000 rpm. By turbocharging, the intake pressure is boosted twice as that for the naturally aspirated design; the volumetric efficiency is increased to 110%. The air-fuel ratio is 17:1 for both turbocharged and naturally aspirated designs. What is the displacement volume required for the turbo engine to produce the same power at same rated rpm?

For this engine at 4000 rpm, if the fuel injection started 12 CAD bTDC and lasted for 600μs, at what crank angle did the injection end? Determine the fuel flow rate (cc/min) per cylinder per cycle for the turbocharged engine given that the density of diesel is 850 kg/m3.

## Homework Equations

P=((η

_{vol}*ρ

_{a}*V

_{sw}*N*η

_{f}*Q

_{f})/2)*(1/AFR)

**Mod note: Added the following explanation for the variables in this equation.**

η

_{vol}=Volumetric efficiency

ρ

_{a}=density of air

V

_{sw}=Swept Volume

N=engine speed

η

_{f}=combustion of fuel efficiency

Q

_{f}=Heating value of fuel

AFR=Air fuel ratio

## The Attempt at a Solution

For the first question I used the equation above. Since AFR ratio, Q

_{f}, N, η

_{f}are the same for both they can be crossed out. That leaves a simple equation. Converted the HP into kw so 200HP=149.1KW multiplied by 2 gives 298kw=η

_{vol}*ρ

_{a}*V

_{sw}. Plugged in the other known values and got a swept volume of 135.45. Seems a little off might need a little help here.

For the second and third question I'm not even sure where to begin or what equation to use. My professor isn't that great so I'm not left with much and the internet is of little help. I need help with these.

Last edited by a moderator: