Chapter 3 Fuel, Air, and Combustion Thermodynamics
Problem 3.1
Compare the h and s values for CO2 in Example 3.1 with h and s computed from the curve-fit
equations
Solution
From Example 3.1,
The molar value of h for CO2 is 393,522 + 33,397 = 360,125 kJ/km

Chapter 4 Fuel-Air Cycles
Problem 4.1
Show that the Second Law efficiency, Eq. (4.8), reduces to the first law efficiency, Eq. (4.1)
when there is only heat transfer to the system instead of combustion
Solution
Eq. (4.8) is
II = W/(mf ac)
The available en

Chapter 10 Fuels and Lubricants
Problem 10.1
What is the chemical structure of 3-methyl-3ethylpentane, and 2,4 diethylpentane ?
Solution
a) 3-methyl-3ethylpentane
This pentane has methyl CH3 and an ethyl C2H5 on the third carbon. From Section 10-2, a
pent

Chapter 7 Air, Fuel, and Exhaust Flow
Problem 7.1
Obtain an expression similar to Eq. (7.27) for the case of a supercharged engine.
Solution
With a supercharged engine, since the intake manifold pressure is always greater than the
cylinder pressure, there

Chapter 9 Combustion and Emissions
Problem 9.1
Compute the laminar flame speed at ignition as a function of the spark angle s and the
compression ratio r.
Solution
The relations given are
S = 0.2525 Ps-0.13 (Ts /298)2.19 (1 2.1*f)
Ts = 350 (Vbdc /Vs) (-1)

Chapter 8 Heat and Mass Transfer
Problem 8.1
What is the uncertainty in Qamb given a 5% uncertainty in other energy balance terms ?
Solution
The most probable error equation for Qamb is
Qamb = [Qin2 + Qex2 + Qwater2 + Qoil2 + Ws2] 1/2
If each term on the

Chapter 11 Overall Engine Performance
Problem 11.1
Find the fuel economy, bore, and maximum power for three engine types.
Solution
Assume that the engine is operating at its best economy point at V=100 km/hr, the power Wb =
15 kW, the number of cylinders

Chap 10 Fuels & Lubricants
HC fuel structure and general properties
Engine fuel requirements
Octane number determination
Alternative fuels
Lubricants
Gasoline / Diesel Fuel
Contain 200 300 different species
Almost every class (family) of HC
Lots of alk

Class Participation Rules
#1: If I ask a question, you have to
answer.
#2: If you are not able to answer, ask your
neighbors.
#3: If you are assigned a discussion
problem, you are required to lead it.
Welcome to ME 449
Combustion Engines
Internal vs.

Chapter 5 Engine Testing and Control
Problem 5.1
Find the wet concentration of HC and NOx, dry concentration of CO2, O2, and CO, and for a
given exhaust composition.
Solution
a). If the FID responds to all carbon atoms equally, then the hydrocarbon concen

Chapter 2 Gas Cycles
Problem 2-1
Show T3/T2 = T4/T1 for an Otto cycle
Solution:
(a) From the cycle analysis of Section 2.2:
T2
= r 1
T1
T4
1
= ( ) 1
T3
r
T2 T4
=1
T1 T3
and
T3 T4
=
T2 T1
(b)
= 1
Qin
Qout
Qout = mc (T4 T1 )
Qin = mc (T3 T2 )
T
T1 4 1
T
T

Chapter 1 Introduction to Internal Combustion Engines
Problem 1.1
(a)
Derive an expression for the dimensionless cylinder volume V()/V(0) = f(,r, = s/2l)
Solution:
From Figure 1.1, and using trig relations, we have
The instantaneous stroke is y = l + a -

Chap 3 Fuel, Air and Combustion
Thermodynamics
How to calculate properties of a mixture How to balance a chemical reaction
A/F ratio, ,
How to predict the composition of combustion
products
How to compute energy release from combustion and
flame T

Chap 5 Engine Testing and Control
ppm, g
BSCO, BSHC
BSNOx, BSPM
[g/kWh]
Power, BSFC
Torque & speed
Emission
analyzers
Engine
Dyno
Cylinder pressure
imep, isfc, HRR, combustion duration .
Dynamometer
Control speed or torque
Energy dissipated into heat
an

Chap 4 Fuel-Air Cycles
1st law efficiency vs. 2nd law efficiency
Ideal cycles, parametric study
Actual engine cycles recorded from
experiments
1st law efficiency: (thermal efficiency)
work output
W
w
I =
=
=
(normalized by fuel mass)
fuel energy input

ME 449 Exam 1 10/07/2011 Name
1. (20%) This question is to compare the combustion of diesel fuel and ammonia (NH3). The
stoichiometric air-fuel ratio of diesel fuel is 14.3. The lower heating value for diesel fuel is 42
MJ/kg and the lower heating value

Chap 7 Air, Fuel, and Exhaust Flow
About the gas exchange and fuel preparation
I will only focus on a number of topics.
Please refer to fluids eqns compressible flow
Flow thru the valve opening limited area
Effective flow area is much less than the ac

Chap 8 Heat and Mass Transfer
Liquid cooling system vs. air cooling system
Larger engines
Qwater
( mC )
p water
(Tout Tin )
Smaller engines
(< 20 kW)
or motorcycle engines
What about oils cooling effects?
Ultimately the oil heat is also carried away by c

HW # 2 Heat Release Rate Analysis
Everyone can run computer simulations
and produce figures
Need to be able to explain!
Need to be able to justify results
Right or wrong?
Limitations of computer models
Obtain guidance from simulation results
Stimul

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Chap 2 Gas Cycles
What is a gas cycle? consider only air
Normally, combustion is a chemical reaction process. But
here, we only use imaginary heat release to represent it.
Heat release
Constant volume heat release instantaneous
Constant pressure heat