Xin Q. Diesel Engine System Design

Подождите немного. Документ загружается.

Advanced cooling module

HTR

LTR

CAC, sink

LTR, sink

HTR, sink2

Cooling

air

High

temperature

radiator

Low

temperature

radiator

HTR, sink1

Cooling

air

Air-

cooled

CAC

For a given cooler heat transfer area

multiplied by heat transfer coefﬁ cient

Baseline of (m˙ c

)

min

/(m˙

cal

)

max

Increased (m˙ c

)

min

/(m˙

cal

)

max

at high altitude with thinner air

New operating condition

Model calibration condition

cal

Effectiveness, e

Reduction

liz

()



()



()



()

cal

()

cal

()

cal

()

min

12.13 Concepts of cooler capability and cooling sink temperature.

Diesel-Xin-12.indd 852 5/5/11 12:03:02 PM



853Diesel engine heat rejection and cooling

reaches the highest (worst) value at peak torque or at medium speed and

full load. The coolant temperature is higher at hotter ambient temperatures,

and higher at high altitude. Figure 12.14 shows a simulation example at the

full-load lug curve.

The methodology introduced in this section on cooler sink temperature

and cooling capability is not only important for predicting the radiator inlet

temperature in cooling system design and heat rejection control, but also

necessary to close the loop in the prediction of engine coolant heat rejection

by iterating the cooler sink temperature in the engine cycle simulation model

until convergence.

12.5 Engine warm-up analysis

Engine warm-up is a typical transient process that affects emissions, noise,

and friction. Although warm-up is not a typical condition used for diesel

engine system design, understanding its transient heat rejection is helpful for

engine modeling. For completeness some references on warm-up investigation

are included here (Shayler et al., 1993, 1997; Jarrier et al., 2000, 2002;

Samhaber et al., 2001).

12.6 Waste heat recovery and availability analysis

Waste heat recovery (WHR) is an important area for modern diesel engines.

EGR heat recovery and turbocompounding are the two primary WHR

technologies. In high-EGR engines, although the coolant heat rejection is

250

240

230

220

210

200

190

180

170

160

150

Top tank temperature (°F)

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Engine speed (rpm)

Sea level, 77°F

ambient, 0°F

ROA

Sea level, 10°F

ambient, 15°F

ROA

Sea level, 122°F

am bient, 15°F

ROA

5500 ft, 100°F

ambient, 15°F

ROA

10,000 ft, 85°F,

15°F ROA (10%

fueling derating

except for peak

torque)

12.14 HD diesel engine coolant temperature simulation at full load.

Diesel-Xin-12.indd 853 5/5/11 12:03:02 PM



854 Diesel engine system design

high, the availability of the engine coolant is rather low due to its relatively

low temperature. A large amount of exhaust gas ows to the EGR circuit

instead of going through the turbine. Therefore, the exhaust availability at

the turbine outlet in high-EGR engines is lower than that in the non-EGR

engines, thus the importance of turbocompounding is not so critical. Instead,

the highest potential for WHR is the EGR heat. Organic Rankine cycle has

been attempted to recover the EGR heat to convert part of it to mechanical

shaft power for the engine in order to both reduce coolant heat rejection and

improve fuel economy. More detailed information about WHR can be found

in DiBella et al. (1983), Diehl et al. (2001), Crane et al. (2001), Kapich

(2002), Li and Figliola (2004), Chammas and Clodic (2005), Arias et al.

(2006), Stobart and Weerasinghe (2006), Hountalas et al. (2007), and Teng

et al. (2006, 2007a, 2007b).

12.7 References and bibliography

Adams M (1999), ‘New developments in oil/coolant heat exchangers for heavy duty

engine and transmission applications’, SAE paper 1999-01-2823.

Adams M, Banzhaf M and Weiss E G (1999), ‘First-time use of aluminum for engine

oil coolers in heavy commercial vehicles’, SAE paper 1999-01-0235.

Agarwal A K and Goyal S K (2007), ‘Experimental and numerical investigations of jet

impingement cooling of piston of heavy-duty diesel engine for controlling the non-tail

pipe emissions’, SAE paper 2007-01-0763.

Alkidas A C (1993), ‘Effects of operating parameters on structural temperatures and

coolant heat rejection of a SI engine’, SAE paper 931124.

Ap N S (1999), ‘A simple engine cooling system simulation model’, SAE paper 1999-

01-0237.

Ap N S (2000), ‘Exhaust heat exchange coefcient in a pipe of an internal combustion

engine: EGR cooler and passenger compartment heating applications’, SAE paper

2000-01-0966.

Arias D A, Shedd T A and Jester R K (2006), ‘Theoretical analysis of waste heat recovery

from an internal combustion engine in a hybrid vehicle’, SAE paper 2006-01-1605.

Assanis D N (1989), ‘Effect of combustion chamber insulation on the performance of a

low heat rejection diesel engine with exhaust heat recovery’, Heat Recovery Systems

and CHP, 9(5), 475–484.

ASTM American National Standard (reapproved 2005), ‘Standard test method for estimation

of net and gross heat of combustion of burner and diesel fuels’, D4868-00.

Avequin S, Potier M, Mahe C, Gille G and Martins C (2001), ‘Engine cooling multi-

exchanger’, SAE paper 2001-01-1749.

Bosch D J and Real J D (1990), ‘Heavy truck cooling systems’, SAE paper 900001.

Bowman J P, Krishnan S S and Nalim R (2005), ‘Cooling challenges of modern truck

diesel engines’, Proceedings of ICES2005, ASME Internal Combustion Engine Division

2005 Spring Technical Conference, April 5–7, Chicago, IL, pp. 439–445.

Brosel M B (1999), ‘Overview of engine coolant testing in Europe with particular regard

to its development in Germany’, ASTM Special Technical Publication, Issue 1335,

pp. 392–408.

Diesel-Xin-12.indd 854 5/5/11 12:03:02 PM



855Diesel engine heat rejection and cooling

Bryzik W, Schwarz E, Kamo R and Woods M (1993), ‘Low heat rejection from high output

ceramic coated diesel engine and its impact on future design’, SAE paper 931021.

Burke J and Haws J (2001), ‘Vehicle thermal systems modeling using FLOWMASTER2’,

SAE paper 2001-01-1696.

Burke R D, Brace C J, Hawley J G and Pegg I (2010), ‘Review of the systems analysis of

interactions between the thermal, lubricant, and combustion processes of diesel engines’,

Proc. IMechE, Part D: Journal of Automobile Engineering, 224, 681–704.

Campbell N A F, Hawley J G, Robinson K and Leathard M J (2000), ‘Review of predictive

analysis applied to IC engine coolant heat transfer’, Journal of the Institute of Energy,

73(495), 78–86.

Chalgren R D and Allen D J (2005), ‘Light duty diesel advanced thermal management’,

SAE paper 2005-01-2020.

Chalgren R D, Parker G G, Arici O and Johnson J (2002), ‘A controlled EGR cooling

system for heavy duty diesel applications using the vehicle engine cooling system

simulation’, SAE paper 2002-01-0076.

Chalgren R D, Barron L and Bjork D R (2004), ‘A controllable water cooled charge air

cooler (WCCAC) for diesel trucks’, SAE paper 2004-01-2614.

Challen B and Baranescu R (eds) (1999), Diesel Engine Reference Book, second edition,

SAE International, Warrendale, PA.

Chammas R E and Clodic D (2005), ‘Combined cycle for hybrid vehicles’, SAE paper

2005-01-1171.

Chang F-C, Malipeddi S, Uppuluri S and Shapiro S (2003), ‘Underhood thermal

management of off-highway machines using 1D-network simulations’, SAE paper

2003-01-3405.

Crane D, Jackson G and Holloway D (2001), ‘Towards optimization of automotive waste

heat recovery using thermoelectrics’, SAE paper 2001-01-1021.

Cui Y, Deng K and Wu J (2001), ‘A direct injection diesel combustion model for

use in transient condition analysis’, Proc. IMechE, Part D: Journal of Automobile

Engineering, 215, 995–1004.

DiBella F A, DiNanno L R and Koplow M D (1983), ‘Laboratory and on-highway testing

of diesel organic Rankine compound long-haul vehicle engine’, SAE paper 830122.

Diehl P, Haubner F, Klopstein S and Koch F (2001), ‘Exhaust heat recovery system for

modern cars’, SAE paper 2001-01-1020.

Franco A and Martorano L (1999), ‘Methods to evaluate in-cylinder heat transfer and

thermal load in the small internal combustion engines’, SAE paper 1999-01-1252.

French C C J (1972), ‘Piston cooling’, SAE paper 720024.

Habchi S D, Ho S Y, Elder J and Singh S (1994), ‘Airow and thermal analysis of

underhood engine enclosures’, SAE paper 940316.

Hannigan H J (1993), ‘Review of automotive engine coolant technology’, ASTM Special

Technical Publication, Issue 1192, pp. 6–10.

Hergart C-A, Louki A and Peters N (2005), ‘On the potential of low heat rejection DI

diesel engines to reduce tail-pipe emissions’, SAE paper 2005-01-0920.

Heywood J B (1988), Internal Combustion Engine Fundamentals, McGraw-Hill, New

York.

Hires S D and Pochmara G L (1976), ‘An analytical study of exhaust gas heat loss in a

piston engine exhaust port’, SAE paper 760767.

Honma J, Murao T, Yamashita Y, Tsujita M and Sugihara H (2004), ‘Development of a

highly efcient and reliable multi-tube EGR cooler’, SAE paper 2004-01-1446.

Hountalas D T, Katsanos C O and Lamaris V T (2007), ‘Recovering energy from the

Diesel-Xin-12.indd 855 5/5/11 12:03:02 PM



856 Diesel engine system design

diesel engine exhaust using mechanical and electrical turbocompounding’, SAE paper

2007-01-1563.

Hughes C A V and Wiseman M W (2001), ‘Feasibility of intelligent control strategies

to reduce cooling system size’, SAE paper 2001-01-1759.

Hughes C, Mitts C, Jacquelin F and Wiseman M (2001), ‘Heavy duty truck cooling

system design using co-simulation’, SAE paper 2001-01-1707.

Imabeppu S, Shimonosono H, Hirano Y, Fujigaya K and Inoue K (1993), ‘Development of

a method for predicting heat rejection to the engine coolant’, SAE paper 931114.

Jaichandar S and Tamilporai P (2003), ‘Low heat rejection engines – an overview’, SAE

paper 2003-01-0405.

Jaichandar S and Tamilporai P (2004), ‘The status of experimental investigations on low

heat rejection engines’, SAE paper 2004-01-1453.

Jarrier L, Champoussin J C, Yu R and Gentile D (2000), ‘Warm-up of a DI diesel engine:

experiment and modeling’, SAE paper 2000-01-0299.

Jarrier L, Gyan P and Champoussin J C (2002), ‘Thermo-hydraulic oil loop modeling

for ICE warm-up investigation’, SAE paper 2002-01-2197.

Kamo L S (2000), ‘Preliminary investigation of developmental low heat rejection engine

piston tribology’, ASME Internal Combustion Engine Division (publication) ICE, 33,

155–164.

Kamo L S, Kleyman A S, Bryzik W and Mekari M (1996), ‘High temperature tribology

for piston ring and cylinder liner in advanced low heat rejection engines’, ASME

Internal Combustion Engine Division (publication) ICE, 27, 89–96.

Kamo L, Woods M, Bryzik W and Mekari M (2000a), ‘Thermal barrier coatings for

monolithic ceramic low heat rejection diesel engine components’, SAE paper 2000-

01-1236.

Kamo L, Kamo R, Bryzik W, Mekari M, Jin Y S and Li S H (2000b), ‘Advancements

in high temperature cylinder liner and piston ring tribology’, SAE paper 2000-01-

1237.

Kamo L, Saad P, Mnatsakanov R, Bryzik W and Mekari M (2003), ‘Development of

high temperature diesel engine piston ring and cylinder liner tribology’, SAE paper

2003-01-1104.

Kamo R, Bryzik W and Glance P (1987), ‘Adiabatic engine trends – worldwide’, SAE

paper 870018.

Kanefsky P, Nelson V A and Ranger M (1999), A Systems Engineering Approach to

Engine Cooling Design, the 44th L. Ray Buckendale Lecture, SP-1541, SAE paper

1999-01-3780, SAE International, Warrendale, PA.

Kapich D (2002), ‘Turbo-hydraulic engine exhaust power recovery system’, SAE paper

2002-01-2731.

Kern J and Wallner R (1986), ‘Water-cooled charge air coolers for heavy diesel engines’,

IMechE paper C116/86.

Kimura S, Matsui Y and Itoh T (1992), ‘Effects of combustion chamber insulation on the

heat rejection and thermal efciency of diesel engines’, SAE paper 920543.

Kluck C E, Olsen P W and Skriba S W (1986), ‘Lubrication system design considerations

for heavy-duty diesel engines’, SAE paper 861224.

Kobori S, Kamimoto T and Toralde M (1992), ‘Combustion in low-heat-rejection diesel

engines’, JSME International Journal, Series 2: Fluids Engineering, Heat Transfer,

Power, Combustion, Thermophysical Properties, 35(1), 1–9.

Koch F W and Haubner F G (2000), ‘Cooling system development and optimization for

DI engines’, SAE paper 2000-01-0283.

Diesel-Xin-12.indd 856 5/5/11 12:03:02 PM



857Diesel engine heat rejection and cooling

Li H and Figliola R S (2004), ‘Optimization of an automotive cooling system based on

exergy analysis’, SAE paper 2004-01-3541.

Luján J M, Serrano J R, Arnau F and Dolz V (2003), ‘Heat transfer model to calculate

turbocharged HSDI diesel engines performance’, SAE paper 2003-01-1066.

Malchow G L, Sorenson S C and Buckius R O (1979), ‘Heat transfer in the straight

section of an exhaust port of a spark ignition engine’, SAE paper 790309.

Melgar A, Horrillo A, Cabaco G, Castaño C and Grande J A (2004), ‘Theoretical and

experimental methodology for the improvement of EGR-coolers design’, SAE paper

2004-01-0052.

Mian M A (1997), ‘Design and analysis of engine lubrication systems’, SAE paper

970637.

Mohan K V, Arici O, Yang S L and Johnson J H (1997), ‘A computer simulation of the

turbocharged diesel engine as an enhancement of the vehicle engine cooling system

simulation’, SAE paper 971804.

Morel T, Keribar R, Blumberg P N and Fort E F (1986), ‘Examination of key issues in

low heat rejection engines’, SAE paper 860316.

Mosburger M, Fuschetto J, Assanis D, Filipi Z and McKee H (2008), ‘Impact of high

sulfur military JP-8 fuel on heavy duty diesel engine EGR cooler condensate’, SAE

paper 2008-01-1081.

Muto S, Sugimoto T, Utikawa A and Yamamoto M (2001), ‘Development of a cooling

module containing a radiator and a condenser, part 1: product design’, SAE paper

2001-01-1018.

Norris P M, Wepfer W, Hoag K L and Courtine-White D (1993), ‘Experimental and

analytical studies of cylinder head cooling’, SAE paper 931122.

Pantow E, Kern J, Banzhaf M, Lutz R and Tillmann A (2001), ‘Impact of US02 and

Euro4 emission legislation on power train cooling challenges and solutions for heavy

duty trucks’, SAE paper 2001-01-1716.

Pearson R J, Bassett M D, Winterbone D E and Bromnick P A (2000), ‘Comprehensive

charge-cooler model for simulating gas dynamics in engine manifolds’, SAE paper

2000-01-1264.

Pimenta M M and Filho R (1993), ‘Cooling of automotive pistons: study of liquid-cooling

jets’, SAE paper 931622.

Rahman S and Sun R (2003), ‘Robust engineering of engine cooling system’, SAE paper

2003-01-0149.

Rahman S, Kayupov M, Li J and Mourelatos Z P (2007), ‘Balance between reliability and

robustness in engine cooling system optimal design’, SAE paper 2007-01-0594.

Rakopoulos C D and Giakoumis E G (2007), ‘Study of the transient operation of low

heat rejection turbocharged diesel engine including wall temperature oscillations’,

SAE paper 2007-01-1091.

Reddy C S, Domingo N and Graves R L (1990), ‘Low heat rejection engine research

status: where do we go from here?’, SAE paper 900620.

Rush J H (1976), ‘Exhaust port heat rejection in a piston engine, a preliminary report’,

SAE paper 760766.

Saad D, Saad P, Kamo L, Mekari M, Bryzik W, Schwarz E and Tasdemir J (2007),

‘Thermal barrier coatings for high output turbocharged diesel engine’, SAE paper

2007-01-1442.

SAE Surface Vehicle Standard J631 (2007), ‘Radiator Nomenclature’.

SAE Surface Vehicle Information Report J814 (2007), ‘Engine coolants’.

SAE Surface Vehicle Information Report J1004 (2004), ‘Glossary of engine cooling

system terms’.

Diesel-Xin-12.indd 857 5/5/11 12:03:02 PM



858 Diesel engine system design

SAE Surface Vehicle Recommended Practice J1148 (2004), ‘(R) Engine charge air cooler

(CAC) nomenclature’.

SAE Surface Vehicle Recommended Practice J1244 (2008), ‘(R) Oil cooler nomenclature

and glossary’.

SAE Surface Vehicle Recommended Practice J1339 (2009), ‘Test method for measuring

performance of engine cooling fans’.

SAE Surface Vehicle Recommended Practice J1393 (2004), ‘(R) Heavy duty vehicle

cooling test code R’.

SAE Surface Vehicle Recommended Practice J1468 (2006), ‘Application testing of oil-

to-air oil coolers for heat transfer performance’.

SAE Surface Vehicle Information Report J1498 (2005), ‘Heating value of fuels’.

SAE Surface Vehicle Recommended Practice J1994 (2008), ‘Laboratory testing of vehicle

and industrial heat exchangers for heat transfer and pressure drop performance’.

SAE Surface Vehicle Information Report J2082 (1992), ‘Cooling ow measurement

techniques’.

SAE Surface Vehicle Standard J2414 (2005), ‘Application testing of oil-to-water oil

coolers for heat transfer performance’.

Sakai T, Ishiguro S, Sudoh Y, Raab G and Hager J (1994), ‘The optimum design of

engine cooling system by computer simulation’, SAE paper 942270.

Samhaber C, Wimmer A and Loibner E (2001), ‘Modeling of engine warm-up with

integration of vehicle and engine cycle simulation’, SAE paper 2001-01-1697.

Savage J, Tang Y, Xie Z and Rahman S S (2007), ‘Sensitivity analysis of powertrain

cooling system performance’, SAE paper 2007-01-0598.

Schwarz E, Reid M, Bryzik W and Danielson E (1993), ‘Combustion and performance

characteristics of a low heat rejection engine’, SAE paper 930988.

Scott T C, McDonald L K (2005), ‘Cooling fan modeling to support robust AC/cooling

system simulation’, SAE paper 2005-01-1905.

Shah R K (2003), ‘Advances in automotive heat exchanger technology’, SAE paper

2003-01-0533.

Sharma J K and Gaur R R (1990), ‘Some analytical investigations on a four stroke diesel

engine for high specic output and low heat rejection’, SAE paper 900618.

Shayler P J, Christian S J and Ma T (1993), ‘A model for the investigation of temperature,

heat ow and friction characteristics during engine warm-up’, SAE paper 931153.

Shayler P J, Chick J P and Ma T (1996), ‘Effect of coolant mixture composition on

engine heat rejection rate’, SAE paper 960275.

Shayler P J, Chick J P and Ma T (1997), ‘Correlation of engine heat transfer for heat

rejection and warm-up modeling’, SAE paper 971851.

Sitkei G (1974), Heat Transfer and Thermal Loading in Internal Combustion Engines,

Akademiai Kaido, Budapest.

Stobart R and Weerasinghe R (2006), ‘Heat recovery and bottoming cycles for SI and

CI engines – a perspective’, SAE paper 2006-01-0662.

Stolz A, Fleischer K, Knecht W, Nies J and Strähle R (2001), ‘Development of EGR

coolers for truck and passenger car application’, SAE paper 2001-01-1748.

Sun X, Wang W G, Bata R M and Gao X (1994), ‘Performance evaluation of low heat

rejection engines’, Transactions of the ASME, Journal of Engineering for Gas Turbines

and Power, 116(4), 758–764.

Sutor P, Schwarz E E and Pangilinan H (2005), ‘Major advances in tribology for low

heat rejection engines – a ten-year overview’, Proceedings of the World Tribology

Congress III – WTC 2005, pp. 575–576.

Diesel-Xin-12.indd 858 5/5/11 12:03:02 PM



859Diesel engine heat rejection and cooling

Tamilporai P, Baluswamy N, Jawahar P M, Subramaniyam S, Chandrasekaran S, Vijayan

K, Jaichandar S, Rani J J and Arunachalam K (2003), ‘Simulation and analysis of

combustion and heat transfer in low heat rejection diesel engine using two zone

combustion model and different heat transfer models’, SAE paper 2003-01-1067.

Tang Y, Grall N and Savage J (2008), ‘Various impacting factors on a radiator top tank

temperature’, SAE paper 2008-01-1438.

Taraza D, Henein N and Bryzik W (2000), ‘Friction losses in multi-cylinder diesel

engines’, SAE paper 2000-01-0921.

Taylor S, Clark N, Gautam M and Wayne W S (2004), ‘Diesel emissions prediction from

dissimilar cycle scaling’, Proc. IMechE, Part D: Journal of Automobile Engineering,

218, 341–352.

Teng H, Regner G and Cowland C (2006), ‘Achieving high engine efciency for heavy-

duty diesel engines by waste heat recovery using supercritical organic-uid Rankine

cycle’, SAE paper 2006-01-3522.

Teng H, Regner G and Cowland C (2007a), ‘Waste heat recovery of heavy-duty diesel

engines by organic Rankine cycle, part I: hybrid energy system of diesel and Rankine

engines’, SAE paper 2007-01-0537.

Teng H, Regner G and Cowland C (2007b), ‘Waste heat recovery of heavy-duty diesel

engines by organic Rankine cycle, part II: working uids for WHR-ORC’, SAE paper

2007-01-0543.

Valaszkai L and Jouannet B (2000), ‘Cooling system optimization for Euro4 – EPA/02

heavy duty trucks’, SAE paper 2000-01-0964.

Varghese M B, Goyal S K and Agarwal A K (2005), ‘Numerical and experimental

investigation of oil jet cooled piston’, SAE paper 2005-01-1382.

Wallace S J and Kremer G G (2009), ‘Diesel engine energy balance study operating on

diesel and biodiesel fuels’, Proceedings of ASME International Mechanical Engineering

Congress and Exposition, 17, 337–343.

Woods M, Bryzik W and Schwarz E (1992), ‘Heat rejection from high output adiabatic

diesel engine’, SAE paper 920541.

Xin Q and Zheng J (2009), ‘Theoretical analysis of internal combustion engine miscellaneous

heat losses’, SAE paper 2009-01-2881.

Yasar H (2008), ‘First and second law analysis of low heat rejection diesel engine’,

Journal of the Energy Institute, 81(1), 48–53.

Yonushonis T M (1997), ‘Overview of thermal barrier coatings in diesel engines’, Journal

of Thermal Spray Technology, 6(1), 50–56.

Diesel-Xin-12.indd 859 5/5/11 12:03:02 PM



860

Diesel engine air system design

Abstract: This chapter develops the design theory of diesel engine air

system (including the turbocharger, the manifolds, and the exhaust gas

recirculation (EGR) system) with engine cycle simulations. It addresses

the applications of the theory of pumping loss control and subsystem

interactions that is developed in Chapter 4. The chapter begins with an

overview of the air system requirements determined by the emissions

recipe (i.e., air–fuel ratio, EGR rate, intake manifold gas temperature, etc.),

followed by a discussion of different EGR system congurations, before

elaborating turbocharger matching and exhaust manifold design. The chapter

concludes with a comprehensive system analysis of the second law of

thermodynamics for modern turbocharged EGR diesel engines.

Key words: air system, turbocharger matching, manifold, EGR system,

engine cycle simulation, pumping loss, subsystem interaction, second law of

thermodynamics.

13.1 Objectives of engine air system design

The diesel engine air system consists of intake and exhaust manifolds,

turbocharger, charge air cooler (CAC), EGR circuit, intake throttle (IT) and

exhaust back-pressure valve (EBP valve), other air/gas control valves, and

valvetrain. Its relationship with other systems is shown in Fig. 13.1. The goal

of air system design is to achieve desirable air–fuel ratio, EGR rate, exhaust

gas temperature, and oxygen concentration to meet the requirements of both

engine-out emissions and aftertreatment operation with minimum pumping

loss and low BSFC without violating the design constraints in the desirable

operating region of engine speed and load under all driving and ambient

conditions. Low pumping loss is achieved via high volumetric efciency or

low engine delta P. The design constraints include the maximum limits of

cylinder pressure, exhaust manifold gas pressure and temperature, compressor

outlet air temperature, turbocharger speed, and coolant heat rejection. The

design constraints also include certain minimum limits such as acceptable

intake manifold gas temperature and compressor surge margin. Note that the

requirements resulting from aftertreatment devices are new challenges for the

air system. The core of air system design is pumping loss control. Chapter 4

discusses the pumping loss theory and the mathematical formulations behind

air system design principles. This chapter focuses on their engine applications.

Figure 13.2 illustrates the direct correlation between engine delta P and

Diesel-Xin-13.indd 860 5/5/11 12:04:41 PM



In engine air system design, how well are all subsystems deﬁned?

Charge air cooler size

(intake manifold T,

heat rejection)

EGR cooler size

(intake manifold T,

heat rejection)

EGR circuit ﬂow

restriction (EGR cooler,

valve, piping)

Cylinder head

(volumetric efﬁciency,

valve size, swirl,

port ﬂow coefﬁcient)

Valvetrain

(valve timing,

valve lift proﬁle)

Turbine (effective

area, ﬂow range,

efﬁciency)

Engine

air system

performance

at different

speed and load

Cylinder cooling

(exhaust manifold T,

coolant heat rejection)

Compressor

(ﬂow range,

efﬁciency)

Intake and exhaust

manifolds (pressure

loss)

Intake throttle or

exhaust back pressure

valve

Fuel injection

timing (BSFC,

exhaust T)

Aftertreatment

(exhaust restriction,

soot load change,

SCR/DPF efﬁciency)

13.1 The boundary of diesel engine air system design.

Diesel-Xin-13.indd 861 5/5/11 12:04:42 PM

