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1 * ( ) 88/10/1 : 88/7/5 : / * () ( ) (). () (). : Warm up  1 MATLAB / / / 
2 ... 0/1 0/1. 0/1 0/1. ). (. % %60.. %80 %80.[1]... ()... [3] [2]. » «. .. : / / /  16
3 / Bio (2) hl k / XU7.. 5mm : hl h cool Bio bl h blcool 510 (3) k 100 W/mK h blcool (3). 0/2 [6] h blcool h blcool. 0/1 %10.[2] [4].. (). () /1 :.[5] hl Bio (1) k k l h (1) [5] W/mK : 10. W/m K / / / 
4 / 1 R wall. R wall.(1 ) [8] Sitkei [7] Li. %10.. : Q pi Q con.1 Q pi 1 Q s 0 (8) pi : dt dt Q pi s : (9) pi (9) con Q pi s ( mc) pi ( mc) : dt pi 1 ( Q pi Q pi oil Q r Q con ) (4) dt ( mc) pi ( mc) con : pi : ( mc ( mc) : con () Q pi : Q pi oil () : Q r : Q con. Q pi : (5) Qpi oil ( ha) oil ( Tpi Toil ) Qr ( UA) r ( Tpi Tbl ) dt dt (6) (UA) r : 1 ( UA) r (7) Rwall Q con : 1388 / / /  18
5 / : Q vtr. Q vtr Q bl Q hd Q bl Q pi.[3]. %16 %14 %14 %26 %24. %16. : (17) Q Feul m Fuel Q LHV (17) Q LHV. kg/s. 42/ /J kg dt oil 1 dt ( mc) oil Q Q pi oil hd Q con ( ha) cr oil Q Feul : Q oil amb vtr ( T Q oil T fr op amb Q dt fr cr (18).. : ) Q Q r pi oil con (10) Q dt dt Q bl 9 1 mc bl : (11) Q Q bl r bl cool habl T bl Tamb dt : Q bl : Qbl cool ( ha) bl( Tbl cool out Tbl cool in) dt Qbl cool (12) dt hd 1 dt ( mc) hd Q hd Q exh Q vtr Q : ( mc ) T hd cool oil ( Toil oilin) (13) : Q hd : Qbl cool ( ha) bl( Tbl cool out Tbl cool in) dt Q hd cool (14) : Q exh Q ( ha) ( T T dt (15) exh p g w ). : h p.. : h 75 p avg 0.25hevo 0. h (16) evc (19) Q hd oil ( mc ) oil ( Thd Toilin ) h evc h evo. [9] / / / 
6 Q : V fmep cylinder (22) friction d # # V d (22) : dt dt blcool 1 ( mc) bl coolant ( Q (23) blcool Q blcool flow.. : (24) Q mc ) ( T T ) (24) blcool flow ( bl coolant bl cool out bl cool in : dt 1 hdcool ( Q hdcool Q hdcool flow) (25) dt ( mc) hd coolant : (25). (26) Q hd cool flow ( mc ) hd coolant ( Thd cool out Thd cool in ) :. () : dtbl cool in dthd cool out (27) dt dt ) : : Q fr op Q fr cr [6] SI : N N fmep ss ( kpa) (20) rpm N (20). [3]. fmep 2 warm up fmepss (21). [6] fmep 1 fmep (1). (1).. (22) fmep 1388 / / /  20
7 / ().. XU7 (2).. ) ( %4.... () : (28) dtbl dt Q in wp m E rad radcool C min C Lbl m m C T T m C T T amb rad C hd cool rad 1 cool cool ( C bl cool bl cool 2 blin hd cool hd : m rad cool : m rad : m cool : Q wp : E rad Cair, Cc : C min Cc m cool C hd (29) cool Cair V A C (30) air air rad air ) / / / 
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10 (1618) / / /  24
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13 / Refrence: [1] Shahbakhti. M, Dynamic Modeling of MPFI for Air Fuel Ratio Control During Cold Start and Warmup Conditions & Investigation Of Effective Factors on Air Fuel Ratio Mixture Preparation, Pollutants Formation Mechanisms and Emission Reduction Methods in Cold Start and Warmup Conditions, M.Sc Thesis of mechanical engineering of K.N.T. University of Technology, 2002 [2] Veshagh, A. and Chen, C. A Computer Model for Thermofluid Analysis of Engine WarmUp Process SAE paper [3] Shayler, P. J. and Christian, S. J. A Model for the Investigation of Temperature, Heat Flow and Friction Characteristics During Engine WarmUp SAE paper [4]Kaplan, A. and Heywood, J. B. Modeling the Spark Ignition Engine WarmUp Process to Predict Component Temperatures and Hydrocarbon Emissions SAE paper [5] Incropra, F. and Dewitt, D., Fundamentals of Heat and Mass Transfer, John Wiley and Sons [6] Heywood, J.B., Internal Combustion Engine Fundamentals, Mc Graw Hill. [7] Li, C.H. Piston Thermal Deformation and Friction Consideration, SAE paper [8] Sitkey, G. Heat Transfer and Thermal Loading in Internal Combustion Engine, Academic Kiado, Budapest, pp 7794, 1974 [9] Caton, J.A. and Heywood, J.B. An Experimental and Analytical Study of Heat Transfer in an Engine Exhaust Port, International Journal of Heat Mass Transfer, Vol. 24, pp , Great Britain, / / / 
14 A.Ghasemian / S. A. Jazayeri Reducing of Transient Warmup Period in an Internal Combustion Engine by Preheating of Engine Parts A.Ghasemian* S. A. Jazayeri MSc. Student Mechanical Engineering K. N. Toosi University *Corresponding Authors Received: Sep. 27, 2009 Accepted in Revised Form: Dec. 22, 2010 Abstract The transient period that lasts from engine starting to achieve engine coolant to its performance temperature is called warmup. This study tries to decrease the time of warmup period in a spark ignition engine. To achieving to this goal, at first the coolant thermal operation should be analyzed. For that, engine divided to seven major parts. These components are piston, cylinder block, cylinder head, engine oil, cylinder block coolant, cylinder head coolant and radiator coolant. Because warmup period is a transient period, one of the transient heat transfer analyze methods should be applied. The method that is used in this study is lumped thermal capacitance method. Using heat transfer rules including conduction and convection and ignoring radiation, the thermal equations of mentioned parts are calculated. These equations are nonlinear differential equations that can be arranged in form of a set of differential equations. Because of some complicated nonlinear terms in the differential equations, they can not be solved with analytical methods and so MATLAB software is applied to solve the differential equations set. After solving the differential equations set and finding the temperature changes of major parts, these answers should be validated. To verifying the accuracy of theoretical answers, the answers are compared whit experimental result of engine test that is carried out in IPCO (Irankhodro Powertrain Company). After assuring of the correction and accuracy of theoretical method, some solutions are introduced to reduce the warmup period. The criterion of warmup period is the thermal operation of engine coolant. So, after applying these solutions, the temperature changes of coolant during warmup period is calculated for each method and at the end, the advantages and deficiencies of each solution are discussed. Keywords: Warmup, Lumped Thermal Capacitance, Coolant The Journal of Engine Research/Vol. 17 / Winter 2009