نویسندگان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The transient period that lasts from engine starting to achieve engine coolant to its performance temperature
is called warm-up. This study tries to decrease the time of warm-up 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 warm-up 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 warm-up period. The criterion of warmup
period is the thermal operation of engine coolant. So, after applying these solutions, the temperature
changes of coolant during warm-up period is calculated for each method and at the end, the advantages and
deficiencies of each solution are discussed.
کلیدواژهها [English]
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