อิทธิพลของอุณหภูมิไอดีและการใช้ไอเสียย้อนกลับต่อการจุดระเบิดของเครื่องยนต์ HCCI

Name: อาทิตย์ คำทา

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Homogeneous Charge Compression Ignition Engine

; Liquefied Petroleum Gas

; Intake Temperature

; Exhaust Gas Recirculation

; Location Ignition

; Spontaneous Ignition Temperature

Abstract: HCCI engines have some characteristics similar to both SI and CI engines, i.e. fuel and air arehomogeneously mixed before entering into combustion chamber as a SI engine, while the mixture isignited spontaneously by compression as a CI engine. However the HCCI combustion mechanism isunique. The start of combustion in a HCCI engine is occurred from various locations and flamepropagates in a very short distance, so the burn duration is extremely short. The objective of theresearch was to study factors influencing on ignition of HCCI engines. Single cylinder diesel enginewas chosen and LPG was used in the experiment. All test runs were conducted at constant speed.Parameters of interest were intake temperature, equivalence ratio, and EGR. The results show thatthe engine operational region was confined by the combination of intake temperature andequivalence ratio. The engine can operate satisfactorily at the speed of 1500 rpm when the intaketemperatures are set in the range of 115 - 180 OC and the equivalence ratio of 0.38-0.56. At speed of2000 rpm the intake temperatures have to be set at 130 - 170 OC and the equivalence ratio of0.38 - 0.56. While the intake temperature is increased, the equivalence ratio has to be decreased.Furthermore, it is found that the operating region for low speed of 1500 rpm is slightly larger thanthat for higher speed of 2000 rpm.The study of increasing intake temperature reveals that maximum pressure, rate of pressure rise andburning rate are increased with temperature. IMEP and thermal efficiency are initially increasedwith temperature until they reach the peak value at 140 OC then they are decreased with increasingtemperature. In the study the values of IMEP are relatively in the range of low to medium.The values of COV of Pmaxa nd COV of IMEP are significantly small and tend to decrease withincreasing temperature in the range of 115 - 180 Oc.The study is also discovered that increasing equivalence ratio gives rise to increase maximumpressure, rate of pressure rise, IMEP, and thermal efficiency. Burn duration is decreased withincreasing equivalence ratio while the values of COV of Pmax and COV of IMEP are small and alsodecreased with increasing equivalence ratio. For the case of using EGR, it is found that increasingamount of EGR gives adverse affect to maximum pressure, rate of pressure rise, IMEP, thermalefficiency, COV of Pmax and COV of IMEP.Considering from the three parameters, it is indicated that without EGR the ignition location isdependent upon the values of intake temperature and equivalence ratio. The ignition location of theHCCI engine occurs before top dead center and its location shifts further from the TDC when thevalues of intake temperature and equivalence ratio are increased. It is also found that therelationship among the start of combustion (SOC), equivalence ratio (4) and intake temperature (T)can be constructed in the empirical formula as follow:SOC = (61.275 0')-(68.750 4) - 0.050(T-273.000) + 21.277With EGR, the ignition location occurs more closely to TDC. When the amount of EGR is constant,increasing intake temperature shifts the ignition location further from TDC. On the contrary,increasing equivalence ratio produces small affect on ignition location. In conclusion, it is foundthat the HCCI engine gives the highest thermal efficiency of 52 percent at speed of 1500 rpm withignition location at 4 degrees BTDC when intake temperature and equivalence ratio are set at 140 OC and 0.55, respectively.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: รศ.ดร.สมชาย จันทร์ชาวนา

Role: อาจารย์ที่ปรึกษา

Created: 2545

Issued: 2005-11-08

Modified: 2006-05-24

วิทยานิพนธ์/Thesis

ISBN: 9749605829

CallNumber: MEE1408

tha

DegreeName: วิศวกรรมศาสตรมหาบัณฑิต

Level: ปริญญาโท

Descipline: วิศวกรรมเครื่องกล

Grantor: มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

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