天津大学学报
天津大學學報
천진대학학보
JOURNAL OF TIANJIN UNIVERSITY SCIENCE AND TECHNOLOGY
2013年
8期
737-742
,共6页
赵昌普%钟博%朱云尧%张军%董大陆%李小毡
趙昌普%鐘博%硃雲堯%張軍%董大陸%李小氈
조창보%종박%주운요%장군%동대륙%리소전
缸内直喷汽油机%可变气门升程%数值模拟%滚流比%湍流强度
缸內直噴汽油機%可變氣門升程%數值模擬%滾流比%湍流彊度
항내직분기유궤%가변기문승정%수치모의%곤류비%단류강도
GDI engine%variable valve lift%numerical simulation%tumble ratio%turbulence intensity
采用数值模拟方法对不同最大进气门升程(MVL)下涡轮增压缸内直喷汽油机缸内气体的流动特性进行分析,以掌握变气门升程对缸内流动的影响规律.结果表明,MVL 的减小使过进气门中心线的纵截面内的顺时针滚流增强,在120°,CA时刻,MVL为7.7,mm时截面内气体流动以逆时针滚流为主,而MVL为1.0,mm时截面内气体流动以顺时针滚流为主;低 MVL 有利于进气初期缸内滚流比的提高,而在进气后期及压缩过程中,MVL 为1.0,mm时缸内滚流比明显低于MVL为7.7,mm和4.0,mm时的缸内滚流比;随着进气门升程的减小,湍流强度第一个峰值明显升高(MVL为7.7,mm时峰值为0.54,而MVL为1.0,mm时峰值达1.03),但小MVL条件下湍流强度衰减较快,在压缩末期3种MVL下的湍流强度差别较小.
採用數值模擬方法對不同最大進氣門升程(MVL)下渦輪增壓缸內直噴汽油機缸內氣體的流動特性進行分析,以掌握變氣門升程對缸內流動的影響規律.結果錶明,MVL 的減小使過進氣門中心線的縱截麵內的順時針滾流增彊,在120°,CA時刻,MVL為7.7,mm時截麵內氣體流動以逆時針滾流為主,而MVL為1.0,mm時截麵內氣體流動以順時針滾流為主;低 MVL 有利于進氣初期缸內滾流比的提高,而在進氣後期及壓縮過程中,MVL 為1.0,mm時缸內滾流比明顯低于MVL為7.7,mm和4.0,mm時的缸內滾流比;隨著進氣門升程的減小,湍流彊度第一箇峰值明顯升高(MVL為7.7,mm時峰值為0.54,而MVL為1.0,mm時峰值達1.03),但小MVL條件下湍流彊度衰減較快,在壓縮末期3種MVL下的湍流彊度差彆較小.
채용수치모의방법대불동최대진기문승정(MVL)하와륜증압항내직분기유궤항내기체적류동특성진행분석,이장악변기문승정대항내류동적영향규률.결과표명,MVL 적감소사과진기문중심선적종절면내적순시침곤류증강,재120°,CA시각,MVL위7.7,mm시절면내기체류동이역시침곤류위주,이MVL위1.0,mm시절면내기체류동이순시침곤류위주;저 MVL 유리우진기초기항내곤류비적제고,이재진기후기급압축과정중,MVL 위1.0,mm시항내곤류비명현저우MVL위7.7,mm화4.0,mm시적항내곤류비;수착진기문승정적감소,단류강도제일개봉치명현승고(MVL위7.7,mm시봉치위0.54,이MVL위1.0,mm시봉치체1.03),단소MVL조건하단류강도쇠감교쾌,재압축말기3충MVL하적단류강도차별교소.
In order to understand the effect of variable valve lift on in-cylinder flow,numerical simulation method was used to analyze the flow characteristics of in-cylinder air under different max valve lift(MVL)in a turbocharged gasoline direct injection(GDI)engine. The results show that,with the valve lift decreasing,the clockwise tumble on the cross-section through the axis of intake valve increased,and at 120°,CA,the air flow is counter-clockwise large-scale tumble when MVL is 7.7,mm,while it is clockwise large-scale tumble when MVL is 1.0,mm;it can improve the tumble ratio at the beginning of intake process under low MVL condition,but at the end of intake process and compression process,the tumble ratio when MVL is 1.0,mm is significantly lower than that when MVL is 7.7,mm and 4.0,mm;with the MVL decreasing,the first peak of turbulence intensity significantly increased,with the peak value being 0.54 and 1.03 when MVL is 7.7,mm and 1.0,mm,respectively,while the decay rate is fast under low MVL condition,and at the end of compression the turbulence intensity is similar for three MVLs values.