基于TC1728的高压共轨柴油机判缸研究

Cylinder Detection for High-Pressure Common Rail Diesel Engine Based on TC1728

对高压共轨柴油机判缸过程中的曲轴转角变化进行了试验研究,使用32位TC1728芯片作为发动机ECU进行判缸程序开发,通过检测曲轴和凸轮轴信号,依靠两者的装配关系判断得到当前的曲轴转角,并使用60倍倍频信号计算曲轴转过角度,使曲轴转角的计算精度达到0.1°。在正常判缸模式中,使用检测独特信号片段的判缸方法,能够使判缸周期缩减到360°以内;单凸轮轴判缸中,若先测得凸轮轴独特信号片段0、片段1或片段2,判缸周期不大于360°,若先测到片段3或片段4,判缸周期不大于720°,且只有在先检测到片段3的情况下会发生一次误喷;单曲轴判缸中,检测到曲轴缺齿信号时预赋曲轴转角值,基于此角度喷油并判断是否产生加速,若预赋值正确,则不会产生误喷,若预赋值错误,则会产生一次误喷,但在360°后找到另一曲轴缺齿信号时,曲轴转角即能被修正。

The change of crank angle during the cylinder detection of high‐pressure common rail diesel engine was researched by the experiment .The cylinder detection procedure was developed based on ECU of 32‐bit TC1728 chip and the current crank angle was acquired by detecting the crankshaft and camshaft signals and analyzing the structure of assembling .The rotation an‐gle of crankshaft was calculated according to 60 times frequency signals and therefore the accuracy of crankshaft reached 0 .1° . In normal mode of cylinder detection ,the period of cylinder detection could be less than 360° by detecting the special signal se‐quence .For the camshaft signal ,the period of cylinder detection was not more than 360° if 0 ,1 or 2 signal sequence was first detected and was not more than 720° if 3 or 4 signal sequence was first detected .Only when 3 signal sequence was first detec‐ted ,one wrong injection would happen .For the single crankshaft signal ,the pre‐defined crank angle was assigned when the missing teeth were detected .Based on the pre‐assigned value ,the fuel injection was conducted and the injection timing was judged .When the assigned value was correct ,the wrong injection would not happen .On the contrary ,the wrong injection would happen and the wrong value would be corrected when the missing teeth was second detected .