| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an abnormality diagnosis apparatus for a high pressure fuel system of a cylinder injection type internal combustion engine, capable of accurately diagnosing the abnormality of a spill valve, when the abnormality occurs on the spill valve of a high pressure fuel pump. <P>SOLUTION: The abnormality diagnosis apparatus for a high pressure fuel system of a cylinder injection type internal combustion engine comprises an accumulator 12, a high pressure fuel pump 18, the spill valve 33, injectors 15, a fuel pressure sensor 19, and a fuel pressure control means 30. A control period for the high pressure fuel pump 18 covers a fuel intake period and a fuel discharge period. The fuel discharge period covers a spill valve closing period and a spill valve opening period. The fuel pressure control means 30 includes a spill valve control period setting means for adjusting the spill valve closing/opening periods, a determination period detecting means for detecting the spill valve opening period during the fuel discharge period in the engine operation as a determination period, a pressure change arithmetic means for calculating change of the fuel pressure on the basis of the determination period, and a diagnosing means for determining that the spill valve 33 is under an abnormal condition on the basis of the change of the fuel pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
