SYSTEM FOR DETECTING FAILURE OF FUEL PRESSURE SENSOR

摘要

A system for detecting failure of a fuel pressure sensor in an internal combustion engine, including an injector (32) provided at an intake system o f the engine downstream of a throttle valve (38), a fuel supply passage (16) connected to a fuel supply source (fuel tank 12) for supplying fuel to the injector (32), pressure regu lator (28) provided in the fuel supply passage (16) and operating to maintain a differe nce between the fuel pressure (PF2A) and the manifold absolute pressure at a constant value, a fuel pressure sensor (PF2 sensor 54) for detecting the fuel pressure (PF2A) in the fuel su pply passage (16) downstream of the pressure regulator, and a manifold absolute pressure sensor (62) for detecting the manifold absolute pressure (PBA) downstream of the throttl e valve (38). In the system, an index indicative of a ratio (.DELTA.PF2A) of the fuel pres sure (PF2A) fluctuation relative to the manifold absolute pressure (PBA) fluctuation is compared to reference values (#PF2L, #PF2H) which define a range. Sensor failure is disc riminated when the index (.DELTA.PF2A) is found to have remained outside of the range for a predetermined maximum time (tmP2STK). The system enables rapid and accurate detection of fuel pressure sensor abnormality (failure).