Patent ID: 8280614
Filing Date: 2012-10-02
Classification: F02D,Y02T

Abstract:
1. A fuel injection control device, comprising: a central processing unit (CPU); a driving unit configured to start to open a fuel injection valve of an engine at a valve opening start time set by the CPU and start to close the fuel injection valve at a valve closing start time set by the CPU; an analog-to-digital (A/D) converter configured to receive a fuel pressure signal to be an analog signal from a fuel pressure sensor for detecting a pressure of a fuel pumped by a fuel pump to the fuel injection valve and perform A/D conversion of the fuel pressure signal to produce an A/D conversion value; and a fuel pressure acquisition storage circuit that is a circuit operating independently from the CPU and is configured to detect a coming of an A/D conversion time to be a start time of A/D conversion set by the CPU and activate the A/D converter to perform A/D conversion of the fuel pressure signal to produce the A/D conversion value, and which is configured to store the A/D conversion value of the AID converter, wherein: the CPU is configured to perform a first process routine started in synchronization with rotation of a crankshaft of the engine and perform a second process routine started after completion of the first process routine; in the first process routine, the CPU sets the valve opening start time in the driving unit and sets the A/D conversion time in the fuel pressure acquisition storage circuit; in the second process routine, the CPU calculates the valve closing start time required for the fuel injection valve opening on coming of the valve opening start time to inject the fuel of a required injection quantity, based on the valve opening start time set in the driving unit in the first process routine, a required injection quantity associated with a state of the engine, and the A/D conversion value stored by the fuel pressure acquisition storage circuit, and sets the calculated valve closing start time in the driving unit; and the fuel pressure sensor is located in a fuel supply line extending from a common rail holding the fuel pumped by the fuel pump to the fuel injection valve and detects the pressure of the fuel supplied from the fuel supply line to the fuel injection valve.