Patent 7318421 was granted and assigned to Denso on January, 2008 by the United States Patent and Trademark Office.
A startup controller calculates a fuel pressure difference across a discharge stroke of a high-pressure pump at an end of an initial discharge after cranking is started. At the injection setting, the startup controller estimates a fuel pressure increment from an injection setting to an injection start based on the fuel pressure difference. The startup controller adds the fuel pressure increment to a fuel pressure sensed at the injection setting to estimate a fuel pressure at the injection start. The startup controller determines whether to perform or to prohibit the injection based on whether the estimated fuel pressure at the injection start is equal to or higher than an injection permission fuel pressure.