Patent ID: 9677489
Date: 2017-06-13
CPC Classifications: F02D

Claim:
1. A method for carrying out a high-pressure start of an Otto engine having direct injection, the method comprising: increasing, at a start of the Otto engine, before a release of an injection of fuel into at least one cylinder of the Otto engine, the fuel pressure in the high-pressure system to a starting pressure, which lies between an upper system pressure and a maximum pressure; wherein a fuel pressure in a high-pressure reservoir of a high pressure system is generated by a high-pressure pump, wherein the fuel pressure in the high-pressure reservoir of the high-pressure system are measured using a high-pressure sensor, wherein the fuel is injected from the high pressure reservoir via at least one fuel injector into at least one cylinder of the Otto engine, wherein the fuel pressure, an injection quantity and a conveyed fuel quantity are specified by a control unit as a function of a signal of the high pressure sensor supplied to the control unit, wherein the fuel pressure is specified as a function of an operating point of the Otto engine up to an upper system pressure, wherein the fuel pressure in the high-pressure reservoir and in the high-pressure system is limited to a maximum pressure by an opening pressure of a pressure limiting valve, wherein the starting pressure is at least about 85% of the maximum pressure, and wherein a starting pressure between the upper system pressure and the maximum pressure is provided if the temperature of the fuel or of the Otto engine or of the cooling arrangement of the Otto engine lies below a specified temperature threshold, and a starting pressure below the upper system pressure is provided if the temperature lies above the specified temperature threshold.