CONTROL METHOD OF A COMMON-RAIL TYPE SYSTEM FOR DIRECT FUEL INJECTION INTO AN INTERNAL COMBUSTION ENGINE
First Claim
1. ) A control method for a direct fuel injection system (1) into an internal combustion engine (2) provided with a number of cylinders (3);
- the method comprises the stages of;
supplying pressurised fuel to a common rail (5) by means of a high-pressure pump (6);
cyclically driving a number of injectors (4) having an hydraulically actuated needle (21) and connected to the common rail (5) to inject fuel directly into the cylinders (3);
establishing a desired fuel pressure level within the common rail (5); and
regulating the actual fuel pressure level within the common rail (5) according to the desired level by regulating the fuel flow rate (mHP) from the high-pressure pump (6) during the compression or pumping stage of the high-pressure pump (6) itself;
the method is characterised in that it comprises the further stages of;
determining a threshold value (ETmin) for the injectors (4) so that no fuel is injected by each injector (4) if it is driven for a time interval shorter than the threshold value (ETmin); and
reducing the actual fuel pressure within the common rail (5) according to the desired level by driving the injectors (4) for a driving time interval (ETred) shorter than the threshold value (ETmin) when the injectors (4) themselves are not used to inject the fuel required by the combustion process.
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Abstract
A control method for a direct fuel injection system into an internal combustion engine provided with a number of cylinders; the method presents the stages of: supplying pressurised fuel to a common rail by means of a high-pressure pump; cyclically driving a number of hydraulically actuated injectors having an hydraulically actuated needle to inject fuel into the cylinders; establishing a desired fuel pressure level within the common rail; determining a threshold value for the injectors so that no fuel is injected by each injector if it is driven for a time interval shorter than the threshold value; and reducing the actual fuel pressure within the common rail by driving the injectors for a driving time interval shorter than the threshold value.
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Citations
17 Claims
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1. ) A control method for a direct fuel injection system (1) into an internal combustion engine (2) provided with a number of cylinders (3);
- the method comprises the stages of;
supplying pressurised fuel to a common rail (5) by means of a high-pressure pump (6);
cyclically driving a number of injectors (4) having an hydraulically actuated needle (21) and connected to the common rail (5) to inject fuel directly into the cylinders (3);
establishing a desired fuel pressure level within the common rail (5); and
regulating the actual fuel pressure level within the common rail (5) according to the desired level by regulating the fuel flow rate (mHP) from the high-pressure pump (6) during the compression or pumping stage of the high-pressure pump (6) itself;
the method is characterised in that it comprises the further stages of;
determining a threshold value (ETmin) for the injectors (4) so that no fuel is injected by each injector (4) if it is driven for a time interval shorter than the threshold value (ETmin); and
reducing the actual fuel pressure within the common rail (5) according to the desired level by driving the injectors (4) for a driving time interval (ETred) shorter than the threshold value (ETmin) when the injectors (4) themselves are not used to inject the fuel required by the combustion process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- the method comprises the stages of;
Specification