Internal-combustion engines – Charge forming device – With fuel pump
Reexamination Certificate
1999-11-05
2001-08-14
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
With fuel pump
C073S114220
Reexamination Certificate
active
06273069
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This is the 35 USC 371 national stage of International application PCT/SE98/00653 filed on Apr. 8, 1998, which designated the United States of America.
FIELD OF THE INVENTION
The present invention relates to a method for calibrating the injection time of a first fuel in a diesel engine, comprising the step of feeding adjustment fluid under pressure to an injection adjuster, which comprises an adjuster plunger. The invention also relates to a method for calibrating the injection time of a second fuel in a diesel engine.
BACKGROUND OF THE INVENTION
It is already known to use a feedback control system to calibrate the injection time of fuel in a diesel engine. A needle lift spreader, which comprises a transmitter for needle lift, sends signals to a control unit when the time for the injection of fuel in the diesel engine starts. A sensor, which is also coupled to the control unit, measures the angle position of the crankshaft at the same time. On the basis of the information fed into the control unit relating to the injection time and the angle position of the crankshaft at the injection time, an injection adjuster can be calibrated by means of an adjuster plunger arranged in the injection adjuster being set in a position which corresponds to an injection time which accords with the predetermined injection time.
A disadvantage of such an arrangement is that the needle lift spreader with a transmitter for needle lift is a relatively expensive component. A further disadvantage is that the diesel engine is provided with a further component if a needle lift spreader with a transmitter for needle lift is used, which gives rise to a further possible source of error on shutdown of the diesel engine.
SUMMARY OF THE INVENTION
The object of the present invention is to make available a method for calibrating the injection time of a first fuel in a diesel engine by means of recording the diesel engine properties and characteristics during the calibration.
According to the invention, this is achieved by the fact that:
the diesel engine is made to run at a constant speed,
the adjuster plunger, which is coupled to a roller-bearing ring for adjusting the injection time, is adjusted with the aid of the pressure of the adjustment fluid,
the fuel consumption of the diesel engine is measured,
the injection time, when the fuel consumption converts from varying to being constant, and/or vice versa, is recorded,
the recorded injection time is compared with a predetermined injection time, and
the injection adjuster is calibrated by regulating the pressure of the adjustment fluid so that the adjuster plunger is set in a position which corresponds to an injection time which accords with the predetermined injection time.
Another object of the present invention is to make available a method for calibrating the injection time of a second fuel in a diesel engine which has been calibrated, by means of the properties and characteristics of the diesel engine having been recorded during the calibration with a first fuel.
According to the invention, this is achieved by the fact that:
a first fuel which has been used for calibrating the diesel engine is replaced by the second fuel which has a viscosity differing from the viscosity of the first fuel,
the second fuel is fed under pressure to an injection adjuster which comprises an adjuster plunger,
the diesel engine is made to run at a constant speed,
the adjuster plunger, which is coupled to a roller-bearing ring for adjusting the injection time, is adjusted with the aid of the pressure of the second fuel,
the fuel consumption of the diesel engine is measured,
the injection time, when the fuel consumption converts from varying to being constant, and/or vice versa, is recorded,
the recorded injection time is compared with the injection time which was obtained upon calibration with the first fuel, at a speed which corresponds to the said constant speed, and
the injection adjuster is calibrated by regulating the pressure of the second fuel so that the adjuster plunger is set in a position which corresponds to an injection time which accords with the injection time which was obtained upon calibration with the first fuel.
Such calibration methods eliminate the need for an injector with a needle lift transmitter, which results in a less costly and more operationally reliable engine construction compared with the feedback control system.
REFERENCES:
patent: 4265200 (1981-05-01), Wessel et al.
patent: 0 598 602 (1994-05-01), None
patent: 2 070 686 (1981-09-01), None
AB Volvo Penta
Miller Carl S.
Young & Thompson
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