Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1991-10-02
1992-09-29
Wolfe, Willis R.
Internal-combustion engines
Charge forming device
Fuel injection system
361154, F02D 4120
Patent
active
051506874
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a supply circuit for operation of an electromagnetic load of a vehicle provided with a generator (dynamo) and battery, and more particularly, for operation of at least one solenoid valve of a fuel-injection system of an internal-combustion engine of the vehicle.
BACKGROUND OF THE INVENTION
When an electromagnetic load is switched on, the load current does not increase suddenly; rather, it rises relatively slowly. As a result, the load comes up to its rating only with a certain time delay after the turn-on time. This peculiarity is a drawback in many technical devices.
In the case of electromagnetic injection valves of an internal-combustion engine of a vehicle, this turn-on time delay is responsible for the fact that the fuel injection time cannot be determined with sufficient accuracy. To overcome this drawback, it is known to generate the control pulse for the solenoid valve in such a way that a relatively high current surge (pull-in current) is present which leads to very rapid actuation of the solenoid valve, and which is followed by a lower, steady-state current value (hold current) for maintaining the solenoid valve in its operated position. Electronic circuits of great complexity are required for the generation of such control pulses. (German published patent application 28 28 678.)
SUMMARY OF THE INVENTION
The supply circuit of the present invention offers the advantage of providing, through relatively simple means for building up the excitation of the electromagnetic load, in other words, for the pull-in phase of the solenoid valve, a sufficiently large current for the solenoid valve to be actuated reliably and within a minimum of time. Once this state has been attained, a changeover to a considerably lower energy input occurs, that is, the load current is reduced to the hold current of the solenoid valve. For the implementation of the operation just described, the invention utilizes means already in place in the vehicle. These are the generator (dynamo) and the battery.
Since the generator charges the battery while the internal-combustion engine is in operation, its terminal voltage is made larger than that of the battery. The invention takes advantage of this by providing a circuit arrangement which connects the load (i.e., the solenoid valve) for a buildup of its excitation, in other words, for the pull-in phase, to the generator, so that it is supplied with a relatively high voltage resulting in rapid excitation. If in the exemplary embodiment here considered the solenoid valve is the load, then it is actuated within a very short time. Once this state has been attained, that is, when the load is in its desired state of excitation, the circuit arrangement effects, in accordance with the invention, such a changeover that a connection to the battery is established to maintain sufficient excitation and the connection to the generator is interrupted. The excitation is preferably reduced to a value which, though relatively low, is sufficient to maintain the valve in its operated position. The pull-in current flowing initially can consequently be reduced to the hold current.
As a further feature, the invention provides for a voltage booster to be located between generator and load. This makes it possible to send in a relatively short time a very large current through the excitation coil of the solenoid valve. With an inductance of 170 millihenrys, for example, the pull-in current pulse is preferably of the order of magnitude of 70 amperes. A voltage of the order of about 100 volts is thus required. The voltage booster consequently must raise the vehicle electrical system voltage, which usually is between 12 and 14 volts, to that voltage level.
In a preferred embodiment of the invention, the voltage booster is designed as a transformer. The generator is preferably an alternating-current generator; a three-phase generator, in particular, may be used.
A rectifier may be connected between generator and load. This rectifier may be located in p
REFERENCES:
patent: 4417201 (1983-11-01), Reddy
patent: 4774624 (1988-09-01), Quanlich
patent: 4884160 (1989-11-01), Pasquarella
patent: 4925156 (1990-05-01), Stoll et al.
patent: 4949215 (1990-08-01), Studtmann et al.
patent: 4950974 (1990-08-01), Pagano
Paganon Henri
Pichon Guy
Robert & Bosch GmbH
Wolfe Willis R.
LandOfFree
Supply circuit for operation of an electromagnetic load does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Supply circuit for operation of an electromagnetic load, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Supply circuit for operation of an electromagnetic load will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1962920