Method for controlling a dc-dc voltage converter
AssigneeVitesco Technologies GmbH
InventorsJean CANNAVO, Thierry BAVOIS
Life of this patent
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Abstract
Disclosed is a method for controlling a DC-DC voltage converter for current-driving at least one fuel injector of a motor vehicle internal combustion engine. The method notably includes the steps of determining a time referred to as the “recovery” time at which the output voltage crosses the predefined high voltage threshold, of determining a time referred to as the “drop” time, corresponding to the start of injection, at which the output voltage decreases below the predefined high voltage threshold, and of calculating the time elapsed between the recovery time and the drop time.
Claims20
A method for controlling a DC-DC voltage converter (1) for current-driving at least one fuel injector (2) of a motor vehicle internal combustion engine, said converter (1) comprising a control module (10) and an induction coil (20) that is connected to a field-effect transistor (30) comprising a drain (D), a source (S) and a gate (G), said gate (G) being connected to the control module (10) in order for said control module (10) to command the transistor (30) to an on state in which current passes between the drain (D) and the source (S) or to an off state in which current does not pass between the drain (D) and the source (S), the alternation of the on and off states of the transistor (30) generating a sawtooth current called the peak current (Ipeak), the amplitude of which varies between 0 and a variable maximum amplitude value that is bounded by a minimum threshold (Ipeak_min) and a maximum threshold (Ipeak_max) and that allows the converter (1) to deliver an output voltage (Vout) across the terminals of a capacitor referred to as the “intermediate” capacitor (Cint), the discharging of which is commanded by a computer via a drive module in order to command at least one fuel injector (2), the converter (1) being configured to make said output voltage (Vout) tend toward a target value, the method comprising:
- a step (S1) of determining a time referred to as the “recovery” time (T1) at which the output voltage (Vout) crosses a predefined high voltage threshold (VTH_high),
- a step (S2) of determining a time referred to as the “drop” time (T2), corresponding to the start of injection, at which the output voltage (Vout) decreases below the predefined high voltage threshold (VTH_high),
- a step (S3) of calculating the time (ΔT) elapsed between the recovery time (T1) and the drop time (T2),
- if the calculated time (ΔT) is above a predefined time threshold, referred to as the “target” time threshold (ΔT0), and if the value of the maximum amplitude of the peak current (Ipeak) is above the minimum threshold (Ipeak_min), a step (S4) of decreasing the value of the maximum amplitude of the peak current (Ipeak),
- if the calculated time (ΔT) is below said target time threshold (ΔT0) and if the value of the maximum amplitude of the peak current (Ipeak) is below the maximum threshold (Ipeak_max), a step (S5) of increasing the value of the maximum amplitude of the peak current (Ipeak).
A DC-DC voltage converter (1) for current-driving at least one fuel injector (2) of a motor vehicle internal combustion engine, said converter (1) comprising a control module (10) and an induction coil (20) that is connected to a field-effect transistor (30) comprising a drain (D), a source (S) and a gate (G), said gate (G) being connected to the control module (10) in order for said control module (10) to command the transistor (30) to an on state in which current passes between the drain (D) and the source (S) or to an off state in which current does not pass between the drain (D) and the source (S), the alternation of the on and off states of the transistor (30) generating a sawtooth current called the peak current (Ipeak), the amplitude of which varies between 0 and a variable maximum amplitude value that is bounded by a minimum threshold (Ipeak_min) and a maximum threshold (Ipeak_max) and that allows the converter (1) to deliver an output voltage (Vout) across the terminals of a capacitor referred to as the “intermediate” capacitor (Cint), the discharging of which is commanded by a computer via a drive module in order to command at least one fuel injector (2), the converter (1) being configured to make said output voltage (Vout) tend toward a target value, the converter (1) being configured to:
- determine a time referred to as the “recovery” time (T1) at which the output voltage (Vout) crosses the predefined high voltage threshold (VTH_high),
- determine a time referred to as the “drop” time (T2), corresponding to the start of injection, at which the output voltage (Vout) decreases below the predefined high voltage threshold (VTH_high),
- calculate the time (ΔT) elapsed between the recovery time (T1) and the drop time (T2),
- if the calculated time (ΔT) is above a predefined time threshold, referred to as the “target” time threshold (ΔT0), and if the value of the maximum amplitude of the peak current (Ipeak) is above the minimum threshold (Ipeak_min), decrease the value of the maximum amplitude of the peak current (Ipeak),
- if the calculated time (ΔT) is below said target time threshold (ΔT0) and if the value of the maximum amplitude of the peak current (Ipeak) is below the maximum threshold (Ipeak_max), increase the value of the maximum amplitude of the peak current (Ipeak).
Dependencies are inferred from the claim text.