Method and circuitry for controlling discharge of a solenoid valve

A discharge circuit configured to control a solenoid valve comprising an inductor and a plunger arranged to be moved by the inductor from a hold position to a rest position, whereby a nozzle of the solenoid valve is opened or closed, wherein the discharge circuit comprises:

• fast decay current path configured to discharge the inductor at a fast decay rate;
• a slow decay current path configured to discharge the inductor at a slow decay rate, wherein fast decay rate is faster than the slow decay rate;
• and
• control circuitry configured to selectively connect the inductor to the fast and slow decay current paths, wherein the discharge circuit is configured to, by means of the fast and slow decay current paths and the control circuitry, perform a method of:
• discharging the inductor at a fast decay rate during a first at least one other-time period during a first part of movement of the plunger from the hold position to the rest position, wherein the plunger is stagnant during at least a part of said first other-time period;
• discharging the inductor at a slow decay rate during a second time period following the first time period during a second part of movement of the plunger from the hold position to the rest position, wherein the fast decay rate is faster than the slow decay rate;
• monitoring a discharge current for discharging the inductor during discharging the inductor at least during discharging the inductor at the slow decay rate during the second time period;
• and
• further controlling discharging of the inductor at either the fast decay rate or the slow decay rate in a third time period based on the monitored discharge current until the plunger reaches the rest position.

A vehicle comprising a discharge circuit configured to control a solenoid valve, said solenoid valve comprising an inductor, a plunger arranged to be moved by the inductor from a hold position to a rest position, whereby a nozzle of the solenoid valve is opened or closed, wherein the discharge circuit comprises:

• fast decay current path configured to discharge the inductor at a fast decay rate;
• a slow decay current path configured to discharge the inductor at a slow decay rate, wherein fast decay rate is faster than the slow decay rate;
• and
• control circuitry configured to selectively connect the inductor to the fast and slow decay current paths,
• wherein the discharge circuit is configured to, by means of the fast and slow decay current paths and the control circuitry, perform a method of:
• discharging the inductor at a fast decay rate during a first at least one other time period during a first part of movement of the plunger from the hold position to the rest position, wherein the plunger is stagnant during at least a part of said first other time period;
• discharging the inductor at a slow decay rate during a second time period following the first time period during a second part of movement of the plunger from the hold position to the rest position, wherein the fast decay rate is faster than the slow decay rate;
• monitoring a discharge current for discharging the inductor during discharging the inductor at least during discharging the inductor at the slow decay rate during the second time period;
• and
• further controlling discharging of the inductor at either the fast decay rate or the slow decay rate in a third time period based on the monitored discharge current until the plunger reaches the rest position.