Measuring Apparatus and Method and Apparatus for Determining a Leakage of an Injection Valve

A method for determining a leakage of an injection valve comprising an injection nozzle, a cavity, a valve needle moveable in the cavity to prevent a fluid flow out of the injection nozzle in a closing position and enable the fluid flow out of the injection nozzle in a position apart from the closing position, and a fuel inlet hydraulically coupled to the cavity and to a fluid supply unit configured to provide a testing fluid to the fuel inlet with a given supply pressure, with the injection valve being arranged relative to a measuring apparatus including a first chamber, a second chamber, a membrane separating the first chamber and the second chamber, a notch in an outer wall of the first chamber in which the injection valve is received such that the injection nozzle opens into the first chamber, and a sensor configured and arranged to capture a first measured variable representative of a strain of the membrane, the method comprising:

• during a measurement phase:
• filling the first, chamber and the second chamber of the measuring apparatus with a testing fluid,
• controlling the injection valve such that the valve needle prevents the fluid flow out of the injection nozzle,
• controlling the fluid supply unit to provide a particular test pressure to the testing fluid in the cavity,
• controlling the fluid supply unit to maintain the particular test pressure during a particular time period,
• using the sensor of the measuring apparatus to capture the first measured variable representative of the strain of the membrane, and
• determining a fluid volume of the testing fluid that may be delivered from the injection valve into the first chamber based on the first measured variable representative of the strain of the membrane.

An apparatus for determining a leakage of an injection valve comprising an injection nozzle, a cavity, a valve needle moveable in the cavity to prevent a fluid flow out of the injection nozzle in a closing position and to enable the fluid flow out of the injection nozzle in a position apart from the closing position, and a fuel inlet hydraulically coupled to the cavity and to a fluid supply unit configured to provide a testing fluid to the fuel inlet with a given supply pressure, with the injection valve being arranged such relative to a measuring apparatus including a first chamber, a second chamber, a membrane separating the first chamber and the second chamber, a notch in an outer wall of the first chamber in which the injection valve is received such that the injection nozzle opens into the first chamber, and a sensor configured and arranged to capture a first measured variable representative of a strain of the membrane,

• wherein the first and second chambers of the measuring apparatus are filled with a testing fluid during a measurement phase, and
• wherein the apparatus is configured to, during the measurement phase:
• control the injection valve such that the valve needle prevents fluid flow out of the injection nozzle,
• control the fluid supply unit to provide a particular test pressure to the testing fluid in the cavity,
• control the fluid supply unit to maintain the particular test pressure is maintained during a particular time period,
• use the sensor of the measuring apparatus to capture the first, measured variable representative of the strain of the membrane, and
• determine a fluid volume of the testing fluid that may be delivered from the injection valve into the first chamber based on the first measured variable representative of the strain of the membrane.