USB Autoscope

Analytics and diagnosctic equipment for automotive industry

Fuel injectors

Application:

  • single point injection;
  • multi-point injection;
  • direct injection.

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injector_2

injector_3

Typical voltage waveform on the control pin of a fuel injector. The current waveform in the circuit is also shown.

1 – voltage on the control pin;

2 – current in the injector circuit.

A – start of the electrical injector pulse;

B – start of the actual fuel injection;

C – end of the electrical injector pulse;

D – end of the actual fuel injection.

A‑C – electrical injector pulse;

B‑D – actual fuel injection duration.

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injector_5

Voltage and current waveforms in a properly functioning fuel injector circuit.

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injector_7

Voltage and current waveforms of a malfunctioning injector. The injector pintle is sticking.

1 – voltage on control pin;

2 – current in the injector circuit.

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injector_9

Voltage waveform on the control pin of a peak and hold injector circuit sometimes used on low-resistance fuel injectors used in single point injection or Throttle Body Injection. (Opel Vectra 1.6 1995).

A B – Peak phase where the pintle is forced to move;

B C – Hold phase where the pintle is held open.

injector_10

injector_11

Voltage waveform on the control pin of a peak and hold injector circuit sometimes used on low-resistance fuel injectors used in single point injection or Throttle Body Injection. (Ford Orion 1.4 1993).

A B – Peak phase where the pintle is forced to move;

B C – Hold phase where the pintle is held open.

injector_12

injector_13

Voltage waveform on the control pin of a peak and hold injector circuit sometimes used on low-resistance fuel injectors used in single point injection or Throttle Body Injection. Magneti Marelli (Peugeot 405 1.6 1994).

A B – Peak phase where the pintle is forced to move;

B C – Hold phase where the pintle is held open.

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injector_15

Voltage and current waveforms in injector  circuit of a direct fuel injection system.(VW Passat 1.8TSI 2008).

1 – current in the injector circuit;

3 – voltage on supply pin;

4 – voltage on control pin.

A B – peak phase when the pintle moves;

B C – hold phase where the pintle is held open.

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injector_17

Voltage and current waveforms in a common rail electromagnetic diesel injector circuit.

1 – current in the injector circuit;

3 – voltage on the supply pin;

4 – voltage on the control pin.

A B – peak phase when the pintle is moving;

B C – hold phase where the pintle is held open.

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injector_19

injector_20

Voltage and current waveforms in a common rail piezoelectric diesel injector circuit (VW Touareg 3.0TDI 2005).

1 – current in the injector circuit;

3 – voltage on supply pin;

4 – voltage on control pin.

A‑B – injector opening;

C‑D – injector closing.

The USB Oscilloscope program is required for waveform playback. Get the latest USB Oscilloscope program here.