Sensors for TDC Determination, Valve Timing and Needle Lift Movement

Sensors for exact determination of TDC (top dead center) and for determination of valve timing and needle lift movement.

AVL Approach

Top Dead Center (TDC) Sensor 428
AVL 426 valve lift sensor
Customer specific needle lift sensor adaptation

Benefits at a Glance

  • TDC 428 offers simple installation, is usable for dynamic operation and delivers exact results due to the used horizontal cut principle
  • AVL 426 works with the accurate inductive half-bridge principle
  • Custom tailored solutions for needle lift adaptation

Technical Data


Product family



TDC(OT) Sensor

AVL Valve Lift


Crank angle accuracy (428)

Δϕ ≤ 0.1 deg. CA 
at Δn = 0 to 3 000 rpm


Engine / charger's speed

Evaluation recommended 
at 3000 rpm


Temperature range at sensor:



Output pulses

± 10V



Probe length 260mm, 360mm




approx. 6 V / mmm at 3076A01, max. gain


All Products


Product Family




TDC(OT) Sensor 42

The capacitive TDC Sensor 428 is a precise measuring instrument for dynamic TDC determination of motored or non fired cylinders of internal combustion engines.
A specially developed electronic circuit and the related software "Horizontal-Cut-Principle"
provide the engine's accurate TDC position.

  • Precondition of all indicating investigations

TDC Sensor 428 - match ing the 365 encoder in combination with AVL indicating devices

Valve Lift

It allows measurement of the valve lift movement.

  • For measurement of the valve lift in engines with valve controlled intake and exhaust systems. It may also be applied
    to any other static or dynamic lift measurements of a similar nature.


Needle Lift

The Nozzle Needle Lift Indicating Sensor enables the customer to measure the movement of the injector nozzle needle in diesel fuel injectors. This allows a precise determination of the beginning, the end, and the duration of the injection pulse. This especially developed sensor is installed within the customer's original injector.

  • To measure the movement of the injector nozzle needle
  • The adaptation is available for small and medium size injectors used in car, or light duty engines. It is also available for large injectors in heavy duty or marine engines.

Design of custom tailored solutions


Key Features

Key features


TDC(OT) Sensor 428


  • Dynamic determination of the angular TDC position under motored or non-fired operating conditions better than ± 0.1 deg. CA
  • AVL Indicating Software IndiCom recognizes the compression TDC and calculates the TDC symmetry angle (horizontal cut principle)
  • Simple installation of the sensor via the pressure sensor bore, spark bore plug or injector bore
  • Comparison of the TDC-sensor and the cylinder pressure signals (engine thermodynamic loss angle)
  • Perfect matching AVL´s measurement chain

AVL 426
Valve lift sensor

The transducer housing is mounted to the valve cover by means of an adjustment plate. The valve lift movement is transmitted by means of a magnetic core with extension rod. The extension rod is provided with excessive length and may be cut by the user as necessary for the individual application. The extension rod is subsequently brazed to the mounting bolt provided with the transducer which can then be mounted to the valve.

Needle lift adaption

The needle lift sensor uses the eddy current principle to measure the movement of the nozzle needle. The eddy current principle is based on the extraction of energy from an oscillating circuit. The change of the impedance is calculated by, the AVL Bridge Amplifier 3010 (incl. Oscillator box 3077), looking at the change of the amplitude and phase position of the magnetic field.