عضویت 
ورود اعضا
راهنمای خرید
Diesel & Gas: Part 40 pages
DIESEL AND GAS
ENGINES
ENGINES
Speed measurement of Turbochargers
VR-Sensors
A strong magnet and a coil system build the core of these sensors. The target is
normally a disc which is located in the bearing section of the turbocharger. That
disc has notches or holes so that the air-gap alters at these sections when the
disc rotates with the turbo. The induced voltage is the desired output signal.
Many different sizes and housings are available to adapt the sensors to the
properties and specific mechanical needs of the application.
Introduction
Turbocharger speed mainly depends on
the exhaust and the conditions under
which the engine is running. Under
certain circumstances the speed can
reach critical values for the safety and
lifetime of the turbocharger. As the
need for higher pressure values and
hence higher nominal turbo speeds has
constantly increased over recent years
it has become more and more
important to know the instantaneous
speed of the turbo. This is valid for
nearly all sizes of turbochargers from
the very small and fast rotating
passenger car turbochargers up to the
large units used in 2-stroke ship
engines.
There are 2 main concepts of sensors
used in this application. VR-sensors
looking at a target in the bearing
section of the turbo and eddy current
sensors aimed at the compressor wheel
counting the blades.
JAQUET is the world leader in speed
sensor solutions for all turbocharger
applications ranging from passenger
cars, through truck and railway engine
sizes right up to large turbos for ships’
engines. Well over 8 million of these
sensors
are
reliably
protecting
turbochargers worldwide, day after day.
D&G SpeedPackage 4.1
The common features and properties of these sensors are:
•
•
•
•
•
Very robust and reliable construction
Can withstand high temperatures (up to 320 °C)
The amplitude of the output signal depends from the speed of the
turbo. It is not possible to measure zero-speed condition.
They actively produce an output signal without the need for a supply
voltage.
They can be delivered with mating connectors or with integral cables.
Eddy Current Sensors
The eddy current sensor aims at the compressor wheel of the turbocharger. The
sensor creates a HF-field at its front end and generates a signal from every
compressor blade that interacts with this HF-field.
The main properties of this class of sensors are:
•
•
•
•
•
www.jaquet.com
Sensor must be supplied with 10 .. 30 VDC
Sensors with integral electronic can withstand temperatures -40 ..
+125 °C
Sensor head without electronic are capable up to +180 °C (the
electronics can be placed in a separate terminal box which is located at
a cooler spot).
Sensor is capable to delivering speed information close to zero-speed.
Output signal is a clear rectangular pulse stream that can be divided to
1 pulse per revolution.
Tel.: +41 61 306 88 22
Page 1/2
"
