SENSORS

Delphi Flat Response Knock Sensor
The Delphi Flat Response Knock Sensor is a self-generating
piezoelectric sensor. Commonly mounted on an engine block or
cylinder head, it produces an output voltage in proportion to the
engine vibrations caused by knock. When knock is present on the
sensor signal, the engine control module (ECM) controls knock by
retarding spark timing, or diesel injection timing.

Benefits
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Self-generating piezoelectric design requires no power to
the sensor
Flat frequency response allows the same senor to be used on
different engines and the sensor responds to knock frequencies
higher than the primary frequency
Ground-isolated design with two-wire shielded harness helps
protect the sensor signal from electro-magnetic interference
(EMI)
Large mounting hole accommodates mounting bolts up to
10 mm in diameter

Typical Applications

Delphi Flat Response Knock Sensors
(Conventional and Mini Sensor configurations
shown with integrated and pigtail connectors.)

The Delphi Flat Response Knock Sensor is designed for use on
virtually any internal combustion engine, including:
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Two stroke engines
Alternative fuel engines

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Diesel engines
Flexible fuel engines

Performance Advantages
The Delphi Flat Response Knock Sensor has a flat frequency response over a range of from 1 to 18 kHz,
thus the same sensor can be used on different engines by simply adjusting the filter frequency of the signal
processing electronics to match the knock frequency of the engine. In addition, the sensor responds to
knock frequencies higher than the primary knock frequency. This allows the higher knock frequencies to be
used by a control system, either individually or combined with the primary knock frequency.

Performance Specifications
Voltage output
Linearity
Mounting hole
Operating temperature range
Environment
Electrical connectors
Package size

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Average output 27 ± 10 mV/g over 1 to 18 kHz into a 100 K Ω resistive load
Output stays within ± 15 percent of average value at the limits of 1 to 18 kHz
Accommodates mounting bolts up to 10 mm in diameter
-40° C to 150° C
Sensor and connector are sealed to withstand humidity, salt spray, automotive
fluids and general automotive environments
Various harness lengths, alternative connectors, or connector at sensor body
can be accommodated
A: Available in sizes of 29.8 mm and 25 mm
B: Available in sizes of 24.35 mm and 20 mm

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