| Manufacturer | ROTKEE (Ukraine) |
| Number of simultaneously diagnosed coils | 4 |
| Output connector | BNC |
| Supply voltage | not provided |
| Output Signal Type | analog |
| Operating temperature range | -20 to 80℃ |
| Output Signal | |
| Weight | |
| Recommended Sampling Rate | not less than 250 kHz |
| Signal Cable Length | 2.5 m |
| Housing Material | polyurethane |
Diagnosing an ignition system with the help of a Lx4 sensor and automotive oscilloscope MT Pro, connecting the sensor to the engine, oscilloscope tuning, oscillogram recording while idle running and increased load. I’ll demonstrate all of this with an example of Seat Ibiza.
Four detecting heads mean making measurements using 4 ignition coils simultaneously, which allows analyzing signals from all the engine cylinders. As ignition pulses never occur instantly, signals from all detecting heads can be summed to get one signal with a series of sequential pulses identifying the ignition system as a whole.
Signal cables have such a length so as to be compatible with in-line, opposing and V-engines.
A soft microphone cable with thick braided screen is used as a cord. BNC is used as a sensor - oscillograph connector.
Sensor case is made of polyurethane, which makes a sensitive sensor element damage-proof.
Under sensor development high emphasis has been placed on a signal cables joint as this junction is damage-prone. Each of these joints includes a circuit board with the sensor’s electronic components. The board not only supports the loads, but also fixes the cable. Such solid joints prevent cable breakdown and increase its durability.
The sensor was developed as compatible with MT Pro automotive oscilloscope as well as any other oscilloscope, analog channel.
The detecting element of an Lx4 sensor is an inductance coil. In order to detect a secondary voltage signal, the sensor’s detecting heads are to be fixed on the surface of the ignition coil, within its electromagnetic field. Generally, the upper part of the ignition coil is a flat area for the detecting head to be placed on. Double-sided foam sticky tape will do for the fixing on the coil case. Before assembling the surface of the coil and sensor is to be cleaned and dusted.
In order to get a synchronizing signal, you also need to use an Lx1 sensor, which is placed on the ignition coil of the first cylinder, near the Lx4 detecting head.
The ignition coil of the internal-combustion engine operates on the principle of a step-up transformer and has two windings and a shared core. Therefore, when current strength in the primary winding changes, it triggers emf, which results in current strength change in the secondary winding, and vice versa. If an extra inductance coil is placed in the ignition coil’s electromagnetic field, it’ll cause emf in proportion to the changes in the coil’s magnetic field. This is how a secondary voltage oscillogram is obtained.
The secondary voltage signal’s shape depends on the sensor’s location in relation to the coil’s electromagnetic field. That’s why when placing a detecting head it’s advisable to keep in mind the following. The symmetry axis of the sensor’s detecting coil is to be placed along the axis of the ignition coil’s core. The distance between the coil and the head is to be as minimum as possible. If you can’t define the ignition coil’s type by eye, you can then change the sensor’s location in relation to the ignition coil until the oscillograph receives a signal with the biggest amplitude.
The precise Lx1 synchronizing sensor’s location isn’t that crucial, as its function is restricted to detecting breakdown impulse.
