Electronic Oil Checking

Electronic Oil Checking

Electronic oil checking
In a running production change, the engines receive an oil level sensor instead of the oil condition sensor.
The electronic oil level check in the 2nd generation is implemented with this oil level sensor. Additionally, a new, simplified display and operating concept will be introduced.

NOTE: The M GmbH vehicles retain the oil condition sensor. However, the new display and operating concept will also be introduced here.

Brief component description
This section describes the following components related to the electronic engine oil level check:

Oil-level sensor
The oil level sensor is attached to the oil sump and is accessible from below. There is no longer an oil dipstick on vehicles with an oil level sensor. These engines have an electronic oil level check. The concept for the display is also new (see Owner's Handbook).
The oil level sensor consists of the evaluation electronics and a measuring tube. There is engine oil in the measuring tube.
dependent on the motorization: In addition, a signal for the engine oil temperature is supplied.







The evaluation electronics transmit ultrasonic pulses. These ultrasonic pulses are reflected at the transition point from oil to air (echo impulse). The evaluation electronics receive and amplify these echo impulses. The amplified echo pulses are then converted into a digital signal.
The distance travelled by the sound wave determines the echo lag time. The evaluation electronics calculate the oil level on the basis of the echo lag time. Changes in the engine oil (e. g. ageing or infiltration in the engine oil) and the engine oil temperature influence the signal propagation delay. For this reason compensation is effected in the oil level sensor.
The signals are transmitted to the engine control as pulse-width-modulated signals.

System functions
This section describes the following system functions related to the electronic oil level check:

Oil level measurement
It was possible to perform the engine oil level check of the 1st generation via oil condition sensor while driving. However, this resulted in the following requirements:
- Increased effort for the adaptation of the application software (longitudinal acceleration, lateral acceleration, engine speed, oil pressure)
- Each change to the oil circuit requires new adaptations
- System response sometimes not comprehensible for the customer

The engine oil level check of the 2nd generation via oil level sensor differs to the previous version as follows:
- Qualitative measurement while driving
- Quantitative measurement during vehicle standstill

Display and operating concept
The engine oil level check with the oil level sensor is coupled with a change to the display and operating concept.

Qualitative measurement while driving
- Status display (oil level OK, oil level at or below minimum)
- Display available at all times
- Warning by means of Check Control message from oil level at minimum







Quantitative measurement during vehicle standstill
- Driver must actively request measurement
- Measurement only possible under defined marginal conditions
- Time: approx. 1 minute







Notes for Service department

General notes

NOTICE: Higher idle speed.

The idle speed is increased slightly during the detailed measurement.

We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.