Mercedes EQ All Electric Forum banner
1 - 4 of 4 Posts

· Registered
Joined
·
139 Posts
Discussion Starter · #1 ·
The story of my car’s grille shutter actuator failure – and replacement – is covered in the recent thread entitled EQA intermittent mechanical rattle.

Prior to that experience, I wasn’t aware that the EQA was fitted with movable shutters. However, given the vehicle’s sophistication, it’s not surprising – after all, our family’s late 1950s Škoda 440 was fitted with a mechanically-operated grille blind and my 1987 Citroën 2CV had a removable plastic grille blanking panel, both of which served a similar purpose.

In the case of the Škoda and the Citroën, those devices were intended to help the vehicle operate in climates far colder than where I live. Does the EQA’s grille shutter serve a similar purpose?

I think the answer is, to some extent, “yes” (i.e. when the battery cooling system becomes heated beyond the optimum temperature range) – and “no”: to assist the battery warm-up when the coolant and battery is below the optimum range. dBC also commented (in the EQA intermittent mechanical rattle thread) that the shutters probably contribute to the car’s aerodynamics. Maybe there are other factors, but it’s apparent that various parameters determine whether the shutters are open or closed. A further question: are they either fully open of fully closed – or is the system so sophisticated that it also controls the amount of opening?

No doubt there’s a technical bulletin which provides the definitive answer to these questions, but in the absence of such information, I thought I’d attempt to investigate the operation of my car’s shutters by temporarily – and non-destructively! (i.e. no holes drilled or other irreversible changes made) – installing some observation equipment.

I mentioned in the EQA intermittent mechanical rattle thread that I planned to fit a reversing camera in the shutter area to observe its operation. Accordingly, I ordered the camera kit and a 4-channel remote relay online.

In the meantime, I fitted a simple ‘idiot’ light to monitor shutter opening and closing. A small LED was attached to the driver’s windscreen wiper arm – almost in line of sight with the HUD – which is activated by a micro switch mounted adjacent to the shutter actuator. The frame of the shutter actuating mechanism moves up or down according to whether the shutters are closed or open. I have adjusted the micro switch so that its (long!) actuating lever is depressed when the shutters are open (LED off).

The camera kit has now arrived, and I’ve fitted the camera – and a bank of 3 LEDs (to illuminate the area when the shutters are closed) – between the shutters and the radiator so that I can observe them opening and closing. All of my observation equipment is powered from the 12 volt car battery via a fused circuit controlled by the 4-channel remote relay device. The camera monitor – which is located on top of the dashboard above the MBUX display – is powered by the cigarette lighter.

I have made some initial observations, but I will report more comprehensively once I’ve gathered more information. At this stage, it appears that the shutters are either open or closed (no part-opening) and typically they are open when the car is stationary in the garage overnight and closed during normal running. But I’ve already learnt that it’s not that simple – and I also acknowledge that my further experience will be limited by the operational circumstances of my car.

More in due course.
 

· Registered
EQA 300
Joined
·
107 Posts
The story of my car’s grille shutter actuator failure – and replacement – is covered in the recent thread entitled EQA intermittent mechanical rattle.

Prior to that experience, I wasn’t aware that the EQA was fitted with movable shutters. However, given the vehicle’s sophistication, it’s not surprising – after all, our family’s late 1950s Škoda 440 was fitted with a mechanically-operated grille blind and my 1987 Citroën 2CV had a removable plastic grille blanking panel, both of which served a similar purpose.

In the case of the Škoda and the Citroën, those devices were intended to help the vehicle operate in climates far colder than where I live. Does the EQA’s grille shutter serve a similar purpose?

I think the answer is, to some extent, “yes” (i.e. when the battery cooling system becomes heated beyond the optimum temperature range) – and “no”: to assist the battery warm-up when the coolant and battery is below the optimum range. dBC also commented (in the EQA intermittent mechanical rattle thread) that the shutters probably contribute to the car’s aerodynamics. Maybe there are other factors, but it’s apparent that various parameters determine whether the shutters are open or closed. A further question: are they either fully open of fully closed – or is the system so sophisticated that it also controls the amount of opening?

No doubt there’s a technical bulletin which provides the definitive answer to these questions, but in the absence of such information, I thought I’d attempt to investigate the operation of my car’s shutters by temporarily – and non-destructively! (i.e. no holes drilled or other irreversible changes made) – installing some observation equipment.

I mentioned in the EQA intermittent mechanical rattle thread that I planned to fit a reversing camera in the shutter area to observe its operation. Accordingly, I ordered the camera kit and a 4-channel remote relay online.

In the meantime, I fitted a simple ‘idiot’ light to monitor shutter opening and closing. A small LED was attached to the driver’s windscreen wiper arm – almost in line of sight with the HUD – which is activated by a micro switch mounted adjacent to the shutter actuator. The frame of the shutter actuating mechanism moves up or down according to whether the shutters are closed or open. I have adjusted the micro switch so that its (long!) actuating lever is depressed when the shutters are open (LED off).

The camera kit has now arrived, and I’ve fitted the camera – and a bank of 3 LEDs (to illuminate the area when the shutters are closed) – between the shutters and the radiator so that I can observe them opening and closing. All of my observation equipment is powered from the 12 volt car battery via a fused circuit controlled by the 4-channel remote relay device. The camera monitor – which is located on top of the dashboard above the MBUX display – is powered by the cigarette lighter.

I have made some initial observations, but I will report more comprehensively once I’ve gathered more information. At this stage, it appears that the shutters are either open or closed (no part-opening) and typically they are open when the car is stationary in the garage overnight and closed during normal running. But I’ve already learnt that it’s not that simple – and I also acknowledge that my further experience will be limited by the operational circumstances of my car.

More in due course.
Looking forward to hearing the results of your experiments, it’ll be interesting to know if the shutter operation is speed related or temperature controlled.
 

· Registered
Joined
·
139 Posts
Discussion Starter · #4 ·
I am monitoring front shutter opening and closing in relation to various activities in my EQA250, including various types of journey in different temperatures (to the extent available with our current weather; it's early summer here) and with the vehicle stationary, either being charged - or not - with my 3-phase charger. As I'm retired and the car spends a reasonable amount of time idle in our garage, I employ a low rate of charge: 6A.

I thought it might be helpful to this project overall to provide a photo of the equipment I've installed under my car's bonnet (see below).

The equipment includes:
  • a wireless 12 volt relay which is powered via a 7.5A fuse from the vehicle's 12 volt battery;
  • the relay, in turn, powers the following:
    • the micro-switch-activated LED circuit which directly monitors the shutters: LED on - shutters closed; LED off - shutters open.
      • the LED is mounted on the driver's side wiper arm, facing the driver.​
    • a 4-channel remote relay, which at this stage only powers the wireless (reversing) camera - and an LED (to illuminate the area) - mounted in the shutter area of the car.
      • the camera monitor rests on top of the dashboard above the MBUX display and the monitor is powered by a switchable 12v adapter installed in the car's standard cigarette lighter socket.
  • a bluetooth 4-sensor BBQ temperature monitor, which can be monitored via an app on my mobile phone. The 4 sensors are labelled in the photo below and that image reflects the current temperature at sensor No. 4 (21 degC); that the monitor's battery is being charged and that there's bluetooth connection. No. 1 sensor monitors the ambient temperature under the bonnet and sensors 2-4 monitor the temperatures of hoses I've identified as follows:
    • 2 and 3 were the hoses on which I recorded the highest temperature with my infra-red temperature sensor at the end of a 55 km journey.
    • hose No. 4, I believe, is the supply hose to the cabin heater.
Motor vehicle Automotive design Automotive exterior Automotive fuel system Automotive air manifold


Please let me know if anyone has any queries about this setup - which is temporary - or if you have any further suggestions.

As I say, I will report some findings in the not too distant future.
 
1 - 4 of 4 Posts
Top