×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Limiting the max RPM during cold start

Limiting the max RPM during cold start

Limiting the max RPM during cold start

(OP)
Hi everyone,

I came across the BMW M5 engine management system. It is kinda interesting how the ECU limits the maximum engine rev during cold start to 4000rpm only.

Anyway, I am looking for the possibility in using the ECU to limit the engine rpm during -30 C cold start.

My question is, at such a low temperature, how will the ECU know that the engine will be started at such a low temperature. Is it through the coolant water temperature sensor only, or there is other mean in knowing that the engine is about to be started at such a low temperature?

AO

RE: Limiting the max RPM during cold start

It ultimately doesnt matter how cold ambient air is for the start, does it?  What i mean by this is if the engine is hot already then the coolant temp is hot and it is no longer a cold start.  Thus, the coolant sensor is all you would need.  Unless, however, the coolant sensor cant see temperatures that low.

RE: Limiting the max RPM during cold start

(OP)
Gregdach

Here is the situation, a grandma in Tempe Arizona uses 15W50 engine oil for her car. During very cold winter, she drives to Canada to visit her grandchildren. One freezing morning, she was in a hurry and was on full throttle to climb a steep hill right after she started the engine.

The question is, does the ECU know that the at -30 centigrade the 15W50 oil viscosity is bad? Will the ECU be able to stop bearing and piston seizure or excessive wear to the moving component from happening?

I would agree with you that the ambient air doesnt matter much if the cold temperature does not affect the coolant and oil. Unfortunately, the tests that we conducted in the cold chamber revealed that the ambient air really affected the coolant and oil. As a result, the moving components of the engine got really affected.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources