M271 DI carbon build up - anyone translate German?
Thread Starter
Super Member
Joined: Oct 2012
Posts: 583
Likes: 24
2026 GLC300 4Matic (X254)
M271 DI carbon build up - anyone translate German?
Do these two videos show the intake valves fully closed before direct injection and fuel ignition? If so....that's good news for the M271 CGI, right? If valve is closed, no soot can get into intake to causes carbon deposits. I don't know what the video means exactly, since I don't speak German. Anyone translate? There are two (max 2 mins long) below:
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Carbon like deposits in the inlet manifold & on the valve tulips is not created from combustion blowback during valve overlap.
It is caused by the by-products of poor fuel collecting in the inlet system from captive crankcase breathers & from burnt on VI improver from oil coming down the valve stems through the guide seals.
Pre DI vehicles allowed the detergeant in the fuel to clean this off but only where it can get. With a DI engine the fuel does not really get into the inlet manifold to clean requiring the use of better fuels. Benz tries to pulse the injector while the inlet valves are open to try & help with this. Other manufacturer like VW & Toyota have now put a LP injector in the inlet system to control deposits.
Here is a M271 pre DI run on Techron. You can see where the fuel could get & keep clean/cleanup.
It is caused by the by-products of poor fuel collecting in the inlet system from captive crankcase breathers & from burnt on VI improver from oil coming down the valve stems through the guide seals.
Pre DI vehicles allowed the detergeant in the fuel to clean this off but only where it can get. With a DI engine the fuel does not really get into the inlet manifold to clean requiring the use of better fuels. Benz tries to pulse the injector while the inlet valves are open to try & help with this. Other manufacturer like VW & Toyota have now put a LP injector in the inlet system to control deposits.
Here is a M271 pre DI run on Techron. You can see where the fuel could get & keep clean/cleanup.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Both are spark ignition direct injection. The first shows fuel injected just before the top of the compression stroke whereas the second shows injection during the intake stroke which would give greater cooling & mixing.
I don't speak German. Will try & get us some help from a colleague.
I don't speak German. Will try & get us some help from a colleague.
Trending Topics
Newbie
Joined: Nov 2014
Posts: 9
Likes: 6
W211
Translation
Here goes the translation, i will get around to doing the second video later, sorry!
First Video:
From the sucked-in air mass, the motor electronics calculate the amount of fuel to be injected, and corrects it additionally through oxygen sensor emission control.
Using this operation method, a torque increase of up to 5% can be achieved.
This is attributed to:
1. The thermodynamically favourable cooling effect of the direct vaporization of the fuel inside the burning chamber.
2. higher compression of motors with benzin direct injection in general.
For these various opertaion types, the motorol controller MED7 is faced with two central tasks:
1. The injection time instance has to be adjustable based on operating point between "late" during the compression phase, and "early" during the suction phase.
2. The setting of the sucked-in air mass has to be decoupled from the accelerator pedal position. This is to allow unthrottled motor operation in the lower load area, and throttle control in the upper load area.
By optimal use of the benzin direct injection, an average saving of 15% can be achieved using this technique in relation with the European driving cycle.
-------------
First Video:
From the sucked-in air mass, the motor electronics calculate the amount of fuel to be injected, and corrects it additionally through oxygen sensor emission control.
Using this operation method, a torque increase of up to 5% can be achieved.
This is attributed to:
1. The thermodynamically favourable cooling effect of the direct vaporization of the fuel inside the burning chamber.
2. higher compression of motors with benzin direct injection in general.
For these various opertaion types, the motorol controller MED7 is faced with two central tasks:
1. The injection time instance has to be adjustable based on operating point between "late" during the compression phase, and "early" during the suction phase.
2. The setting of the sucked-in air mass has to be decoupled from the accelerator pedal position. This is to allow unthrottled motor operation in the lower load area, and throttle control in the upper load area.
By optimal use of the benzin direct injection, an average saving of 15% can be achieved using this technique in relation with the European driving cycle.
-------------
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
