Piston and/or Valve Carbon Deposit Cleaning in IC engine by Over-Advanced Ignition
Original Publication Date: 2002-Jun-01
Included in the Prior Art Database: 2003-Jul-23
Frédéric Galtier: AUTHOR [+1]
In actual gasoline internal combustion (IC) engine, mainly due to fuel quality or combustion chamber efficiency or running Parameters, some Carbon De- posit appears and grows on combustion chamber parts (generally on top of the piston and valve seat). This invention is dedicated to a method for removing this Carbon Deposit without external intervention.
Piston and/or Valve Carbon Depo-sit Cleaning in IC engine by Over-Advanced Ignition
Idee: Frédéric Galtier, Regensburg;
Dr. Hong Zhang, Regensburg
In actual gasoline� internal combustion� (IC) engine,mainly due to fuel quality or combustion chamberefficiency or running Parameters, some Carbon De-posit� appears� and� grows� on� combustion� chamberparts (generally on top of the piston and valve seat).
This invention is dedicated to a method for removingthis Carbon Deposit without external intervention.
This method will only use the standard properties ofcombustion (Knock or Pinging effect) and the normaldriving parameters of the engine ( Ignition Angle� � -referred� as� IGA).� This� appears as an attractivemethod for engine efficiency improvement all alongengine life time avoiding some maintenance on theengine.
Up to now, from a literature‘s analysis, there is nosimple solution only using driving parameter of theengine to solve this problem.
In actual EMS, Basic IGA is normally defined as thebest possible ignition angle taking into account theknock boundary (see drawing at end):
•� � For Gasoline IC engines, to have an optimumusage of the combustion mixture energy insidethe chamber it is necessary to ignite this mixturevia a spark discharge. The time or crank angularlocation of this spark discharge is defined by theIGA to be applied to the engine. A proper set upof the IGA� (around� 20-25°� CRK� BTDC)� willallow the optimal conversion of fuel energy.This is the first intention in the definition of theBasic IGA
•� � On the other hand, one has to think about engineprotection versus Knock occurrences. Knock is aself-inflammation of� fuel� mixture� that� appearswhen IGA is not accurately tuned, when IGA is,,too much advanced“. This phenomenon, sinceit� generates� high� pressure� waves� inside thechamber, can damage the combustion chamber(piston, valve or spark plug).Knock apparition and intensity are known to bestrongly linked to the IGA over-advance fromthe Basic one.To prevent any knock appearance and damages,some safe margin are thus normally included inthe tuning of the Basic IGA.
Depending on its intensity, Knock area can be sepa-rated in some different state. Within a knock drivingoperation, in relation to IGA increase, knock will:
1.� � � � first� appear� an� same� part� of� the combustionchamber, then
2.� � � � will grow up in its intensity to become sensitivefor the chamber� elements� (piston,� valves,� ...),then
3.� � � � audible for passenger of the car and finally
4.� � � � damageable or even
5.� � � � destructive for the engine components
Most of the actual EMS include an anti-knock func-tion that aims to remove the knock occurrence. Themost common and generalised strategy is to reducethe IGA to make any knock event to disappear.
The idea here is to use the Knock phenomenon effect(high over-pressure waves� inside� the� chamber)� toremove the Carbon Deposit inside the chamber:
•� � By controlling the knock intensity...