Kamsensor og effekttap, E39

[RaymondJ]

Leste i en annen tråd her at en nevnte at defekt kamsensor kan medføre effekttap? Trodde en defekt kamsesnor medførte at motoren ikke startet. Noen som vet hva kamsensoren brukes til i motorstyringen? Hvis info fra den brukes til å justere Vanos skjønner jeg jo at den kan gi effekttap, men trodde egentlig Vanos kun justerte seg etter turtall.

[Otis]

Egentlig har du helt rett, veiv/kam sensor skal kun benyttes under oppstart. Det står mye om dette i WDS.

http://spaghetticoder.org/bmw/wds/

Så jeg skjønner det egentlig ikke jeg heller. Men folk opplever uansett effekttap...

[RaymondJ]

Jeg glemmer at spagetticoder inneholder mer enn skjemaer! Takk for påminnelsen! Fant dette, her står det jo egentlig i klartekst at kamsensoren brukes nettopp til justering av kam med Vanos:

Use of the camshaft sensor

It is necessary for the fully sequential injection system (fuel injection takes place individually for each cylinder at the specific firing point).

The variable camshaft control requires feedback of the current position of the camshaft for adjustment purposes.

Og om Vanos, den slår ikke bare inn/ut på et gitt turtall, men justeres trinnløst i forhold til en masse parameter:

The required position of the intake and exhaust camshafts is calculated from the engine speed and load signal depending on the intake air and engine temperature and the VANOS

[Otis]

Aha, ja da har jeg tydeligvis blandet info fra diesel motorene... Ikke bra.

[RaymondJ]

Og både kam og veivsensor brukes nok hele tiden, ikke bare under oppstart. Fant noe interresant her forresten! Hvis veivsensoren ryker, bruker den kamsensoren som "Engine speed sensor"! Men mulig motoren da gåri nødmodus, med redusert effekt?

Steps taken by engine control unit in the event of a fault in the crankshaft position/rpm sensor.

If the crankshaft position/rpm sensor is faulty, a corresponding fault code "crankshaft position/rpm sensor" is stored in the fault code memory of the engine control unit. The camshaft sensor signal is then used as the engine speed signal (emergency operation).

Possible effect: Misfiring is possible and start characteristics deteriorate.

[RaymondJ]

Tviler egentlig på at veivsensor kun brukes under oppstart på en dieselmotor heller, men det kan jo hende den GÅR, men ikke optimalt. Sakset fra Veivsensor på dieselmotor:

The inductive rpm sensor is installed on the engine block near the flywheel. Four pins are mounted on the flywheel which move past the rpm sensor at defined distance. The DDE control unit evaluates the resulting voltage signals for the purpose of calculating the engine speed.

The rpm sensor signal is used as a measurement variable for:

* Exhaust gas recirculation

* Checking start conditions

* Calculating start volume

* Start of injection control

* Checking switch-on conditions for air conditioning system

* Calculating limitation volume

* Calculating external delivery rate intervention

* Boost pressure control

* Injection rate control

* Idle speed control

Men kamsensoren, de blir faktisk bare brukt under oppstart på Diesel:

Consequences:

* In case of failure during engine operation: No effect, however, the engine will not start during the next start attempt.

With the aid of the camshaft signal, when the engine is started, the DDE control unit determines whether there is an injection or a gas flow TDC and can thus activate the correct injector for fuel injection.

Engine start is not possible without synchronization!

[Otis]

Stemmer det.