Originally Written by
munro
there are basically 3 types of ecu/engine, that is, the full group,the sequential semifasato,and the sequential
self-seal.
in a nutshell:the full group=are driven all together, the injectors, for example, in a 4-cylinder at each turn regardless
from the position of the pistons are activated, all four of the injectors and the gas stop in the collectors until
opens the inlet valve, which sucks in everything.the power can be with ditributore rotating or wasted spark
that is a spark lost simply because on the two lighted candles if it uses only one and the other goes to the vacuum,
of course, the life of the candle is cut in half,to understand better the various delta, thema, etc. with ecu marelli iaw were
all full group this system brings a number of problems including high fuel consumption and high emissions, especially at cold
because of the gas that condenses in the intake manifolds as well as having a management of the engine a bit "empty"
especially at low speeds.
ignition and injection seeds multipoint= are driven two injectors for a time, then an injector injects vacuum
and even here the petrol is stopping in the intake manifold waiting to be sucked,also here you have
a certain irregularity, especially in the cold because, as in the full group the gas condenses in the manifold,also
if much less due to the fact that "uses" a conduit at a time,
higher consumption compared with the sequential injection but minor of the full group,
has the advantage of having the best hardware is simple in that it uses half of the components and with this to manage the engine
goes very well at high speed.
the power is called a wasted spark or spark lost here of course on the two lighted candles
if it only uses one and the other goes to the vacuum,naturlamete here, too, the life of the candle is cut in half,
has the advantage of using half of the components and does not require a sensor only turns to pilot ignition
and injection.
injection and ignition sequential timed= there is a need for the phase sensor in addition to the sensor, of course,
it is controlled by an injector at a time and lit a candle at a time in phase with the cylinder which stands for"shoot".
with this strategy it reduces the dead times of the injectors,also called the latency time
that is, the time that is wasted to open the injectors after that came the impulse,
and this gives the possibility to inject more fuel at high rpm with injectors smaller than a semifasato.
the other useful thing is the possibility to choose the angle of injection used to inject fuel valve open
and then it settles on the walls of the intake manifold and you could have a stratified charge
in addition to reducing consumption. for the ignition the main advantage is that you double the life of the candles,in addition
to have for example the possibility to map the cylinders individually.
with these three main strategies of operation there are three methods of control of injection/ignition is that is
the system a "hot wire" or also called "maf load" using a mass air flow sensor for "weigh" the incoming air
the motor at various rpm and thus add fuel to get a given afr and ignition advance,this
system of course, then there are sensors scattered around the engine that monitor specific parameters, and inform the ecu to
implement the necessary corrections.
then there is the speed-density-that is, a system that injects fuel and gives the ignition spark
in function of the rpm and the pressure in the intake manifold using in the ecu maps
working with the volumetric efficiency of the theoretical engine, and even here, among the many sensors it uses the lambda probe to
correct "feedback" the stoichiometric ratio,for example.
and finally we have the alpha-N, where engine management is entrusted to two fundamental parameters, i.e. the engine rpm
and the opening angle of throttle or potentiometer to the pedal provided by a tps sensor,also here then we are all
a series of sensors and maps in the ecu to make the engine what it wants.
I hope you all clear.
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