Hi, After I found a very good documentation about FAP system and his management I decided to make an experiment and to modify the car to work whit out FAP filter. Differential pressure sensor from FAP is the one that monitor the FAP filter state as it is explained in this doc: The differential pressure sensor constantly measures the difference in pressure between the inlet and outlet of the catalytic converter/anti-particle filter assembly. This measurement makes it possible to determine the blockage level of the filter. The sensor consists of: - an electronic circuit for amplifying the signal, - a sensitive diaphragm. The diaphragm is subjected on one side to the catalytic converter inlet pressure (upstream) and on the other side to the filter outlet pressure (downstream). The sensor provides a voltage proportional to the differential pressure measured by the diaphragm (?P = upstream pressure - downstream pressure) The particles trapped on the filter walls, together with the additive and the other residues, naturally increase the loss of the load measured at the ends of the anti-particle filter during the course of its use. The engine management node permanently checks: - the state of the filter (by means of a "filter control" function), - regeneration aid (by means of an "aid" function). PARTICLE FILTER CONTROL FUNCTION The role of the control function is to: - determine the state of the filter (blockage level), - determine, if necessary, the activation of the regeneration aid function, - check the efficiency of the artificial regeneration. The following information is used by the engine management node in this area: - distance travelled, - differential pressure value, - exhaust gas temperature downstream of the catalytic converter, - exhaust gas temperature upstream of the catalytic converter, - total quantity of additive injected, - intake air flow rate. Determining the filter blockage level The total quantity of particles, cerium oxide and various residues present in the filter cause a variation in the load loss of the actual filter (the inlet pressure is different from the outlet pressure). This figure, constantly measured by the pressure sensor, represents the filter blockage level. The engine management node map includes six different operating areas, determined starting from the calculation of the exhaust gas flow rate. The exhaust gas flow rate is basically calculated using the following parameters: - differential pressure, - exhaust gas temperature downstream of the catalytic converter, - intake air flow rate, - atmospheric pressure. Filter blockage level The following graph illustrates the six different filter operating areas.... http://i220.photobucket.com/albums/dd237/L_DM500s/pressure.jpg ? P - differential pressure c, intermediate zone l/h, exhaust gas flow rate d, partly blocked filter a, perforated filter e, blocked filter b, regenerated filter f, completely blocked filter The areas from "a" to "f" represent the different filter states calculated by the engine management node. Regeneration is designed to keep the filter within states "b" or "c" irrespective of the mileage covered or the driving style. The engine management node activates the forced regeneration in the following cases: - when the differential pressure values go from zone "c" to "d", - when the differential pressure values entre zone "e", - when the differential pressure values enter zone "c" and the driving conditions are favourable for regeneration (conditions in which regeneration will be faster). Normal operating area from "b" to "d" When moving from zone "c" towards zone "d" (more or less quickly depending on the driving conditions), the engine management node makes a request for regeneration aid to return the differential pressure values to within zone "b" or to zone "c" (depending on driving conditions). Critical operating area: "e" When regeneration is carried out in critical conditions or is interrupted, the quantity of particles stored by the filter is only partly destroyed. Under these circumstances the filter may become too clogged, the difference in pressure at the ends of the filter vary more rapidly; the engine management node detects that the filter is overloaded and signals this by switching on the diagnostic warning light in the instrument panel. In these conditions the engine management node implements a reduced fuel flow rate strategy which, as a result, restricts the speed of the vehicle. Abnormal operating areas: "a" and "f" Zones "a" and "f" represent conditions in which the differential pressure is abnormal. Zone "f" filter completely blocked: the differential pressure is constantly above 900 m/bar or above a level that varies according to the exhaust gas flow rate. In this condition the engine management node signals that the filter is overloaded by switching on the diagnostic warning light. Zone "a" filter perforated: the differential pressure is below a certain level which is dependent on the flow rate. In this condition the engine management node signals that the filter is perforated by switching on the diagnostic warning light. In these conditions the engine management node implements a reduced fuel flow rate strategy which, as a result, restricts the speed of the vehicle. Filter blockage development During the combustion of the particles, the cerium oxide does not burn, but is deposited on the walls of the filter; these deposits inevitably increase the load on the filter. The graph below illustrates the gradually clogging of the anti-particle filter due to the accumulation of cerium oxide. ? P - differential pressure c, intermediate zone l/h, exhaust gas flow rate d, partly blocked filter a, perforated filter e, blocked filter b, regenerated filter f, completely blocked filter during normal operation the differential pressure measued at the anti-particle filter develops on the basis of the quantity of cerium oxide accumulated, in other words it depends on the mileage of the vehicle. ... This difference in pressure increases very quickly in proportion to the exhaust gas flow rate. The capacity of the particle filter is calculated to ensure normal engine operation for 80,000 - 120,000 km (or 180,000 km starting from 12/2004). Correction of the blockage level depending on the quantity of cerium oxide accumulated in the particle filter. A used anti-particle filter has a different loss of capacity compared with a new filter. The graph below illustrates the affect of the presence of cerium oxide on the filter blockage level. For the same flow rate Qv1, depending on whether the filter is new or has been used for 80,000 - 120,000 km (or 180,000 km starting from 12/2004), the parameter ?p will be different. The move from the operating condition identified by point ax to the one identified by point ay is therefore no longer due to the accumulation of particles in the filter, but to the amount of cerium oxide deposited on the anti-particle filter walls. In order to differentiate between the loss in capacity due to particles and that caused by cerium oxide, the engine management node continuously adapts the blockage level maps according to the quantity of additives present in the filter.... 1) so the solution is to trick FAP computer to think that sensor report all the time the value from area b, regenerated filter. How we can do this: there are 3 wires that come to this sensor: - Vcc 5V or any other constant value - GND - V from sensor to computer. ( I have 4.64V constant value no matter of speed and temperature of engine with that warning message ) we will cut the V wire and will insert a resistor from VCC to this line that will make the voltage to be constant all the time and will make the FAP computer to think that the value correspond for a regenerated filter ( we just invented 100% ecological fuel and Eolys additive for this car ). The FAP filter will need to be replaced with a pipe or even easy will drill a big hole in blocked FAP core so exhaust gas and particle will go out easy. 2) to solve the Eolys additive low problem we can try to trick the low level sensor from additive injector or maybe to reroute the pipe from this injector in the additive tank so additive will not get low any more. Or maybe just ignore it and filled with diesel when the message come on screen. It is not possible to remove the whole FAP system because it is constant monitored by few computers and integrated in car ECM so the solution is to trick his sensors to think that all it is working OK. p.s. you can take the FAP documentation from here: http://www.phones-direct.ro/public/FAP/ Luc.
