宝马Z4_E85燃油系统维修培训手册（英文版） .pdf

e85 fuel system course contents/background material information status: april 2002 bmw service aftersales training chapter 1-2 e85 fuel system background material bmw service aftersales training contents page chap 1introduction1 chap 2e85 fuel system1 introduction1 - new features of system1 system overview2 - e85 fuel system (eu version)2 - e85 fuel system (us version)4 components6 - fuel tank with filler pipe7 - carbon canister13 - fuel delivery unit16 - tank sensors20 system functions22 - tank venting22 country-specific version24 - diagnostic module for tank leakage (dmtl) for usa25 drive bmw service aftersales training e85 fuel system background materialchapter 1 p.1 . hgk-e85_0330.frb, 13. 05. 2002 introduction introduction this documentation contains descriptions of all the fuel-system compo- nents that belong to the vehicle. the following fuel-system components are vehicle-specific: - fuel tank with filler pipe - integrated venting system - swirl pot with fuel pump, right tank sensor and suction-jet pump - fuel lines - carbon canister - purge-air line - service cap with fuel filter and fuel-pressure regulator - left tank sensor with suction-jet pump - pressure valves for tank ventilation and venting - diagnostic module for tank leakage (dmtl) (us version) the engine-specific components are described in the relevant chapter pertaining to the engine (chapter fuel system m54). the following parts are engine-specific fuel-system components: - fuel rail - fuel injectors drive bmw service aftersales training e85 fuel system background materialchapter 2 p.1 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system e85 fuel system introduction the e85 fuel system has been developed from the e46 fuel system. - new features of system abstract:in order to comply with the increasingly stringent emissions legislation, the fuel system has the smallest number of apertures and ports as possible. for example, the fuel filter and the the pressure regulator are integrated in the fuel tank. the following components are located in the fuel tank: - fuel filter - pressure regulator - electric fuel pump - swirl pot and right tank sensor - suction-jet pump, right - suction-jet pump and tank sensor, left - service vent valve - filler vent valve - overpressure safety valve - slosh baffle drive bmw service aftersales training e85 fuel system background materialchapter 2 p.2 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system system overview - e85 fuel system (eu version) fig. 1:e85 fuel system (eu version) kt-10397 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.3 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system indexexplanationindexexplanation 1air cleaner17filler vent valve (rollover valve) 2intake pipe18overpressure safety valve 3engine19tank grounding and filler cap 4exhaust system20mushroom valve 5oxygen sensor21slosh baffle 6tank vent valve22fuel tank 7engine control unit (dme)23swirl pot and right tank sensor 8purge-air line24electric fuel pump 9carbon canister25fuel filter 10-26pressure regulator 11-27suction-jet pump and tank sensor, left 12atmosphere line with spider screen28right suction-jet pump 13vent line i29fuel feed line 14vent line ii30fuel rail 15venting system31filler pipe 16service vent valve (rollover valve) drive bmw service aftersales training e85 fuel system background materialchapter 2 p.4 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system - e85 fuel system (us version) fig. 2:e85 fuel system (us version) kt-10396 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.5 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system indexexplanationindexexplanation 1air cleaner17filler vent valve (rollover valve) 2intake pipe18overpressure safety valve 3engine19tank grounding and filler cap 4exhaust system20mushroom valve 5oxygen sensor21slosh baffle 6tank vent valve22fuel tank 7engine control unit (dme)23swirl pot and right tank sensor 8purge-air line24electric fuel pump 9carbon canister25fuel filter 10diagnostic module for tank leakage (dmtl) 26pressure regulator 11dust filter27suction-jet pump and tank sensor, left 12atmosphere line with spider screen28right suction-jet pump 13vent line i29fuel feed line 14vent line ii30fuel rail 15venting system31filler pipe 16service vent valve (rollover valve) drive bmw service aftersales training e85 fuel system background materialchapter 2 p.6 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system components the system consists of the following components: - fuel tank with filler pipe - integrated venting system - swirl pot with fuel pump, right tank sensor and suction-jet pump - fuel lines - carbon canister - purge-air line - service cap with fuel filter and fuel-pressure regulator - left tank sensor with suction-jet pump - pressure valves: filler vent valve, service vent valve, overpressure safety valve. - diagnostic module for tank leakage dmtl (us version) the diagnostic module for tank leakage (dmtl) is fitted in us vehicles. the dmtl is described in the section headed country-specific version. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.7 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system - fuel tank with filler pipe installation location abstract:the fuel tank is installed over the rear axle. fig. 3:fuel tank installed indexexplanation 1fuel tank 2service cap kt-10392 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.8 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system design abstract:the fuel tank has a capacity of 55 litres. it includes a reserve capacity of 8 litres. the fuel tank has 2 chambers (because of the installation position of the propeller shaft and exhaust system and on account of the space requirements dictated by the e85 rear end). the two chambers are connected to each other over the propeller shaft. the design of the fuel tank is illustrated in the figure below. fig. 4:fuel tank kt-10393 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.9 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system the fuel tank is held in place by 2 retaining bands. the tank is secured at the side by a fuel lug welded to the right side of the tank. all points of contact with the body are insulated with foam or rubber in order to prevent the transmission of acoustic vibrations. indexexplanationindexexplanation 1vent line6tank sensor, left 2filler pipe7suction-jet pump, left 3service vent valve8overpressure safety valve 4fuel delivery unit9fuel filter and fuel-pressure regulator 5filler vent valve10foam cushion drive bmw service aftersales training e85 fuel system background materialchapter 2 p.10 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system fuel-tank service aperture abstract:the fuel-tank service aperture is located in the tunnel area of the tank. the following components can be accessed from the outside through the service aperture (without having to go through the vehicle interior): - service cap with fuel filter and fuel-pressure regulator - swirl pot with fuel pump, right tank sensor and suction-jet pump the service cap incorporates the fuel ports for the fuel pump and the 6-pin wiring-harness connector. the fuel feed line is connected to the service cap with a quick-release coupling. the 6-pin wiring-harness connector has 2 wires for the fuel-pump power supply and 2 wires for both tank sensors. operating principle: leak-tightness abstract:fuel diffusion is extensively prevented by the following measures: - the plastic walls of the fuel tank are made up of several layers. - the number of interfaces and apertures has been reduced as far as possible. - the filler pipe is welded to the fuel tank. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.11 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system operating principle: filling the tank abstract:the following safety requirements are met when the tank is filled: grounding/earthing, discharge of static charges, prevention of fuel gases escaping and of fuel sloshing back, triggering of automatic cutout of fuel-pump nozzle, overfilling protection, venting via a venting system. grounding/earthing: the fuel tank (22) is filled via the welded filler pipe (31). the filler area is provided with a metal bayonet cap, which accommodates the filler cap or the fuel-pump nozzle. the filler pipe is simultaneously grounded/earthed by way of the bayonet-cap mounting. discharge of static charges: the filler pipe has an electroconductive inner coating in order to discharge static charges. prevention of fuel gases escaping (us version): the filler pipe is designed in such a way that no gases can flow back through the pipe to atmosphere during refuelling: the fuel flows through the filler pipe and seals of the pipe cross-section. this prevents any gases from escaping from the tank (see also the section headed country-specific version). prevention of fuel sloshing back: a slosh baffle (21) is fitted at the point where the filler pipe enters the tank. this component stops the fuel from sloshing back into the filler pipe. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.12 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system triggering of automatic cutout of fuel-pump nozzle: the air displaced in the tank and the fuel vapours generated during refuelling are discharged from the tank via the venting system (15). venting is continued until the rising fuel level lifts the float in the filler vent line (17), thereby sealing off the outlet. when the vent outlet is sealed off, a pressure cushion is created in the tank which forces the fuel back into the filler pipe. when this fuel reaches the fuel-pump nozzle, the latter cuts out automatically. when the fuel nozzle cuts out, a compensating volume of approx. 6 litres is maintained above the fuel level (see also dotted line in system overview). overfilling protection: the service vent valve (16) in the tank remains open and is equipped with an overfilling protection facility. the maximum fill level is precision-set by the filler vent valve (17). venting via venting system: the gases discharged from the tank by the venting system (15) flow through the vent lines (13 and 14) to the carbon canister (see also section headed country-specific version). drive bmw service aftersales training e85 fuel system background materialchapter 2 p.13 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system - carbon canister abstract:the carbon canister serves to remove fuel vapour from the evaporative emissions from the fuel tank. the carbon canister discharges the cleaned air to atmosphere. installation location abstract:the carbon canister is located on the underbody at rear right. fig. 5:e85 fuel system (eu version) kt-10391 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.14 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system indexexplanation 1fuel feed line 2purge-air line 3vent line 4atmosphere line with spider screen 5carbon canister drive bmw service aftersales training e85 fuel system background materialchapter 2 p.15 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system operating principle abstract:the carbon canister, which is located between the discharge opening for the vent gases and atmosphere, cleans the fuel vapour and only allows cleaned air to be discharged to atmosphere. the carbon canister is cleaned again while the vehicle is being driven: the tank vent valve is operated in cycles by the dme depending on the engine operating conditions. this valve admits the fuel vapour in the carbon canister to the intake system. a distinction is made between the following vent gases according to the polluter-pays principle: - service vent gases: service vent gases are created e.g. at high ambient temperatures by heating of the fuel. - refuelling vent gases the service vent gases follow the same route out of the tank as the refuelling vent gases and are directed via the vent line (3) to the carbon canister (5) (see also section headed country-specific version). the connection to atmosphere is located on the right under the rear bumper. its orifice is equipped with a spider screen (4) to prevent the intrusion of small animals and larger contaminants. the carbon canister is regenerated (cleaned) again while the vehicle is being driven as follows: air is drawn in through the purge-air line (2) from atmosphere in the opposite direction through the canister. the air is enriched with the fuel vapour in the carbon canister. the enriched air is directed to the combustion system via the tank vent valve and the intake system. since additional mixture enrichment is not good for the engine in every load situation, a tank vent valve is connected between the intake system and the tank. this valve is located in the engine compartment on the intake system and is activated by the dme (depending on the engine load status and lambda oxygen-sensor control). drive bmw service aftersales training e85 fuel system background materialchapter 2 p.16 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system - fuel delivery unit abstract:the fuel delivery unit ensures bubble-free fuel delivery under all operating conditions. installation location abstract:the complete fuel delivery unit is located in the fuel tank. fig. 6:fuel delivery unit indexexplanation 1swirl pot with electric fuel pump and right suction-jet pump 2tank sensor, right 3suction-jet pump, left 4tank sensor, left kt-10394 drive bmw service aftersales training e85 fuel system background materialchapter 2 p.17 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system design abstract:the fuel delivery unit consists of the following components: - swirl pot with electric fuel pump, suction-jet pump and tank sensor in right half of tank - fuel filter with pressure regulator - suction-jet pump with tank sensor in left half of tank operating principle abstract:the fuel delivery unit performs the following functions: regulation of fuel pressure (returnless fuel system) and delivery of bubble-free fuel under all operating conditions. delivery of fuel: the fuel flow is: swirl pot = fuel pump = fuel filter. the fuel is pumped into the right tank half. depending on the fill level, the fuel flows from the top or from the bottom through the outlet protection valve into the swirl pot, which contains the fuel pump. the pump is supplied with 12 v, draws in the fuel from the right tank half and pumps it into the fuel filter. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.18 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system regulation of fuel pressure: the fuel flow is: pressure regulator = left tank half = suction-jet pump in left tank half = swirl pot in right tank half: the fuel filter incorporates the pressure regulator, which limits the pressure in the fuel feed line to 3.5 bar. if the pressure rises above 3.5 bar, the pressure regulator opens a discharge port. the excess amount of fuel delivered flows through the discharge port back into the tank. the fuel feed line thereby delivers the fuel at 3.5 bar to the fuel rail. the fuel discharged by the pressure regulator no longer has to return from the fuel rail to the tank (as in previous systems). the system is therefore called a “returnless fuel system.“ the fuel discharged by the pressure regulator is routed via a line back into the left tank half where it drives a suction-jet pump. the suction-jet pump directs the fuel from the left tank half into the swirl pot in the right tank half. the volume of the left tank half is thereby fully utilised during refuelling. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.19 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system delivery of bubble-free fuel under all operating conditions: the fuel flow is: fuel in right tank half = suction-jet pump in swirl pot = swirl pot = fuel pump: the swirl pot also contains a suction-jet pump. the suction-jet pump in the swirl pot draws up fuel from the bottom of the right tank half. this ensures that there is always fuel in the swirl pot and the volume of the right chamber is fully utilised. suction-jet pumps exploit the venturi effect to draw in further fuel by means of a driving jet and continue to deliver both quantities of fuel. the swirl pot ensures that the fuel pump is always immersed in fuel so that the pump does not draw in air. bubble-free fuel delivery is very important particularly at low fill levels and under high driving-dynamics conditions: engine sputtering must be avoided even when the tank is almost completely empty. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.20 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system - tank sensors abstract:the fuel tank contains 2 tank sensors, one in each tank half. installation location abstract:the right tank sensor is situated behind the service aperture on the fuel pump. it forms a single component with the swirl pot with fuel pump and the suction-jet pump. the left tank sensor forms a single component with the left suction-jet pump. see fig. fuel delivery unit. note: the right tank sensor can be replaced as it can be accessed through the service aperture. the left tank sensor can only be replaced in conjunction with the fuel tank. (the left tank sensor is permanently mounted behind the welded installation aperture.) design abstract:the tank sensors operate with float elements, which are attached to a pivoted arm. the float elements float perma- nently on the fuel surface. the fluctuating arm angles are thereby measured. drive bmw service aftersales training e85 fuel system background materialchapter 2 p.21 . hgk-e85_0331.frb, 13. 05. 2002 e85 fuel system operating principle abstract:a specific angle of the tank-sensor joint corresponds to each tank fill level. the tank-sensor joint incorporates a system with wipers and resistor paths. i