Evaporative Emission System Schematic
Scheme of the system for monitoring and reducing the toxicity of exhaust gases and trapping fuel vapors of a 1.6-liter engine with an on-board diagnostics system
1 - control relay; 2 - ECM amplifier; 3 - ignition lock; 4 - ignition coil; 5 - spark plug; 6 - camshaft position sensor; 7 - crankcase ventilation valve; 8 – flow meter and air temperature sensor; 9 - acceleration sensor; 10 - ECM; 11 - air filter; 12 - valve of the idle speed control system; 13 - throttle position sensor; 14 - valve for cleaning the canister with activated carbon; 15 - canister with activated carbon; 16 – fuel tank; 17 - silencer; 18 - crankshaft angle sensor; 19 - knock sensor; 20 - coolant temperature sensor; 21 - oxygen sensor; 22 - catalytic converter; 23 - oxygen sensor
Scheme of the system for monitoring and reducing the toxicity of exhaust gases and trapping fuel vapors of engines 1.6 / 1.8 / 2.0 l (leaded fuel)
1 - control relay; 2 - ECM amplifier; 3 - ignition lock; 4 - ignition coil; 5 - spark plug; 6 - camshaft position sensor; 7 - crankcase ventilation valve; 8 – flow meter and air temperature sensor; 9 - ECM; 10 – the valve of a control system of frequency of rotation of idling; 11 - air filter; 12 - throttle position sensor; 13 - valve for cleaning the canister with activated carbon; 14 - canister with activated carbon; 15 – fuel tank; 16 - silencer; 17 - crankshaft angle sensor; 18 - knock sensor; 19 - coolant temperature sensor
The Evaporative Emission System prevents fuel vapors from escaping into the atmosphere from the fuel tank, thereby preventing the formation of photochemical smog.
Fuel vapors are accumulated in the activated carbon canister. When the engine is running, the electronic control unit opens the valve, and fuel vapors enter the engine, where they are burned.
The control valve is used to control the fuel vapor pressure in the fuel tank.
Examination
1. Disconnect the vacuum hose from the throttle assembly and connect a vacuum pump with a vacuum hose instead.
2. Check the following parameters on a cold engine when the coolant temperature is less than 60°C and on a hot engine when the coolant temperature is more than 80°C.
Cold engine
Operating mode of the engine | Underpressure | Result |
Idling | 50 kPa | Vacuum maintained |
3000 min-1 |
Hot engine
Operating mode of the engine | Underpressure | Result |
Idling | 50 kPa | Vacuum maintained |
Within 3 min after increasing the speed to 3000min–1 | Attempt to change vacuum | No vacuum |
3 min after increasing the speed to 3000 min–1 | 50 kPa | The vacuum is maintained for a short time, after which it is absent |