Emission Control Systems - 1.8L: Other Kia Spectra II

EVAP SYSTEM MONITORING: LEAKAGE DETECTION

Kia applies an improved leakage detection module (heated type) in 2001 model year of Sephia and Spectra.

Using the heated DM-TL (Diagnostic Module Tank Leakage) can completely eliminate the humidity influence. So, the leakage detection is never stopped caused by the current fluctuation (due to dew effects at extreme high humidity).

The heating element is inserted into pump hosing. Diagnosis of the heater of DM-TL is checked by circuit malfunction.

Scheme 284

The heated DM-TL (Diagnostic Module Tank Leakage) is used to monitor the evaporative system for leaks.

The diagnostic module consists of an air filter, an heating element, an electrical driven air pump, a change-over valve and a 0.02 inch orifice for reference measurement as shown in the following figure.

Scheme 285

LEAKAGE DETECTION PROCEDURE

In switched off condition the fuel tank breathes through the canister, the changeover valve and the air filter. For purging the canister, the purge control valve is opened and fresh air-flows via air filter, changeover valve and canister into the intake manifold

Scheme 286

For a reference current measurement the motor pump is switched on for a small period of time while the changeover valve and purge control valves are closed. In this mode fresh air is pumped through the 0.02 inch reference orifice and the pump motor current is measured. At some unusual operating conditions the pump current may not stabilize. In this case an optional 0.02 or 0.04 inch leak checks demand will not be performed (delay to the next monitoring event). To prevent a permanent disablement of the leak check due to a DM-TL module problem, the number of subsequent irregular current measurements are counted and a module error is set as soon as the counter exceeds a calibrated value.

In the following monitoring mode the change over valve is switched on (the purge control valve remains closed). The motor current drops to a zero load level. Fresh air is now pumped through the canister into the tank. This creates a small overpressure at a tight evaporative system which leads to a current increase.

The rough leak check (> 0.04 in) is performed by monitoring the pump motor current gradient. Therefore the current is measured after a calibrated time. If the difference in the current is above an upper limit the rough leak check has passed without a fault. If this high gradient is not detected (at lower fuel tank levels), a second gradient measurement is performed by a longer measurement.

Scheme 287

If the conditions for a small leak check (> 0.02 in) are set, the pump motor remains on (monitoring mode) until its current exceeds the reference current or until the motor current gradient is closed to zero (current stabilizes below the reference current). If the motor current exceeds the reference current, the system is monitored as tight. In case of stabilizing below, the system is assumed as untaught. In this case the stabilized current is compared against a calibrated limit to prevent the detection of a small leak fault in case of an opened fuel filler cap during the small leak check. If the motor current decreases during one of the checks, the check is aborted and above-mentioned counter is increased.

Scheme 288

BASE MONITORING CONDITIONS

1. ECM in power down mode
2. engine speed = 0 RPM
3. altitude < 2500 m1)
4. engine coolant temperature at start > 4°C
5. no error on engine coolant temperature sensor
6. ambient temperature in 4°C-35°C
7. canister load < close to full canister
8. fuel level steady and in range of 15%-85%2)
9. engine-on time > 20 min.
10. vehicle speed = 0.0 km/h
11. no error on vehicle speed sensor
12. battery voltage in range of 11.5V-14.5V
13. last engine-off time > 5hr
14. no error on power stages heated DM-TL pump and valve
15. no error on purge valve, including power stage
16. above criteria true for the second time

1. altitude adapted from engine load detection (throttle position, air mass flow and engine speed)
2. condition is only used as long as the fuel level sensor is monitored without a fault

CONDITIONS FOR SMALL LEAK CHECK (0.02 IN)

or . refueling detected (difference in volume > 5L)

or . number of rough leak tests > 14 times since last small leak test

or . 0.02 inch leak detected in previous driving cycle

or . last 0.02 inch leak check disabled by instable motor pump current and last engine off time > 5hr

MONITORING CONDITIONS

The misfire monitoring begins as soon as 650 RPM and 4 ignitions pass after engine start. It is disabled while the ECM detects a sudden change of engine speed or load. The misfire monitoring covers the full range of engine operation.

MONITORING PROCESS

A new function for pre-filtering of sensor wheel segment duration signal is introduced to Sephia in order to enlarge the misfire monitoring range. The sensor wheel segment duration is pre-filtered by this function and then the filtered value is used to calculate the engine roughness which is compared with the reference value to detect misfiring. With this function, it is possible to eliminate the influence of the crankshaft-synchronous oscillations on the detection of misfire. These oscillations can be caused by sensor wheel tolerance or crankshaft torsional vibration. The misfire monitoring of Sephia covers nearly the full range of engine operation in case of random or continuous misfire, and for symmetrical misfire.

MIL ILLUMINATION

The MIL is illuminated when a misfire is detected which can cause the damage of catalyst or exhaust emission higher than 1.5 times certification standard (I/M failure). The MIL flashes while a catalyst damaging misfire is being detected.

COMPREHENSIVE COMPONENTS MONITORING

Any input or output components that can affect emissions or any input or output component used to monitor any other monitored component/system is monitored.

The lack of circuit continuity and rationality, and out-of-range values to ensure proper operation of the input devices, are monitored for proper response to ECM commands.

Scheme 289

Scheme 290

1. Warm up engine to normal operating temperature.
2. Disconnect vacuum hose from EVAP canister purge valve side of hose.
3. Verify that no vacuum is felt at EVAP canister purge control solenoid valve.
4. If not as specified, check EVAP canister purge valve operation.
5. If valve is operating properly, reinstall vacuum hose.

Scheme 291

Scheme 292

1. Visually check for damage and replace if necessary.
2. Measure canister close valve resistance. Resistance: Approximately 26ohm at 68°F (20°C)
3. If not as specified, replace the canister close valve.