METHOD AND DEVICE FOR WARNING VEHICLE DRIVER THAT OBD NOX CONTROL TORQUE LIMITER HAS BEEN ACTIVATED IN CASE OF FAULTY MIL LAMP
Publication Date: 2010-Aug-10
The IP.com Prior Art Database
The invention relates to a method and device for warning heavy-duty vehicle driver that NOx control torque limiter is about to be activated, or has been activated, in case of faulty Malfunction Indicator Lamp (MIL).It is proposed to alter the engine speed with a special pattern that will warn vehicle driver, in case of nitrogen oxide emission out of range or when torque limitation is activated. When the heavy-duty vehicle reaches the low idle mode (and not the fast idle mode), with gearbox set to neutral or in park position, a speed pattern is applied with brief low range oscillations (from 200 rpm up to 300 rpm over low idle speed). The duration of such pattern will not last more than few seconds (less than 5 seconds). Another type of speed pattern is used to warn about torque limitation activation. Such temporary engine speed patterns, easily visible on engine speedometer and audible, will inform the driver.
Continental Automotive France S.A.S.
Idea : Frédéric PASIAN (LHERM - France)
METHOD AND DEVICE FOR WARNING VEHICLE DRIVER THAT OBD NOX CONTROL
TORQUE LIMITER HAS BEEN ACTIVATED IN CASE OF FAULTY MIL LAMP
FIELD OF APPLICATION OF THE INVENTION
The invention relates to a method and device for warning heavy-duty vehicle driver that NOx control torque limiter is about to be activated, or has been activated, in case of faulty Malfunction Indicator Lamp (MIL).
STATE OF THE ART
Nowadays, nitrogen oxide (NOx) control emissions become a major challenge and heavy-duty vehicles manufacturers, pushed by emission standards, try to reduce drastically NOx concentration in exhaust gas.
On-Board Diagnostics systems (OBD) are mandatory to monitor and diagnose the engine system. This OBD identifies malfunctions by mean of fault codes stored in Engine Control Unit (ECU) memory. OBD is able to identify types of faults and malfunction over the entire lifetime of the vehicle. In case of problem, the OBD indicates the failure (of an emission related component or system) when that failure ends up with gas emission exceeding the threshold limits given by regulation.
On heavy-duty vehicles, OBD monitors the exhaust gas after treatment system and other emission relevant functions. In addition, OBD is checking the NOx concentration. When NOx level is exceeding a set threshold (7.0 g/kWh for instance), a torque limitation procedure is started. A MIL is switched on to warn the driver as soon as the NOx emissions start to be out of range. MIL blinking is meaning that vehicle may be operated during some amount of hours before torque limitation becomes effective (50 hours for instance).
Torque limiter reduces vehicle maximum available torque by 25% to 40%, depending on vehicle weight (this figures are linked with the applicable regulation), as soon as the vehicle is stopped. Of course, in order to prevent accidents or dangerous situations, this torque limitation is not activated in all conditions. After such torque limitation is effective, the vehicle may be operated but with reduced power, un...