1 EP 2 100 018 B1 2  Description FIELD OF THE INVENTION [0001] The present invention relates generally to the field of vehicle engine thermal management, and more particularly,toan apparatus andmethod forrapidly cool- ing an engine in preparation for effecting idle shutdown. [0002] Manyengines, particularly those in commercial service, spend a substantial amount of time idling; i.e., running while the vehicleisstationary.Many factors con- tribute to extended periods of engine idling. Under some circumstances, the driver does not desire to shutdown the engine, even if it will be running at idle for compara- tivelylong periods. One example is a delivery truck mak- ing frequent, but relatively short stops. It is not unusual for the driver to leave the engine running during these short stops even though fuelcould be saved by stopping and restarting the engine. Typically, the driver does not want to be inconvenienced or otherwise delayed. Still others believe thatstopping and restarting an engine can use more fuel than what they perceive the engine will consume during the delivery stop. Another reason that a driver might keep the engine running at idle speed is to keepothervehicle systems energized;suchsystems can include air brakes, air conditioning systems, audio sys- tems, PTO, and the like. Still further, extended engine idling may be experienced in heavily congested areas where traffic is frequently at a standstill. [0003] Under many of these conditions, it is desirable to have a mechanism (method or device) by which the enginecan beautomatically,safelyshutdown afteridling (i.e., running without vehicle motion) for a certain period of time, to prevent wasteful and unnecessary consump- tion of fuel. [0004] Certain factors make an engine idle shutdown routine desirableinan automaticshutdown system. One of these factors is the engine temperature. If the engine is shutdown above certain temperatures,for above 200° F. (approximately 93 °C), there is potential for engine damage.A cool down periodwould be advan- tageous to allow the engine to reach a safer shutdown temperature. Properly shutting down the engine can ex- tend the life of the engine and other connected compo- nents, which is highly desirable. Another factor relates to laws orregulations prohibiting extended engine idling, such as in cities or other populated areas, or in locations where the vehicle is positionednearventilationair intake systems.An example ofthe latterisaloading dockwhere a driver might be tempted to leave his truck idling, but near air-conditioning intakes, which might undesirably take up exhaust from idling delivery vehicles. [0005] On a more general note, exhaust from idling vehicles is a pollutant and is undesirable. Reducing pol- lution,complying withlaws and regulations,and conserv- ing fuel are attributes which reflect well on the operator, vehicle manufacturer, and vehicle owner (whose name is often emblazoned on the vehicle). Also, in vehicles having hybriddrives (an internalcombustion engine cou- pledwithan electricmachine,forexample),itisdesirable to shutdown the internal combustion engine quickly for fueleconomy.Therefore,an automated engine idleshut- down mechanism is desirable as it turns the engine off after certain preconditions are met. [0006] Stoppingthe enginequicklyisalso desirablefor vehicles with exhaust aftertreatment devices with cata- lysts, e.g., catalyzed diesel particulate filters or selective catalytic reduction devices. These devices require high catalyst temperatures to be operational, the so-called "light off" temperature. Extended idling can cool the cat- alyst by flowing relatively cool idle exhaust over the cat- alyst, requiring a heating period after restarting the en- gine. The catalyst cools relatively slowly with the engine off, so quickly shutting down the engine can allow the aftertreatmentcatalysttomorequicklyreach lightofftem- perature after a restart. [0007] U.S. Pat.No. 4,088,110 to Sperline discloses a system having atimer controlthatdelays shutdown after receiving a manual signal (e.g., key turn) for a set time duration to allow the engine to cool. The patent does not disclose sensing or monitoring temperature, and may continue idle for too short a time, which may subject the engine to damage, or too long a time, which is wasteful. [0008] U.S. Pat. No. 4,656,973 to Endres discloses a system that is activated when the operator turns the ig- nition key to shut down the engine. The system senses engine temperature and will override the key shutdown if the engine temperature is above a pre-set shutdown temperature, and continue to run the engine untilthe en- gine temperature is below the pre-set temperature. [0009] U.S. Pat. No. 6,227,153 to Till discloses an ap- paratusandmethod forcooling an engine aftershutdown but prior to engine maintenance work forworkpersonnel safety. The ’153 patent discloses providing an operator with a key to activate a cool down mode in which the coolant pump and fan are active. Using ambient and en- gine coolanttemperatures, the system determines when the engine has cooled to a temperature sufficiently low to minimize injury to maintenance personnel. However, there is a large variation in the amount of time it takes for the engine to actually shut down. This is caused by the inclusion ofa "maximumengine coolanttemperature" parameter,which prevents theenginefromactuallyshut- ting down until the coolant temperature has reached a certain temperature considered to be safe for engine shutdown. Depending on engine and ambient tempera- tures, there can be as much as a 30 minute variation in overall time elapsed before actual shutdown. According to its abstract,DE 32 23 318 A1 discloses that in automatically stopping or restarting an engine on a basis of detecting an operational state of each compo- nentofa vehicle withthe enginemounted thereon,judge- ment as to whether first condition of setting the function BACKGROUND AND SUMMARY 2