A method of maintaining a temperature of an aftertreatment system of a vehicle, the method including: operating, by a controller, a retarder reducing driving force of a propeller shaft of the vehicle in response to a retarder operation request signal; operating, by the controller, a jake brake device which discharges a fuel-air mixture compressed in an explosion stroke of the engine to an exhaust pipe and decreases revolutions per minute (RPM) of the engine or an exhaust brake device which blocks a discharge of the exhaust gas of the engine to a rear end of the exhaust pipe and decreases the RPM of the engine, in order to remove the output error value; and controlling, by the controller, the engine so that an amount of exhaust gas introduced into the aftertreatment system is decreased.

A method is for route identification that is conducive for successful diagnosis of an exhaust gas treatment system of a vehicle. In the method, an ECU in the vehicle receives a value of GPS coordinates from a GPS module, and the ECU retrieves a value of day, date, and time from an ECU clock. The ECU monitors a value of engine operating conditions with reference to the received value of GPS coordinates and the retrieved value of day, date, and time. The ECU identifies a segment of GPS coordinates for successful diagnosis of an exhaust gas treatment system based on the monitored value. Upon the identification, the segment of GPS coordinates is stored in ECU memory.

Methods and systems are provided for adjusting a position of an exhaust valve that regulates engine exhaust noise. In one example, the position of the exhaust valve is adjusted according to a road grade estimate. The road grade estimate may be based on a vehicle's present position on a road or a position that is a distance away from the vehicle's present position.

A method for planning a vehicle diagnosis in a vehicle includes: estimation of an operating characteristic of the vehicle on a route to be traveled by the vehicle; and planning of the vehicle diagnosis based on a probability that the estimated operating characteristic of the vehicle will correspond to an operating characteristic suitable for the vehicle diagnosis.

Provided is an exhaust gas purifying apparatus capable of making a filter entrance temperature reach a target temperature while suppressing excessive temperature increases and release of THC even upon extension of the exhaust path or decreases in outside air temperature. The exhaust gas purifying apparatus includes an oxidation catalyst 18 and a filter 19 that are placed in an exhaust path 5 of an engine 1, a fuel injection device 13 for injecting fuel in accordance with a fuel injection pattern, and a control device 50 configured to be capable of setting the fuel injection pattern including post-injection, wherein an upper-limit value of post-injection quantity increases with decreasing outside air temperature and/or with elongating path length of the exhaust path 5.

Provided is a diesel engine capable of regenerating a DPF even during no-load and/or light-load operation. In a DPF regeneration process, opening-degree reduction control S2 for an exhaust-air throttle valve is performed after a start condition S1 of the regeneration process of the DPF in which PM is deposited is satisfied. When exhaust air reaches a temperature equal to or higher than a predetermined after-injection permissible temperature TA, after-injection control is subsequently started S5. Post-injection control is started S7 after the exhaust air reaches a temperature equal to or higher than a predetermined post-injection permissible temperature TP by combustion of after-injection fuel. The PM deposited in the DPF is incinerated by the exhaust air increased in temperature by catalytic combustion of post-injection fuel in a valve downstream-side DOC.

Methods and systems for operating an engine that includes a catalyst and a particulate filter are described. In one example, release of reductant from an injector may be determined according to a plurality of metrics so that reliability of a release indication may be improved. In addition, operation of an engine may be adjusted responsive to the release indication so that exhaust system temperatures may be maintained.

A system for controlling a sound level of a prime mover permitted to emanate from or within a vehicle includes a global positioning satellite (GPS) receiver operable for receiving a GPS signal and a sound control device. The sound control device is operable for increasing or decreasing a sound level of the prime mover in response to a control signal. A controller in communication with the GPS receiver includes a calendar and clock, and is programmed to execute a method, including receiving the GPS signal via the GPS receiver, and determining an actual location of the vehicle using the GPS signal. The controller also determines an actual date and time of day using the calendar and the clock, respectively, and transmits the control signal to the sound control device to increase or decrease the sound level using at least one of the actual location, date, and time of day.

An exhaust gas purification apparatus includes: a reduction catalyst converter that reduces and purifies nitrogen oxides in exhaust gas; a tank that stores a liquid reducing agent or precursor thereof; and an injection nozzle that injects the liquid reducing agent or precursor thereof stored in the tank on an exhaust gas upstream side of the reduction catalyst converter. Some of the exhaust gas flowing through an exhaust pipe is diverted to the tank by a bypass pipe, to cause an exchange of heat between the diverted exhaust gas and the liquid reducing agent or precursor thereof stored in the tank, thereby thawing the liquid reducing agent or precursor thereof frozen in the tank.

In a method for operating a urea dosing system in an exhaust aftertreatment system (EATS) of an engine, an ambient temperature is measured in an environment in which the EATS is disposed, one or more temperatures associated with the EATS to which there is a relationship to a temperature of area in the urea dosing system are monitored. After turning off the engine, whether urea in the urea dosing system is subject to freezing is determined based on the measured ambient temperature and the one or more monitored temperatures. A reversion operation is performed after turning off the engine with a delay until one or more events occur, the one or more events including determining that urea in the urea dosing system is subject to freezing. An engine system is also provided.