Systems and methods for controlling engine idle speed based on electrical load are provided. A system includes a logic device configured to perform various operations for controlling an idle speed of an engine. The logic device is configured to determine a state of charge (SOC) of a battery, a maximum output of an alternator at a current idle speed of an engine, and a load on the alternator. The logic device is further configured to initiate an increased idle speed of the engine based on the determined SOC of the battery and based on the load being greater than the maximum output. The logic device is further configured to initiate a decreased idle speed of the engine based on the SOC being less than an SOC threshold. Associated methods are also provided.

A vehicle has an engine, a CVT and at least one ground engaging member. A method of controlling the engine includes the steps of: determining an idle speed set point based at least in part on a first speed proportional to a driven pulley speed, the idle speed set point being less than an engagement speed when the driven pulley speed is less than a predetermined driven pulley speed and being less than an actual engine speed when the driven pulley speed is greater than the predetermined driven pulley speed; and controlling the engine to operate under conditions corresponding to the idle speed set point when a desired engine speed is less than the idle speed set point. Controlling the engine to operate under conditions corresponding to the idle speed set point causes engine braking when the driven pulley speed is greater than the predetermined driven pulley speed.

A vehicle has an engine, a CVT and at least one ground engaging member. A method of controlling the engine includes the steps of: determining an idle speed set point based at least in part on a first speed proportional to a driven pulley speed, the idle speed set point being less than an engagement speed when the driven pulley speed is less than a predetermined driven pulley speed and being less than an actual engine speed when the driven pulley speed is greater than the predetermined driven pulley speed; and controlling the engine to operate under conditions corresponding to the idle speed set point when a desired engine speed is less than the idle speed set point. Controlling the engine to operate under conditions corresponding to the idle speed set point causes engine braking when the driven pulley speed is greater than the predetermined driven pulley speed.

Various systems and methods are described for controlling pre-ignition in a boosted engine in a newly manufactured vehicle. One method comprises, during a pre-delivery phase of the vehicle, operating the boosted engine in a pre-delivery calibration with a first, higher enrichment, in response to a pre-ignition event. The pre-delivery calibration is deactivated during a post-delivery phase and the boosted engine is operated with a second, lower enrichment in response to a pre-ignition event.

Various systems and methods are described for controlling pre-ignition in a boosted engine in a newly manufactured vehicle. One method comprises, during a pre-delivery phase of the vehicle, operating the boosted engine in a pre-delivery calibration with a first, higher enrichment, in response to a pre-ignition event. The pre-delivery calibration is deactivated during a post-delivery phase and the boosted engine is operated with a second, lower enrichment in response to a pre-ignition event.

An exhaust gas recirculation control device controls an exhaust gas recirculation device that includes an exhaust gas recirculation passage adapted to circulate a portion of exhaust gas of an internal combustion engine from an exhaust passage downstream of a turbine of a turbo supercharger along an exhaust flow to an intake passage upstream of a compressor of the turbo supercharger along an intake flow and downstream of an air flow meter along the intake flow, and a recirculation control valve adapted to adjust an amount of exhaust gas circulated to the intake passage. Furthermore, the exhaust gas recirculation control device includes recirculation ratio setting means adapted to set a lower target recirculation ratio for a smaller intake air amount of the internal combustion engine.

An exhaust gas recirculation control device controls an exhaust gas recirculation device that includes an exhaust gas recirculation passage adapted to circulate a portion of exhaust gas of an internal combustion engine from an exhaust passage downstream of a turbine of a turbo supercharger along an exhaust flow to an intake passage upstream of a compressor of the turbo supercharger along an intake flow and downstream of an air flow meter along the intake flow, and a recirculation control valve adapted to adjust an amount of exhaust gas circulated to the intake passage. Furthermore, the exhaust gas recirculation control device includes recirculation ratio setting means adapted to set a lower target recirculation ratio for a smaller intake air amount of the internal combustion engine.

A rotational speed control apparatus for an engine that drives an air conditioning compressor includes an electronic control unit. The electronic control unit corrects a calculated value of a load torque of a compressor in accordance with a deviation between a rotational speed of the engine and a target rotational speed, as a changeover transition period control, in a changeover transition period. The electronic control unit also sets an execution period of the changeover transition period control such that the execution period in a changeover transition period from the stopped state to the driven state of the compressor is longer than an execution period of the changeover transition period control in a changeover transition period from the driven state to the stopped state of the compressor.

A rotational speed control apparatus for an engine that drives an air conditioning compressor includes an electronic control unit. The electronic control unit corrects a calculated value of a load torque of a compressor in accordance with a deviation between a rotational speed of the engine and a target rotational speed, as a changeover transition period control, in a changeover transition period. The electronic control unit also sets an execution period of the changeover transition period control such that the execution period in a changeover transition period from the stopped state to the driven state of the compressor is longer than an execution period of the changeover transition period control in a changeover transition period from the driven state to the stopped state of the compressor.

The abnormality diagnosis system 1, 1, 1 of an ammonia detection device 46, 71 comprises: an air-fuel ratio detection device 41, 72 arranged in the exhaust passage 22 at the downstream side of the catalyst 20; an air-fuel ratio control part 51 configured to control an air-fuel ratio of exhaust gas; and an abnormality judgment part 52 configured to judge abnormality of the ammonia detection device. The air-fuel ratio control part performs rich control making the air-fuel ratio of the inflowing exhaust gas richer than a stoichiometric air-fuel ratio. The abnormality judgment part judges that the ammonia detection device is abnormal if, after start of the rich control, an output value of the ammonia detection device does not rise to a reference value before the air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio richer than a stoichiometric air-fuel ratio.