Methods and systems are provided for controlling a vehicle engine to deliver desired torque to a power take off device coupled to the engine. In one example, the method may include, learning a filtered PTO torque demand during vehicle acceleration, and steady state operation, and during transition in engine states using the learned PTO torque demand to adjust engine speed in order to deliver a desired engine torque output for optimal operation of the PTO device.

Methods and systems are provided for reducing a spark plug soot load and a combustion chamber soot load by controlling spark plug timing while injecting water or washer fluid. In one example, water or washer fluid is injected during a torque reduction while advancing spark timing so as to provide at least a portion of the torque reduction while opportunistically cleaning soot from the spark plug and combustion chamber. By reducing spark plug soot load, misfire occurrence is reduced, while pre-ignition occurrence is reduced by decarbonizing the combustion chamber.

Methods and systems are provided for reducing a spark plug soot load and a combustion chamber soot load by controlling spark plug timing while injecting water or washer fluid. In one example, water or washer fluid is injected during a torque reduction while advancing spark timing so as to provide at least a portion of the torque reduction while opportunistically cleaning soot from the spark plug and combustion chamber. By reducing spark plug soot load, misfire occurrence is reduced, while pre-ignition occurrence is reduced by decarbonizing the combustion chamber.

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 control device of an engine includes an adjustment mechanism and a controller. The adjustment mechanism is configured to adjust an intake air amount. The controller is configured to save a first learning value in a volatile storage medium, the first learning value being obtained by learning an operation amount of the adjustment mechanism when the engine is idle. The controller is configured to control the adjustment mechanism according to the first learning value. The controller is configured to save a second learning value in a non-volatile storage medium, the second learning value being equal to the first learning value. The controller is configured to correct the first learning value using the second learning value after the first learning value is cleared.

Methods for controlling a Methods for controlling a valve disposed at an engine of a vehicle are disclosed. In one form of the disclosure, the method includes: determining whether an engine is an idle state; measuring a fuel pressure of the engine when the engine is the idle state; comparing the measured fuel pressure with a first threshold value; and operating the valve by applying a current to a valve operation coil when the measured fuel pressure is equal to or less than the first threshold value for a predetermined time or longer.

Methods for controlling a Methods for controlling a valve disposed at an engine of a vehicle are disclosed. In one form of the disclosure, the method includes: determining whether an engine is an idle state; measuring a fuel pressure of the engine when the engine is the idle state; comparing the measured fuel pressure with a first threshold value; and operating the valve by applying a current to a valve operation coil when the measured fuel pressure is equal to or less than the first threshold value for a predetermined time or longer.

An ECU avoids engine stall by putting a compressor into a stationary state in a case where the rotation speed of a crankshaft is equal to or less than a predetermined speed during an idle operation of an internal combustion engine. During the idle operation, the ECU calculates a total load torque applied to the crankshaft by the compressor and an alternator. The ECU calculates the maximum torque of the internal combustion engine during the idle operation based on a target speed during the idle operation. Then, the ECU raises the predetermined speed in a case where the value obtained by subtracting the load torque from the maximum torque is equal to or less than a predetermined value.

A vehicle drive system includes an internal combustion engine, a clutch, an engine rotation speed detector, an output shaft rotation speed detector, and a processor. The internal combustion engine includes cylinders and a crankshaft. The clutch is connected to the crankshaft via a torsion element and includes an output shaft. The engine rotation speed detector detects a crankshaft rotation speed. The output shaft rotation speed detector detects an output shaft rotation speed. The processor is configured to calculate a torque generated in each of the cylinders based on the crankshaft rotation speed. The processor is configured to decrease transmission torque of the clutch so that a difference between the crankshaft rotation speed and the output shaft rotation speed to be a target value when misfiring occurs. The processor is configured to identify a misfiring cylinder among the cylinders based on the torque calculated while the transmission torque is decreased.

The inhibition device includes a micro-controller configured with a triggering condition including a number of intervals and, for each interval, a corresponding duration and a corresponding threshold. Each interval is a range specifying how much the vehicle's acceleration pedal has changed its position in terms of percentages of a pedal stroke. Each duration specifies the fastest time duration allowable for the acceleration pedal to attain a corresponding interval of pedal position change. The micro-controller converts progress signals of the acceleration pedal to corresponding percentages, obtains a difference DEF between the successive percentages, records a time duration RES between successive progress signals, and calculates DEF/RES=X. When X is greater than or equal to a threshold of a corresponding interval, the micro-controller sends an idle signal to the vehicle's engine control unit or intercepts the progress signals to prevent them from reaching the engine control unit.