CONTROLLING DEVICE FOR INTERNAL COMBUSTION ENGINE EQUIPPED WITH TURBOCHARGER

摘要

A target first air amount for achieving a requested torque by an operation of an intake property variable actuator is calculated by using a first parameter. A target second air amount for achieving the requested torque by an operation of a turbocharging property variable actuator is calculated by using a second parameter. A value of a first parameter changes to a value that reduces a conversion efficiency of an air amount into torque in response to the requested torque decreasing to a first reference value or lower. Further, a value of the second parameter starts to change to a direction to reduce the conversion efficiency in response to the requested torque decreasing to a second reference value that is larger than the first reference value, or lower, and gradually changes to a direction to reduce the conversion efficiency in accordance with the requested torque further decreasing from the second reference value to the first reference value. The target air-fuel ratio is set at a first air-fuel ratio in a period in which the requested torque is larger than the first reference value, and is switched to a second air-fuel ratio which is leaner than the first air-fuel ratio in response to a decrease of the requested torque to the first reference value or lower.

主权项

1. A controlling device for an internal combustion engine equipped with a turbocharger, that has a first actuator that changes an amount of air that is taken into a cylinder, a second actuator that supplies fuel into the cylinder, and a third actuator that ignites a mixture gas in the cylinder, and is configured to be capable of selecting an operation by a first air-fuel ratio and an operation by a second air-fuel ratio that is leaner than the first air-fuel ratio, comprising:
requested torque reception means for receiving a requested torque; target air amount calculation means for calculating a target air amount for achieving the requested torque backwards from the requested torque by using a parameter that gives a conversion efficiency of an air amount into torque; parameter value changing means for changing a value of the parameter to a value that reduces the conversion efficiency in response to a decrease of the requested torque to a reference value or smaller; target air-fuel ratio switching means for switching a target air-fuel ratio from the first air-fuel ratio to the second air-fuel ratio, after the value of the parameter is changed to the value that reduces the conversion efficiency; first actuator control means for determining an operation amount of the first actuator based on the target air amount, and operating the first actuator in accordance with the operation amount; second actuator control means for determining a fuel supply amount based on the target air-fuel ratio, and operating the second actuator in accordance with the fuel supply amount; and third actuator control means for determining an ignition timing for achieving the requested torque based on a torque that is estimated from the operation amount of the first actuator and the target air-fuel ratio, and the requested torque, and operating the third actuator in accordance with the ignition timing, wherein the target air amount calculation means includes target first air amount calculation means for calculating the target first air amount for achieving the requested torque backwards from the requested torque by using a first parameter that gives a conversion efficiency of an air amount into torque, and target second air amount calculation means for calculating a target second air amount for achieving the requested torque backwards from the requested torque by using a second parameter that gives a conversion efficiency of the air amount into torque, the parameter value changing means includes first parameter value changing means for changing a value of the first parameter to a value that reduces the conversion efficiency in response to the requested torque being reduced to a first reference value or smaller, and second parameter value changing means for starting to change a value of the second parameter to a direction to reduce the conversion efficiency in response to the requested torque being decreased to a second reference value that is larger than the first reference value, or smaller, and gradually changing the value of the second parameter to a direction to reduce the conversion efficiency in accordance with the requested torque further decreasing from the second reference value to the first reference value, the target air-fuel ratio switching means includes means for switching the target air-fuel ratio from the first air-fuel ratio to the second air-fuel ratio, after the value of the first parameter is changed to a value that reduces the conversion efficiency, the first actuator includes an intake property variable actuator that changes an intake property of air that is taken into the cylinder in an intake passage at a downstream side of the turbocharger, and a turbocharging property variable actuator that changes a turbocharging property of the turbocharger, and the first actuator control means includes intake property variable actuator control means for determining an operation amount of the intake property variable actuator based on the target first air amount, and operating the intake property variable actuator in accordance with the operation amount, and turbocharging property variable actuator control means for determining an operation amount of the turbocharging property variable actuator based on a target turbocharging pressure that is calculated from the target second air amount, and operating the turbocharging property variable actuator in accordance with the operation amount.