Control device of engine with turbocharger and method of controlling the engine

1. A control device of an engine including an exhaust gas

turbocharger having an exhaust gas driven turbine with a turbine wheel and a compressor

wheel, the control device comprising:

an electronic control unit configured to

(a) set a target output torque based on a required value of an output torque for the engine;

(b) regulate the output torque of the engine to the target output torque by controlling a waste gate, throttle valve and fuel injectors; and

(c) when the target output torque is larger by at least a predetermined amount than the actual output torque and the rate of increase of the actual output torque is equal to or smaller than the predetermined value, limit an increase of an actual output torque of the engine from a timing at which a rate of increase of the actual output torque would exceed a predetermined value.

2. The control device according to claim 1 , wherein the electronic control unit is configured to limit the increase of the actual output torque by controlling an opening of a throttle valve.

3. The control device according to claim 1 , wherein the electronic control unit is configured to put a reduced limitation on the increase of the actual output torque, when the required value of the output torque for the engine increases while the increase of the actual output torque is being limited.

4. The control device according to claim 1 , wherein the electronic control unit is configured to finish limiting the increase of the actual output torque, when the actual output torque reaches the required value of the output torque for the engine while the increase of the actual output torque is being limited.

5. The control device according to claim 1 , wherein the electronic control unit is configured to limit the increase of the actual output torque by reducing the target output torque to a value that is smaller than the required value of the output torque for the engine and then increasing the target output torque at a predetermined rate of increase.

6. The control device according to claim 5 , wherein the electronic control unit is configured to, when the required value of the output torque for the engine changes while the increase of the actual output torque is being limited, change the rate of increase of the target output torque according to the required value that has changed.

7. The control device according to claim 1 , wherein:

the electronic control unit is configured to calculate a maximum torque that is generated from the engine under a boost pressure to be achieved after a predetermined period of time elapses, when the target output torque is larger by at least the predetermined amount than the actual output torque of the engine and the rate of increase of the actual output torque is equal to or smaller than the predetermined value; and

the electronic control unit is configured to determine a timing at which the rate of increase of the actual output torque exceeds the predetermined value by monitoring the maximum torque, and limit the increase of the actual output torque from the timing.

8. The control device according to claim 1 , wherein:

the electronic control unit is configured to prohibit limiting the increase of the actual output torque of the engine when the engine is required to decrease torque temporarily by a control other than a speed control by a transmission which is connected to the engine while the increase of the actual output torque of the engine is being limited; and

the electronic control unit is configured to control the actual output torque of the engine in accordance with a requirement to decrease torque temporarily.

9. A method of controlling an engine including an exhaust gas turbocharger having an exhaust driven turbine with a turbine wheel and a compressor wheel, with an electronic control unit, the method comprising:

setting, by the electronic control unit, a target output torque based on a required value of an output torque for the engine;

regulating, by the electronic control unit, the output torque of the engine to the target output torque by controlling a waste gate, throttle value and fuel injectors; and

when the target output torque is larger by at least a predetermined amount than the actual output torque and the rate of increase of the actual output torque is equal to or smaller than the predetermined value,

limiting, by the electronic control unit, an increase of an actual output torque of the engine from a timing at which a rate of increase of the actual output torque would exceed a predetermined value.