Control apparatus for vehicle

1. A control apparatus for a vehicle that includes a drive wheel, an engine and an automatic transmission configured to transmit power from the engine toward the drive wheel,

wherein, when the automatic transmission is shifted, the control apparatus is configured to execute a shifting-time torque-down control by using one of an ignition retard method of retarding an ignition timing of the engine and a fuel cut method of restricting fuel supply to the engine, and

wherein, when the shifting-time torque-down control is requested to be executed, the control apparatus is configured to estimate a temperature of a predetermined portion of an exhaust pipe of the engine in a case in which the shifting-time torque-down control is executed by using the ignition retard method, and to execute the shifting-time torque-down control by using the fuel cut method when an estimated value of the temperature of the predetermined portion of the exhaust pipe is not lower than a predetermined upper-limit temperature value.

2. The control apparatus according to claim 1 ,

wherein, when executing the shifting-time torque-down control by using the fuel cut method, the control apparatus is configured to control an electronic throttle valve of the engine such that the electronic throttle valve is opened while the fuel supply is restricted.

3. The control apparatus according to claim 1 ,

wherein the temperature of the predetermined portion of the exhaust pipe is a temperature of a catalyst provided in the exhaust pipe, and

wherein, when a current value of the temperature of the catalyst is not lower than a predetermined deterioration temperature value at which deterioration of the catalyst is expected in a case in which the fuel cut method is used to execute the shifting-time torque-down control, the control apparatus is configured to execute the shifting-time torque-down control by using the ignition retard method regardless of whether the estimated value of the temperature is not lower than the upper-limit temperature value.

4. The control apparatus according to claim 1 ,

wherein the temperature of the predetermined portion of the exhaust pipe includes a temperature of a catalyst provided in the exhaust pipe and a temperature of an exhaust gas which is exhausted from the exhaust pipe and which rotates a turbine of a turbocharger provided in the engine,

wherein the control apparatus is configured to calculate an estimated value of the temperature of the catalyst and an estimated value of the temperature of the exhaust gas, and to determine whether or not the estimated values of the temperatures are not lower than the upper-limit temperature values separately predetermined for the catalyst and the exhaust gas, and

wherein the control apparatus is configured to execute the shifting-time torque-down control by using the fuel cut method when at least one of the estimated values of the temperatures is not lower than a corresponding one of the upper-limit temperature values.

5. The control apparatus according to claim 1 , comprising:

an overheat-suppression control portion configured to execute a fuel increase control for increasing an amount of the fuel supply to the engine in order to suppress overheating of the predetermined portion of the exhaust pipe when the temperature of the predetermined portion of the exhaust pipe reaches a predetermined overheat-determination temperature value,

wherein the predetermined upper-limit temperature value is predetermined based on the overheat-determination temperature value such that execution of the fuel increase control by the overheat-suppression control portion is suppressed.