| 摘要 |
PROBLEM TO BE SOLVED: To provide a throttle opening control device of an internal combustion engine capable of suppressing output down of the internal combustion engine.SOLUTION: An opening motion of a throttle valve 4 is limited by guard processing so that an opening of the throttle valve 4 does not increased to a guard value or more. The higher an alcohol concentration of a fuel is, the smaller the guard value is determined (value at close side). Thus the smaller guard value is set in accordance with increase of a combustion speed of a fuel in a cylinder by increase of alcohol concentration, and the opening motion of the throttle valve 4 is limited to smaller opening. As a result, an intake air amount to the cylinder is reduced in accordance with increase of the alcohol concentration, and a maximum value of a combustion pressure is hardly increased. If the intake air amount is excessively low when the alcohol concentration of the fuel is low by the limitation of the opening of the throttle valve 4 by a constant guard value, the output down of the internal combustion engine 1 is led, but it can be suppressed by variably setting the guard value.SELECTED DRAWING: Figure 1 |
