Air-to-fuel ratio control method

Abstract

Abstract PURPOSE:To prevent bad emission and imperfect starting by modifying the studying value on the basis of the arithmetic mean for values of correction, in which the correction at the transient point in the air-to-fuel ratio sensor is taken in, and bt enhancing thereby the control accuracy for the air-to-fuel ratio in the whole driving range of the engine. CONSTITUTION:Digital value 104 in accordance with the cooling temp. 13, intake gas temp. 12 and suction amount 11 is taken in the CPU100, where operation is performed for a correction amount K2 for the air-to-fuel sensor 14, and the result is housed in an RAM107 as the studying value Kmn upon undergoing an operational process. In this case, three conditions are set-if the studying condition 400 corresponding to the transient time point, i.e. air-to-fuel ratio sensor, is in activated state, if the cooling water temp. is over the set value, and if the air-to-fuel ratio is being increased. In case non of the above conditions is met, the studying value Kmn is employed as K2 in the same manner as it was, and, in case any of them is met, the value K2 is processed for the arithmetic mean 405, 406 depending upon whether the set number of times N1 401 for the changing point in the rich/lean output from the sensor 14 is met. The value Kmn is thus housed. Accordingly, a studying value Kmn including no variations at the transient point can be employed in accordance with the actual condition of driving.

Inventors

• 👤 Takashi Arimura
• 👤 有村　孝士
• 👤 Hisamitsu Idezoe
• 👤 出添　久光
• 👤 Toshimi Matsumura
• 👤 敏美 松村

Bibliographic Details