Engine starting control has a significant impact on engine emissions. Conventional methods use several different approaches to start an engine. Some approaches use fixed fuel injection values based on empirical testing, while others read sensors and attempt to calculate fueling based on the current state of the sensor information
One method to adjust fuel during an engine start is described in U.S. Pat. No. 5,870,986. This apparatus provides a start timing fuel injection controlling apparatus for an internal combustion engine. The fuel injection is performed in synchronism with an intake stroke of each cylinder in starting the internal combustion engine provided with a plurality of cylinders. The apparatus counts a total number of fuel injections in all the cylinders from a start of an operation of the engine. It advances by a predetermined period a fuel injection start timing when the count is equal to or more than a predetermined number.
The inventors herein have recognized several disadvantages of this approach. Namely, the approach focuses simply on changing when the fuel injection is performed, but does not recognize that air quantity changes for each cylinder during a start depending on injection count. Therefore, the above-mentioned approach does not fuel the engine as accurately as possible since the air that actually enters the cylinders changes throughout the engine start and depends on when the fuel injection is first started, as well as various other parameters. In addition, the above-mentioned approach does not predict future engine events, which also reduces fueling accuracy. Yet another disadvantage of the before-mentioned approach is that it does not have the ability to adapt to engine wear or manufacturing variation.