| 摘要 |
A cetane number estimating device (1) comprises cylinders which are provided to an internal combustion engine where a part of the exhaust gas can be fed back from the exhaust system to the intake system, injection means (30) for injecting fuel into the cylinders, measuring means (40) for measuring the ignition timings in the cylinders, and estimating means (20) for estimating the cetane number of the fuel according to the measured ignition timing as well as any one of a first correlation between the ignition timing corresponding to the stage at which when one cylinder is in the intake stroke, another cylinder in the exhaust stroke exhausts non-burned gas and the cetane number and a second correlation between the ignition timing corresponding to the stage at which when one cylinder is in the intake stroke, another cylinder exhausts burned gas and the cetane number. |
