However, at decreasing BMEP, the model overestimates the [MFB.sub.10-50] duration, especially for eEGR operations, where a maximum error of 4 CADs is obtained at medium/high speeds and low load.
* The model underpredicts the duration of the initial combustion stage ([MFB.sub.0-50]), with higher errors at decreasing engine load and increasing eEGR rate.
The resulting maps of [MFB.sub.0-10] are shown in Figure 20a for EGR-free operations and in Figure 20b for the case with eEGR. Comparing these results with those obtained ignoring the flame stretch (Figure 17b and Figure 18b, respectively), it is observed that significant improvements arise for loads lower than 4 bar BMEP.
The EEGR system, which can be used with 12 or 24 V electrical systems, has several advantages over conventional EGR designs, Lucas Control Systems said.
While initially developed with an eye toward heavy trucks, Lucas Control Systems said the EEGR valve can be designed for a wide range of diesel applications and meets emission legislation such as Euro3 and Euro4, when used as part of a wider engine control strategy.