Reduction of Hyperbrid Diesel Engine Emission by EGR: [An Only Possible Method to Meet US Emission Standard of the Year 2004] 1999-01-0971

Historically Diesel engines with turbocharger (TC) suffer so called “Turbo-Lag”, which presents deficiency in intake air-supply during the low engine speed stage. This insufficient air-supply causes emissions much higher than their normal operating conditions. For this a “Hybrid” supercharge-engine has been proposed [1], where a mechanically driven supercharger (SC) is used during the low engine speed zone. This paper proposes a new EGR (Exhaust Gas Return) system concept applicable to Diesel engines, which will achieve the compatibility to the stringent emission standard of USA in the year 2004, which is more stringent than EURO-3. S.P.Edwards et al [2] discussed some measures to clear EURO-3 values are discussed, but those, “D” and “E” in the Figure 1 are not possibly achievable in the near future. Therefore only EGR among those discussed in the paper is realistic. Hence this proposed system seems the only system currently conceivable for clearing such stringent regulation that require the values measured even during the transient condition of the engine operations. The system further indicates that realization of very high BMEP (Break Mean Effective Pressure) as well as quite low fuel consumption [3] is possible.