In the light commercial vehicle (LCV) segment, almost exclusively Diesel engines are used today. The reasons are high mileage, low real-world fuel consumption, high loading capacity and therefore low total cost of ownership. In the next decade, very demanding CO2 targets as well as more stringent legal requirements for pollutant and noise emissions, especially in urban areas, require a substantial increase of electrified powertrain concepts. LCVs are typically employed for freight and passenger transport within urban areas, but are also used in interurban and/or motorway operation. These diverse cases of operation are often not suitable for full electric powertrain concepts, limiting their large-scale introduction. In this context, a Diesel Hybrid powertrain represents a highly capable and flexible propulsion system with attractively low real-world fuel consumption and the ability to achieve ultra-low pollutant emissions.

This paper presents an average value model for the real-time estimation of residual and reaspirative gas in a cylinder of an innovative diesel engine with variable valve lift. Based on a mean-value-model over a combustion cycle, the oxygen mass fraction before the combustion is calculated with information of an oxygen sensor in the intake and a lambda sensor in the exhaust manifold. Furthermore, a model for the residual and reaspirative gas mass is introduced that employs information of the cylinder gas mass, the fuel mass and the intake oxygen. The model equations are validated at an engine with a series high pressure line. Finally, a method for estimating the scavenging mass is introduced. Experimental results point out the benefits of the proposed estimation scheme.