Diesel engine performance and Dual fuel operation assessment

MAN and IDIADA are developing within HDGAS project an advanced dual-fuel LNG prototype truck. This advanced truck will feature a LPI gas system. And will demonstrate EUVI compliance and enhanced CO2 reduction compare to state of the art technology.

The main advantages of the development concept, LPI Dual fuel engine system, will be:

  • Performance advantage: Same diesel performance and drivability
  • Economic advantage: less complex injection system hardware compared to High pressure injection system and spark ignited engines (useful for a still small LNG trucks market with around 30 to 50% extra-costs to the equivalent truck)
  • Versatility advantage: Capability to revert to full diesel operation when required as well thus allowing LNG dual-fuel MAN trucks run solely on diesel, in the light of the current lack of LNG stations around Europe and in case of LNG is not available for any reason.

Dual fuel trucks allow fleet operators to use LNG all around Europe thanks to the high power density and larger fuel range when compared to pure Spark ignited LNG trucks. While LNG infrastructure on Europe is still limited, Dual fuel system allows truck to shift from Diesel to Gas mode easily thus providing excellent flexibility.

To validate engine concepts and to set up a reference values of CO2 emissions and efficiency, Diesel MAN engine was tested at IDIADA. Moreover a first initial Dual Fuel assessment was performed using a tailored solution.

Certification like tests demonstrated the full compliance of the baseline diesel engine with Euro VI emissions and best in class efficiency and fuel consumption. Furthermore, the MAN engine tested demonstrated power and torque as declared.

To simulate the worst conditions for methane emissions, a mild dual-fuel conversion of the engine was performed. By means of a Master-Slave approach engineers gathered initial information about the engine operation in Dual Fuel. Test demonstrated that using such approach, it was possible to reproduce similar conditions to the 2013 Dual Fuels state of the art. To achieve the same power and torque for a given engine operating point, much higher air consumption was observed by the engine through the 2-state waste-gated turbochargers. This point confirms the expectations of IDIADA about the need of a boost management control for the future engineered engine with a different engine management system to the Master-Slave approach. Both detailed injection calibration (Diesel and Gas) and aftertreatment, to oxidize methane, is necessary to achieve EUROVI level

The performed tests were useful to validate some engine strategies which are in develop and integrated in the new engine management system, tailored by IDIADA, which will replace the baseline Engine Control Unit, and which will manage totally the engine both in Diesel and Dual fuel operation

In addition the data gathered during the activity is useful for the tasks related to the CFD – Gas exchange and Injection systems, since data coming from the engine test bed, is useful for the generation and correlation of a virtual engine modeled by means of 1D tool (Gt-Power) and 3D tool (AVL Fire).

Figure 1: Data acquisition schematics

D5.1 - Figure 1

Figure 2: Master Slave dual-fuel initial configuration

D5.1 - Figure 2

 View the report: Dual fuel performance evaluation by Idiada (Public summary)