Ricardo has previously reported on a simulation environment set up to enable the study of engine and after-treatment technology over RDE cycles, incorporating post-processing with the EMROAD and CLEAR tools.

In the SIA paper, Ricardo reported on the use of this simulation environment to further explore the challenge and capability of LNT (lean NO_x trap)-based solutions. Solutions were also tested on an engine dyno, providing steady-state test results to help understand the mechanisms involved, and provide input data for the simulation.

The vehicles on which the research was based were representative of current production models at the more aggressive end of the downsizing spectrum in terms of engine capacity and output, but modeled with a future three cylinder 1.5 liter diesel engine.

The drive cycles to which they were subjected exceeded the finally adopted RDE boundary conditions in the motorway phase, but nonetheless provide a useful indication of performance.

The research shows that RDE legislation represents a significant challenge for light duty diesel manufacturers, and will require large steps in the application of existing technologies. While known technologies were shown to be capable of appropriate NO_x control, they come with downsides to other product attributes, notably cost, reductant fill frequency where applicable, and ultimately, fuel consumption.

Attribute analysis presented in SIA paper. The cost comparison is with respect to a Euro 5 baseline. Click to enlarge.

It is expected that application of exhaust thermal management to improve urban phase NO_x control will see the combination of low pressure cooled EGR together with an oxidation catalyst and actively dosed combined SCR/DPF (SCRF) as an acceptable solution for both C-segment and SUV products.

For premium applications where inter-service reductant fill would be unacceptable—or where two-stage boosting adds to the complexity of exhaust temperature control—the combination of LNT and actively dosed SCR is likely to be attractive.

The introduction of RDE regulations in Europe represents a very significant challenge, particularly for those automakers offering light duty diesel products. However … this is a challenge that can be met in a cost-effective manner through the application of a combination of aftertreatment technologies appropriate to each vehicle type. We are pleased to be sharing the results of this work at the SIA Powertrain international powertrain conference—results that demonstrate that the requirements of RDE regulations can be met in future, light duty clean diesel products.

—Ian Penny, managing director – engines business, Ricardo

At the SIA conference, Ricardo also exhibiting a the ADEPT concept vehicle, combining low-cost 48V, mild-hybrid technologies with the aim of reducing 1.5L Diesel C-segment CO₂ emissions by a further 15-20 percent, and showing a clear pathway to 70g/km. The ADEPT project is led by Ricardo in partnership with CPT, Ford, EALABC, Faurecia, the University of Nottingham, RedDeer, and Provector, and is supported by Innovate UK.

Also on display was the Doosan DL06 Tier 4 final engine, which uses the Ricardo patented Twin Vortex Combustion System and achieves US Tier 4 final – Stage IV emissions with EGR and SCR, but no requirement for a DPF.