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The electrified internal combustion engine can contribute to further improving air quality and reducing impact on climate change. A previous publication looked into ultra-low initial cold-start emissions with the implementation of a state-of-the-art emission control system on a gasoline vehicle with market E10 gasoline. This paper reports additional investigations on different drop-in sustainable renewable fuels, including e-fuels. The gasoline demonstrator vehicle is equipped with a 48V mild-hybrid powertrain with a 1.5 L direct injection engine. The innovative emission control system consists of an electrically pre-heated catalyst (EHC) and first three-way catalyst (TWC) in close-coupled position, in combination with an underfloor catalysed gasoline particulate filter (cGPF), second TWC and ammonia slip catalyst (ASC). Pollutant emission tests are conducted on a challenging chassis dyno test for cold-start emissions at 23 °C and -10 °C.

Heavy-duty vehicles represent a significant portion of road transport and they need to operate in a clean and efficient manner. Their emission control systems need to be enhanced to sustain the high conversion efficiencies seen during motorway conditions inother operating conditions. The European Commission is developing legislative proposals for Euro 7 emissions regulations for light- and heavy-duty vehicles. The new Euro 7regulation will likely focus on ensuring the emissions from heavy-duty vehicles are minimized over extensive on-road operating conditions and specifically on operating conditions such as urban driving and cold-start operation. These challenges are increased by the need to ensure low secondary emissions like NH3 and N2O, as well as a low impact on CO2 emissions. The paper outlines the low pollutant emissions achieved by a heavy-duty Diesel demonstrator vehicle.

The gap between diesel vehicle emissions in laboratory tests compared to those in use has been addressed by the introduction of the Real Driving Emissions (RDE) requirements. Modern diesel technology now demonstrates low emissions on the road over a wide range of driving conditions. This paper further demonstrates that consistent low nitrogen oxide (NOx) and particle number (PN) emissions can be achieved over a wide range of driving conditions beyond Euro 6d RDE requirements, with emission control technologies combined in an integrated approach. An LNT (Lean NOx Trap) is combined with a dual-dosing SCR (Selective Catalytic Reduction) system. Low-load NOx control is achieved by the LNT in combination with a close-coupled SCR coated on the Diesel Particulate Filter (SDPF). High load conditions, on the other hand, are covered by the underfloor SCR system with a second AdBlue® injector.

The market share of Gasoline Direct Injection (GDI) vehicles has been increasing, promoted by its positive contribution to the overall fleet fuel economy improvement. It has however been reported that this type of engine is emitting more ultrafine particles than the Euro 6c Particle Number (PN) limit of 6·1011 particles/km that will be introduced in Europe as of September 2017 in parallel with the Real Driving Emission (RDE) procedure. The emissions performance of a Euro 6b GDI passenger car was measured, first in the OEM build without a Gasoline Particulate Filter (GPF) and then as a demonstrator with a coated GPF in the underfloor position. Regulated emissions were measured on the European regulatory test cycles NEDC and WLTC and in real-world conditions with Portable Emissions Measurement Systems (PEMS) according to the published European RDE procedure (Commission Regulation (EU) 2016/427 and 2016/646).

Hydrogen-fuelled internal combustion engines are an attractive alternative to current drive trains, because a high efficiency is possible throughout the load range and only emissions of oxides of nitrogen (NOx) can be emitted. The latter is an important constraint for power and efficiency optimization. Optimizing the engine with experiments is time consuming, so thermodynamic models of the engine cycle are being developed to speed up this process. Such a model has to accurately predict the heat transfer in the engine, because it affects all optimization targets. The standard heat transfer models (Annand and Woschni) have already been cited to be inaccurate for hydrogen engines. However, little work has been devoted to the evaluation of the flow-field based heat transfer model, which is the topic of this paper. The model is evaluated with measurements that focus on the effect of the fuel, under motored and fired operation.

Models for the convective heat transfer from the combustion gases to the walls inside a spark ignition engine are an important keystone in the simulation tools which are being developed to aid engine optimization. The existing models have, however, been cited to be inaccurate for hydrogen, one of the alternative fuels currently investigated. One possible explanation for this inaccuracy is that the models do not adequately capture the effect of the gas properties. These have never been varied in a wide range because air and ‘classical’ fossil fuels have similar values, but they are significantly different in the case of hydrogen. As a first step towards a fuel independent heat transfer model, we have investigated the effect of the gas properties on the heat flux in a spark ignition engine.

The internal combustion engine with compression ignition is still the most important power plant for heavy duty transport, railway transport, marine applications and generator sets. Fuel cost and emission regulations drive manufacturers to switch to alternative fuels. The understanding and prediction of these fuels in the spray and combustion process will be very important for these issues. In the past, lot of research was done for conventional diesel fuel by optically analyzing both spray and combustion. However comparison between different groups is difficult since qualitative results and accuracies are depending in the used definitions and methods. The goal of present research is to verify the behavior pure oils compared to more standard fuels while paying lot of attention to the interpretation of the measurement results.

The use of light alcohols as SI engine fuels can help to increase energy security and offer the prospect of carbon neutral transport. These fuels enable improvements in engine performance and efficiency as several investigations have demonstrated. Further improvements in efficiency can be expected when switching from throttled stoichiometric operation to strategies using mixture richness or exhaust gas recirculation (EGR) to control load while maintaining wide open throttle (WOT). In this work the viability of throttleless load control using EGR (WOT EGR) or mixture richness (WOT lean burn) as operating strategies for methanol engines was experimentally verified. Experiments performed on a single-cylinder engine confirmed that the EGR dilution and lean burn limit of methanol are significantly higher than for gasoline. On methanol, both alternative load control strategies enable relative indicated efficiency improvements of about 5% compared to throttled stoichiometric operation.

The use of methanol and ethanol in spark-ignition (SI) engines forms a promising approach to decarbonizing transport and securing domestic energy supply. The physico-chemical properties of these fuels enable engines with increased performance and efficiency compared to their fossil fuel counterparts. An engine cycle code valid for alcohol-fuelled engines could help to unlock their full potential. However, the development of such a code is currently hampered by the lack of a suitable correlation for the laminar flame speed of alcohol-air-diluent mixtures. A literature survey showed that none of the existing correlations covers the entire temperature, pressure and mixture composition range as encountered in spark-ignition engines. For this reason, we started working on new correlations based on simulations with a one-dimensional chemical kinetics code. In this paper the properties of methanol and ethanol are first presented, together with their application in modern SI engines.

Hydrogen-fueled internal combustion engines (H₂ICEs) are an affordable, practical and efficient technology to introduce the use of hydrogen as an energy carrier. They are practical as they offer fuel flexibility, furthermore the specific properties of hydrogen (wide flammability limits, high flame speeds) enable a dedicated H₂ICE to reach high efficiencies, bettering hydrocarbon-fueled ICEs and approaching fuel cell efficiencies. The easiest way to introduce H₂ICE vehicles is through converting engines to bi-fuel operation by mounting a port fuel injection (PFI) system for hydrogen. However, for naturally aspirated engines this implies a large power penalty due to loss in volumetric efficiency and occurrence of abnormal combustion. The present paper reports measurements on a single-cylinder hydrogen PFI engine equipped with an exhaust gas recirculation (EGR) system and a supercharging set-up.