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The electrification of powertrains provides a critical opportunity to change the way that engines are designed and developed, allowing their efficiency to be increased and their cost reduced. This paper draws on ongoing Ricardo projects in the field of dedicated hybrid engines (DHEs). The Magma xEV combustion concept employs very high compression ratio, long stroke architecture, and advanced ignition and knock mitigation technologies, for DHEs requiring the highest efficiency. In the latest research project a pre-chamber combustion system (with both active and passive operation) has been applied to the Magma xEV engine, in order to enable the highest levels of charge dilution and further increase brake thermal efficiency. The research focussed on benefits of pre-chamber ignition as compared to conventional spark ignition and corona discharge ignition. The comparison of charge dilution using excess air (lean operation) and exhaust gas recirculation are presented.

The automotive market’s need for ever cleaner and more efficient powertrains, delivered to market in the shortest possible time, has prompted a revolution in digital engineering. Virtual hardware screening and engine calibration, before hardware is available is a highly time and cost-effective way of reducing development and validation testing and shortening the time to bring product to market. Model-based development workflows, to be predictive, need to offer realistic combustion rate responses to different engine characteristics such as port and fuel injector geometry. The current approach relies on a combination of empirical, phenomenological and experienced derived tools with poor accuracy outside the range of experimental data used to validate the tool chain, therefore making the exploration of unconventional solutions challenging.

The increasing need for cleaner and more efficient combustion systems has promoted a paradigm shift in the automotive industry. Virtual hardware and engine calibration screening at the early development stage, has become the most effective way to reduce the time necessary to bring new products to market. Virtual engine development processes need to provide realistic engine combustion rate responses for the entire engine map and for different engine calibrations. Quasi Dimensional (Q-D) combustion models have increasingly been used to predict engine performance at multiple operating conditions. The physics-based Q-D turbulence models necessary to correctly model the engine combustion rate within the Q-D combustion model framework are a computationally efficient means of capturing the effect of port and combustion chamber geometry on performance.

In an era of rapidly increasing vehicle electrification, the gasoline engine remains a vital part of the passenger car powertrain portfolio. Lean-burn combustion is a formidable means for reducing the CO2 emissions of gasoline engines but demands the use of sophisticated emissions control. A 2.0 litre turbocharged direct-injection gasoline engine has been developed with a lean homogeneous combustion system matched to a robust lean and stoichiometric-capable exhaust aftertreatment. The aftertreatment system includes an SCR system and a GPF with filtration down to 10 nm particle size. The engine is equipped with a continuously variable valve-lift system, high-tumble ports and a high-energy ignition system; the boosting system comprises a variable geometry turbocharger and a 48 V electrical supercharger. The work reported formed part of the PaREGEn (Particle Reduced, Efficient Gasoline Engines) project under the Horizon 2020 framework programme.

Hydrogen has been identified as a promising decarbonization fuel in internal combustion engine (ICE) applications in many areas including heavy-duty on- and off-road, power-generation, marine, etc. Hydrogen ICEs can achieve high power density and very low tailpipe emissions. However, there are challenges; designing systems for a gaseous fuel with its own specific mixing, burn rate and combustion control needs, which can differ from legacy products. The primary pollutant of concern for Hydrogen ICEs is NOx which can be addressed by running the engine at very lean equivalence ratios and the use of Exhaust Gas Recirculation (EGR). Computation Fluid Dynamics (CFD) is a valuable tool to model the combustion characteristics under different conditions, as presented in SAE-2023-01-0197 [1], which can also be used to predict thermal loading.

The Magma engine concept is characterised by a high compression ratio, central injector combustion system employed in a downsized direct-injection gasoline engine. An advanced boosting system and Miller cycle intake-valve closing strategies are used to control combustion knock while maintaining specific performance. A key feature of the Magma concept is the use of high CR without compromise to mainstream full-load performance levels. This paper focuses on development of the Magma combustion system using a single-cylinder engine, including valve event, air motion and injection strategies. Key findings are that Early Intake Valve Closing (EIVC) is effective both in mitigating knock and improving fuel consumption. A Net Indicated Mean Effective Pressure (NIMEP) equivalent to 23.6 bar Brake Mean Effective Pressure (BMEP) on a multi-cylinder engine has been achieved with a geometric compression ratio of 13:1.

Hydrogen-fuelled internal combustion engines (ICEs) offer a zero-carbon fuel option for many applications. As part of the global effort to study hydrogen ICEs Ricardo has developed single-cylinder and multi-cylinder heavy-duty engines. The engines are representative of a 13 litre Euro VI heavy-duty production application converted to run on hydrogen fuel with limited changes. The engine is fitted with direct hydrogen injectors which enable flexible injection strategies and reduce hydrogen in the intake system. Steady-state testing was carried out over an array of speed and load points covering a typical heavy-duty drive-cycle area. Engine test results are presented and analysed in this paper. The combustion system can run to values exceeding lambda 5 and 40% exhaust gas recirculation (EGR) can be tolerated.