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The absence of combustion information continues to be one of the key obstacles to the intelligent development of engines. Currently, the cost of integrating cylinder pressure sensors remains too high, prompting attention to methods for extracting combustion information from existing sensing data. Mean-value combustion models for engines are unable to capture changes of combustion parameters. Furthermore, the methods of reconstructing combustion information using sensor signals mainly depend on the working state of the sensors, and the reliability of reconstructed values is directly influenced by sensor malfunctions. Due to the concentration of operating conditions of hybrid vehicles, the reliability of priori calibration map has increased. Therefore, a combustion information reconstruction method based on priori calibration information and the fused feature deviations of existing sensing signals is proposed and named the "Deviation-based Centroid Displacement Method" (DCDM).

Computational Fluid Dynamics (CFD), as an effective analytical tool, has been applied at China North Engine Research Institute (CNERI) for combustion chamber design and combustion system optimization on a V8 heavy -duty diesel engine in order to meet increasingly stringent emission targets. The design of combustion system involves great number of parameteric optimizations such as the number of nozzle holes, the spray angle, the swirl ratio and the piston bowl shape. 3-D CFD was a convenient and cheap tool to explore the effects of all these parameters to the engine performance, compared with extensive hardware testing. 1-D modeling was used to set up boundary conditions at intake valve closure for 3-D CFD modeling during the closed-cycle. AVL FIRE software with a widely used combustion model, ECFM-3Z model, was used for 3-D simulation. Two sets of nozzle holes, four spray angles and three swirl levels were utilized and optimized under rated power.

In diesel engines, valve avoiding pit (VAP) is often designed on the top of the piston in order to avoid the interference between the valves and the piston during the engine operation. With the continued application of the downsized or high power density diesel engines, the depth of VAP has to be further deepened due to increased valve lift for more air flow into and out of the cylinder and decreased piston top clearance for less HC/CO and soot emissions. The more and more deepening of VAP changes the combustion chamber geometry, the top clearance height and the injector relative position to the piston crown. In this paper, a 3-D in-cylinder combustion model was used for a heavy duty diesel engine to investigate the effects of the depth of VAP on combustion process and emissions. Five depths of VAP were designed in this study. In order to eliminate the influence of compression ratio, the piston clearance height was adjusted for each VAP depth to keep the same compression ratio.

This paper deals with the experimental and numerical investigation of a 2.0 litre single cylinder Heavy Duty Diesel Engine fuelled by natural gas and diesel oil in Dual Fuel mode. Due to the gaseous nature of the main fuel and to the high compression ratio of the diesel engine, reduced emissions can be obtained. An experimental study has been carried out at three different load level (25%, 50% and 75% of full engine load). Basing on experimental data, the authors recreated a 45° mesh sector of the engine cylinder and performed CFD simulations for the cases at 50% and 75% load levels. Numerical simulations were carried out on the 3D code Ansys FORTE. The aim of this work is to study combustion phenomena and, in particular, the interaction between natural gas and diesel oil, respectively represented by methane and n-dodecane. A reduced kinetic scheme for methane auto-ignition was implemented while for n-dodecane two set of reactions were utilised.

In order to meet increasingly stringent emissions standards and lower the fuel consumption of heavy-duty (HD) vehicles, significant efforts have been made to develop high efficiency and clean diesel engines and aftertreatment systems. However, a trade-off between the actual engine efficiency and nitrogen oxides (NOx) emission remains to minimize the operational costs. In addition, the conversion efficiency of the diesel aftertreatment system decreases rapidly with lower exhaust gas temperatures (EGT), which occurs at low load operations. Thus, it is necessary to investigate the optimum combustion and engine control strategies that can lower the vehicle’s running costs by maintaining low engine-out NOx emissions while increasing the conversion efficiency of the NOx aftertreament system through higher EGTs.

In this paper, a novel cost-effective air hybrid powertrain concept for buses and commercial vehicles, Brunel Regenerative Engine Braking Device (RegenEBD) technology, is presented and its performance during the braking process is analysed using the Ricardo WAVE engine simulation programme. RegenEBD is designed to convert kinetic energy into pneumatic energy in the compressed air saved in an air tank. Its operation is achieved by using a production engine braking device and a proprietary intake system design. During the braking operation, the engine switches from the firing mode to the compressor mode by keeping the intake valves from fully closed throughout the four-strokes by installing the Variable Valve Exhaust Brake (VVEB) device on the intake valves. As a result, the induced air could be compressed through the opening gap of intake valves into the air tank through the modified intake system.

An experimental study has been carried out with the end goal of minimizing engine-out methane emissions with Premixed Micro Pilot Combustion (PMPC) in a natural gas-diesel Dual-Fuel™ engine. The test engine used is a heavy-duty single cylinder engine with high pressure common rail diesel injection as well as port fuel injection of natural gas. Multiple variables were examined, including injection timings, exhaust gas recirculation (EGR) percentages, and rail pressure for diesel, conventional Dual-Fuel, and PMPC Dual-Fuel combustion modes. The responses investigated were pressure rise rate, engine-out emissions, heat release and indicated specific fuel consumption. PMPC reduces methane slip when compared to conventional Dual-Fuel and improves emissions and fuel efficiency at the expense of higher cylinder pressure.