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Alcohols offer high resistance to autoignition which is necessary to attain the required load in heavy duty (HD) spark ignition (SI) engines. Dilution increases thermal efficiency and reduces propensity to autoignition making it an important combustion strategy. Reliable and robust prediction at increased dilution is necessary to support development of high efficiency spark ignition engines and the transition to renewable fuels. A previous experimental study demonstrated 25 bar gross IMEPg for ethanol and methanol at λ=1.4 excess air ratio and over 48% indicated efficiency at λ=1.6 on a single cylinder engine. Based on this dataset, a semi-predictive model (SITurb) was fitted for a range of excess air ratios and engine loads. With the default model, poor accuracy was observed above λ=1.4. Ignition delay was incorrectly predicted at λ=1.6 and λ=1.8.

With increasing demands to reduce fuel consumption and CO2 emissions, it is necessary to recover waste heat from modern Heavy Duty (HD) truck engines. Organic Rankine Cycle (ORC) has been acknowledged as one of the most effective systems for Waste Heat Recovery (WHR) due to its simplicity, reliability and improved overall efficiency. The expander and working fluid used in ORC WHR greatly impact the overall performance of an integrated engine and WHR system. This paper presents the effects of volumetric expanders on the ORC WHR system of a long haulage HD truck engine at a steady-state engine operating point chosen from a real-time road data. Performance of a long haulage HD truck engine is analyzed, based on the choice of three volumetric expanders for its WHR system, using their actual performance values. The expanders are: an oil-free open-drive scroll, a hermetic scroll and an axial piston expander with working fluids R123, R245fa and ethanol, respectively.

Knock in heavy duty (HD) spark ignition (SI) engines is exacerbated by a large bore diameter and a higher flame travel distance. An increase in turbulence close to TDC can improve combustion speed and reduce knock through low residence time for end gas auto-ignition. Since HD SI engines are usually derived from diesel engines, it is common to have a swirl motion that does not dissipate into turbulence. To increase flame speed and limit knock, squish can be used to produce turbulence close to TDC. In this study, two different piston bowl geometries are examined: the re-entrant and quartette. The influence of squish area on turbulence production by these piston geometries were investigated using motored simulations in AVL FIRE. The effect of increased turbulence on knock reduction was analyzed using a calibrated 1D GT-Power model of a HD SI engine and the performance improvement was estimated.

Fuel filters serve as a safety belt for modern compression ignition engines. To meet the requirements from environmental regulations these engines use the common rail injection system, which is highly susceptible to contamination from the fuel. Furthermore, the public awareness towards global warming is raising the need for renewable fuels such as biodiesel. An increased fuel variety brings a higher requirement for fuel filters as well. To better understand the process of filtration, awareness of the different possible contaminants from the field is needed. This study used several chemical characterization techniques to examine the deposits from plugged fuel filters collected from the field. The vehicle was run with a biodiesel blend available on the market.

The introduction of renewable alcohols as fuels for heavy-duty engines may play a relevant role for the reduction of the carbon footprint of the transport sector. The direct injection of ethanol as main fuel and diesel as pilot fuel in the engine combustion chamber through two separate injectors may allow good combustion controllability over the entire engine operating range by targeting diffusive combustion. Closed-cycle combustion simulations have been carried out using AVL FIRE coupled to AVL TABKIN for the implementation of the Flamelet Generated Manifold (FGM) chemistry reduction technique in order to investigate the influence of the injection system geometry and the injection strategy of pure ethanol and diesel fuel on ignition characteristics and combustion at different operating conditions.