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Since the Euro VI/6 regulation came into force in 2013/2014, most of the Diesel applications are equipped with both selective catalytic reduction (SCR) systems and Diesel particulate filters (DPF). On the one hand, SCR requires ammonia for the reduction of nitrogen oxides (NOx) created during the combustion process. An aqueous urea solution (AUS) containing 32.5% wt. urea, such as AdBlue® is injected into the hot exhaust gas upstream of the SCR catalyst to produce ammonia for NOx reduction. On the other hand, DPF demonstrates very high particle filtration efficiency, but requires to be periodically regenerated at high temperature to burn off accumulated soot. The regeneration temperature and duration can be significantly lowered by using fuel additives (fuel-borne catalyst or FBC) or by washcoating a catalyst into the DPF (catalyzed DPF or cDPF).

The knock resistance of gasoline is a key factor to decrease the specific fuel consumption and CO2 emissions of modern turbocharged spark ignition engines. For this purpose, high RON and octane sensitivity (S) are needed. This study shows a relevant synergistic effect on RON and S when formulating a fuel with isooctane, cyclopentane and aromatics, the mixtures reaching RON levels well beyond the ones of individual components. The same is observed when measuring their knock resistance on a boosted single cylinder engine. The mixtures were also characterized on a rapid compression machine at 700 K and 850 K, a shock tube at 1000 K, an instrumented and an adapted CFR engine. The components responsible for the synergistic effects are thus identified. Furthermore, the correlations plotted between these experiments results disclose our current understanding on the origin of these synergistic effects.

Diesel Exhaust Fluid (DEF) like Adblue® is a urea/water solution injected upstream from the SCR catalyst. Urea decomposes into ammonia (NH3) which acts as reducing agent in the de-NOx reaction process. However, incomplete decomposition of urea can lead to unwanted deposits formation, thereby resulting into backpressure increase, loss of NOx reduction efficiency, and durability issues. The phenomenon is aggravated at low temperatures and can lead to restriction or stop of DEF injection below certain exhaust temperatures. This paper focuses on the influence of the additivation of DEF on deposits formation in a passenger car close-coupled SCR on filter Diesel exhaust line installed in a laboratory flow bench test. The behavior of two different additivated DEF was compared to Adblue® in terms of deposits formation on the mixer and SCRF canning at different temperatures comprised between 240°C and 165°C, and different air flows.

In order to be ever more fuel efficient the use of Direct Injection (DI) is becoming standard in spark ignition engines. When associated with efficient turbochargers it has generated a significant increase in the overall performance of these engines. These hardware developments lead to increased stresses placed upon the fuel and the fuel injection system: for example injection pressures increased up to 400 bar, increased fuel and nozzle temperatures and contact with the flame in the combustion chamber. DISI injectors are thus subjected to undesirable deposit formation which can have detrimental consequences on engine operation such as reduced power, EOBD (Engine On Board Diagnostics) issues, impaired driveability and increased particulate emissions. In order to evaluate the sensitivity of DI spark ignition engines to fuel-related injector deposit formation, a new engine test procedure has been developed.

With the emergence of stringent emissions standards and needs for fuel diversification, many countries are considering a massive use of natural gas for transportation. In this context, dual fuel diesel-CNG combustion is considered as a promising solution for highly efficient internal combustion engines. This concept offers the possibility to combine a diesel pilot injection as a high energy combustion initiation event, with an indirect injection of methane as main energy source. Low CO2 emissions can be reached thanks to the use of a conventional compression ignition engine with high compression ratio, and thanks to methane's high knocking resistance and low carbon content. Another benefit of dual fuel operation with high diesel substitution rates is the drastic reduction of PM emissions since methane is a very stable molecule containing no soot precursor.

The use of CNG in modern spark ignition turbocharged engine offers many advantages such as high knocking resistance, low CO₂ emissions and high specific power outputs. On the other hand, compared to gasoline, the volumetric efficiency is significantly decreased when CNG is port-injected due to its low energy density. In order to address this issue, recent studies have successfully highlighted the advantages on port-injection engines of the CIGAL™ concept (Concomitant Injection of Gas And Liquid fuels) from IFP Energies Nouvelles. However, the combination of port-injection of CNG with direct injection of gasoline remains unexplored. This paper investigates this novel injection concept on the four-cylinder 1.6L turbocharged GDI engine with inlet variable valve timing resulting from the cooperation between PSA Peugeot-Citroen and the BMW Group.

In order to address the CO₂ emissions issue and to diversify the energy for transportation, CNG (Compressed Natural Gas) is considered as one of the most promising alternative fuels given its high octane number. However, gaseous injection decreases volumetric efficiency, impacting directly the maximal torque through a reduction of the cylinder fill-up. To overcome this drawback, both independent natural gas and gasoline indirect injection systems with dedicated engine control were fitted on a RENAULT 2.0L turbocharged SI (Spark Ignition) engine and were adapted for simultaneous operation. The main objective of this innovative combination of gas and liquid fuel injections is to increase the volumetric efficiency without losing the high knocking resistance of methane.

New environmental regulations require for car constructor and lubricant manufacturer reduction of engines emissions. This implies new set-up like post treatment systems (catalyst, DPF), reduction of oil consumption and new engine settings and design. Due to those modifications, new problems appear like lubricant dilution by fuel, clogging and poisoning of post treatment system, wear, etc. Those new engines become more and more complex and settings must be more and more precise, manufacturer need accurate tools to measure and understand those new problems. In this paper, we describe the latest results obtained using or combining innovative radionuclide techniques for real-time oil consumption (including blow-by contribution), real-time monitoring of poisoning of after-treatment systems, real-time monitoring of fuel dilution and real time wear measurement. New radiotracer techniques are powerful tools to better understand and solve these different issues.

On-line measurement of oil consumption is of interest in light of new environmental regulations imposed on today’s high-performance engines. Lubricant consumption has a negative impact on the environment, but it also reduces the lifetime of post-treatment systems by poisoning catalysts and clogging particle filters. A new method was recently developed by Delta Services Industriels (DSi) and TOTAL France for monitoring oil consumption on running engines. It is based on lubricant labeling using new radiotracer compounds, which are made representative of the distillation interval of the base oil. Oil consumption measurement is performed in the exhaust line where tracer residues are trapped in a filter and are monitored continuously. This paper describes the new methodology and presents experimental results obtained on various fired engines, for various operating conditions.

The lifetime of the new technologies of after-treatment devices is influenced by the composition of engine oil, making it necessary to study the compatibility of lubricants with these devices. These compatibility tests usually evaluate parameters such as the long-term performance of after-treatment systems, the quantity and nature of accumulated residues due to the lubricant used, back-pressure increase, etc. This paper presents a novel, non-destructive radionuclide technique based on labeling the different elements in the engine oil (e.g. zinc and calcium), that provides additional information to after-treatment system compatibility tests: on-line measurement in the after-treatment device of the accumulation of elements from oil additives, and visualization of their distribution inside the device (inlet/outlet). Most of the work presented here focuses on the accumulation of zinc and calcium from the lubricant in a Diesel Particulate Filter (DPF).

This paper describes a methodology using FTIR analysis for monitoring the degradation by oxidation of lubricants. This methodology is based on the interpretation of the viscosity increase and of the carbonyl compounds formation measured by Peak Area Increase (PAI). This physicochemical approach was applied to the development of an innovative in-house bulk oxidation test, the Modified ICOT, and to in-service oil evaluation. This work provided the opportunity to confirm hypotheses and gave new information on the oxidation process of lubricants, especially concerning catalytic action of soluble iron and relationship between viscosity increase and carbonyl compounds formation. Laboratory test results showed a good correlation between PAI and TAN on bulk-oxidized oils, in which acidity is only related to the carbonyl compounds formed during the oxidation.