Wassereinspritzung für ottomotorische Brennverfahren

Self Cite

104

103

Increasing carbon dioxide accumulation in earth's atmosphere and the depletion of fossil resources pose huge challenges for our society and, in particular, for all stakeholders in the transportation sector. The Cluster of Excellence 'Tailor-Made Fuels from Biomass' at RWTH Aachen University establishes innovative and sustainable processes for the conversion of whole plants into molecularly well-defined fuels exhibiting tailored properties for low-temperature combustion engine processes, enabling high efficiency and low pollutant emissions. The concept of fuel design, that is, considering fuel's molecular structure to be a design degree of freedom, aims for the simultaneous optimisation of fuel production and combustion systems. In the present contribution, three examples of tailor-made biofuels are presented. For spark ignition engines, both 2-methylfuran and 2-butanone show increased knock resistance compared to RON95 gasoline, thus enabling a higher compression ratio and an efficiency gain of up to 20% at full-load operation. Moreover, both fuels comprise a good mixture formation superior to the one of ethanol, especially under difficult boundary conditions. For compression ignition engines, 1-octanol enables a remarkable reduction in engine-out soot emissions compared to standard diesel fuel due to the high oxygen content and lower reactivity. This advantage is achieved without sacrificing the high indicated efficiency and low NO X emissions.

Section: Tmfb For Highly Boosted Si Enginesmentioning

confidence: 98%

Section: Tmfb For Highly Boosted Si Enginesmentioning

confidence: 99%

Tailor-made fuels for future engine concepts

Hoppe

Heuser

Thewes

et al. 2015

Self Cite

104

103

“…As a modification of a Reynolds–Ohnesorge diagram presented by Thewes and colleagues, 25,32 Figure 3 shows a comparison between water at different injection pressures and isooctane at 20 MPa injection pressure. The latter is considered as a surrogate for gasoline again.…”

Section: Direct Condensate Injection Conceptmentioning

confidence: 99%

“…Combustion system investigations regarding the potential benefits of this concept were carried out on a homogeneously operated DI spark-ignited single-cylinder research engine, as already described in previous publications. 25,32,35…”

Section: Engine Specificationmentioning

confidence: 99%

Water injection for gasoline engines: Potentials, challenges, and solutions

Hoppe

Thewes

Baumgarten

et al. 2015

Self Cite

164

Further significant CO 2 emission reduction beyond 2020 is mandatory in the United States and might also become mandatory in Europe, depending on the passenger car CO 2 legislation, which is to be enacted. Hybrid and plug-in hybrid vehicles might account for a big portion of these CO 2 reductions as a consequence of the favourable current legislative treatment which does not associate CO 2 emissions from electric power generation with vehicle CO 2 emissions. Nevertheless, these powertrains benefit from a highly efficient combustion engine. Exhaust heat recovery poses new synergetic possibilities for technologies to mitigate knock like cooled external exhaust gas recirculation and condensed water injection. The condensed water injection concept, which is proposed in this article, demonstrates a potential for efficiency increase of 3.3%-3.8% in the region of the minimum specific fuel consumption on a stoichiometric combustion concept with Miller cycle and cooled external exhaust gas recirculation. Further improvement of the efficiency of up to 16% is possible at full-load operation. If water injection is used in addition to homogeneous lean combustion, an efficiency gain of 4.5% in the region of the minimum specific fuel consumption is achieved.

“…In the recent past, many possible fuel candidates have already been proposed by this CoE and were successfully tested in engines. 5 –8 For both CI and SI engines, an adapted oxygen content and high volatility is targeted in order to enable a good mixture formation and to reduce soot emissions. Moreover, for SI engines, a compact molecule structure is favorable to improve anti-knock behavior.…”

Section: Introductionmentioning

confidence: 99%

Combustion and emission behavior of linear C₈-oxygenates

Heuser

Mauermann

Wankhade

et al. 2015

Alternative fuels have become of great importance in order to secure a sustainable mobility within the next decades. Within the Cluster of Excellence, ''Tailor-Made Fuels from Biomass'' at RWTH Aachen University, several possible fuel candidates could be derived from (hemi-)cellulose by selective catalytic conversion. The proposed fuel candidates include furans, ethers, alcohols, and ketones. Experiments with the isomers di-n-butyl ether and 1-octanol have proven their suitability for diesel-type combustion. With di-n-butyl ether being prone to auto-ignition, overall hydrocarbon, carbon monoxide, and soot emissions are reduced compared to diesel. In contrast, the prolonged ignition delay with 1-octanol causes an increase in HC and CO emissions particularly at low engine loads. However, soot emissions are even below those of di-n-butyl ether. With regard to particulate matter, an Exhaust Emissions Particulate Sizer Spectrometer (EEPS ä ) has been utilized to investigate the particle size or number distribution. Compared to diesel, a reduction of the total particle number up to 80% was seen with the oxygenates next to a shift toward reduced particle mobility diameter. The HC emissions of both di-n-butyl ether and 1-octanol have been studied in detail by means of gas chromatographymass spectrometry. As a main result, not only the general emission reduction potential of the biofuel alternatives 1-octanol and di-n-butyl ether can be shown with this work. Gas chromatography-mass spectrometry revealed that the composition of hydrocarbons emitted with the C 8 -oxygenates is almost equal to those with diesel, except for the unburned fuel that is present in the exhaust gas. Quantification showed that the carcinogenic component 1,3-butadiene increased with the alternative fuel candidates, whereas particularly benzene and ethyl benzene reduced. Since both di-n-butyl ether and 1-octanol are found in high proportions in the exhaust gas, the effects on the aftertreatment system have to be investigated in a subsequent campaign.