The effect of compression ratio on exhaust emissions from a PCCI diesel engine

Laguitton, O.; Crua, Cyril; Cowell, T. A.; Heikal, Morgan; Gold, Martin

doi:10.1016/j.enconman.2007.07.016

Cited by 118 publications

(42 citation statements)

References 11 publications

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“…PCCI combustion avoids circumstances which result in high NO x and soot emission [1][2][3]. Very low NO x emissions are achieved in this concept by operating with a highly diluted mixture which lowers the in-cylinder temperature, resulting in low-temperature combustion (LTC).…”

Section: Introductionmentioning

confidence: 99%

Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

Egüz

Maes

Leermakers

et al. 2013

Int.J Automot. Technol.

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Premixed charge compression ignition (PCCI) is a clean and efficient alternative for classical diesel combustion. The concept of PCCI combustion is associated with early injection of the fuel whilst applying high exhaust gas recirculation (EGR) levels and operation with a highly lean mixture such that ignition takes place (well) after the injection event. Thus, it is possible to reduce soot and oxides of nitrogen (NO x ) emissions simultaneously. PCCI combustion is analyzed using a multi-zone model. In the multi-zone model, chemical mechanisms which are much more detailed compared to those used in computational fluid dynamics (CFD) approaches can be introduced directly. The CFD model is still used to predict the initial fuel stratification in the cylinder which is important to improve the quality of the model. For the analysis, dedicated experiments with n-heptane are used to evaluate the results of the model. In such a multi-zone model, 10 zones prove to be sufficient to describe the stratification with adequate resolution. It is observed that different fuel distributions have a large influence on the emissions when there is no mixing between the zones. To overcome this dependence, a basic inter-zonal diffusive 2 mixing is applied. The level of mixing is estimated with a sensitivity study. When the inter-zonal mixing is included, emission results become much less sensitive to the crank angle (CA) at which the charge stratification is sampled and the simulation is initialized.

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Section: Introductionmentioning

confidence: 99%

Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

Egüz

Maes

Leermakers

et al. 2013

Int.J Automot. Technol.

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“…In order to overcome these problems various modifications in engine operating parameters are suggested. The various modifications suggested are varying the compression ratio [16][17][18], injection pressure [19][20][21], use of multiple injections, oil preheating, and so forth [22][23][24]. Table 1 presents the comparison of properties of diesel and biodiesel (Jatropha).…”

Section: Introductionmentioning

confidence: 99%

Investigations on Performance and Emission Characteristics of Diesel Engine with Biodiesel (Jatropha Oil) and Its Blends

Pandhare

Padalkar²

2013

Journal of Renewable Energy

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This paper presents the performance of biodiesel blends in a single-cylinder water-cooled diesel engine. All experiments were carried out at constant speed 1500 rpm and the biodiesel blends were varied from B10 to B100. The engine was equipped with variable compressions ratio (VCR) mechanism. For 100% Jatropha biodiesel, the maximum fuel consumption was 15% higher than that of diesel fuel. The brake thermal efficiency for biodiesel and its blends was found to be slightly higher than that of diesel at various load conditions. The increase in specific fuel consumption ranged from 2.75% to 15% for B10 to B100 fuels. The exhaust gas temperature increased with increased biodiesel blend. The highest exhaust gas temperature observed was 430 ∘ C with biodiesel for load conditions 1.5 kW, 2.5 kW, and 3.5 kW, where as for diesel the maximum exhaust gas temperature was 440 ∘ C. The CO 2 emission from the biodiesel fuelled engine was higher by 25% than diesel fuel at full load. The CO emissions were lower with Jatropha by 15%, 13%, and 13% at 1.5 kW, 2.5 kW, and 3.5 kW load conditions, respectively. The NO emissions were higher by 16%, 19%, and 20% at 1.5 kW, 2.5 kW, and 3.5 kW than that of the diesel, respectively.

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“…Results comparing an injection timing swing using bowl B6 and work on a similar engine from reference [13] are shown in figure 5. It can be seen that much lower NOx and particulate emissions were achieved at 35% EGR and at very low NOx levels, there was a significant particulate emissions penalty at the higher EGR rates required for the conventional combustion system.…”

Section: Bar Imep Key Pointmentioning

confidence: 99%

A Late Injection Combustion Strategy Using a Novel Ramped Combustion System

Morgan

Heikal

Pike-Wilson

2017

SAE Technical Paper Series

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Traffic related NOx and particle emission remain a significant concern particularly in the urban environment. Electrification offers a medium to long term solution, but there remains a need to significantly reduce internal combustion engine emissions in the short and medium term, and potentially in the long term for long range inter city transportation. Late injection low temperature combustion (LTC) has the potential to achieve ultra-low emissions levels in a compression ignition engine by increasing the lean pre-mixed burn fraction. However, significant quantities of diluent are normally required to achieve the required delay in ignition and pre-mixing to achieve LTC. This results in high boost requirements, increased pumping work and the complexity of the air handling system and potentially adversely impacting fuel economy. In this paper, results from a single cylinder light duty research engine are presented using a novel ramped combustion chamber focused at mid to high engine loads. The ramped combustion chamber improves mixing and enables more retarded injection timings than those possible on conventional bowl designs. This combustion strategy has enabled LTC conditions to be achieved at lower dilution rates, typically 20-30% at loads up to 15bar IMEP. CFD analysis of the air-fuel interaction indicates the ramped bowl effectively deflects fuel away from the squish region enabling very late injection timings. One dimensional analysis of the engine system was used to investigate the potential of late exhaust valve opening in improving work recovery, resulting in improved fuel consumption over the baseline LTC valve timings.

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The effect of compression ratio on exhaust emissions from a PCCI diesel engine

Cited by 118 publications

References 11 publications

Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

Investigations on Performance and Emission Characteristics of Diesel Engine with Biodiesel (Jatropha Oil) and Its Blends

A Late Injection Combustion Strategy Using a Novel Ramped Combustion System

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