Engine performance and emissions analysis in a cold, intermediate and hot start diesel engine

Presented in this paper is an in-depth analysis of the impact of engine start during various stages of engine warm up (cold, intermediate, and hot start stages) on the performance and emissions of a heavy-duty diesel engine. The experiments were performed at constant engine speeds of 1500 and 2000 rpm on a custom designed drive cycle. The intermediate start stage was found to be longer than the cold start stage. The oil warm up lagged the coolant warm up by approximately 10 °C. During the cold start stage, as the coolant temperature increased from ~25 to 60 °C, the brake specific fuel consumption (BSFC) decreased by approximately 2% to 10%. In the intermediate start stage, as the coolant temperature reached 70 °C and the injection retarded, the indicated mean effective pressure (IMEP) and the brake mean effective pressure (BMEP) decreased by approximately 2% to 3%, while the friction mean effective pressure (FMEP) decreased by approximately 60%. In this stage, the NOx emissions decreased by approximately 25% to 45%, while the HC emissions increased by approximately 12% to 18%. The normalised FMEP showed that higher energy losses at lower loads were most likely contributing to the heating of the lubricating oil.</p

The effect of transient operation on diesel particulate emission

One adult male inhales about 10.8 m3 of air per day. Therefore, achieving good air quality is a global concern from a health point of view. As one of the most prevalent toxic pollution sources are emissions from diesel fleets, researchers have been introducing various approaches to reduce the exhaust emission, such as introducing new fuels and engine modifications (Ristovski, 2012). Most of the current research has focused on emission reduction methods in steady-state operating modes; however, the daily driving schedule of automotive and truck vehicles is inherently unsteady. Moreover, the most critical conditions encountered by engines are met during transient operations. Despite the increased complexity, results from tests involving transient operation are more closely related to reality than steady-state testing, in most cases (Giakoumis, 2012). Generally, transient operation could refer to operating conditions that are not steady-state, such as: free acceleration, load changes, cold start and driving cycles. For example, cold start emissions from a heavy duty vehicle reported to be 15 times higher than their steady-state values (Giakoumis, 2012). This study intends to show the effect of transient operation on exhaust particulate emission by adapting the stall test, as outlined in MDG29, Guideline for the management of diesel engine pollutants in underground environments in New South Wales-Australia (MDG29, 2008), to a repeatable engine testbed drive cycle. For this implementation, the stall test is designed to be performed on three speeds, (1500, 2000 and 2400) with a similar pattern. At each speed the engine is on idle for 20 s, then accelerated from idle to full load (100% throttle) as quickly as possible and held there for a defined period at which point the throttle is return to 0%. Each point is repeated three times with 20 s of idle between each test. To ensure integrity between the tests, there is 50 s of idle between the unique tests (varying period at full load). The full load time are defined as 5, 10, 20, 30, 40, 50 and 60 s. In this experimental study a heavy-duty, six cylinder, turbo-charged, after-cooled diesel engine with a common rail injection system is used. Engine load and speed are controlled by an electronically water brake dynamometer. DMS500 MkII Fast Particle Analyzer utilised to measure diesel particulate matter. The results show that the amount of emission depends on the duration of full load operation. Figure 2 shows the average particulate mass of three repeats under different durations of full load at 2000 RPM on the stall test. It shows that by increasing the duration of full load operation from 5 s to 60 s, the measured diesel particulate emission reduces significantly by 40 %. This work was supported by Biofuel Engine Research Facility (BERF), Queensland University of Technology. Giakoumis, E. G., Rakopoulos, C. D., Dimaratos, A. M., &amp; Rakopoulos, D. C. (2012). Exhaust emissions of diesel engines operating under transient conditions with biodiesel fuel blends. Progress in Energy and Combustion Science, 38(5), 691-715. MDG29. (2008). Guideline for the management of diesel engine pollutants in underground environments. New South Wales Mine Safety Operations Division. Ristovski, Z. D., Miljevic, B., Surawski, N. C., Morawska, L., Fong, K. M., Goh, F., &amp; Yang, I. A. (2012). Respiratory health effects of diesel particulate matter. Respirology, 17(2), 201-212

Particulate number emissions during cold-start with diesel and biofuels: A special focus on particle size distribution

The share of biofuels in the transportation sector is increasing. Previous studies revealed that the use of biofuels decreases the size of particles (which is linked to an increase in particulate toxicity). Current emission regulations do not consider small particles (sub-23 nm); however, there is a focus in future emissions regulations on small particles. These and the fact that within cold-start emissions are higher than during the warmed-up operation highlight the importance of a research that studies particulate matter emissions during cold-start. This research investigates the influence of biofuel on PN and PM concentration, size distribution, median diameter and cumulative share at different size ranges (including sub-23 nm and nucleation mode) during cold-start and warm-up operations using diesel and 10, 15 and 20% mixture (coconut biofuel blended with diesel). During cold-start, between 19 and 29% of total PN and less than 0.8% of total PM were related to the nucleation mode (sub-50 nm). Out of that, the share of sub-23 nm was up to 9% for PN while less than 0.02% for PM. By using biofuel, PN increased between 27 and 57% at cold-start; while, the increase was between 4 and 19% during hot-operation. The median diameter also decreased at cold-start and the nucleation mode particles (including sub-23 nm particles) significantly increased. This is an important observation because using biofuel can have a more adverse impact within cold-start period which is inevitable in most vehicles’ daily driving schedules.<br/

Experimental Investigation of Diesel Engine Performance, Combustion and Emissions Using a Novel Series of Dioctyl Phthalate (DOP) Biofuels Derived from Microalgae

Physico-chemical properties of microalgae biodiesel depend on the microalgae species and oil extraction method. Dioctyl phthalate (DOP) is a clear, colourless and viscous liquid as a plasticizer. It is used in the processing of polyvinyl chloride (PVC) resin and polymers. A new potential biofuel, hydrothermally liquefied microalgae bio-oil can contain nearly 11% (by mass) of DOP. This study investigated the feasibility of using up to 20% DOP blended in 80% diesel fuel (v/v) in an existing diesel engine, and assessed the performance and exhaust emissions. Despite reasonable differences in density, viscosity, surface tension, and boiling point, blends of DOP and diesel fuel were found to be entirely miscible and no separation was observed at any stage during prolonged miscibility tests. The engine test study found a slight decrease in peak cylinder pressure, brake, and indicated mean effective pressure, indicated power, brake power, and indicated and brake thermal efficiency with DOP blended fuels, where the specific fuel consumption increased. This is due to the presence of 16.4% oxygen in neat DOP, responsible for the relatively lower heating value, compared to that of diesel. The emission tests revealed a slight increase in nitrogen oxides (NOx) and carbon monoxide (CO) emissions from DOP blended fuels. However, particulate matter (PM) emissions were lower from DOP blended fuels, although some inconsistency in particle number (PN) was present among different engine loads

Ignition delay in an ethanol fumigated common rail diesel engine

A novel method for determining ignition delay is presented. This method utilises combustion resonance as a means of determining the onset of ignition. Results are shown from an ethanol fumigation study comprising of substitutions up to 50% at full, three-quarter and half load. It has been demonstrated that at full load there is a decrease in ignition delay with increasing ethanol substitutions, whereas at half load there is an increase in ignition delay with increasing ethanol substitutions. It is suggested that this conflicting result is a consequence of the auto ignition of ethanol

Continuous remote emissions monitoring - the lynchpin for air quality management

Diesel particulate matter (DPM), in particular, has been likened in a somewhat inflammatory manner to be the ‘next asbestos’. From the business change perspective, there are three areas holding the industry back from fully engaging with the issue: 1. There is no real feedback loop in any operational sense to assess the impact of investment or application of controls to manage diesel emissions. 2. DPM are getting ever smaller and more numerous, but there is no practical way of measuring them to regulate them in the field. Mass, the current basis of regulation, is becoming less and less relevant. 3. Diesel emissions management is generally wholly viewed as a cost, yet there are significant areas of benefit available from good management. This paper discusses a feedback approach to address these three areas to move the industry forward. The six main areas of benefit from providing a feedback loop by continuously monitoring diesel emissions have been identified: 1. Condition-based maintenance. Emissions change instantaneously if engine condition changes. 2. Operator performance. An operator can use a lot more fuel for little incremental work output through poor technique or discipline. 3. Vehicle utilisation. Operating hours achieved and ratios of idling to under power affect the proportion of emissions produced with no economic value. 4. Fuel efficiency. This allows visibility into other contributing configuration and environmental factors for the vehicle. 5. Emission rates. This allows scope to directly address the required ratio of ventilation to diesel emissions. 6. Total carbon emissions - for NGER-type reporting requirements, calculating the emissions individually from each vehicle rather than just reporting on fuel delivered to a site

In-cylinder pressure and inter-cycle variability analysis for a compression ignition engine : Bayesian approaches

This thesis introduced Bayesian statistics as an analysis technique to isolate resonant frequency information in in-cylinder pressure signals taken from internal combustion engines. Applications of these techniques are relevant to engine design (performance and noise), energy conservation (fuel consumption) and alternative fuel evaluation. The use of Bayesian statistics, over traditional techniques, allowed for a more in-depth investigation into previously difficult to isolate engine parameters on a cycle-by-cycle basis. Specifically, these techniques facilitated the determination of the start of pre-mixed and diffusion combustion and for the in-cylinder temperature profile to be resolved on individual consecutive engine cycles. Dr Bodisco further showed the utility of the Bayesian analysis techniques by applying them to in-cylinder pressure signals taken from a compression ignition engine run with fumigated ethanol

Presentation and Evaluation of a New Graduate Unit of Study in Engineering Product Development

Engineering education has a key role to play in equipping engineers with the design skills that they need to contribute to national competitiveness. Product design has been described as &ldquo;the convergence point for engineering and design thinking and practices&rdquo;, and courses in which students design, build, and test a product are becoming increasingly popular. A sound understanding of product development and the implications associated with developing a product have been strongly linked to sustainability outcomes. This paper presents an evaluation of a new Master level engineering unit offered at Deakin University in product development technology. The unit allowed the students an opportunity to engage with the entire product development cycle from the initial idea to prototyping and testing through strategic assessment, which drove the unit content and student learning. Within this, students were also afforded an opportunity to explore resource usage and subsequent minimisation. Student evaluation surveys over two successive years found that students were responsive to this type of learning and appreciated the opportunity to do hands-on work. Improved student effort and engagement indicate that the students likely had better learning outcomes, as compared to traditionally taught units

Practicalities and driving dynamics of a real driving emissions (RDE) Euro 6 regulation homologation test

&copy; 2019 by the authors. One of the most important sources of air pollution, especially in urban areas, is the exhaust emissions from passenger cars. New European emissions regulations, to minimize the gap between manufacturer-reported emissions and those emitted on the road, require new vehicles to undergo emission testing on public roads during the certification process. Outlined in the new regulation are specific boundary conditions to which the route on which the vehicle is driven must comply during a legal test. These boundary conditions, as they relate to the design and subsequent driving of a compliant route, are discussed in detail. The practicality of designing a compliant route is discussed in the context of developing a route on the Gold Coast in Queensland, Australia, in a prescriptive manner. The route itself was driven 5 times and the results compared against regulation boundary conditions