Heavy-duty Diesel Engine Research Articles

Research on Destructive Knock Combustion Mechanism of Heavy-Duty Diesel Engine at Low Temperatures

Research on Destructive Knock Combustion Mechanism of Heavy-Duty Diesel Engine at Low Temperatures

Effects of Intake Valve Closure Timing on Heavy-Duty Diesel Engine Performance

Effects of Intake Valve Closure Timing on Heavy-Duty Diesel Engine Performance

Study on Exhaust Gas Heating with Electric Heater for Heavy-Duty Diesel Engine

Study on Exhaust Gas Heating with Electric Heater for Heavy-Duty Diesel Engine

Технические и экологические аспекты новых требований к эксплуатационным свойствам перспективных моторных масел

The modern development of transport is at the stage of energy transition to its zero-carbon operation with the use of alternative energy sources instead of traditional liquid fuel. It is assumed that the operation of transport using electric motors and hydrogen fuel cells in the future will be able to represent a significant segment of the global economy. Manufacturers of heavy-duty vehicles and buses are currently actively investing in so-called carbon neutrality technologies and are activating the technical capabilities of options for using electric vehicles for heavy operating conditions. At the same time, along with the electrification of vehicles, the popularity of traditional piston internal combustion engines remains, including in hybrid car models. The new environmental regulations Euro-7, which are part of the European "Green Agreement", include stricter emission standards for all gasoline and diesel cars, vans, trucks and buses. This is part of the EU's commitment to support the goal of achieving carbon neutrality by 2050. In connection with the latest achievements in the design of diesel engines, the development of a new category of PC-12 engine oil for heavy-duty diesel engines is officially underway in order to replace the oils of the existing categories CK-4 and FA-4 according to API. The category of oils in the projected specification is planned to be divided into subcategories that provide conditions for their use in heavy-duty transport: off-road conditions, including those with a high temperature load, assuming a high oil viscosity at 150 oC and a shear rate of 106 s-1 (High Temperature High Shear - HTHS), and highway operation. It is assumed that the new PC-12 specification will provide increased thermal-oxidative stability of oils and improved compatibility with elastomers in both subcategories, as well as wear tests with the inclusion of new methods.

Numerical Study of Wall-Impinging Ignition at Different Wall Distances for Cold Start of Heavy-Duty Diesel Engine

Numerical Study of Wall-Impinging Ignition at Different Wall Distances for Cold Start of Heavy-Duty Diesel Engine

Data Driven Modeling of Turbocharger Turbine using Koopman Operator

A turbocharger plays an essential part in reducing emissions and increasing the fuel efficiency of road vehicles. The pulsating flow of exhaust gases, along with high heat exchange from the turbocharger casing, makes developing control-oriented models difficult. Several researchers have used maps provided by manufacturers to solve this problem. These maps often fail to incorporate any heat transfer effects and are unsuitable for wide operating regions. Also, with the availability of more and better sensor data, there is a need for a method that can exploit this to obtain a better predictive model. Koopman approaches rely on the observation that one can lift the nonlinear dynamics of the turbine into an infinite-dimensional function space over which dynamics are linear. The objective of this paper is to develop a model to predict the transient and steady-state behavior of the turbine using the Koopman operator which can be helpful for control design and analysis. Our approach is as follows. We use experimental data from a Cummins heavy-duty diesel engine to develop a turbine model using Extended Dynamic Mode Decomposition, which approximates the action of the Koopman operator on a finite-dimensional subspace of the space of observables. The results demonstrate superior performance compared to a tuned nonlinear autoregressive network with an exogenous input model widely used in the literature. The performance of these two models is analyzed based on their ability to predict turbine transient and steady-state behavior.

Emission characteristics analysis under California low load cycle for a China VI heavy-duty diesel engine

A 6.2 L diesel engine that meets China VI emission standard was selected to run world harmonized transient cycle (WHTC) and California Low Load Cycle (LLC) to measure the pollutants. The brake specific emission under the two cycles were compared, and nitrogen oxides (NOx) emission were analyzed carefully. The results show that the NOx emission of the LLC of this engine is about 15 times than that of the hot WHTC, and 4.7 times than that of the limitation of current China VI emission standard. The low inlet temperature of selective catalytic reduction (SCR) is the predominant reason for the high NOx emission in the LLC. The SCR inlet temperature of lower than 200°C in LLC accounts for 52% of the total time with an average inlet temperature of only 190°C. While the inlet temperature of lower than 200°C of the hot WHTC only accounts for 7% with the average inlet temperature of 275°C. The average SCR catalytic efficiency calculated by NOx sensor amounted on the upstream and downstream of LLC is only 75%, while the efficiency is 98% for hot WHTC. It is necessary to focus on thermal management of the aftertreatment system and the SCR catalytic performance at low temperature.

Effect of Injection Timing on Knock Combustion and Pollutant Emission of Heavy-Duty Diesel Engines at Low Temperatures

Effect of Injection Timing on Knock Combustion and Pollutant Emission of Heavy-Duty Diesel Engines at Low Temperatures

Study on impinging ignition and wall-attached fuel film combustion characteristics of light- to heavy-duty diesel engines at low temperatures

The difference in impinging ignition characteristics of light- to heavy-duty diesel engines at low temperatures and the heating effect of fuel film combustion on the wall are still not well understood. Thus, visualization experiments are conducted in a constant volume combustion chamber using Mie-scattering and direct photography methods, and 3-D simulation is used to supplement and explain the experimental phenomena. The results show that the autoignition initiates in the free spray and then hits the wall for the 0.12 mm nozzle. However, 30% of the liquid fuel under the 0.32 mm nozzle adheres to the wall, and the cooling effect causes the evaporation rate to decrease by orders of magnitude. The mixture at the initial flame is mainly distributed in the low-temperature and low-concentration region, and coupled with the excessive fuel diffusion caused by spray-wall interaction, the transition from the cool flame to hot flame is severely slowed down. With the increase of nozzle diameter from 0.12 mm to 0.32 mm, the hot flame position shifts from the fuel-rich side to the fuel-lean side, the flame fluctuates greatly and the area decreases, and the critical ignition temperature increases from 753 K to 793 K. When the wall-attached fuel accumulated in a misfire or an unstable ignition condition is ignited again, the combustion lasts for nearly 100 ms. As the nozzle diameter increases from 0.12 mm to 0.32 mm, the peak wall temperature rises from 487 K to 556 K, and the heat flux increases nearly twice, which inevitably increases the heat load of the wall.

Effects of speed extension on PCCI combustion and emissions in a heavy-duty diesel engine at medium load

Effects of boost pressure, engine speed and multi-pulse injection timing on premixed charge compression ignition (PCCI) combustion and emissions in a heavy-duty diesel engine at medium load were studied experimentally and numerically. Results show that, intake boost makes the high temperature ignition timing advance, but the mass fraction of lean mixture increases dramatically and the mass fractions of rich and over-rich mixtures decrease significantly, indicating that intake boost helps the formation of lean and homogeneous mixture; the indicated thermal efficiency increases and the combustion loss decreases. When the engine speed is increased with other variables constant, the high temperature ignition timing is retarded, the mass fraction of over-rich mixture decreases; the NOx, soot, CO and UHC emissions are all decreased; the indicated thermal efficiency increases, the combustion loss decreases, but the exhaust loss increases. The delay of multi-pulse fuel injection timing with other variables constant shortens the mixing time, increases the mass fraction of over-rich mixture, and increases the initial soot generation. However, due to the combined effect of mixing space and combustion temperature, the final soot, CO and UHC emissions are all decreased, and the NOx emissions have little change; the indicated thermal efficiency increases, the combustion loss decreases, but the exhaust loss increases.

Evaluation of thermal processing and properties of 422 martensitic stainless steel for replacement of 4140 steel in diesel engine pistons

The thermal and mechanical properties of martensitic stainless steel 422 were evaluated for suitability as a drop-in replacement for 4140 steel in next generation heavy-duty diesel engine (HDDE) pistons. The time and temperature of the austenitization and tempering steps were studied to achieve optimum materials performance in piston applications, including the balance of thermal and mechanical properties and resistance to long-term thermal aging. Reducing the tempering temperature from 700 to 600 °C caused a substantial increase in elevated temperature strength from 25 to 600 °C, but had no significant influence on thermal conductivity, suggesting that thermal conductivity in 422 is dominated largely by composition and distribution of alloying elements and mostly independent of the sub-grain structure size and precipitate size. Compared to the current HDDE piston alloy 4140, 422 exhibits substantially higher elevated temperature strength and lower thermal conductivity, the latter which will cause 422 to operate at higher temperatures in pistons, possibly requiring a piston redesign to take advantage of the improved high temperature strength of 422. Piston material selection and alloy design strategies with potential to mitigate some of the shortcomings of martensitic stainless steels, such as 422, as drop-in replacements are discussed.

Measurements and analysis of a solar-assisted city bus with a diesel engine

The volatility nature of world fossil fuel economy and stringent emission regulations around the globe have routed to search for sustainable renewable energy resources for automotive applications. Photovoltaic is one of the finest sustainable energy resources which can make significant contributions in power generation applications and act as decarbonization method for greenhouse gas reductions. This research work is a novel attempt to develop hybrid photovoltaic solar electric system for electricity production in a heavy-duty diesel engine driven city bus. A dedicated solar PV system of 2.88 kWp rated power has been installed in a city bus roof for electricity generation and its solar radiation rate has been analysed in one year duration on monthly basis under all ambient conditions in the Lublin city of Poland. A well-equipped data acquisition system is used to collect all the data for estimating the energy savings and carbon dioxide reduction. The real investigation of solar assisted city bus has shown remarkable enhancement of electricity generation of 900 W in summer season at mid-day. Interestingly, the hybrid solar PV system provided 89% of total electricity demand of city bus during clear weather conditions and substantial contributions are obtained even during winter season as well. Out of total electricity demand of 6327.9 kWh of city bus, the solar hybrid PV systems shared nearly 1257.4 kWh of electricity for 64,000 km distance coverage in one complete year. It has also been observed that nearly 21% of total electricity demand of city bus is supplied by solar hybrid PV systems which can save the annual diesel consumption of 630 L and also reduce 1.6 tonnes of green house gas emissions. Finally, it is concluded that suitable photovoltaic technology for automotive applications would improve the world fuel economy and can also produce the clean environment in near future.

Gaseous and particulate emissions analysis using microalgae based dioctyl phthalate biofuel during cold, warm and hot engine operation

Presented in this study is an analysis of gaseous and particulate emissions for three selected fuels during cold, warm and hot engine operation; low sulphur neat diesel (D100), and 10 and 20% (% v/v) of dioctyl phthalate (DOP) blended with diesel. Experiments were conducted on a turbocharged common rail heavy-duty diesel engine over a custom-designed drive cycle. The impact of engine temperature and fuel properties during warm-up on emissions has been analysed. The presence of oxygen molecules in DOP was found to have a major influence on emissions. NOx emissions were higher by ∼ 10%, while the HC emissions were lower by ∼ 150% with DOP blended fuels, compared to D100, during cold engine operation. Total particle number (PN) concentration and total particle mass (PM) followed the same trend and decreased as the engine warmed up. Compared to both DOP blended fuels, total PN with D100 was higher during cold engine operation and reduced significantly as the engine warmed up. The particle count median diameter (CMD) was found to have an opposite trend with D100 (increasing with engine warm-up) compared to both DOP blended fuels (decreasing with engine warm-up).

Platinum Recovered from Automotive Heavy-Duty Diesel Engine Exhaust Systems in Hydrometallurgical Operation

The current study is focused on platinum recovery from the secondary sources of end-of-life heavy-duty diesel oxidation catalysts (DOCs) and heavy-duty catalyzed diesel particulate filters (c-DPFs) in order to reduce the supply–demand gap within the European Union. The extraction of platinum was based on a hydrometallurgical single-step low acidity leaching system (HCl-H2O2-NaCl) and a calcination step that takes place before the leaching process. The parameters of calcination and leaching process were thoroughly investigated in order to optimize recovery efficiency. The optimized results proved that a calcination step (at 800 °C for 2 h) improves the recovery efficiency by a factor of 40%. In addition, optimal Pt recovery yield was achieved after 3 h of leaching at 70 °C, with a solid-to-liquid (S/L) ratio of 70 g/100 mL (70%) and 3 M HCl-1% vol H2O2-4.5 M NaCl as leaching conditions. The optimum Pt recovery yield was 95% and 75% for DOC and c-DPF, respectively. Since the secondary feedstock investigated is highly concentrated in platinum, the pregnant solution can be used as a precursor for developing new Pt-based catalytic systems.

Consideration of the effects of increasing spray cone angle and turbulence intensity on heavy-duty diesel engine pollution and specific outputs using CFD

In this article, the effects of increasing spray cone angle and turbulence intensity on the performance and emission of heavy-duty diesel engine has been examined in two separate stages using AVL-Fire CFD code. First, the injector and its spray have been simulated with various geometries. In this step, the Eulerian-Eulerian model has been applied for injector simulation and the Eulerian -Lagrangian model has been applied for spray simulation. The numerical results of this step indicate that creating swirly flow inside the nozzle decreasing penetration length while, fuel spray cone angle increasing during the injection process. In the subsequent step, the heavy-duty diesel engine has been simulated with its conventional and different nozzle hole geometries. In this step, the Eulerian-Lagrangian model has been applied to simulate the engine cycle. The numerical results of this step show that the nozzle with spiral rifling like guides has better performance and lower emission compared to other nozzle geometries. In this case, the fuel consumption is decreasing 32% than cylindrical nozzle hole, while the engine power and its torque increasing 63%. In addition, the amount of nitrogen oxide (NOx) and carbon monoxide (CO) for the spiral convergent conical nozzle geometry reducing 15% and 30% respectively than cylindrical nozzle hole while engine has no soot emission problem. Diesel injector and engine CFD results and experimental data have been validated from previous researches.

Effect of SCR downsizing and ammonia slip catalyst coating on the emissions from a heavy-duty diesel engine

The combination of diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF) and selective catalytic reduction (SCR) is the most effective way to reduce particulate emission and nitrogen oxide (NOx) from diesel engines. In this study, the effects of a DOC+CDPF+SCR system on the emissions including carbon monoxide (CO) total hydrocarbon (THC), NOx, particle number (PN) and particle mass (PM) from a heavy-duty diesel engine were evaluated. In addition, the influences of ammonia (NH3) slip catalyst (ASC) coating and SCR catalyst downsizing on the NOx conversion efficiency, nitrous oxide (N2O) emissions and NH3 slip were also investigated. Results showed that the installation of the after-treatment system had negligible effect on the power and BSFC of the engine. The upstream DOC reduced by an average of 97.0% of the CO and 67.5% of the THC, in combination with CDPF, the CO and THC emission further decreased with an average drop of 97.8% and 72.5%, respectively. In terms of particulate emissions, the single DOC reduced 48.0% of the PN and 50.9% of the PM, and the combination of DOC and CDPF led to a reduction of 98.0% in the PN and 96.9% in the PM on average. The SCR was effective in reducing NOx emission, but resulted in higher N2O emission by more than 3 times, meanwhile led to an average NH3 slip of 3.80 ppm. Downsizing the SCR length by 1/3 could still ensure a 91.9% conversion efficiency of NOx, and produced less N2O, but led to an increase of the NH3 slip by 2 times, reaching 7.63 ppm on average. By coating Pt-based ASC catalyst on the back end of the SCR could eliminate the NH3 slip. Considering the cost and performance, the combination of DOC, CDPF and a downsized SCR with ASC coating may be a better choice.

Methodology of diesel particulate filter testing on test bed for non-road engine application

This paper describes the methodology and test results of diesel particulate filter (DPF) functional testing performed on non-road compression ignition engine installed on test bed. The scope of work included testing of various DPF regeneration strategies, backpressure and balance point tests and emission performance evaluation during a legislative test cycles. The aim of this study was to observe and investigate the influence of exhaust gas parameters on DPF functionality in terms of soot loading, type and duration of the regeneration and emission performance. Under investigation was also the capability of soot burning rate. The DPF sample under test was part of the complete exhaust aftertreatment system (ATS) which consisted of: a diesel oxidation catalyst (DOC), a DPF and a selective catalytic reduction system (SCR). Testing was carried out on a heavy-duty diesel engine installed on a test stand with a dynamic dynamometer and equipped with an emission bench. The test program allowed to assess the engine matching to exhaust aftertreatment system with regard to emissions compliance, in-service operation and necessary engine control unit (ECU) calibration works. The results show the influence of the DPF regeneration strategy on its duration and on the soot mass burn rate. Passive DPF regeneration was a favorable mode of DPF cleaning, due to lack of fuel penalty and lower aging impact on the entire ATS. Optimization of soot flow rate, exhaust gas temperature and the chemistry of the DOC/DPF was further recommended to ensure the long-term durability of the entire system.

Optimization of multiple-stage fuel injection and optical analysis of the combustion process in a heavy-duty diesel engine

The goals of this study were to optimize multiple-stage fuel injections and optically analyze the effects of multiple injections of fuel on the combustion process in a heavy-duty compressed ignition engine. The engine experiments consisted of pilot injection and post-injection experiments. The pilot injection quantities and timings were varied. The post-injection quantities and number of post injections were analyzed. Combustion images was obtained to calculate the flame temperature and soot density. The results revealed that premixed combustion by a single injection led to engine noise and vibration because of the long ignition delay. The optimal pilot injection strategy improved the engine noise, vibration, thermal efficiency, and nitrogen oxide emissions. However, a pilot injection induced diffusion combustion, and an increase in particulate matter emissions was inevitable. The optimized post-injection promoted the oxidization of incomplete combustion materials and provided a lower peak cylinder pressure, resulting in low nitrogen oxides and particulate matter emissions. The combustion images revealed that the pilot injection caused a moderate increase in flame temperature and high soot production. The post injection, however, effectively reduced the soot density during the late combustion period, resulting in a low soot density at the end of the observation period.

A methodology to assess mixer performance for selective catalyst reduction application in hot air gas burner

The active SCR aftertreatment system is one of the most crucial technology for the NOx reduction of diesel engines. One of the essential parameters of this technology is the urea spray performance on the catalyst. This study presents an experimental and numerical investigation of urea spray behavior used in the heavy-duty diesel engine's selective catalytic reduction (SCR) aftertreatment systems.The custom test rig is designed and built to simulate exhaust aftertreatment systems of heavy-duty diesel vehicles. Urea injector parameters were observed in this test rig with optic windows for spray and flow visualization. This test rig is available to simulate diesel engines in the sense of exhaust mass flow rate, temperature and spray control unit. The discussion is made about the effects of droplet size of spray and velocity distribution upon flow characterization.A detailed assessment of the numerical model was presented, and validation was carried out for different interest measurement locations. The predicted droplet size distributions, breakup performance, and velocities are numerically and correlated with the experimental data. The validated model is subsequently used to study the urea-flow mixing dynamics to develop a urea mixer numerically. Test results show that smaller droplets enhance the mixing and thus catalyst efficiency. Mixer design performance can be assessed numerically in the droplet size break up based on the developed criteria called mixer performance criteria. Upstream and downstream of the mixer, droplet size can be extracted from the simulation, and different mixer designs can be compared in terms of the breakup performance.

Extreme Miller cycle with high intake boost for improved efficiency and emissions in heavy-duty diesel engines

This study experimentally investigates the impact of extreme Miller cycle strategies paired with high intake manifold pressures on the combustion process, emissions, and thermal efficiency of heavy-duty diesel engines. Well-controlled experiments isolating the effect of Miller cycle strategies on the combustion process were conducted at constant engine speed and load (1160 rpm, 1.76 MPa net IMEP) on a single cylinder research engine equipped with a fully-flexible hydraulic valve train system. Late intake valve closing (LIVC) timing strategies were compared to a conventional intake valve profile under either constant cylinder composition, constant engine-out NOx emission, or constant overall turbocharger efficiency ([Formula: see text]) to investigate the operating constraints that favor Miller cycle operation over the baseline strategy. Utilizing high boost with conventional intake valve closing timing resulted in improved fuel consumption at the expense of sharp increases in peak cylinder pressures, engine-out NOx emissions, and reduced exhaust temperatures. Miller cycle without EGR at constant [Formula: see text] demonstrated LIVC strategies effectively reduce engine-out NOx emissions by up to 35%. However, Miller cycle associated with very aggressive LIVC timings led to fuel consumption penalties due to increased pumping work and exhaust enthalpy. LIVC strategies allowed for increased charge dilution at the baseline NOx constraint of 3.2 g/kWh, resulting in significant fuel consumption benefits over the baseline case without compromising exhaust temperatures or peak cylinder pressures. As Miller cycle implementation was shown to affect the boundary conditions dictating [Formula: see text], the LIVC and conventional IVC cases were studied at an equivalent [Formula: see text] point representative of high boost operation. With high boost, LIVC yielded reduced NOx emissions, reduced peak cylinder pressures, and elevated exhaust temperatures compared to the conventional IVC case without compromising fuel consumption.