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This work experimentally investigates the impact of premixed fuel composition (methane/ethane, methane/propane, and methane/hydrogen mixtures having equivalent chemical energy) and pilot reactivity (cetane number) on diesel-pilot injection (DPI) combustion performance and emissions, with an emphasis on the pilot ignition delay (ID). To support the experimental pilot ignition delay trends, an analysis technique known as Mixing Line Concept (MLC) was adopted, where the cold diesel surrogate and hot premixed charge are envisioned to mix in a 0-D constant volume reactor to account for DPI mixture stratification. The results show that the dominant effect on pilot ignition is the pilot fuel cetane number, and that the premixed fuel composition plays a minor role. There is some indication of a physical effect on ignition for cases containing premixed hydrogen.

In this study, the impacts of fuel volatility and reactivity on combustion stability and emissions were studied in a light-duty single-cylinder research engine for a three-injection catalyst heating operation strategy with late post-injections. N-heptane and blends of farnesane/2,2,4,4,6,8,8-heptamethylnonane were used to study the impacts of volatility and reactivity. The effect of increased chemical reactivity was also analysed by comparing the baseline #2 diesel operation with a pure blend of mono-ether components (CN > 100) representative of potential high cetane oxygenated bioblendstocks and a 25 vol.% blend of the mono-ether blend and #2 diesel with a cetane number (CN) of 55. At constant reactivity, little to no variation in combustion performance was observed due to differences in volatility, whereas increased reactivity improved combustion stability and efficiency at late injection timings.

Bioethanol is being used as an alternative fuel throughout the world based on considerations of reduction of CO2 emissions and sustainability. It is widely known that ethanol has an advantage of high anti-knock quality. In order to use the ethanol in ethanol-blended gasoline to control knocking, the research discussed in this paper sought to develop a fuel separation system that would separate ethanol-blended gasoline into a high-octane-number fuel (high-ethanol-concentration fuel) and a low-octane-number fuel (low-ethanol-concentration fuel) in the vehicle. The research developed a small fuel separation system, and employed a layout in which the system was fitted in the fuel tank based on considerations of reducing the effect on cabin space and maintaining safety in the event of a collision. The total volume of the components fitted in the fuel tank is 6.6 liters.

The effect of low level ethanol fuel on the power and emissions characteristics was studied in a small, mass produced, carbureted, spark-ignited, Briggs and Stratton Vanguard 19L2 engine. Ethanol has been shown to be an attractive renewable fuel by the automotive industry; having anti-knock properties, potential power benefits, and emissions reduction benefits. With increasing availability and the possible mandates of higher ethanol content in pump gasoline, there is interest in exploring the effect of using higher content ethanol fuels in the small utility engine market. The fuels in this study were prepared by gravimetrically mixing 98.7% ethanol with a balance of 87 octane no-ethanol gasoline in approximately 5% increments from pure gasoline to 25% ethanol. Alcor Petrolab performed fuel analysis on the blended fuels and determined the actual volumetric ethanol content was within 2%.

In this work we studied the effects of piston bowl design on combustion in a small-bore direct-injection diesel engine. Two bowl designs were compared: a conventional, omega-shaped bowl and a stepped-lip piston bowl. Experiments were carried out in the Sandia single-cylinder optical engine facility, with a medium-load, mild-boosted operating condition featuring a pilot+main injection strategy. CFD simulations were carried out with the FRESCO platform featuring full-geometric body-fitted mesh modeling of the engine and were validated against measured in-cylinder performance as well as soot natural luminosity images. Differences in combustion development were studied using the simulation results, and sensitivities to in-cylinder flow field (swirl ratio) and injection rate parameters were also analyzed.

With accelerating exhaust gas regulations in recent years, not only CO / HC / NOx but also PN regulation represented by Euro 6 d, China 6 are getting stricter. PN reduction by engine combustion technology development also progresses, but considering RDE, PN reduction by after treatment technology is also indispensable. To reduce PN exhausted from the gasoline engine, it is effective to equip GPF with a filter structure. Considering the installation of GPF in limited space, we developed a system that so far replaces the second TWC with GPF for the TWC 2 bed system. In order to replace the second TWC with GPF, we chose the coated GPF with filtering and TWC functions. Since the initial pressure drop and the catalyst amount (purification performance) of coated GPF have a conflicting relationship, we developed the coated GPF that can achieve both the low initial pressure drop and high purification performance.

In recent years along with stringent the regulations, vehicles equipped with gasoline particulate filter (GPF) have started to launch. Compared to bare GPF, coated GPF (cGPF) requires not only PN filtration efficiency, low pressure drop, but also purification performance. In the wall flow type cGPF having a complicated the pore shape, the pore structure further irregularly changes depending on the coated state of the catalyst, so it is difficult to understand the matter of in-wall. In order to advance of cGPF function, it was researched that revealing the relevance between pore structure change in the wall and GPF function. Therefore, to understand the catalyst coated state difference, cGPF of several coating methods were prepared, and their properties were evaluated by various analyses, and performance was tested.

To evaluate the relationship between the exhaust gas purification performance and the catalyst pore properties related to gas diffusion, an elementary reaction model was combined with gas diffusion into catalyst pores, referred to as the pseudo-2D gas diffusion/reaction model. It was constructed for Pt/Al2O3 + CeO2 catalyst as lean NOx catalyst. The gas diffusion was described as macro pore diffusion between the catalyst particles and meso pore diffusion within the particle. The kinetic model was composed of 26 reactions of NO/CO/O2 chemistry including 17 Pt/Al2O3 catalyst reactions and 9 CeO2 reactions. Arrhenius parameters were optimized using activity measurement results from various catalysts with various pore properties, meso pore volume and diameter, macro pore volume and diameter, particle size, and washcoat thickness. Good agreement was achieved between the measured and calculated values.

When a vehicle is driven in snowy conditions, if a proper air intake design is not adopted, the snow lifted by the leading vehicles may penetrate into the engine air intake, in case of large snow ingress amount, causing a power drop. The evaluation of such risk for the intake is carried out through climatic wind tunnel tests, which cannot be conducted at the early stage of vehicle development when the prototype vehicle does not exist. In order to study that risk prior to the prototype vehicle delivery, computational fluid dynamics (CFD) which predicts the snow ingress amount accurately was established with taking into account unsteady air flow and snow accumulation. Large Eddy Simulation (LES) was used to reproduce the unsteady flow field, leading to a good agreement of the flow downstream from the snow generator with the experimental one measured by Particle Image Velocimetry (PIV). As for the snow particle behavior model, the Lagrangian method was chosen.

Honda diesel engine vehicles that go on the market in 2018 will be equipped with a newly developed silver (Ag)-type catalyzed diesel particulate filter (cDPF). Ag has high particulate matter (PM) oxidation performance, but conventional catalyst-carrying methods cause weak contact property between PM and Ag; therefore, the newly Ag-type cDPF was developed on the concept of enhancing the property of contact between PM and the catalyst to realize contact property enhancement at the macro, meso, and nano scales. As a result, the newly developed catalyst showed an enhancement of T90 performance by a factor of approximately 2 relative to the conventional Ag-type catalyst in fresh condition. Durability in the environment of an automobile in use was examined through hydrothermal aging, lean-rich (L/R) aging, sulfur (S) poisoning, and ash deposition. The results have confirmed that hydrothermal aging is the greatest factor in deterioration.

Lean-burn is an effective means of reducing CO2 emissions. To date, Homogenous Lean Charge Spark Ignition (HLSI) combustion, which lowers emissions of both CO2 and NOx, has been studied. Although HLSI realizes lower emission, it is a major challenge for lean-burn engines to meet SULEV regulations, so we have developed a new aftertreatment system for HLSI engines. It consists of three types of catalysts that have different functions, as well as special engine control methods. As the first stage in achieving SULEV emissions, this study focused on enhancing performance under lean conditions. HLSI engine exhaust gases contain high concentrations of hydrocarbons, including a large amount of paraffin, which are difficult to purify, rather than low concentrations of NOx. Therefore, the key point in low emissions is to purify not only NOx, but also high concentrations of paraffin at the same time.

We present an approach in which we use simulation to capture the two-way coupling between the dynamics of a vehicle and that of a fluid that sloshes in a tank attached to the vehicle. The simulation is carried out in and builds on support provided by two modules: Chrono::FSI (Fluid-Solid Interaction) and Chrono::Vehicle. The dynamics of the fluid phase is governed by the mass and momentum (Navier-Stokes) equations, which are discretized in space via a Lagrangian approach called Smoothed Particle Hydrodynamics. The vehicle dynamics is the solution of a set of differential algebraic equations of motion. All equations are discretized in time via a half-implicit symplectic Euler method. This solution approach is general - it allows for fully three dimensional (3D) motion and nonlinear transients. We demonstrate the solution in conjunction with the simulation of a vehicle model that performs a constant radius turn and double lane change maneuver.

The aim of this study is to clarify the mixture formation in the combustion chamber of our developed natural gas engine incorporating the sub-chamber injection system, in which natural gas is directly injected into a combustion sub-chamber in order to completely separate rich mixture in the sub-chamber, suitable for ignition, from ultra-lean mixture in the main chamber. Mixture distributions in chambers with and without sub-chamber were numerically simulated at a variety of operating conditions. The commercial software of Fluent 16.0 was used to conduct simulations based on Reynolds averaged Navier-Stokes equations in an axial 2 dimensional numerical domain considering movements of piston. Non-reactive flow in the combustion chamber was simulated before the ignition timing at an engine speed of 2000 rpm. The turbulence model employed here is standard k-ε model. Air-fuel ratio is set with a lean condition of 30.

The performance of Gasoline Direct Injection (GDI) engines is governed by multiple physical processes such as the internal nozzle flow and the mixing of the liquid stream with the gaseous ambient environment. A detailed knowledge of these processes even for complex injectors is very important for improving the design and performance of combustion engines all the way to pollutant formation and emissions. However, many processes are still not completely understood, which is partly caused by their restricted experimental accessibility. Thus, high-fidelity simulations can be helpful to obtain further understanding of GDI injectors. In this work, advanced simulation and experimental methods are combined in order to study the spray characteristics of two different 3-hole GDI injectors.

In recent years, adhesive bonding is increasingly being applied in the construction of vehicle frames in order to improve body stiffness and crash performance. Regarding crash performance, the behavior of impacted components is affected by the fracture energy value of the adhesive. However, the relationship between the ductility and fracture energy values under mixed-mode loadings has not been sufficiently evaluated. In this paper, the fracture energy of three structural adhesives in a static mixed-mode loading using Double Cantilever Beam (DCB) specimens is presented. To derive the fracture energy values, the Compliance Based Beam Method (CBBM) was used, which allowed for precise determination of fracture energy values. Static mixed-mode loading tests were performed in six configurations of mixed-mode loading, ranging from pure peel mode state to almost pure shear mode state.

In recent years, improvements in the fuel economy and exhaust emission performance of internal combustion engines have been increasingly required by regulatory agencies. One of the salient concerns regarding general purpose engines is the larger amount of CO emissions with which they are associated, compared with CO emissions from automobile engines. To reduce CO and other exhaust emissions while maintaining high fuel efficiency, the optimization of total engine system, including various design parameters, is essential. In the engine system optimization process, cycle simulation using 0-D and 1-D engine models are highly useful. To define an optimum design, the model used for the cycle simulation must be capable of predicting the effects of various parameters on the engine performance. In this study, a model for predicting the performance of a general purpose SI (Spark Ignited) engine is developed based on the commercially available engine simulation software, GT-POWER.

Compression ignition combustion with a lean mixture has high potential in terms of high theoretical thermal efficiency and low NOx emission characteristics due to low combustion temperatures. In particular, a Dual-Fuel concept is proposed to achieve high ignition timing controllability and an extended operation range. This concept controls ignition timing by adjusting the fraction of two fuels with different ignition characteristics. However, a rapid combustion process after initial ignition cannot be avoided due to the homogenous nature of the fuel mixture, because the combustion process depends entirely on the high reaction rate of thermal ignition. In this study, the effect of mixture stratification in the cylinder on the combustion process after ignition based on the Dual-Fuel concept was investigated. Port injection of one fuel creates the homogeneous mixture, while direct injection of the other fuel prepares a stratified mixture in the cylinder at the compression stroke.

In the early stages of aerodynamic development of commercial vehicles, the aerodynamic concept is balanced with the design concept using CFD. Since this development determines the aerodynamic potential of the vehicle, CFD with high accuracy is needed. To improve its accuracy, spatial resolution of CFD should be based on flow phenomenon. For this purpose, to compare aerodynamic force, pressure profile and velocity vector map derived from CFD with experimental data is important, but there are some difficulties to obtain pressure profile and velocity vector map for actual vehicles. At the point of pressure measurement for vehicles, installation of pressure taps to the surface of vehicle, i.e., fuel tank and battery, is a problem. A new measurement method developed in this study enables measurement of surface pressure of any desired points. Also, the flexibility of its shape and measuring point makes the installation a lot easier than the conventional pressure measurement method.

It is important to take action regarding environmental issues on a global scale, and automakers are adding downsized turbocharged engines to their line-ups as a means of reducing CO2 emissions, particularly in Europe. Honda has recently announced a next-generation powertrain series that realizes a good balance between environmental performance and driving pleasure. As part of this series, the company has developed a downsized and turbocharged 2.0L gasoline direct injection engine. This is a high-powered sports car engine positioned in the European “hot hatch” category. The development balanced engine power with good environmental performance.

Several attempts have been reported in the past decade or so which measured the sizes of particles in lubricant oil in order to monitor sliding conditions (1). Laser light extinction is typically used for the measurement. It would be an ideal if only wear debris particles in lubricant oil could be measured. However, in addition to wear debris, particles such as air bubbles, sludge and foreign contaminants in lubricant oil are also measured. The wear debris particles couldn't have been separated from other particles, and therefore this method couldn't have been applied to measurement devices for detection when maintenance service is required and how the wear state goes on. It is not possible to grasp the abnormal wear in real time by the conventional techniques such as intermittent Ferro graphic analysis. In addition, it is no way to detect which particle size to be measured by the particle counter alone.