On-board diagnosis of engine and transmission systems has been mandated by government regulation for light and medium vehicles since the 1996 model year. The regulations specify many of the detailed features that on-board diagnostics must exhibit. In addition, the penalties for not meeting the requirements or providing in-field remedies can be very expensive. This course is designed to provide a fundamental understanding of how and why OBD systems function and the technical features that a diagnostic should have in order to ensure compliant and successful implementation.
This course is designed to provide an overview of the fundamental design objectives and the features needed to achieve those objectives for generic on-board diagnostics. The basic structure of an on-board diagnostic will be described along with the system definitions needed for successful implementation.
This study experimentally investigates the combustion stability in RCCI engines along with the gaseous (regulated and unregulated) and particle emissions. Multifractal analysis is used to characterize the cyclic combustion variations in the combustion parameters (such as IMEP, CA50, Pmax) of the RCCI engine. The investigation is carried out on a modified single-cylinder diesel engine to operate in RCCI combustion mode. The RCCI combustion mode is tested for different fuel premixing ratio (r_p) and diesel injection timing (SOI) at fixed engine speed (1500rpm) and load (1.5 bar BMEP). The particle number characteristics and gaseous emissions are measured using a differential mobility spectrometer (DMS500) and Fourier Transform Infrared Spectroscopy (FTIR) along with Flame Ionizing Detector (FID), respectively. The results indicate that the NOx emissions decrease with advanced SOI while the methane (CH4) emission increases.
Due to increasingly strict emission regulations, the demand for internal combustion engine performance has enhanced. Combustion stability is one of the main research focuses due to its impacts on the emission level. Moreover, the combustion instability becomes more significant under the lean combustion concept, which is an essential direction of internal combustion engine development. The combustion instability is represented as the cycle-to-cycle variation. This paper presents a quasi-dimensional model system for solving the cycle-to-cycle variation in 0D/1D simulation. The modeling is based on the cause-and-effect chain of cycle-to-cycle variation of spark ignition engines, which is established through the flow field analysis of large eddy simulation results. In the model system, varying parameters are turbulent kinetic energy, the distribution of air-to-fuel equivalence ratio, and the in-cylinder velocity field.
An experimental study of the spark ignition process for SI engines was conducted to study spark plug erosion and its effect on breakdown voltage and electrode wear characteristics. The experiments were conducted outside of an engine, in both a pressurized constant volume optical chamber and in a high-pressure vessel heated within a furnace with gas temperatures as high as 700C. J-gap spark plugs designed for natural gas engines were studied at elevated temperature and under a range of pressures to investigate electrode wear characteristics. Both iridium-alloy and platinum-alloy electrode cathode and anode spark plugs were investigated. In addition, single spark events were performed on polished platinum cathode surfaces to allow the visualization of craters from individual spark events in order to quantify how their size and shape were affected by energy deposition and breakdown characteristics.
The passive pre-chamber is valued for its jet ignition and is widely used in the field of gasoline direct injection (GDI) for small passenger cars, which can improve the performance of lean combustion. However, the scavenging and ignition combustion stability of the engine at low speed is a shortcoming that has not been overcome. Simply changing the structural design to increase the fluidity of MC and PC may lead to a reduction in jet ignition performance, which in turn will affect engine dynamics. This investigation is based on a non-uniformly nozzles distributed passive pre-chamber, which is adjusted according to the working fluid exchange between PC and MC. The advantages and disadvantages of the ignition mode of PC and SI in the target engine speed range are compared through optical experiments on a small single cylinder GDI engine. The results show that with the increase of λ from 1.0 to 1.6, the promotion effect of PCJI on load performance gradually decreases.
Ammonia (NH3), a zero-carbon fuel, has great potential for internal combustion engine development. However, its high ignition energy, low laminar burning velocity, a narrow range of flammability limits, and high latent heat of vaporization are not conducive for engine application. This paper numerically investigates the feasibility of utilizing ammonia in a heavy-duty diesel engine, specifically through the method of low-pressure direct injection (LP-DI) of hydrogen to ignite ammonia combustion. The study compares the engine's combustion and emission performance by optimizing four critical parameters: excess air ratio, hydrogen blending ratio, ignition timing, and hydrogen injection timing. The results reveal that excessively high hydrogen blending ratios lead to an advanced combustion phase, resulting in a reduction in indicated thermal efficiency.
To satisfy recent stringent exhaust gas regulations, large amounts of Rh and Pd have been often employed in three-way catalysts (TWCs) as main active components. However, application of Pt-based TWCs are limited due to their lower thermal stability than Pd. Previously, we found that Pt-based TWCs with a small amount of CeO2 showed high catalytic performance in gasoline vehicles test. Especially, calcined CeO2 at high temperature before Pt loading (cal-CeO2) showed higher catalytic activity than untreated CeO2 after endurance at 1000 degree centigrade. This result could be attributed to higher redox performance and Pt dispersion derived from strong interaction between Ce and Pt. Even though cal-CeO2 has low specific surface area (SSA) given by preliminary calcination, it shows strong effects on catalytic performance. In other word, improvement of its SSA could be the most powerful way to prepare highly active Pt catalysts.
Engine knock is a major barrier to achieving higher engine efficiency by increasing the compression ratio of the engine. It is an abnormal event caused by the autoignition of air-fuel mixture ahead of the propagating flame front. A higher octane number fuel can be a good solution to reduce or eliminate the higher knock intensity and obtain better engine performance. Methanol is a promising alternative fuel, which has a higher octane number and can be produced from conventional and non-conventional energy resources to reduce pollutant emissions. This study compares the combustion characteristics of gasoline and methanol fuels in an optical spark-ignition engine using multiple spark plugs. The experiment was performed on a single-cylinder four-stroke optical engine. A customized metal liner equipped with four circumferential spark plugs was used to generate multiple flame kernels inside the combustion chamber.
This paper presents a feedback control strategy to minimize noise during dog clutch engagement in a hybrid transmission. The hybrid transmission contains an internal combustion engine(ICE) and 2 electric motors in P1 and P3 configurations. For efficiency during driving, at high vehicle speeds ICE is connected to wheels, via the dog clutch, hence shifting the vehicle from series to parallel hybrid mode. It is shown by experimental results that if the speed difference between the two sides of the dog clutch is below a certain level the engagement will be without clonk noise. In this paper the designed state feedback Linear Quadratic Integral (LQI) control provides the synchronization torque request to the P1 motor, hence matching the speed of one side of dog clutch with the other under the disturbance from combustion torque of the engine.
The growing global adoption of electric vehicles (EVs) emphasizes the pressing need for a comprehensive understanding of thermal runaway in lithium-ion batteries. Prevention of the onset of thermal runaway and its subsequent propagation throughout the entire battery pack is one of the pressing challenges of lithium-ion batteries. In addition to generating excess heat, thermal runaway of batteries also releases hazardous flammable gases, posing risks of external combustion and fires. Most existing thermal runaway models in literature primarily focus on predicting heat release or the total amount of vent gas. In this study, we present a model capable of predicting both heat release and the transient composition of emitted gases, including CO, H2, CO2, and hydrocarbons, during thermal runaway events. We calibrated the model using experimental data obtained from an 18650 cell from the literature, ensuring the accuracy of reaction parameters.
During the development of an Internal Combustion Engine-based powertrain, traditional procedures for control strategies calibration and validation produce huge amount of data, that can be used to develop innovative data-driven applications, such as emission virtual sensing. One of the main criticalities is related to the data quality, that cannot be easily assessed for such a big amount of data. This work focuses on an emission modeling activity, using an enhanced Light Gradient Boosting Regressor and a dedicated data pre-processing pipeline to improve data quality. First thing, a software tool is developed to access a database containing data coming from emissions tests. The tool performs a data cleaning procedure to exclude corrupted data or invalid parts of the test. Moreover, it automatically tunes model hyperparameters, it chooses the best set of features, and it validates the procedure by comparing the estimation and the experimental measurement.
The global energy crisis and drastic climate change are continuously promoting the implementation of sustainable energy sources. To meet the emission standards and carbon-neutrality targets in vehicle industry, ammonia is considered to be one of the promising carbon-neutral fuels. However, running the engines on high amounts of ammonia may lead to significantly high ammonia slip. This originates huge safety concerns. Therefore, hydrogen is added in certain ratio with ammonia to promote combustion and reduce ammonia slip. Furthermore, adding diesel as a pilot fuel further facilitates the combustion reactions. This experimental study investigated the effect of different ammonia-hydrogen blend ratios on in-cylinder pressure, heat release rate, combustion efficiency, and CA50. This effect of blend ratios was tested for varied diesel pilot amounts and timings.
In the perspective of a reduction of emissions and a rapid decarbonization, especially for compression ignition engines, hydrogen plays a decisive role. The dual fuel technology is perfectly suited to the use of hydrogen, a fuel characterized by great energy potential. In fact, replacing, at the same energy content, the fossil fuel with a totally carbon free one, a significant reduction of the greenhouse gases, like carbon dioxide and total hydrocarbon, as well as of the particulate matter can be obtained. The dual fuel with indirect injection of gaseous fuel in the intake manifold, involves the problem of hydrogen autoignition. In order to avoid this difficulty, the optimal conditions for the injection of the incoming mixture into the cylinder were experimentally investigated. All combustion processes have been carried out on a research engine with optical access. The engine speed has been set at 1500 rpm, while the EGR valve has been deactivated.
Argon power cycle hydrogen engine is the internal combustion engine that employs argon instead of nitrogen of air as the work mass, oxygen as the oxidizer, and hydrogen as the fuel. Since argon has a higher specific heat ratio compared to air, argon power cycle hydrogen engines have theoretically higher indicated thermal efficiencies according to the Otto cycle efficiency formula. However, argon makes the end mixture more susceptible to spontaneous combustion, and thus is accompanied by stronger knock at a lower compression ratio, thus limiting the improvement of thermal efficiency in engine operation. In order to suppress the limitation of knock on the thermal efficiency, this paper adopts a combination of experimental and simulation methods to investigate the effects of port water injection on the knock suppression and combustion characteristics of an argon power cycle hydrogen engine.
The gasoline particulate filter (GPF) represents a practical solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as an essential technology in North America to meet the upcoming US EPA tailpipe emission regulation, as proposed in the “Multi-pollutant Rule for Model Year 2027”. The goal of this study was to introduce advanced, uncoated GPF products and measure their particulate mass (PM) reduction performance within the existing US EPA FTP vehicle testing procedures, as detailed in Code of Federal Regulations (CFR) part 1066. Various state-of-the-art GPF products were characterized for their microstructure properties and lab-bench performance for pressure drop and filtration efficiency, were then subjected to an EPA-recommended 2000mile on-road break-in, and finally were tested on an AWD vehicle chassis-dyno emissions test cell at both 25C and -7C ambient conditions.
The impending emission regulations in both China (CN7) and the United States (Tier 4) are set to impose more stringent emission limits on hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). CN7 places particular emphasis on reducing particulate number (PN) thresholds, while the forthcoming United States Tier 4 legislation is primarily concerned with reducing the allowable particulate matter (PM) to an assumed limit of 0.5 mg/mile. Given the more stringent constraints on both PN and PM emissions, the development of enhanced aftertreatment solutions becomes imperative to comply with these new regulatory demands. Coated Gasoline Particulate Filters (cGPF) play a pivotal role as essential components for effective PN and PM abatement.