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Estimation of soot deposited on a wall flow type DPF, is a vital information to ensure safe and efficient DPF management. Accuracy in determining mass of soot present inside the DPF ensures a correct regeneration management strategy in-terms of fuel efficiency and DPF safety considering soot overloading and too frequent regenerations. It also ensures an efficient detection of anomalies in the PM filtration mandated by the BSVI/EURO VI legislation as a part of On-board diagnostics. Classical approach of determining soot present inside DPF involves monitoring increase in pressure drop. Real time usage of such a model is limited by the inaccuracy of measuring pressure drop at low exhaust flows. Hence, contemporary engine controllers use pressure drop based models as a failsafe and estimate DPF soot loading by modelling soot release rate due to engine combustion and the rate at which it is oxidized.

This paper describes the initial works related to the study of Internal Combustion Engines, as an object of mechanical design, at the Universidad Tecnológica de Pereira. It is reported a concise, complete methodology for simple model of internal combustion engine. The emphasis of the paper is placed on the use of the in-cylinder parameters (pressure and temperature) and inertial loads in the crank-slider mechanism to derive the loads that act on all the components of the crank-slider mechanism as well as the theoretical output torque for a given geometrical structure and inertial properties. These loads can then be used to estimate the preliminary dimensions of engine components in the initial stage of engine development. To obtain the pressure and temperature inside the cylinder, under different operation parameters, such as air fuel ratio and spark angle advance, a Zero dimensional model is applied. The heat transfer from the cylinder and friction are not taken into account.

The influence of engine variables on the concentration of oxides of nitrogen present in the exhaust of a multicylinder engine was studied. The concentrations of nitric oxide (NO) were measured with either a mass spectrometer or a non-dispersive infrared analyzer. The NO concentration was low for rich operation (deficient in oxygen) and increased with air-fuel ratio to a peak value at ratios slightly leaner than stoichiometric proportions. A further increase in air-fuel ratio resulted in reduced NO concentrations. Advanced spark timing, decreased manifold vacuum, increased coolant temperature and combustion chamber deposit buildup were also found to increase exhaust NO concentration. These results support either directly or indirectly the hypothesis that exhaust NO concentration is primarily a result of the peak combustion gas temperature and the available oxygen.

A carburetted, spark ignited gasoline fuelled engine of a 5 kW rated power generator was converted to run on hydrogen. As opposed to large parts of current research, the engine conversion’s foremost goal was not to maximise efficiency and power output but rather to find a cost-effective and low-complexity conversion approach to introduce clean fuels to existing engines. To allow for the increased volumetric fuel flow, the riser of the original carburettor was enlarged. The hydrogen flow into the venturi was metered with the help of a pressure regulator from a widely available conversion kit. The effects of different hydrogen-fuel-feed pressures on engine performance, operational stability and emission levels were examined experimentally. It was found that the hydrogen-line pressure before startup has to be set precisely (±5 mbar) to allow for stable and emission free operation.

AS81044 covers single conductor electric wires made as specified in the applicable detail specification with tin-coated, silver-coated, or nickel-coated copper or copper alloy conductors insulated with crosslinked polyalkene, crosslinked alkane-imide polymer, or polyarylene. The crosslinked polyalkene, crosslinked alkane-imide polymer, or polyarylene may be used alone or in combination with other insulation materials as specified in the detail specification.

Long term control of the AFR (Air/Fuel Ratio) of spark ignition engines is currently accomplished with a selvoscillating PI control loop. Because of the intake/exhaust time delay, the oscillation frequency and hence bandwidth of this loop is small. This paper describes a new approach to the design of this control loop using a novel observer system. In this way the bandwidth of this important loop is increased by a factor of 2 - 6 times, leading to more accurate overall AFR control. Moreover the observer approach is so robust and allows such feedback levels that it reduces significantly the accuracy required in the calibration of the base fuel control system with which it is be used. It can be used with either conventional- or advanced observer based- base fuel strategies.

The detection range of an air-fuel ratio sensor is expanded in the rich A/F region. Using a simulation technique, the limiting cause of the detection range in the rich A/F region is identified as insufficient combustion rates of CO and H2 with O2 on the electrode, which prevent realization of a limited diffusion state which is necessary to detect the air-fuel ratio. Applying an improved diffusion layer to decrease the diffusion rates and an improved electrode to increase the combustion rates, it is demonstrated that the detection limit can be expanded to λ=0.6 while that of a conventional sensor is λ=0.8.

The oxygen ion conductive solid electrolyte cell served as a device for measuring the combustibles content and the oxygen content of an exhaust gas. The cell is comprised of a tubular electrolyte, two opposed electrodes and a porous diffusion layer located on the outer electrode surface. The sensor is employed to measure both rich and lean air fuel ratio through the use of an electronic circuit pumping the oxygen ions to achieve a constant voltage between the electrodes. The wide range detecting capability makes it particularly attractive for air fuel ratio control applications associated with the internal combustion engine. The result of the performance tests are as follows, Detecting range (air excess ratio λ) : 0.8 - “∞ Step response time constant (63%) : 200ms Warm up time. - less than 80 sec at 20°C We found in the durability test concerned with the heat cycle and contamination that if initial aging treatment is applied the output variation ratio (. λ/λ) is limited with in : 5%.

A new air-fuel ratio control algorithm and its effect on automotive engine operation is described. The system consists of a wide range air-fuel ratio sensor and a single point injector with an ultrasonic fuel atomizer. The air-fuel ratio control adopts PID control and it has built-in learning control. A 16 bit microcomputer is used for the latter. The results of three studies are given. The first deals with adaptive PID gain control for various conditions. The second is the new learning control which uses an integration terra. The third is individual cylinder air-fuel ratio control.

This study focused on the technology integration to aim beyond 60% indicated thermal efficiency (ITE) with a single-cylinder heavy-duty diesel engine as an alternative to achieve 55% brake thermal efficiency (BTE) with multiple-cylinder engines. Technology assessment was initially carried out by means of a simple chart of showing ITE and exhaust heat loss as functions of cooling loss and heat conversion efficiency into indicated work. The proposed compression ratio (28:1), excess air ratio and new ideal thermodynamic cycle were then determined by a simple cycle calculation. Except for peak cylinder pressure constraint for each engine, the technical barriers for further ITE improvement are mainly laid in cooling loss reduction, fuel-air mixture formation improvement, and heat release rate optimization under very high temperature and density conditions with very high compression ratio (smaller cavity volume).

Future emission norms in India (BS6) necessitates the 2 wheeler industry to work towards emission optimization measures. Engine operation at stoichiometric Air-Fuel Ratio (AFR) would result in a good performance, durability and least emissions. To keep the AFR close to stoichiometric condition, an Oxygen sensor is placed in the exhaust system, which detects if air-fuel mixture is rich (λ<1) or lean (λ>1) and provides feedback to fuel injection system for suitable fuel control. O2 sensor has a ceramic element, which needs to be heated to a working temperature for its functioning. The ceramic element would break (thermal shock) if water in liquid form comes in contact with it when the element is hot.

Knock occurrence and fuel enrichment, which is required at high engine speed and load to limit the turbine inlet temperature, are the major obstacles to further increase performance and efficiency of down-sized turbocharged spark ignited engines. A technique that has the potential to overcome these restrictions is based on the injection of a precise amount of water within the mixture charge that can allow to achieve important benefits on knock mitigation, engine efficiency, gaseous and noise emissions. One of the main objectives of this investigation is to demonstrate that water injection (WI) could be a reliable solution to advance the spark timing and make the engine run at leaner mixture ratios with strong benefits on knock tendency and important improvement on fuel efficiency.

In a Spark-Ignited engine, there will come a point, as load is increased, where the unburned air-fuel mixture undergoes auto-ignition (knock). The onset of knock represents the upper limit of engine output, and limits the extent of engine downsizing / boosting that can be implemented for a given application. Although effective at mitigating knock, requiring high octane fuel is not an option for most markets. Retarding spark timing can extend the high load limit incrementally, but is still bounded by limits for exhaust gas temperature, and spark retard results in a notable loss of efficiency. Likewise, enriching the air-fuel mixture also decreases efficiency, and has profound negative impacts on engine out emissions. In this current work, a Direct-Injected, Boosted, Spark-Ignited engine with Variable Valve Timing was tested under steady state high load operation. Comparisons were made among three fuels; an 87 AKI, a 91 AKI, and a 110 AKI off-road only race fuel.

The potential of 48V Mild Hybrid is promising in meeting the present and future CO2 legislations. There are various system layouts for 48V hybrid system including P0, P1, P2. In this paper, P2 architecture is used to investigate the effects of water injection benefits in a mild hybrid system. Electrification of the conventional powertrain uses the benefits of an electric drive in the low load-low speed region where the conventional SI engine is least efficient and as the load demand increases the IC Engine is used in its more efficient operating region. Engine downsizing and forced induction trend is popular in the hybrid system architecture. However, the engine efficiency is limited by combustion knocking at higher loads thus ignition retard is used to avoid knocking and fuel enrichment becomes must to operate the engine at MBT (Maximum Brake Torque) timing; in turn neutralizing the benefits of fuel savings by electrification.

Stringent vehicle emissions limits, fuel economy and driveability requirements demand an accurate air-fuel ratio management system. A flex fuel (ethanol capable) engine system without an ethanol sensor requires a precisely tuned air fuel ratio control system. In flex fuel systems without an ethanol sensor, the ethanol content is estimated based on the closed loop adaptation values, therefore; it is important to have a very good open loop estimate of cylinder trapped air and consumed fuel since an error in either of these values will cause a shift in the closed loop adaptation values and ultimately, in the estimated fuel ethanol content. This paper analyzes the effect of volumetric efficiency and stoichiometric air-fuel ratio variation of OTTO port fuel injection (PFI) engines when operating on ethanol. Proposals for correction of these parameters are compared to experimental data.

The schlieren method is a powerful and widely used technique for studying ignition and combustion. Jointly with high-speed photography, this method is often used in both SI- and CI-engines and combustion bombs, including rapid compression machines (rcm). This paper describes tests carried out on a new hydraulically actuated dynamic combustion rig, using schlieren visualisation in two orthogonal directions. The working principle of the rig is briefly described. Results are presented on ignition properties of low quality gas blends using spark ignition and pilot flame. Methane, ethane and nitrogen were blended at different air-fuel ratios and tested as to ignition and early flame development. For spark ignition tests, the pair of images from the two orthogonal directions enables the use of digital image processing to calculate the flame speed, and to compose a three-dimensional volumetric image of the flame front shape.

For engine diagnostics and fault-tolerant control system design provision of analytical models, in the form of virtual sensors, will enable more reliable system design and operation. This paper presents applications of recurrent neural network (RNN)-based architectures for the development of virtual sensors for salient SI engine variables such as manifold absolute pressure, mass airflow rate, air-fuel ratio and engine torque. The RNN architectures developed allow effective sensing of these crucial engine variables while, for computational efficiency, keeping a compact size for the network topology. A nonlinear state-space model strategy is proposed for architecting the stated recurrent neural network and is trained using variants of the real-time recurrent learning (RTRL) algorithm. Representative experimental results obtained for a 5.7 L V8 engine are listed and discussed. The application, dependency and limitations of the proposed approaches are also pointed out.

The effects of air-fuel mixture quality and cylinder-to-cylinder air-fuel distribution on exhaust emissions have been determined on two engine-vehicle combinations. California Motor Vehicle Pollution Control Board (CMVPCB) test cycle emissions were measured on vehicles using a pre-mixed and pre-heated air-fuel charge supplied by a steam jacketed, nine cubic foot vaporization tank. The vaporization tank provided a near constant air-fuel mixture ratio for all operating modes of the 7-mode CMVPCB test cycle. The two vehicles were evaluated at nominal air-fuel ratios of 14:1, 16:1 and 18:1. Cylinder-to-cylinder air-fuel distribution during the transient operation of the 7-mode CMVPCB test cycle was measured on a 200-CID six cylinder and a 289-CID eight cylinder engine. The procedure employed was to record the total carbon emissions (CO + CO2 + CH4 equivalent) for each cylinder during successive test cycles.

A comprehensive EPA emission test analysis program has been developed to determine the nature and relative significance of test variability and to provide consistent evaluation of the performance of catalytic converters. This includes real-time recordings of emission concentrations and mass rates, catalytic converter efficiencies, and air-fuel ratio. Mass accumulations are printed out during the test at the end of each test mode. Test results and analysis of repeatability are summarized on-site immediately following the test. Simplified relationships between gas concentrations and engines variables have been developed.

Design and application techniques of variable nozzle turbochargers for heavy duty diesel engines have been developed using data collected from a series of tests using an II-liter, 6-cylinder diesel engine. Test data showed that at 2000 RPM, brake specific fuel consumption (BSFC) is relatively insensitive to changes in the turbocharger nozzle settings, suggesting that the “rated speed” of the engine should be reduced to an area where BSFC could be improved by adjustments in the air-fuel ratio through use of the variable nozzle turbocharger. The data revealed that only about 1/3 of the mechanically available VNT nozzle travel was used, indicating that a more simplified design of the VNT may be possible. The data also showed the importance of knowing the final application of the engine for best matching results.