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The dependence of the turbulent flame speed and the flame development angle on air-fuel ratio, engine rotational speed, ignition timing and compression ratio has been verified. An isooctane-fueled research engine has been utilized in the experiments. The turbulent flame speed and the flame development angle have been determined with the aid of a spark ignition engine cycle simulation model. The results from this work confirm existing theories on the influence of engine design and operating parameters on the turbulent flame speed and on the flame development angle, but suggest the way they relate is to be better established. The effects of knock and incomplete combustion have also been examined.

This work has as an objective the development of a numerical model to calculate the kinetic formation rate of carbon monoxide in spark-ignited internal combustion engines. The model is added to a computer program that simulates the cycle of spark ignition engines, to calculate the exhaust concentration of carbon monoxide emissions. The model is validated through experimental data from a single-cylinder research engine. Comparisons with calculated equilibrium concentration of carbon monoxide confirm that this pollutant should be modeled according to the theory of kinetic formation, for a better approach to exhaust measured values.

This paper presents the physical adjustments and the incorporation of a control system to injection, ignition and throttle valve parameters for operation of a diesel engine with 100% hydrous ethanol. The control system of the aforementioned parameters integrates three dependent subsystems. The control systems of the throttle valve opening, fuel injection and ignition timings have the purpose to reduce cylinder pressure, control engine speed and the combustion process. The signals generated depend on engine speed and knock sensors, which are operated by microcontrollers programmed in Assembly and C language. The measured parameters during engine operation are relative humidity, temperature in different engine locations, fuel consumption and intake air mass flow rate. The data collected are monitored by a software developed in LabVIEW platform. The software also controls the load applied at each engine operating condition.

This study presents the effects of fuel blends containing 5%, 10%, 15% and 20% of anhydrous ethanol in diesel oil with 20% of biodiesel (B20) on performance, emissions and combustion characteristics of a diesel engine. The engine was tested with its original configuration and in the lower brake specific consumption region, at 1800 RPM. The results showed that in-cylinder peak pressure and heat release rate increased with the use of ethanol. The use of ethanol increased ignition delay and decreased exhaust gas temperature. Brake specific fuel consumption increased with ethanol addition, and fuel conversion efficiency was not affected. Increasing ethanol content in the fuel caused decreased carbon dioxide (CO2), carbon monoxide (CO) and total hydrocarbons (THC) emissions.

In Brazil, since the purchase cost of an electric vehicle (EV) is still very high, the exchange of a conventional vehicle by an EV would only be worth if the vehicle was used as source income, such as the case of taxis. Short run distances and high daily mileage make conventional taxis ideal candidates to be replaced by battery EVs. Recently, São Paulo and Rio de Janeiro received EVs as a test project, but other major cities, such as Belo Horizonte, have yet to be tested. The taxi fleet in this city has currently 7,152 vehicles, all powered by internal combustion engines, significantly contributing to equivalent carbon dioxide (CO2eq) emissions since the daily distance traveled is high. With the aim to characterize the fleet and evaluate taxi driver’s option to EVs, data was collected from a systematic sample of taxi stands, of a total of 375, through a structured interview with the drivers, considering a finite and homogeneous population.

A turbulent flame speed model based on the design and operating parameters of a spark ignition engine has been developed. The flame structure model calculates the flame speed from the flame kernel development, where the flame speed is laminar, throughout transition and turbulent flame. The turbulent flame model was calibrated against experiments carried out in an isooctane-fueled research engine running under several different conditions. The parameters varied during the tests were air-fuel ratio, engine rotational speed, ignition timing and compression ratio. Limiting conditions, where knock or incomplete combustion occurs, were also tested.

The pulsating flow in the intake system of an internal combustion engine has been studied experimentally and numerically, with the objective to improve the system performance. The experiments were carried out in a flow bench, and the intake system studied was composed of a straight pipe connected to a 1000cc engine with a single operating cylinder. The numerical simulations used the method of characteristics. Mass flow and pressure fluctuations obtained from the numerical simulations compared well with the experimental results. A fluid dynamic aperture of the intake valve was verified to differ from the geometrical aperture.