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Novel port dual-injection (PDI) strategy helps to utilize bio-fuels, improve the performance and lower the emissions with higher mass fractions of bio-fuels. PDI strategy in SI engine allows intake manifold blending of two different fuels at any blend ratio. This paper presents the numerical study of PDI strategy using a single cylinder SI Ricardo E6 research engine. The objective of this study is to extend predictive fractal combustion model for ethanol/gasoline blends and assess the influence of ethanol (E10 to E50 mass fractions) addition to gasoline in a PDI engine. Quasi dimensional simulation is carried out using AVL Boost under wide open throttle condition at 1500 rpm. AVL Boost engine model is validated for gasoline and ethanol/gasoline pre-blends port fuel injection (PFI) with the experimental data of published literature obtained for the same engine.

Use of microprocessor-based controllers in place of traditional governor-based controllers for diesel engines is motivated by the requirement of meeting the increasingly stringent legislations on exhaust emissions and fuel economy. Such controllers can also give improved transient performance. In this paper a fourth order nonlinear mean value model of a 600 HP turbocharged diesel engine is developed for the controller design. Differential equations for various subsystems have been derived using first principles, experimental data and characteristic maps. The model is implemented in MATLAB™ and Simulink™ environment for simulation and controller design. The model is generic and can be modified with a little effort for other heavy-duty turbocharged diesel engines. The nonlinear model is linearized at sixteen operating points covering wide operating range. These models are reduced to second and first order models using a balanced realization.

Due to reciprocating nature of IC engine, flow physics in intake manifold is complex and has significant effect on volumetric efficiency. Variable length intake manifold technology offers potential for improving engine performance. This paper therefore investigated effect of intake length on volumetric efficiency for wider range of engine speeds. For this purpose 1-D thermodynamic engine model of a single cylinder 611cc standard CFR engine capable of predicting pressure waves in the intake was developed. For validation, pressure waves were predicted at two different locations on intake manifold and compared against test data. This model was used to predict volumetric efficiency for different intake lengths and engine speeds. Volumetric efficiency was found to be a function of both engine speed and intake length, more so at higher engine speeds. Frequency analysis of intake pressure waves during suction stroke and intake valve closed phase was carried out separately.

Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimizing engineering costs. Development of diesel engines for off-highway application for different power segments need different intake port design solutions to optimise in-cylinder flow structure for efficient combustion. With adaptation of low pressure mechanical fuel injection system, intake port development becomes an important stage for reduction of emission formation at the source and improvement in fuel economy. In this paper, intake port design and development process is elaborated for two different power ratings of 75 hp and 120 hp of off-highway engine. 2-valve and 4-valve configurations are deployed for the same cylinder bore size.

Engine in-cylinder flow structure governs the combustion process and directly influences emission formation and fuel consumption at the source. In naturally aspirated DI diesel engine, combustion process coupled with low pressure mechanical fuel injection systems set different requirements for inlet port performance. In-cylinder swirl needs to be optimized for efficient combustion to meet emission levels and fuel consumption targets. Thus, intake port design optimization process becomes a vital requirement. In the present paper intake port design optimization is carried out for single cylinder naturally aspirated engine using mechanical fuel injection systems. The objective is to investigate in-cylinder flow field developed by intake port designs, study the effects of geometrical details of various port cross sections on flow velocity and pressure fields and establish a relationship with intake port performance parameters i.e. swirl and flow coefficient.

Worldwide IC engine fuels are increasingly blended with oxygenate fuels to reduce the dependency on the conventional petroleum reserves. Among these fuels, biomass-derived ethanol is very popular for SI engine operation as it is not only economical and renewable source of energy, but it also allows increasing the engine performance. High latent heat of vaporization of ethanol combined with its high octane number make the engine less sensitive to knock. However, the real potential of ethanol blended fuels still has to be explored and their impact on engine combustion characterization has to be investigated. The objective of this study is to extend predictive fractal combustion model for ethanol/gasoline blends and assess the influence of ethanol addition to gasoline in a Port Fuel Injection (PFI) engine. Quasi dimensional simulation is carried out using AVL Boost under wide open throttle condition at 1500 and 3000 rpm.

Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimizing engineering costs. DI diesel engines with four valves per cylinder are widely used in off- highway applications because of the fundamental advantages of higher volumetric efficiency, lower pumping loss, symmetric fuel spray & distribution in combination with the symmetric air motion which can give nearly optimal mixture formation and combustion process. As a result, the fuel consumption, smoke levels and exhaust emissions can be considerably reduced. In particular, the four-valve technology, coupled with mechanical low pressure and electronic high pressure fuel delivery systems set different requirements for inlet port performance. In the present paper four valve intake port design strategies are analysed for off highway engine using mechanical fuel injection systems.

Variable valve Actuation (VVA) systems are being increasingly used in IC engine. Recently novel valve actuation mechanism like continuous variable valve lift (CVVL) is being explored to regulate engine output without conventional throttle valve and this reduces the pumping losses especially at part load in SI engines. In this paper numerical model for the kinematic analysis of a CVVL mechanism is presented using MATLAB. It consists of eccentric shaft fitted with a series of intermediate rocker arm, which in turn control the degree of valve lift. The main characteristic of this mechanism is that it uses a general curve contact between the elements, which is determined using theory of envelope curve. The mechanism’s system of equations solving principle is based on the Newton-Raphson numerical method.