B. Ashok

A review on control system architecture of a SI engine management system

Abstract Engine management systems (EMS) has become an essential component of a spark ignition (SI) engine in order to achieve high performance; low fuel consumption and low exhaust emissions. An engine management system (EMS) is a mixed-signal embedded system interacting with the engine through number of sensors and actuators. In addition, it includes an engine control algorithm in the control unit. The control strategies in EMS are intended for air-to-fuel ratio control, ignition control, electronic throttle control, idle speed control, etc. Hence, the control system architecture of an EMS consists of many sub-control modules in its structural design to provide an effective output from the engine. Superior output from the engine is attained by the effective design and implementation of the control system in EMS. The design of an engine control system is a very challenging task because of the complexity of the functions involved. This paper consolidates an overview of the vital developments within the SI engine control system strategies and reviews about some of the basic control modules in the engine management system.

Performance analysis and emissions profile of cottonseed oil biodiesel–ethanol blends in a CI engine

ABSTRACT Biodiesel is identified as a likely alternative fuel for Compression Ignition (CI) engines as it leads to an effective reduction in consumption of petroleum diesel, and of engine exhaust emissions. In the current study, the effects of preheating of intake air on performance, emissions and combustion behavior have been studied for various compositions of cottonseed oil biodiesel–ethanol blends in a compression ignition engine. The characteristics were compared for intake air temperatures of 30°C and 80°C, respectively. An increase in the air intake temperature caused variations in the ignition delay period of the biodiesel–ethanol blend by improving the vaporization characteristic of ethanol, and provides a better combustion. It was found experimentally that the carbon monoxide (CO) as well as the unburned hydrocarbon (HC) emissions decreased with an increase in the preheat temperature, and were found to be slightly lower than those of biodiesel-fueled CI engines. An increase in the relative amount of ethanol blended with the biodiesel was also found to decrease CO and HC emissions. However, in comparison with biodiesel fuel, the ethanol–biodiesel blends resulted in higher emissions of oxides of nitrogen (NOx).

Trends and future perspectives of electronic throttle control system in a spark ignition engine

Abstract Electronic throttle control (ETC) system has turned into an extremely prominent system with a specific end goal to vary the intake airflow rate to provide a better fuel economy, emissions, drivability and also for integration with other systems in spark ignition engines. ETC system consists of mechatronic device called as electronic throttle body (ETB) which is located in the intake manifold of an engine after the air filter and also has a separate control system in the engine management system (EMS). The throttle angle has to be precisely maintained based on the driver and other system requirements to provide an enhanced throttle response and drivability. However, existence of nonlinearities in the system, such as limp-home position, friction, airflow and aging, affects the position accuracy of the throttle valve. A control system strategy is employed in EMS to handle the other system requirements in throttle opening angle estimation and the nonlinearities in position control. This work features developments within the electronic throttle control system and reviews about the various research work carried in this area. This work will not enforce any new results rather than it will discuss the trends followed in past and also proposes some of the future perspectives in the electronic throttle control process.

Implementation of real time low voltage system for enhancement of safety in an electric vehicle

Energy conservation, environmental conservation and sustainable development are the need of the hour and in this regard the development of an electric vehicle has become topmost priority. There is a growing concern about the safety of EVs, which have transformed the future of the automobile industry. With this rapid growth there is a increasing requirement for monitoring and development of safety circuits for battery pack, drivetrain and during emergencies. In this paper we have focused on developing a safety system for a formula electric car keeping design simplicity in mind. All the systems and circuits proposed in this paper are in accordance with the FSAE rules. As part of this project an analysis methodology for analysis of safety systems has been developed and the potential impacts of these circuits have been studied.

Study on the effect of exhaust gas-based fuel preheating device on ethanol–diesel blends operation in a compression ignition engine

Rapid depletion of fossil fuels and stringent emission regulations compel the scientific community to search for alternative energy sources for the internal combustion engines. Among many alternative biofuels, ethanol is getting worldwide attention for compression ignition engine either in the form of partial substitute or complete replacement for diesel fuel. Ethanol fuel has certain undesirable properties like poor flammability limit which results in cold starting issues and higher hydrocarbon emission which restricts their use in compression ignition engine. This issue can be easily overcome by preheating of ethanol fuel before it gets admitted inside the engine cylinder. In the present study, a standard preheating device is designed and fabricated in accordance with engine specifications and simulations were carried out under various operating conditions to evaluate its performance. Furthermore, experimental investigations were carried out in a compression ignition engine fueled with ethanol blends of 20 and 30% with diesel by volume and the fuel blends were preheated using burned exhaust gases. In addition, a comparative study has been carried out for preheated and non-preheated blends of E20 (20% of ethanol and 80% of diesel) and E30 with baseline diesel. The experimental results show that the preheated E20 (20% of ethanol and 80% of diesel) blend has higher brake thermal efficiency of 36.28% with a significant reduction in brake specific fuel consumption when compared with all the other blends. Moreover, the preheated E20 blend reduces the carbon monoxide, unburned hydrocarbon and smoke emissions by 49, 48 and 10%, respectively. However, the NOx emission is increased by 6% as compared to the non-preheating effect. It is also noted that the preheating of ethanol blends produced better combustion results with a significant reduction in the ignition delay period. Hence, it can be concluded that the ethanol fuel can be effectively used in a diesel engine by means of preheating using exhaust gases and could be a viable option for diesel engine applications.

Study of the injector drive circuit for a high pressure GDI injector

In order to meet future emission regulations, increase the power production and reduce the fuel consumption the modern SI engines uses the electronic actuators such as solenoid injector, idle air control actuator, valve timing actuator etc. Engine performance and emissions are mainly depending on the accurate control of both the injection timing and fuel injection quantity of the injector. In order to fully exploit the advantages of modern GDI injector, the electronic system should be capable of driving a high speed solenoid injector at a very fast switching frequency efficiently and with less power consumption. The electric driving circuit is required to be designed with a fast response and precise control. The most serious problem which decreases the injector performance is the response time delay of the injector. There are many reasons for the delay in opening and closing of electromechanical injector such as voltage drop, limitation of injector driving circuit, electromagnetic interference, etc. In this paper, an injector drive circuit has been designed and analyzed for driving a high pressure injector. Also, PWM control using NE 555 timer has been introduced for quickening the cut-off response time. In the process of designing an injector drive circuit high frequency switching component like MOSFET, IGBT and power transistor has been used. Comparison of response time between these three injector driving circuit has been given using NI Multisim. Analysis of switching characteristic among the three injector driving circuit was carried out. In the end, switching characteristic and temperature sweep of all the three IDC have been plotted.