A review on Hybrid Electric Vehicle and simulation on Hybrid Electric Vehicle Drivetrain Abstract

A review on Hybrid Electric Vehicle and simulation on Hybrid Electric Vehicle Drivetrain
Abstract. This paper discusses about the Hybrid Electric Vehicle and the simulation on the Parallel Hybrid Electric Vehicle Drivetrain. The concept and the classification of the Hybrid Electric Vehicle is discussed here and the simulation and analysis of a drivetrain for Parallel Electric Hybrid Engine was formulated on MATLAB Simulink. The methodology of simulation was to accelerate or decelerate the vehicle independently with the electric motor with engine running at constant speed. And the parameters such as electric motor and engine power were compared and observed. And research on CO2 emission and fuel consumption was made between the Parallel Electric Hybrid Engine and Conventional Vehicle (ICE Vehicle). And the conclusion was made according to the research and the simulation that the development of Hybrid Electric Vehicle will have a great potential in fuel economy improvement.

1. Introduction

This paper discusses about the Hybrid electric vehicle and the simulation on the Parallel Hybrid Electric Vehicle Drivetrain. The first Hybrid Electric Vehicle was invented in 1889 by Willian H. Patton and was used in trams and small locomotives and later it was used smaller vehicles such as cars, SUVs, etc but it were not successful because of no oil shortage at that time but the demand grew up in late 1900s during the rise in oil crisis and then many companies shifted their agenda from performance vehicle to efficiency and fuel economical vehicles Such as Toyota Prius which was introduced at that time was having great impact on the market and nearly in 2008, the were many Hybrid Electric Vehicles in the markets and with better efficiency. The EHVs were a booming concept, so every company launched this kind of vehicle like Range Rover Hybrid, Honda Vezel-Hybrid SUV, Audi Q5-Hybrid, BMW 5-Series-Active- Hybrid, BMW 3-series-Hybrid, Ford C-Max-Hybrid, Acura ILX-Hybrid, etc.
A Hybrid Electric Vehicle is a type of hybrid vehicle which consists of combination of two power source to drive the vehicle. The two power sources are ICE (Internal Combustion Engine) and Electric Propulsion System (electric source of energy). Parallel Hybrid electric vehicles basically works efficiently by switching the power source of the vehicle from ICE to Electric propulsion or vice versa as per the driving conditions or can be driven using both the power source on high performance conditions of the vehicle. Basically, the aim of these concept was to build a fuel efficient and less emission car power source. The concept has been a successful and it has been used in many vehicles including trucks, buses and pickup trucks.
The Drivetrain is known to be a group of components which transfers the power generated from the engine to the driving wheels excluding the engine or power source and the wheels. And a simple drivetrain transfers the power generated from the engine to the transmission which is engaged with the flywheel by clutch and the power from the transmission is transferred to the rear differential by long propeller or drive shaft from where power is transferred to axle and from axle to the two wheels which drives the vehicle. There is also a term called ‘Powertrain’, the difference between the power train and drivetrain is just that the powertrain includes all the drivetrain components and includes the power source components such as engine and wheels.
The Drivetrain changes depending on the type of the vehicle such as Front-wheel, Rear-wheel or Four- wheel drive etc. or on the type of the power source such as for electric vehicles, hybrid electric vehicle, Hydraulic hybrid vehicles etc. The hybrid electric vehicle Powertrain has more no of components and more complexity than a simple ICE Powertrain due more electrification. In Hybrid Electric Vehicle powertrain, electrical energy is also used as along with engine to produce torque, so the drive train are designed in such a way that the torque of both sources is combined and distributed to the wheels. And the drivetrain uses the power control units to control or stop the power from the engine or electric motor.
Basically, the Hybrid Electric Vehicle drivetrain consists of ICE, Electric motor, Battery, energy convertor, Transmission and Power Control Unit (PCU). The Hybrid Electric Vehicle drives their wheels on two power source ICE and Electric Motor which are connected to Transmission which are connected to the axle and then to the wheels. The Electric Motor is powered by battery, it is connected to the DC-DC convertor to converts the voltage of the current flowing through it and supply it to the motor. The power sources are controlled by power management unit which commands the sources to switch On/Off according to the performance required and optimization of the vehicle.
The Hybrid Electric Vehicle has Power Management unit or Power Control Unit which is built with control strategy, for power optimization and it controls and commands the power source components based on the driving condition. the control unit continuously observe the vehicle performance parameters and efficiency parameters and to optimize these parameters it commands the power sources of the vehicle. And the control strategy are designed on different conditions such as 1) when the vehicle is travelling with low speed or less acceleration and the performance required is less and the battery is fully charged, so the vehicle operates on Electric motor powered by battery and engine will be shutoff, 2) when the vehicle is accelerating or requires high performance with engine on and the battery charge is full that time, electric motor is started to assist the engine for acceleration and to reduce fuel emissions because at high performance more fuel is consumed, 3) when the vehicle is cruising with engine power and battery charge is low, the engine power is transferred to wheel as well as to the electric motor which becomes generator and generate electricity which is stored in the battery for later requirements, 4) The battery is also charged by other components of the vehicle such as regenerative braking system (RBS) and regenerative shock absorbers (RSA), the regenerative braking system supplies electricity to battery during the braking of the vehicle, the energy wasted in braking is used by the generator to generate and store electricity in the battery and similarly the regenerative shock absorbers, due uneven roads the vehicle gets impulsive shocks and this shocks are used to generate electricity. These regenerative energy sources decrease the fuel consumption which decreases the emissions and increases the range of the vehicle and increases the economy and efficiency of the vehicle.

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