Introduction to HEV and Overall Transmission section

1. TRANSMISSION SYSTEM FOR HEV
(HYBRID ELECTRIC VEVICLE)
SUB TITELS
1) INTRODUCTION
2) MANUAL GEAR TRASMISSION
3) AUTOMATIC GEAR TRANSMISSION
4) AUTOMATIC MANUAL TRANSMISSION
5) CVT (CONTINIOUS VARIABLE TRANSMISSION)
6) e-CVT (ELECTRONIC CONTINIOUS VARIABLE TRANSMISSION)
7) DEDICATED HYBRID TRANSMISSION
8) DIFFRENTAIL
Name : Subodh Patil
Branch : Mechanical
DIV : B
Roll No : 20ME074

2.  INTRODUCTION AND CHARACTERISTICS
 The Mechanism that transmits the power developed by the engine of
automobile to the driving wheel is called the Transmission System.
 The vehicle transmission regulates the transfer of power (torque and speed)
from the power plant to the driveline and the wheels. In case of hybrid vehicle,
the transmission become even more complex then in conventional or electric
vehicles with two or more prime movers and an output to the
driveline/wheels.
 Basically consist of gearbox and a power plant device that can be actuated
mechanically or electrically.
 Dedicated hybrid transmission (DTH) refers to purpose built, full-hybrid
transmission that are introduced as the transmission system for electric/ IC
engine hybrid vehicles.

3.  MANUAL GEAR TRASMISSION
 A manual gear transmission consist of a clutch, a gearbox, a
final drive and a driveshaft. The final drive has a constant
gear ratio. Manual transmissions have a clutch pedal and a
shifter the driver uses to manually change gears. These
types of transmissions consist of a set of gears along a pair
of shafts, called the input and output shafts.
 The driver has to select the proper gear. The transmission
uses a flywheel, pressure plate and clutch to engage and
disengage the engine from the transmission.
 The flywheel and pressure plate are connected to the
engine. The clutch is situated between them is splined to
the transmission input shaft. The term “push in the clutch”
means to release the pressure plate, which disengages the
clutch from the engine.

4.  AUTOMATIC GEAR TRASMISSION
 An automatic transmission is a multi-speed
transmission used in motor vehicles that do not require
any driver input to change gears under normal driving
conditions.
 The most common type of automatic transmission is
the hydraulic automatic, which uses a planetary
gearset, hydraulic controls, and a torque convertor.
 It is also known as self-shifting transmission as this
system operates without a clutch pedal.
 It uses epicyclical gear box. This type of gear box uses
no gears to engage but different gear speeds are
obtained by tightening brake bands on gear drum.

5.  AUTOMATIC MANUAL TRANSMISSION
 It is also known as an auto gear-shift transmission. A manual
gearbox with a hydraulically or electronically controlled
actuator, which automatically shifts the gears.
 The gear ratio depends on the throttle input and the speed of
the vehicle.
 These are fuel-efficient. It is mechanically similar to manual
gear transmission system, except that the sensors and
actuators perform the clutch work and shift gears.
 AMT Transmission uses hydraulics and computers linked with
the Electronic Control Unit or ECU of the car. The gearshift
patterns are pre-programmed on the ECU and work mainly
on the preset RPM (Revolutions Per Minute) range.
 Automatic Manual Transmission also allows manual
gearshifts.

6.  CVT (CONTINIOUS VARIABLE TRANSMISSION)
 The two most common types of transmission are manual
and automatic. But there is a third type called a
continuously variable transmission (CVT).
 CVT is an automatic transmission because the driver
isn't required to shift between the forward gears or
operate a clutch pedal manually.
 CVT does not have a fixed number of preset gears.
Instead, it has unlimited number of gear ratios to
accommodate the driving style and conditions at the
moment.
 CVT transmission is often referred to "single-speed“ i.e. (single
speed transmission).
PRINCIPLE:-

7.  CHARACTERISTICS AND WORKING OF CVT
 A CVT achieves this infinite gear ratio flexibility by using two
opposing cone-shaped pulleys with a chain or belt that runs
between them.
 One cone is connected to the engine output shaft (engine), while
the other cone directs power to the driveshaft and drive wheels.
 Two pulleys which are primary and secondary, primary pulley is
also called as input pulley (Drive) and secondary pulley known as
output pulley ( Driven).
 The pulleys are movable and as they come closer to each
other, the belt or the chain rides higher making the
diameters of the pulleys larger (high ratio) and vice-versa.
 When the Input Pulley is becomes smaller and the output
pulley becomes larger translates into a lower ratio.

8.  e-CVT (ELECTRIC-CONTINIOUS VARIABLE TRANSMISSION)
 E-CVT is an intelligent transmission that has an infinite
number of gear ratios. By constantly analyzing vehicle
speed, road conditions, engine power and driver input, it
selects the optimal gear ratio for that precise moment.
 By means of petrol and electric motors with an
electronically-controlled continuously variable
transmission, is known as E-CVT.
 Motor 1 recharges the HV battery and supply drive
power to motor 2. Motor 2 then works with ICE to drive
the shaft and wheels.
 Motor 2 also provides Regenerative Braking function by
converting kinetic energy into electrical energy.

9.  DEDICATED HYBRID TRANSMISSION
 A hybrid transmission combines at least one electric
motor and a gasoline engine to move the car.
 And hence this system recaptures energy via
regenerative braking.
 Sometimes the electric motor does all the work,
sometimes the gas engine or sometimes they work
together.
 3 types of hybrid transmission are Parallel Series and
Plug-in hybrid.
1. Series Hybrid
2. Parallel Hybrid
3. Plug-In Hybrid

10.  TYPES OF HYBRID TRANSMISSION
 In parallel hybrid the electric motor(s) and gasoline engine are
connected in a common transmission that blends the two power
sources. That transmission can be an automatic, a manual, or a
continuously variable transmission (CVT).
 In series hybrid the electric motor(s) provides all the thrust, and there is
never a mechanical connection between the engine and the wheels. The
gasoline engine just recharges the battery. This results a driving
experience more indicative in an electric car, with smoother, powerful
acceleration.
 A plug-in hybrid enhances the conventional hybrid concept with a much
larger battery pack that, like an electric car's, must be fully recharged
using an external electricity source. It allows for extended all-electric
driving and can significantly reduce fuel consumption.

11.  DIFFRENTAIL
 The differential an integral part of all four wheelers used
to allow the wheel to spin at different speeds. Differential
necessary when the vehicle takes a turn.
 While turning the inner and outer wheels have arcs of
different turning radii. The inner wheels travel less
distance than the outer wheels.
 From the drive shaft transferred to the pinion gear first,
since the pinion gear and ring gear are meshed power
flows to the ring gear.
 Ring gear rotates the spider gear and spider gear rotates
and the power gets transferred to both the gears and
then to the front shafts to the wheels.
 The differential allows the outer drive wheel to rotate
faster than the inner drive wheel during a turn.

12. Thank You