Project
Aim: to do detailed case study on continous variable transmission using BAJA ATV vehicles and present our observation on it.
theory:
Transmission cvt: a continuously variable transmission is an automatic transmission that can change seamlessly through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. The flexibility of a CVT with suitable control may allow the engine to operate at a constant RPM while the vehicle moves at varying speeds.
Block Used
1. Signal Builder:
Signal Builder is used for giving input values of Brake Input and Throttle input and it is connected with Generic Engine Block.
Where,
- Brake Input = 0,
- Throttle Input = 0.3
2. Generic Engine:
Represents a system-level model of spark-ignition and diesel engines suitable for use at initial stages of modeling when only the basic parameters are available. Optional idle speed and red line controllers are included.
3.Engine Sensor:
Engine Sensor is connected with Generic Engine, Engine Sensor contains Ideal Mechanical Rotational Sensor that converts an across variable measured between two mechanical rotational nodes into a control signal proportional to angular velocity or angle.
4.Simple gear:
Engine is Connecting to CVT with Simple Gear ratio for Speed Reduction.
The main components of Continously Variable Transmission (CVT) is given below.
- Primary Pulley
- Secondary Pulley
- Variator
- Belt
Note1: If Variator of Primary Pulley goes outward and Secondary pulley goes inward it will leads to Speed Reduction.
Rp < Rs
Note 2: If Variator of Primary Pulley goes inward and Secondary Pulley goes Outward it will leads to Overdrive.
Rp > Rs
5.vehicle body:
Represents a two-axle vehicle body in longitudinal motion. The block accounts for body mass, aerodynamic drag, road incline, and weight distribution between axles due to acceleration and road profile. The vehicle can have the same or a different number of wheels on each axle. Optionally include pitch and suspension dynamics or additional variable mass and inertia. The vehicle does not move vertically relative to the ground.
Vehicle Body contains Two Front wheel and Two Rear Wheel which is connected with Inertia Output Shaft and Double Shoe Brake.
Other Block:
Simulink to PS Converter - To convert
the Simulink signal to Simscape environment
• Solver Configuration - To specify the solver parameters before starting the
simulation
• Mechanical Reference - To make sure all the components are clamped to the ground
.PS to Simulink Converter - To convert Simscape signal to Simulink environment
• Scope - To view the graph of the parameters for better understanding
• Display - To view the calculated engine power
• Inertia - To represent the solid inertia
. Rotational Motion Sensor - To sense the rotational motion from the engine and give output as rpm
• Variable Gear Ratio - To vary the
speed according to the gear ratios
• PS Terminator - Terminator for
unconnected physical signal outputs
.PS Constant-Generate constant physical signal
• Tire - For transportation of the vehicle
• Rotational Free End - For mechanical component (Tire)
• Vehicle Body - To represent the BAJA ATV model body
.Custom Measure Gauge - To measure
the brake and throttle input
• Knob - To increase, decrease and
vice-versa of throttle and brake inputs
. Lookup Table - To insert the CVT
values from the workspace
Step - To increase or decrease an input value for a defined time interval
RESULT:
In Initial Condition RPM:1 gauge shows 0 RPM and Velocity gauge shows 0 km/hr.
Giving time value as "inf" and Run the Simulation. While simulation is running. throttle input value & Brake Input Value can change in Throttle input gauge & Brake Input gauge in the dashboard and will analyse the variation of RPM and velocity in the RPM gauge and Velocity Gauge.