SMART DUAL-VERIFICATION FUEL PREVENTION SYSTEM FOR VEHICLES
FIELD OF INVENTION
5 The present invention relates to fueling system for vehicles. More particularly, it
pertains to a hardware-integrated smart fuel cap system using ESP32 and dualsensing
to prevent wrong fuel filling. This invention is a physically implemented system
for vehicles that uses an RC522 RFID reader for nozzle authentication and a
TCS34725 op~ical sensor for real-time fuel color/clarity analysis, controlled by an
10 ESP32 microcontroller to actively prevent misfuelling.
DESCRIPTION OF THE RELATED ART
In the current automobile industry, fuel filling is a fully manual process. Drivers depend
15 on human attention to select the correct fuel type-petrol or diesel-while refuelling.
Accidental misfuelling is a common and costly problem, especially in India, where
petrol and diesel nozzles are often similar in shape and colour. Each year, thousands
of drivers, particularly those operating diesel vehicles, mistakenly fill their tanks with
petrol, leading to severe and immediate engine damage. This error results in
20 expensive repairs, often costing between ~50,000 and ~2.00,000, and necessitates
complete fuel system flushing, injector replacement, or even engine overhaul. Beyond
financial loss, misfuelling causes significant vehicle downtime, operational disruptions
for commercial and fleet operators, and potential safety hazards such as sudden
engine failure in traffic. Existing solutions rely heavily on user attention or passive
25 mechanisms, which are frequently overlooked or bypassed, underscoring the need for
an automated, fail-safe system to permanently resolve this pro!:>lem.
Current approaches to address misfuelling include different sized filler necks,
mechanical adapters and warning labels and color-coding. Diesel vehicle filler necks
30 are often larger than petrol counterparts. However, determined users can often force
the incorrect nozzle, and nozzle designs vary across fueling stations, reducing
reliability. Aftermarket devices like Mechanical Adapters act as physical keys, allowing
only the correct nozzle type to connect. These can be lost, damaged, improperly
installed, or circumvented. Warning Labels are placed on fuel caps or inside fuel doors.

Effectiveness depends entirely on user vigilance and is often ignored, especially in
high-stress or unfamiliar situations.
The present invention solves the above-mentioned problems by providing an
5 intelligent fuel safety system to prevent misfuelling in vehicles through a two-stage
verification process. It combines RFID-based nozzle authentication with real-time
optical fuel analysis to detect and block incorrect fuel types. Using an ESP32
microcontroller, the system automatically engages a solenoid lock to physically
prevent misfuelling, ensuring engine protection, user safety, and cost savings. The
I 0 solution is fully automated, highly reliable, and compatible with a wide range of
vehicles and industrial applications.
OBJECTIVE OF THE INVENTION
15 The primary objective of this invention is to design, develop, and deploy an automated,
reliable, and cost-effective system that completely eliminates the occurrence of vehicle
misfuelling-the accidental introduction of incorrect fuel into a vehicle's tank. This will
be achieved through the implementation of a dual-layer verification process that
integrates RFID-based electronic authentication with real-time optical fuel analysis,
20 controlled by an intelligent microcontroller. Key goals include:
1. Prevent Engine Damage: Eliminate costly repairs and mechanical failures caused
by misfuelling, thereby extending vehicle lifespan and reducing maintenance
expenses.
25 2. Enhance User Safety: Provide a fail-safe mechanism that operates independently
of user attention, reducing the risk of accidents and breakdowns due to fuel-related
errors.
3. Automate Refuelling Safety: Create a seamless and intuitive user experience
that requires no additional steps or behaviour changes during refuelling.
M 30 M 4. Ensure System Reliability: Incorporate redundant verification and fail-safe
design principles ·to guarantee consistent performance under diverse
environmental and operational conditions.

5. Enable Broad Adoption: Utilize commercially available, low-cost components to
make the technology accessible for both original equipment manufacturer (OEM)
integration and aftermarket retrofitting across a wide range of vehicle types.
5 BRIEF SUMMARY OF THE INVENTION
The present invention is a smart dual-verification fuel prevention system for vehicles.
It is an integrated hardware-software system designed to prevent vehicle misfuelling
through automated dual-layer verification and physical intervention. The system is built
around an ESP32 microcontroller that serves as the central control unit, coordinating
10 all operations. It incorporates an RC522 RFID reader module for electronic
authentication of fuel nozzles and a TCS34725 optical colour sensor for real-time
analysis of fuel properties. A 12V DC solenoid lock acts as a physical barrier within
the fuel inlet, while visual and audible indicators, including red/green LEDs and a
buzzer, provide clear user feedback. The system is powered through the vehicle's 12V
15 electrical supply, with appropriate voltage regulation to ensure stable operation. All
components are housed in a durable, IP67-rated enclosure to withstand harsh
automotive environments such as temperature variations, dust, moisture, and fuel
exposure. The design emphasizes reliability, cost-effectiveness, and ease of
integration into both new and existing vehicles without altering standard refuelling
20 behaviour.
~ BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

Figure shows the drawing of "Smart Dual-Verification Fuel Prevention System for -N 25 Vehicles"

Fig1. - 3D VIEW
Fig2. - BLOCK DIAGRAM
Fig3. - FLOWCHART

Fig4. -INSTALLATION SCHEMATIC- HAND SKETCH

4. 12V DC SOLENOID LOCK
5. PASSIVE RFID TAGS
6. LED INDICATORS (RED/GREEN)
7. PIEZO BUZZER
5 8. VOLTAGE REGULATOR CIRCUIT
9. CUSTOM PCB
10. ENVIRONMENTAL ENCLOSURE
10 DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO DRAWING
1. ESP32 MICROCONTROLLER
Microcontroller acts as the main control unit of the system. It processes data from
15 RFID reader and optical sensor. It controls solenoid lock based on verification
results. It manages LED indicators and buzzer alerts. ·It runs the programmed
decision-making algorithm.
20
25
2. RC522 RFID READER MODULE
RFID Reader Module Provides first-layer electronic verification for Nozzle
Authentication. It continuously scans for RFID tags within Scm range. It reads fuel
type information from tags on fuel nozzles. It communicates with ESP32 via SPI
protocol.
3. TCS34725 COLOUR SENSOR
Colour sensor is used for optical fuel analysis. It measures RGB (Red, Green,
Blue) light values. It analyses fuel clarity and colour properties. It distinguishes
between clear petrol and darker diesel. It provides real-time chemical verification
30 during fueling. It communicates with ESP32 via 12C protocol.
35
4. 12V DC SOLENOID LOCK
Solenoid Lock acts as a mechanical· lock in the fuel inlet to physically prevent
misfuelling. It is engaged in default position (safe state). It disengages only when
both verifications pass. It re-engages immediately if wrong fuel detected.
5. PASSIVE RFID TAGS
Passive RFID tags are used for fuel type identification. It is mounted on fuel pump
nozzles. It is pre-programmed with fuel type (Petrol/Diesel). It provides unique
5 identification for each fuel type.it does .not require any power. It is activated by RFID
reader field.
6. LED INDICATORS (RED/GREEN)
10 LED indicators provide a visual display of the system status to the user. The green
LED illuminates when verification is successful and fueling is safe. The red LED
activates when an error or mismatch is detected and fueling must be stopped.
Different flashing patterns may be used to represent specific categories of errors,
thereby offering clear anc;:l immediate feedback.
15
7. PIEZO BUZZER
The piezo buzzer serves as the audible alert mechanism of the system. It emits
warning tones whenever an error or abnormal condition occurs. Distinct sound
20 patterns may be generated to represent different· alert levels, ensuring rapid
attention from the user. The buzzer operates together with the LED indicators to
reinforce the warning signals.
25
8. VOLTAGE REGULATOR CIRCUIT
The voltage regulator circuit manages the power requirements of the system by
converting the vehicle's 12V DC supply into regulated 5V and 3.3V outputs. It
delivers stable power to sensitive electronic components while protecting them
"from voltage spikes and fluctuations. This regulation ensures consistent and
30 reliable performance in automotive environments.
35
9. CUSTOM PCB
The custom printed circuit board functions as the integration platform for all
electronic components in the system. It provides secure electrical interconnections
and mechanical stability. The PCB is designed to withstand vibrations and supports
compact and reliable packaging of the device.

10. ENVIRONMENTAL ENCLOSURE
The environmental enclosure protects the electronic assembly from external
5 conditions. It is designed to meet IP67 standards for resistance to dust and water
ingress. The enclosure is constructed from fuel-resistant materials to prevent
degradation and is suitable for installation in harsh under-vehicle environments
AILED DESCRIPTION OF THE INVENTION
The present invention smart dual-verification fuel prevention system is one which
integrates seamlessly into a vehicle's existing fuel inlet assembly, appearing as a
standard fuel cap system to the user while incorporating sophisticated electronic
protection mechanisms internally.
The system's operation begins with the RFID verification stage, where the RC522
reader(2) continuously scans for compatible RFID tags within a Scm range. Each
genuine fuel nozzle is equipped with a passive RFID tag(S) programmed with specific
fuel type information.
When a nozzle approaches the fuel inlet, the reader captures the tag data and
transmits it to the ESP32 microcontroller (1) for authentication. This initial verification
ensures that only nozzles carrying the correct fuel type identification can proceed t9
the next stage.
Following successful RFID authentication, the system activates the second verification
. .
layer using the TCS34725 colour sensor (3). This high-precision optical sensor
analyses the fuel's physical properties by measuring RGB (Red, Green, Blue) and
clear light transmission values.
The sensor is calibrated to distinguish between the distinct optical characteristics of
petrol and diesel - petrol appearing clearer with higher light transmission, while diesel
demonstrates darker properties with reduced light transmission. This real-time

analysis provides chemical verification of the actual fuel being dispensed, adding a
crucial layer of protection against mislabeled or contaminated fuel.
The physical security component consists of a robust 12V DC solenoid lock (4) that
5 serves as an active barrier within the fuel inlet. In its default state, the solenoid remains
engaged, physically preventing nozzle insertion.
Only upon successful completion of both verification stages does the ESP32 (1)
disengage the solenoid (4) , allowing fuel dispensing. The locking mechanism can
I 0 react within milliseconds to re-engage if the optical sensor detects incorrect fuel during
the refueling process, providing continuous protection throughout the entire operation.
User interaction is facilitated through an intuitive interface comprising multi-colour LED
indicators (6) and an audible buzzer (7). The system provides clear status feedback:
15 green LED for approved fueling, red LED with buzzer activation for errors, and specific
alert patterns for different failure modes. This immediate feedback ensures users are
always aware of the system status and any required actions.
Power management is handled through an integrated voltage regulation circuit that
20 converts the vehicle's 12V DC supply to stable 5V and 3.3V outputs required by the
electronic components.
Q) 25
The system incorporates protective features against voltage spikes, reverse polarity,
and electromagnetic interference, ensuring reliable operation 1n the challenging
- automotive environment. -1- N

The product is housed in a custom-designed enclosure manufactured from fuelresistant
materials, featuring IP67 rating for protection against dust and water ingress.
The mechanical design ensures easy integration with various vehicle models while
maintaining the standard fuel inlet dimensions and functionality. Installation options
include both OEM integration during vehicle manufacturing and aftermarket retrofit kits
for existing vehicles, mal