Get to Know the different equipement of VTI
To check the operation of the brake system of a vehicle, in addition to the visual and touch inspections of some of the components, the brake meter is used: it is an electromechanical equipment, composed of a computer and an electric motor.
This motor is installed on the floor of the station, connected to two pairs of rollers.
With this system, the results of the test are recorded automatically in the computer, along with data such as the date, time and even, through a personal code, the name of the inspector who applies it, without this information being altered.
The brake meter is used to measure efficiency and imbalance.
Efficiency: The ratio of the braking force of all the tires of the vehicle with respect to the weight.
Unbalance: It is the difference in the braking force between two wheels of the same axis.
Suspension Test Bench
Suspension Test Bench
It consists of two plates installed in the station floor, connected to electric motors, that make movements to activate the suspension system of the vehicle and to simulate conditions that are normally faced on a road, both in static and dynamic condition; That is, first it is weighed parked and then it is weighed during the movement caused by the plates.
The weight in both situations should be the same, this is called effectiveness. Simultaneously, the equipment sends the information of the two plates to the computer, to mark thus the percentage of effectiveness in each axis.
If one axle marks more than 50% difference from the other, this is considered a slight defect, since it´s about the brakes, even though everything else works well, a tire that is not correctly adhered to the ground could destabilize the vehicle.
For this reason, although it is not a cause of rejection, it is recognized as a slight defect, and it is also to inform the owner of the vehicle of this situation and to correct it as soon as possible.
A gap or slack detector has two plates installed on the floor of the station, connected to an electrohydraulic system, which simulates different driving situations, such as steering curves and contour lines.
In the center of these plates there is a pit, which allows the inspector to observe, from below, the whole suspension system of the vehicle, while the gap detector is working. In this way, it is visually inspected that the tie rods, ball joints and other components do not exhibit excessive wear or incorrect fixings.
If any of the aforementioned problems occur, the driver and passengers of the vehicle would be exposed to sudden collapses on the road, or that the vehicle does not have the necessary grip when braking in an emergency (even if the brakes and tires are in Good condition). Faced with this risk of unfortunate accidents, different defects, both minor and serious, are classified according to each case and their magnitude.
Aligner to step
Aligner to step
The aligner to the step is an electromechanical equipment installed in the floor, with a carpet mounted on ball bearings and sensors, that at the passage of the vehicle on it automatically registers in the computer if there is a deviation or a drift and how much of it.
If a vehicle presents a significant deviation, this causes constant problems of maneuverability to the driver, therefore, in long journeys also causes extreme fatigue, aspects that, in both cases, can cause accidents.
For this reason, the manual describes drift as a slight or severe defect, depending on the range of the measurement that the computer shows.
To carry out the emission control test for cars with diesel engine the opacimeter (diesel engine gas analyzer) is used.
The opacimeter is a computer that is placed in the exhaust outlet of the vehicle and is connected to a computer. This system automatically records the percentage of opacity of the smoke that is emitted, that is, how dark the smoke is. If a vehicle has high percentages of opacity, it is because its fuel injection system does not work properly and, therefore, increases pollution.
To perform this test, the driver is asked to accelerate his vehicle thoroughly, with the intention of unbolting (purging) the exhaust system.
In order to perform the pollutant emissions control test in gas engines, a gas analyzer is used. It is a box that, as the name implies, contains gas analyzers on the inside.
Through a probe connected to the vehicle exhaust, the gases enter this box, from where the information is sent to the computer, which automatically records the levels of carbon dioxide (CO2), carbon monoxide (CO) and Hydrocarbons (HC).
In accordance with the legislation, and according to the year of entry of a vehicle into the country, the values of one, two or three elements are taken into account.
The pit is a structure that allows inspectors to examine the underside of the vehicle, with a wide view from below.
At this stage, the inspection depends on the knowledge and technical ability of the personnel, as it reviews the fastening, wear and state of the components of the steering system, among other elements, ball joints, gearbox, arms of the axes and the column.
The state of the interior of the tires is also evaluated at this stage, because in addition to the wear, the dimensions, bulges or other irregularities must be verified.
The inspection in the pit is one of the most important stages of the technical review, since only from there can you clearly see the condition of many parts of the vehicle.
To check tire wear, inspectors rely on a mark that most manufacturers place, called a tell-tale, and that indicates the limit of their useful life.
If the surface of the tire has already reached that level, it is no longer suitable for circulation and should be considered a serious fault.
If for some reason the tire does not present a witness, the inspectors have an instrument called a depth gauge, which measures the depth of the groove in millimeters.
In the absence of the witness, the MOPT (Ministry of Public Works and Transport) manual indicates that the tires must be at least two millimeters deep.
The instrument is used to measure, with the assessment of the inspector, the orientation and elevation of the high, low beam and fog lights.
If the lights are not properly aligned, the light beam may affect vehicles in the opposite direction or not illuminate the required roadway.
In addition to this test with the regloscope, the inspectors visually make a tour of all the lights and the signaling, to verify their state and correct operation.