The propulsion systems that vehicles now carry have to be friendly to the environment and Firefighters must know how to work on them safely in vehicle fires and be able to rescue people with security in traffic accidents.
Since that car was invented, is has undergone huge development, both mechanical and electronic. Mainly this has been because of high fuel costs, environment care and new form to think people. But, all methods to move a car are old power systems that have been upgraded.
The Electric Vehicle (EV) was invented in 1827 by Ányos István Jedlik. He created the first electric motor and put it inside a small vehicle. In 1866 the first gas engine appeared. In 1883 the first gasoline car. in 1966 the first hydrogen car. And in 1900, a young Ferdinand Porsche created what is considered to be the first hybrid since it had a gasoline engine that charged batteries with a dynamo.
All these propulsion systems have undergone both mechanical and electronic modifications so that they are safe in case of emergency and first responders must be prepared to face them. For this reason, we need to know them, know their risks and know how to work with them to guarantee the safety of people and surroundings.
In European countries, alternatives to the gasoline engine began to appear some time ago. For example, cars with CNG or LPG have been on the road for years. But in Spain, these propulsion systems have arrived recently and they have lost the race with electric and hydrogen cars.
We can see in the market various ways to propel a vehicle, but the type of propulsion that is being imposed in Europe as well as in America and parts of Asia is the EV. These kind of cars present problems with their autonomy systems and the acquisition of materials and cost of manufacturing batteries.
The various systems for moving a vehicle, specifically, present one or more dangers when it comes to suffering an accident. Therefore, we should begin to know the types of propulsion that now exist and their elements to be able to work safely in an emergency.
Let’s talk about Kurt Wallmacher, our colleague who has written in two articles published in the same magazine in March and Junie 2022, for facilitating our work in the rescue of people in a crash car. Kurt created the Standard International known as ISO 17840. This norm establishes how we can identify the different types of propulsion systems by means of symbols that are placed on the registration plates in light cars. In heavy vehicles and coaches these symbols may be placed elsewhere.
ISO 17840 outlines how a Sheet Recue should be conducted by means of 10 points. And this Standard includes cars, trucks, bus and coaches. And will be extended in the future to:
- Railroad vehicles.
- Motorsport vehicles.
- Maritime vehicles.
- Agriculture, construction and heavy machinery vehicles.
- Air vehicles.
- Stationary Energy Storage systems.
- Stationary power producing systems.
- Future systems that need to have the same approach.
Euro nCap has incorporated ISO 17840 in its Rescue Sheet (RS) Guidelines since June 2020 when giving the safety rating to cars.
It is important to say that ISO 17480 shows the different vehicle propulsion systems through a colour code like this…
…and diamonds, with the following meaning:
Although the Standard describes a label for each of the propulsions, in this article we are only going to see the different forms of propulsion present of a car and its fuels, as well as their symbols in the ISO 17840.
I am going to divide these vehicles according to the type of fuel they use. This classification is mono-fuels, bi-fuels, hybrid, electric and hydrogen vehicles.
In this article, we begin with light cars. In these classifications we have mono-fuels, bi-fuels and vehicles that use electricity to move.
1. Mono-fuels:
Diesel and petrol: We already know how diesel and gasoline engines work. But the fact is they are more polluting.
These vehicles are undergoing modifications in the propulsion systems. For example, some have more than one battery. Others carry supercapacitors, and others have regenerative brakes for recharging 48-volt batteries. These last are called Microhybrids by the manufacturers.
These vehicles use motors that have seen many hours of research and development. But currently they are considered polluting engines. Today there are car manufacturers that are developing new fuels like e-fuel. For example, PORSCHE has built the world’s first plant in Chile. Or RESPSOL is already producing carbon-neutral fuels using only water and CO2 as raw materials.
These fuels can be used in any kind vehicle around today such as automobiles, trucks and planes, among others, without the need to adapt their fuel systems. It’s possible that new elements developed and these new fuels will still give gasoline and diesel engines a long life.
2. Bi-fuels:
Autogas or LPG is liquefied petroleum gas (LPG). It is used because its use reduces CO2 exhaust emissions by around 15% compared to petrol. Therefore, these vehicles own two fuel systems, one of gasoline and other of LPG.
Cars with Autogas can be new or adapted. To use Autogas in an older petrol car requires the installation of components that can be dangerous for firefighters, such as the fuel tank which stores the liquefied gas at approximately 116 to 290 psi.
We need to be aware of these risks when we arrive at a traffic accident because we can to enter a cloud of flammable gas. For this reason, we should carry a thermal camera and device that detects dangerous gas.
Compressed natural gas (CNG). This type of propulsion system is very similar to LPG, but there are several differences. For example:
One is that fuel is in stored as gas, which the CNG tank contains at between 2,900 and 4,400psi. The other is that the CNG pipes have gas under pressure and in the engine area there is a device that reduces this pressure to between 29 and 72psi to be able to burn in the engine.
The form of the LPG tank can be toroidal or cylindrical and it is made of steel. While the shape of the CNG tank is always cylindrical and only the size varies, it can be made of various materials such as steel, carbon fibre, etc.
The rest of the components that make up both propulsion systems are very similar. This makes it easier for us to identify the possible existence of gas in the area of a traffic accident. LPG and CNG are dangerous gases if there is a leak in an accident and we can be in a cloud of gas and not know it. For this reason we should have measuring devices as gas detector and thermal vision camera.
3. Vehicles use electricity to move:
This classification of vehicles is according to its maximum working voltage. ISO 6469-3:2018 establishes basically two types of electric cars: class A and B. Class B have a voltage ratio between 60 volts and 1,500 volts in direct current. And here we have the following light vehicles that use high-voltage electricity to move:
Hybrid Electric Vehicles (HEV). This form of propulsion has its beginnings in the 1990s when Toyota launched the Prius. Since then, many of these cars have been sold around the world. These vehicles have two engines, an Internal Combustion Engines (ICE) that runs on gasoline and an electrical motor that is powered by a battery pack.
Normally, the battery pack contains an electrical voltage between 100 and 800 volts, and in a crash this voltage can be dangerous for rescuers arriving at the scene.
Now, we also have plug-in hybrid vehicles (PHEV). These have the same electric devices as the HEV plus a plug system for high-voltage battery recharging. This means that these vehicles have more electric range on the road, but need larger and heavier batteries.
Due to the electrical risk for the rescuers in the event of a traffic accident, the manufacturers have added different safety devices for disconnecting the high voltage. And for this reason, we can disconnect the high voltage in the crashed car. These disconnect elements are strategically placed in the places that we can reach in the event of an accident and thus create a safety zone for firefighters, medics, police and injured occupants.
Now there are different types of HEV and PHEV on our roads and they may carry one or more of these safety devices and we can only know them through the rescue sheet for each particular vehicle.
Electric Vehicles (EV): Unlike the HEV, the EV has no ICE. This means that they move with electric propulsion only. Therefore, they only have one or more electric motors and battery pack with mid and high voltage, and this varies between 100 and 800 volts. They also incorporate a plug-in to recharge the batteries.
The batteries are placed all over the floor of the car and can represent 30% of the total weight of the vehicle, and this position also lowers the centre of gravity to help with the car’s stability.
For us, firefighters, this is a drawback because the manufactures recommend not touching this area during rescue work and this makes that some extrication manoeuvres obsolete.
For this reason, we need to know how to disconnect the high voltage and how we can work to rescue people in an electric vehicle accident. To facilitate our rescue work, it is necessary and very important that the documentation that we can use has the same information and symbols used in the standard so that we can understand it at the accident scene. Only with this information can we disconnect the propulsion system of the accident vehicle.
Hydrogen vehicles: here we have two kinds of propulsion system.
This is the hydrogen car everybody knows with batteries and fuel cell. These cars are really EV and run on electricity, but when the electric power is used up, the hydrogen fuel cell generates electricity to move the vehicle and recharge the batteries.
This propulsion system carries all the elements of an EV: batteries, orange cables, electric motors, etc. and one or more hydrogen tanks with a pressure range between 4,076psi and 10,152psi.
Therefore, we have two risks in a hydrogen car that has suffered an accident. One is the high voltage of batteries and another is the danger due to a leak in the pipework or the rupture of the hydrogen tank and possible gas fire. For this reason, again, we should carry a thermal camera and a device that detects dangerous gas when we approach the scene, as well as having the Recue Sheet to be able disconnect the high voltage.
Another form of hydrogen propulsion system is the bi-fuel car. These carry an ICE to be able to burn gasoline or hydrogen. This system has not spread much because it was found to be as polluting as a gasoline car and provided little autonomy. For example, BMW Hydrogen 7.
And now, Toyota have a new hydrogen combustion engine, which it is testing with its racing team.
All these vehicles have one or more devices for cutting or disconnecting the propulsion systems. In RS of ISO 17840 we can find them in the point 3: Disable direct hazard/safety regulations. Therefore, it is very important that we have the RS when we arrive at the scene of a vehicle fire or traffic accident.
An example for first rescuers to distrust the situation when they arrive at the emergency zone and there is a vehicle involved may be an event that occurred in 2013 in Barcelona. An HEV exploded and the trunk hood was found 40m from the vehicle. The car had an LPG kit that failed for various reasons and caused an explosion that broke the windows and scared people. And the Rescue Sheet could not show the LPG kit because it was added to the vehicle after it had been sold.
We can never trust in the situation; it is always unpredictable and dangerous and we have to be alert all the time. Gas leak, smoke from batteries, release of liquid fuel can appear at any moment and can be very dangerous for us and injured people.
For the moment, these are the different ways to move light vehicles. In the future, perhaps some will undergo changes or modifications, or there may even be new powertrains to consider. And then we will need to get to know them and learn how to work on them because we will always have to rescue injured people from accident cars.
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