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TotalEnergies takes care of hybrids

Hybrid cars are experiencing a genuine boom. They sell very well when new and are also sought after on the aftermarket. TotalEnergies points out their main design features, discusses the most popular types and advises which operating fluids ensure their long and reliable operation.

Hybrid cars, like internal combustion engines, require lubricants and operating fluids. However, due to the specific operation of their powertrains, these must be specially selected products. Here is some basic information to help you understand this rapidly growing market segment and its requirements.

What is a hybrid car?

A hybrid is, in the simplest terms, a car equipped with a drive train consisting of an internal combustion engine and an electric motor. Depending on the make and model, the combustion engine can be a petrol or diesel unit. There are also different ways of constructing the “electric section”. It can be one electric motor or several (e.g. two or three). The electric motor can be combined with the combustion engine under the bonnet or built in elsewhere - e.g. next to the rear wheels. The idea behind hybrid drives is to combine the advantages of the combustion engine and the electric drive, and eliminate their disadvantages. The result is better driving economy and dynamics. For example, in traffic jams, when manoeuvring and for short distances, a hybrid car runs in electric mode, while the combustion engine is only used when driving on the road or at least for longer distances. There are many subdivisions of hybrid drives. The most popular is the division of cars by the degree of hybridisation.

1. Micro-hybrid (nowadays this is every new car)
A micro-hybrid will be an internal combustion car equipped with a Start&Stop system, which allows the engine to be switched off at traffic lights, for example, and then switched on when the accelerator is pressed. The main advantage of a micro-hybrid over an internal combustion car is lower emissions.

2. Mild hybrid
In addition to Start&Stop, such a car has a motor-assist function, i.e. the assistance of the combustion engine by the electric motor. A mild hybrid will also have the ability to recuperate electrical energy from braking. While driving, the car recovers energy, stores it in the battery and then uses it, for example during acceleration, to support the combustion engine. The mild hybrid will thus consume less fuel in a city cycle than a normal combustion car, and is much more efficient than a micro-hybrid, but still cannot run in pure electric mode.

3. Full hybrid
This is currently the most desirable solution. It has all the features of a mild hybrid, but also allows you to drive in pure electric (eV) mode. Although we are talking about a range of a few kilometres, this is enough to get through traffic jams or manoeuvre in car parks in zero-emission mode.

4. Plug-in hybrid
It has all the features of a full hybrid, but adds two more - it has a range of a dozen or even tens of kilometres in eV mode and can be recharged from a socket. The higher the degree of hybridisation of the vehicle, the smaller the size of the combustion engine (downsizing) and the greater the battery capacity.

Specifics of the hybrid power train

This time we will focus on point three, the full hybrids, because they have literally conquered our market. Typically, full hybrids can operate in six modes. These are:
 - Pure electric drive
 - Pure internal combustion drive
 - Regenerative braking (the internal combustion engine is disconnected and the electric motor acts as a generator)
 - Hybrid drive (simultaneously drives the internal combustion engine and the electric motor)
 - Hybrid drive with battery recharging (if the battery is discharged below a critical point, then the internal combustion engine produces excess power)
 - Active standstill (the internal combustion engine recharges the battery while the car is at a standstill).

The vehicle's central controller is responsible for selecting the correct mode (the optimum one at any given time) and does so fully automatically. The choice can also be made by the driver, provided that the driving conditions (e.g. speed) and the state of charge of the electric section battery allow it.

Hybrid operating tips

A hybrid drive works most efficiently if the driver follows certain general operating guidelines. Here are the most important ones:
1. If a hybrid car already has a selectable driving mode, use the electric mode in traffic jams and for short distances.
2. In the urban cycle, it is advisable to use the hybrid mode - combustion engine + electric motor = lowest fuel consumption.
3. If possible, drive smoothly and maintain a constant speed. Most fuel is used when accelerating.
4. Electric mode range can be increased by limiting use of multimedia, heating, air conditioning. Of course, a certain amount of restraint should be exercised, as the safety of the journey is paramount.
5. Anticipating the traffic situation allows optimum use of the regenerative braking function.

Oils for hybrids

Published on 05/07/2023
1 min reading time

Hybrid powertrains require suitable oils due to their specific operating conditions. The idea is to adequately protect the internal combustion engine, which in a system of this type operates under very specific and unfavourable conditions. During city driving, it constantly shuts down and starts up. During acceleration, where there is a greater demand for power just after it has started up, it immediately revs up to a high speed. This means that the oil must lubricate it rapidly. This is why a sufficiently low viscosity and fluidity is required to keep the engine running "dry" for as long as possible. For this reason, a viscosity of 0W-20 is standard in these engines, and some designs even require 0W-8 oil.

Frequent start-ups are not the only challenge. The internal combustion engines in hybrids are often ”underheated”. Therefore, oils must have the right anti-wear additives to effectively protect the engines at lower operating temperatures. Furthermore, some of the unburned fuel containing eco-additives enter the oil during such a duty cycle. The oil must be compatible with them and resist accelerated oxidation or gelation. Examples of TotalEnergies oils meeting the requirements of internal combustion engines in hybrid drives are Quartz 9000 XTRA FUTURE XT 0W-16, Quartz Ineo XTRA EC6 0W-20, Quartz 9000 FUTURE GF-6 0W-20, and Quartz Ineo XTRA DYNAMICS 0W-20.

The latest hybrid systems use downsizing engines. Here, in addition to the aforementioned problems, there are also the “own” issues connected with adequate lubrication of this type of engine. We covered this topic in the article entitled “Oil challenges”:

Oil challenges

Of course, the combustion engine is not the only component that requires special fluids. The transmission that couples the combustion engine and electric drive is also extremely demanding. Depending on the design solution, this can be an automatic, automated dual-clutch, CVT or planetary gearbox, which is often integrated with the electric unit. For these, use a classic transmission fluid such as Fluidmatic DCT MV, Fluidmatic CVT MV, which provides lubrication and cooling for the mechanical components. The future, however, belongs to fluids that simultaneously cool and lubricate the transmission and the embedded electric motor. TotalEnergies has developed this type of fluid, Quartz EV DHT and Quartz EV DCT. These products incorporate both very good anti-wear additives and are also dielectric, allowing cooling of the electric motor windings.