Lexus Hybrid Drive: how it works

lexus hybrid drive

Since its introduction in 2006, Lexus owners have enjoyed premium levels of comfort and refinement twinned with low running costs and excellent fuel economy thanks to self-charging Lexus Hybrid Drive technology. But how does this highly beneficial hybrid technology work in practice?

To help you to have a better understanding of the technology in a Lexus hybrid vehicle, this post clearly explains clearly what Lexus Hybrid Drive is, how it works, and how it brings benefits to the environment and your wallet.

What is a hybrid vehicle?

Vehicles with two or more power sources are usually described as being ‘hybrid’. In most hybrid cars on the road today, the dual power sources are a traditional internal combustion engine and an electric motor. However, the way that the two sources combine to power the car usually follows one of three distinct variations of hybrid arrangements.

The vast majority of Lexus Hybrid Drive models are equipped with what is known as a full hybrid system, meaning that its two power sources – a battery-powered electric motor and a petrol-driven combustion engine – are entirely separate from one another. Either of them can power the car on their own, or the power from both units can be combined. The system is described as self-charging because the hybrid battery is charged during the process of driving; it does not need to be plugged in.

lexus hybrid drive

The second hybrid variation is described as being parallel. This set-up, as experienced in the Lexus RX 500h, receives primary power from a normal combustion engine, but it is directly aided by an electric motor fitted between the engine block and gearbox. By the nature of its configuration, the electric motor has to squeeze into a smaller space in the engine bay between engine and gearbox. In some cases this can reduce the amount of electric assistance the system can provide and the range of the vehicle when operating in all-electric, or EV, mode.

Lastly, the third kind of hybrid is the series type. While this type of hybrid still has two power sources, the vehicle is driven by the electric motor alone. The combustion engine isn’t directly connected to the transmission, so it only serves as a generator to provide electrical power for the electric motor. A particular challenge for series hybrids is maintaining efficiency once the battery power is depleted. For this reason, cars with series type hybrid set-ups are rare; Lexus does not produce any models with this set-up.

How does Lexus Hybrid Drive work?

All Lexus Hybrid Drive vehicles use six main components: petrol engine, electric motor, electric generator, battery, power control unit, and a power split device. The power split device uses a special planetary gearbox to distribute power between the engine, motor and generator.

Through this clever combination of technology, Lexus Hybrid Drive can be described as a smart, fuel-saving technology that switches seamlessly and automatically between the electric motor and petrol engine. By monitoring driving conditions, it intelligently manages the flow of power from both sources and can also detect when to combine the two for maximum efficiency and on-road performance.

The Lexus Hybrid Drive system’s ‘intelligence’ allows the two power sources to operate with a wonderful synergy. When the petrol engine is running, it drives the generator to charge the battery. And when conditions allow it, such as in low-speed urban environments, the generator shuts down the petrol engine and lets the electric motor take over. This means that the car can operate with zero emissions.

The sophisticated engine management system also recognises when the car comes to a halt and switches the engine off to conserve power and cut emissions, automatically firing it up again when necessary.

How are the hybrid batteries charged?

The hybrid battery can be charged in two ways. As well as using energy from the engine for charging, Lexus Hybrid Drive also charges the battery through regenerative braking, a system which recovers energy that would otherwise be wasted during braking. Every time the brake pedal is pressed or the driver releases the accelerator pedal to lose momentum, the electric motor goes into reverse, in effect becoming an electric brake and thereby generating electricity.

lexus hybrid drive

In other words, the braking energy that is usually lost as heat and noise, or simply wasted altogether, is captured and used to power the electric motor later on. In continuous stop/start traffic, a significant amount of energy is recaptured and stored this way, improving the overall efficiency of the Lexus hybrid and maximising the amount of time it can stay in zero emission, all-electric mode within towns and cities.

As the description suggests, plug-in hybrid models such as the Lexus NX 450h+ (below) and RX 450h+ need to have their hybrid batteries charged from an electric outlet in order to maximise their zero-emission range. However, when the battery charge is depleted, the vehicle switches seamlessly to its self-charging hybrid system in order to maintain high fuel and emissions efficiency. This is in contrast to most other systems, where the powertrain defaults to its internal combustion engine alone.

Lexus hybrid battery life: How long do they last?

The battery is designed to last the life of the vehicle. In any case, your battery is warranted for five years. The batteries are much larger than regular car batteries as they need to generate and deliver sufficient voltage to power the car at low speeds without any support from the petrol engine.

Further reassurance of the longevity of the hybrid battery is provided by the free annual Hybrid Health Check which is carried out as part of any Lexus service. Passing this diagnostic test provides an extra one year or 10,000-mile warranty on the car’s hybrid battery.

Battery production does have a small, additional impact on the environment, but this is more than compensated for by the environmental benefits of driving a hybrid car. Procedures are also in place so that each battery can be recycled, arranged through Lexus dealerships.

Is the engine in a Lexus hybrid different to that of a conventional car?

In a manner of speaking, yes. Unlike conventional four-stroke engines, the internal combustion engine used in vehicles with Lexus Hybrid Drive uses a slightly different cycle that produces less heat. This Atkinson cycle also reintroduces cooled exhaust gases into the combustion chambers to make an additional contribution to reduced engine temperatures.

Close-up of Lexus Hybrid Drive

A conventional four-stroke engine sometimes has to inject more fuel than necessary in order to cool the combustion chamber and stop the catalytic converters from overheating. This is a useful way of preserving components but it also uses more fuel. The Lexus Hybrid Drive solution, however, is more fuel-efficient and has proved to be phenomenally reliable.

Do I have to drive differently to make the most of hybrid technology?

No. Lexus Hybrid Drive is fully automatic and designed to optimise the use of precious fossil fuel for each driver. All you have to do is enjoy the road ahead!

124 comments

  1. Hi, thanks for the article, it was really helpful. I just bought my 2010 RX 450H with 143000 mile on it, but I wasn’t aware of that we would need to change the Hybrid battery, so now I am so curious that when am I suppose to replace the battery and how much it is going to cost, Also is there any warranty that I can buy for it?

    1. Hi Sam,

      Welcome to Lexus. The hybrid batteries are designed to last the lifetime of the vehicle, so there is no scheduled time for them to be replaced. We recommend having a Hybrid Health Check carried our by your nearest Lexus centre to check the system and see how it is operating. Please provide your postcode, and we’ll locate them, and ask them to contact you using the email address provided with your comment. Thanks.

    2. Hello ! Dont change battery till vehicle not give you sign or check engine light or any problem.

  2. I am considering a Lexus Hybrid but travel very few short low speed journeys I travel 100 miles a day on a motorway so would the Lexus hybrid be more economical for me than my Audi A5 diesel at around 50 mpg
    Thanks

    1. Hello Dave,

      Thanks for getting in touch with us. Historically, hybrids have not performed as well on motorways as they do on other journey types. The latest hybrid technology, found in the UX and ES, is capable of using EV mode at much higher speeds than before, so improvements have been made. The WLTP fuel consumption figures for for the ES is from 48.5 to 53.6 and for the UX is from 46.3 to 53.2. We’d recommend a test drive to experience our hybrids on the motorway for yourself and would be happy to arrange this for you.

      To learn more about the benefits of Hybrid feel free to follow this link through to our website: https://www.lexus.co.uk/hybrid/#self-charging

      Thank you.

  3. Hello.
    I am looking at a used 2013 RX450H with 86,000 miles and when test driving it at highway speed notice that on the Energy display screen, when regenerating energy to the battery, the battery color bars never fill up the entire square, and leaves at least 1 or 2 spaces of black where it’s not charged. Is this a problem? Does this indicate a potential problem?
    Thanks you.
    Bob

    1. Hello Bob,

      Thanks for getting in touch. The battery is operating as it should be, what you have noticed on the Energy display screen is intentional and relates to battery management. If the battery continually went from fully charged to fully depleted it would damage the battery, however this way is is protected from this.

      You can read more about the longevity of our cars with this article about our used RX 400h 2004 model by following this link: https://mag.lexus.co.uk/lexus-hybrid-health-check-2/

      If you do buy the vehicle you can have it health checked at your nearest Lexus Centre.

      Hope this helps.

  4. Hi . I am hoping to buy a 2008 Lexus 600 hL & have been told that it should not have a tow bar fitted, Can you advise me why this is , as tow bars are available in the USA for this car?
    Cheers Mike.

    1. Hi Mike,

      Thanks for getting in touch. For us to be able to help with this would you please be able to clarify the model you are interested in and if possible provide the Reg?

      Thanks.

  5. I have 2010 450H with 120,000 miles on it. Have had zero problems with it. Have purchased a new one to get newer safety features. Want to store 2010 car over winter in cold weather area. Will trickle cell or battery tender be sufficient & any special type needed for hybrid? Thank you,

    1. Hi there,

      Thanks for getting in touch with us. We would recommend some additional steps for storing a Hybrid, and we have detailed these below.

      To prevent excessive auxiliary battery drainage, charge the battery at least once every two weeks by powering on the hybrid system for 20 minutes with all non-essential electrical accessories turned off. It is not necessary to drive the vehicle, but do not start the hybrid system in an enclosed area unless the tail pipe is connected to an exhaust hose to prevent harmful buildup of fumes. As an alternative, you may disconnect the negative terminal of the auxiliary battery.

      For the hybrid vehicle battery, charge the battery at least once every two months by starting the hybrid system for about 30 minutes. Check that the “ready” light is on and all lights and electrical accessories are off. As with the auxiliary battery charging, it is not necessary to drive the vehicle, but the steps to prevent exhaust buildup must be taken.

      In addition to this, we would recommend inflating the tyres to maximum permissible pressure to avoid flat spots over time.

      Thanks.

  6. I’m looking at a 2015 RX450H on sale with a Lexus dealer. One use for the car is towing a boat, AUW of boat and trailer is 1900Kg. Recovery from the water up a steep slipway is the most challenging task. I see further back (2017) that Lexus does not recommend towing with this model. The dealer says no problem whatsoever, moreover they offer a Lexus towbar and electrics. What is the truth on this matter?

    1. Hi Jon,

      Thanks for getting in touch. There have been some changes regarding towing capacity during 2015, so it depends on the production month what specifications the vehicle has. Therefore, if you could please provide us with the registration of the vehicle you are looking at, we will be able to check that.

      Thanks.

  7. I am looking At purchasing a ux hybrid 4 wheel drive. I regularly do 110 miles on a motorway in a single journey, and am interested in how many miles can be done in battery power to see if a hybrid will actually be worth purchasing. Also does the battery recharge itself just by running the car and if so what length of journey is required to charge the battery? Finally what is the litre capacity of the boot on a ux?

    1. Hello Jane, thank you for your comment. The Lexus Hybrid Drive powertrain is not so much ‘how much on battery power’ as the battery constantly recharges throughout each journey. The best way to understand the luxurious UX would be to arrange an experience with it through your Lexus Centre. With the rear seats up and measuring to the parcel shelf, the UX with E-Four AWD has 283 litres, and to the roof line it has 401 litres of luggage space.

  8. Hello, I have recently purchased a RC300 h. When driving, sometimes the lights on the dash go dim for a few minutes, then go bright again. This happens intermittently. Could you please let me know if this is normal. There is 4,500 miles on the clock at the moments.
    Thanks.
    Paul

    1. Hi Paul,
      Congratulations on your new car. Clearly, you have excellent taste.
      The dashboard lights dim when the headlights turn on. Your car can do this automatically when it senses it is getting dark. For example, when you travel onto a section of road where the trees block the sunlight out, the headlights may turn on. Then your car goes back into the light, and the headlights turn off again. It may also do this when going through tunnels or under bridges. You can reduce the sensitivity of this feature in the car’s settings menu.
      If the dimming is unrelated to this feature, we’d recommend contacting a Lexus centre.
      Thanks.

      1. Hello. I am being offered a Lexus RX 450 h 2019 model and a 7seater same year.
        I prefer the 5 seater also less pricy.
        Dealer tells me the spare parts are different and one runs on lithium hybrid system and the 7 seater on nickel based.
        Unfortunately the dealer has only the seven seater version I am not fond off . So I found a 5 seater Lexus in the market which suits me more.
        Also zero mileage.
        So question is. Are they so much different in body parts and hybrid technology or just sales tricks to persuade to by the dealer car ?

        1. Hi Khalil,

          Thanks for getting in touch. There are some differences, especially with the body shape, as the RX L (seven seat) is longer. Model year 2019 vehicles both have Nickel-Metal Hydride battery though, and the engine and transmission parts are the same. Either way you choose, you will have an excellent vehicle in your ownership.

          Thanks.

  9. It seems the hybrid engine is used to mainly reduce the carbon emissions, not increase gas mileage. Is that correct, because I don’t see any MPH difference between the hybrid and fully gas engine.

  10. Hi
    I am looking to purchase a 2007 ( 07 reg ) RX400h reg. no. LG 07 FXY.
    It has a Tow Bar fitted is this ok ? as in some of your answers it is not advisable to tow with hybrid cars.
    Thanks
    Mike

    1. Hello Mike,
      Thank you for contacting us.
      We have checked with our technical team, and this vehicle seems to have been equipped with a towing package from factory.
      However, their advice would be to have the vehicle checked over due to age and mileage to ensure serviceable condition for this feature.
      Thanks.

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