Today let's talk about: What are the mainstream hybrid technologies on the market right now, what are their technical principles, and which is most effective in saving fuel?
With the continuous rise in oil prices, the cost of using traditional fuel cars is also increasing. Although new energy vehicles have developed rapidly in recent years, there are still many drawbacks that cannot be fundamentally solved. Driving a fuel car is costly, while driving a pure electric vehicle brings anxiety about mileage. Therefore, under the current circumstances, hybrid is a relatively good transition solution.
Hybrid models are divided into two main categories: hybrid electric vehicles (HEV) and plug-in hybrid electric vehicles (PHEV). The primary differences between the two are mainly in three aspects:
1. Presence of an external power charging port: Hybrid electric vehicles do not have an external power charging port and rely directly on the engine for charging. Plug-in hybrid electric vehicles can use an external power charging port for charging.
2. Battery capacity: Hybrid electric vehicles have smaller battery packs and short pure electric driving distances, mostly running in a hybrid mode. Plug-in hybrids have relatively larger battery packs, allowing for longer pure electric driving distances.
3. Licensing issues: Different countries and regions have different licensing policies. PHEVs are popular in Europe, can obtain new energy licenses or enjoy low-emission vehicle policy benefits, such as exemption from congestion charges in London's low-emission zone, and purchase subsidies or tax reductions in countries like Germany. In Russia and Central Asia, HEV models do not receive special licenses or tax benefits, being regarded as fuel-efficient cars. Japan is very friendly to HEVs, providing tax breaks for fuel-efficient cars, and PHEVs enjoy tax benefits and environmental subsidies, with some cities offering parking discounts.
Today, we won't discuss plug-in hybrids but instead delve into the 5 current mainstream hybrid technologies on the market to understand their fuel-saving effects and technical principles, helping you make a clear choice when buying!
Representative models: Prius, Corolla, Camry, Highlander, etc.
Technical features: Planetary gears perfectly combine the torque output of the engine and the motor, achieving a coordinated unification of hybrid power, with excellent fuel economy and smoothness.
Working principle: Toyota's THS hybrid technology can be said to be the pioneer of hybrid technology. Since the first "Prius" was launched in 1997, it has undergone four technical generations in 24 years, with a total of 23,740 electric patents, including core technologies such as motors, control systems, and system control. Its global influence and market share are unparalleled by other hybrid technologies. The core component of the THS system is the power distribution unit, primarily composed of a set of planetary gears and two motors. The MG1 motor, with smaller power, is responsible for generating electricity and starting the engine, while the MG2 motor, with greater power, is responsible for power output. The MG1 and MG2 motors, and the output shaft of the engine, are all respectively fixed to the sun gear, ring gear, and planet carrier of the planetary gear mechanism. By controlling the power output of the MG1 and MG2 motors and the engine through the power control unit, the conversion and distribution of hybrid power are achieved. The planetary gear mechanism, considered the most crucial part of the THS system, has been patented by Toyota. When the vehicle starts, it is driven directly by the electric motor, avoiding the high-load operation of the engine. During constant speed cruising, the engine engages and operates under optimal conditions. During acceleration, the motor and engine output simultaneously, perfectly coordinated to ensure power. No matter what working condition, the THS achieves low fuel consumption, greatly improving fuel economy. Furthermore, since the engine and motor output shafts are fixed on the planetary gear set, they cannot be decoupled. Even during power transitions, the process is seamless and smooth.
Target market: Toyota's hybrid system performs steadily in high-temperature and cold regions and is an ideal choice for many markets focused on fuel efficiency and performance.
Representative models: Civic, Accord, CR-V, etc.
Technical features: Honda's i-MMD system has a series-parallel structure. It drives purely on electric power at low speeds and utilizes both the engine and electric motor at high speeds, achieving a perfect balance of energy conservation and power.
Working principle: It operates as a range-extender electric vehicle. At low to medium speeds, the vehicle is primarily driven by the electric motor, and the engine does not participate in power output. Honda's hybrid technology research began even before Toyota. In 1999, the Insight model with the IMA (Integrated Motor Assist) hybrid system was the first to be released in North America ahead of Toyota. However, due to the small power capacity of the motor and overall performance lagging behind Toyota's THS, Honda gradually moved away from the IMA system and introduced the first generation of the more advanced i-MMD hybrid system in 2013 with the ninth-generation Accord. Today, the i-MMD hybrid system has evolved to the fourth generation. It has optimized features such as increasing engine thermal efficiency from 38.9% to 40.6% and reducing the volume of the PCU (Power Control Unit) by 32%. Structurally, the i-MMD system is a typical series-parallel system comprising an ECVT gearbox, motor, generator, engine, clutch, and other components. Based on different driving conditions, the PCU automatically allocates the strengths of the motor and engine by managing the electric control logic to divert power through the two motors and the engine. In pure electric mode, the motor drives the vehicle alone, and the engine and generator do not work, with the clutch disengaged. In series mode, the motor still drives the vehicle alone, but the engine works under optimal conditions to drive the generator to produce electricity. In parallel mode, both the engine and motor drive the vehicle together, with the engine also generating electricity. The clutch is engaged in this mode. Notably, although the engine in Honda's i-MMD system works most of the time, its main role is to provide electricity to the motor rather than directly driving the wheels. The engine only directly intervenes as the primary power source when the battery is depleted, and the vehicle speed exceeds 70 km/h. Thus, Honda's i-MMD hybrid vehicles often feel like extended-range pure electric vehicles primarily.
Target market: Honda's i-MMD system is suitable for markets with high long-distance driving demands due to its excellent high-speed fuel consumption performance and overall high cost-effectiveness.
Representative models: Sylphy
Technical features: A non-chargeable electric vehicle, where the engine never participates in power output, and the entire process is 100% driven by electricity.
Working principle: Since the debut of the first-generation prototype TIIDA in 2007, the e-POWER technology has undergone 15 years of development and iteration. The second-generation e-POWER technology was first applied to the domestic 14th-generation Sylphy. Among many hybrid technologies, Nissan's e-POWER appears rather unique. It differs from traditional hybrid models and range-extender electric vehicles, with Nissan officially naming it "gasoline-electric drive vehicle." e-POWER is a type of range-extender technology but entirely different from ordinary ones as it does not require charging and has a small battery pack. For example, the Sylphy e-POWER's battery capacity is only 2 kWh, with the engine stepping in to generate power at any time, eliminating the need for a large battery pack. The working principle is relatively simple. The system comprises an engine, generator, drive motor, power battery, and inverter. The engine, which does not directly drive the vehicle, is solely responsible for power generation, making the power source 100% driven by the motor. This makes it significantly different from HEV, PHEV, and EV technologies. When starting, the vehicle uses pure electric mode, powered by the battery, to drive. During cruising, if the battery is sufficient, it powers the vehicle. When the battery level falls, the engine starts generating power to supply the drive motor and charge the battery. During deceleration, the brake energy recovery system uses the motor to charge the battery.
Target market: It is especially suitable for markets with high urban commuting demands, significantly reducing range anxiety.
Representative models: Haval H6, Haval Red Rabbit, Haval Beast, etc.
Technical features: Dual-motor + two-speed parallel shaft configuration, stronger power output and higher torque.
Working principle: the Great Wall lemon DHT hybrid system was released late, in December 2020 before the official launch, the publicity can be said to be unprecedentedly huge, with a variety of technical terms dazzling, its essence is the depth of optimisation of the Honda immd, and to improve, to achieve more flexible switching between series, parallel, and pure electricity. Structurally, the Great Wall Lemon DHT fixes the drive motor and engine on two input shafts respectively, and distributes the power output to the wheels through synchronisers, instead of adopting the form of hollow shafts, thus solving the problem of the lower upper limit of the power borne by the hollow shafts. Secondly, the key component of this system is the transmission mechanism, that is, the 2-speed DHT gearbox, which is more advantageous than the Honda immd single gear ratio. The Great Wall Lemon DHT hybrid system has a DHT highly integrated oil-electric hybrid system that offers two power forms, HEV (normal hybrid) and PHEV (plug-in hybrid), as well as three powertrains. To sum up its features, it is based on a dual-motor hybrid topology. It works with a 2-speed DHT transmission to achieve coordinated operation of the engine and electric motor together. The dual power sources directly enhance the power performance, and realise a variety of working conditions, such as EV driving, series drive, parallel drive, energy recovery, etc., to make full use of the electric motor, generator, and engine, and keep the system as a whole in the high-efficiency zone at all times.
Target market: It's advisable for consumers who commute to and from work in urban areas, occasionally travel long distances, or go off-road.
Representative models: Xingyue L
Technical features: Uses two rows of planetary gears to form a 3-speed DHT transmission mechanism.
Working principle: The core technology of Thor Hybrid is the 3DHT Pro transmission, a highly integrated vehicle generator, electric motor, controller, three-speed multimode transmission and transmission control unit (TCU). However, unlike the single-row planetary gear set of Toyota's THS hybrid system, Thor Hybrid is designed with two rows of planetary gear sets to form a 3-speed transmission mechanism, which enables exclusive functions such as full-speed domain parallelism, two-speed shifting of the drive motors, and catapult starting. Matching the 1-gear large speed ratio at the start can achieve a fast start, and the acceleration ability can be increased by 50%; it can enter the parallel mode when the speed is above 20km/h, which is far lower than the Japanese hybrid's parallel speed limit of at least 70km/h to ensure the efficient operation of the engine. At high speeds, 3rd gear down to 2nd gear again allows for high torque to boost acceleration and make overtaking easy. The complexity of the 3DHT Pro is mainly due to its introduction of a set of 3AT planetary gears, which provides a wider, and more refined, power distribution than a regular hybrid system with a single-speed structure.
Target market: An SUV for most people, and for those who demand low fuel consumption.
Hybrid technology is undoubtedly an ideal transition solution between fuel cars and pure electric vehicles. Whether it is Toyota's classic THS system, Honda's range-extended i-MMD system, or Nissan's unique electric drive e-POWER system, their common goal is fuel savings and environmental protection. For regions with relaxed license restrictions, hybrid technology remains a priority choice, while plug-in hybrids provide solutions for areas with stringent license restrictions.
With the various hybrid technologies available, which one would you choose?
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