Recently, three crossovers have appeared in Ukraine. They are all Japanese, similar in size/class, and all are hybrids. But hybrids are different! I’m not talking about the difference between classic HEV hybrids, simple “mild” MHEV hybrids, or complex and powerful plug-in PHEV hybrids. I am talking about the difference even within the segment of traditional HEV-hybrids. I suggest you consider three modern models: Toyota Corolla Cross, Nissan Qashqai e-POWER, Honda HR-V e:HEV. On their example, there is an excellent opportunity to compare different designs of hybrids in order to clearly trace the advantages and disadvantages of each of them.

Toyota’s hybrid system: a familiar and understandable “classic”

When we say the word hybrid, we immediately think of Toyota: it was this company that was actively involved in the development of hybrid technologies in the 1990s and released the first mass-produced hybrid. Today, hybrid versions are presented for most Toyota models, the company is talking about the introduction of hybrids of the fifth generation: in each subsequent case, technologies have improved – the efficiency of the internal combustion engine, the power of the electric motor, the type of battery.

Here is the Toyota Corolla Cross crossover: the basis of its hybrid design is a 2-liter naturally aspirated gasoline engine and an electric motor connected by a stepless electromechanical transmission e-CVT (planetary transmission). Depending on the operating conditions, the front wheels rotate thanks to the drive from the electric motor, or thanks to the internal combustion engine, or thanks to two motors and the combination of their powers in the same transmission. This design is called a “parallel hybrid”: that is, two motors can work in parallel to turn the wheels. Moreover, in this pair, the gasoline engine is usually more powerful than the electric motor.

The principle of such a design for Toyota has remained unchanged since the appearance of the first hybrids in the late 90s. Internal combustion engines, electric motors, batteries have changed – but the principle of construction remains the same: a parallel hybrid with a gasoline engine, which is more powerful than an electric motor.

Let’s consider an example Toyota Corolla Cross Hybrid: total power 197 hp, average city consumption at the level of 5.5 l per 100 km, acceleration to hundreds in 8.1-8.2 seconds. We will also note a plus Toyota RAV4: such a hybrid crossover has a 2.5-liter engine and one (front-wheel drive) or even two electric motors (four-wheel drive) – note the implementation of four-wheel drive thanks to the presence of an electric motor for driving the rear wheels. By the way, the results of the “elder brother”: city consumption of 7.5-8 liters per 100 km, acceleration to “hundreds” in 8.4 seconds. Usually hybrids Toyota only electric drives can overcome 1-2 km, depending on traffic conditions.

Nissan hybrid system: an example of a series hybrid

With the advent of e-POWER technology, Nissan offers its own vision of a hybrid – and it’s a “sequential hybrid”. That is, all the key components of the system are connected in series to one power line: “wheels-electric motor-accumulator-generator”. In this case, the internal combustion engine is used only to rotate the generator and generate electricity, we have no direct mechanical connection between the wheels and the internal combustion engine at all.

The advantages of such a design are the ability to achieve maximum efficiency: – the electric motor for turning the wheels works separately; the internal combustion engine works independently according to its own program, regardless of the speed of the car, its acceleration or deceleration. Another advantage is the control and behavior of the car in the style of an electric car: we get instant reactions to pressing the accelerator pedal, wide opportunities for more intensive recuperation, you can even do “one-pedal control”.

In this type of hybrid, we have to take into account the power and torque of the electric motor: everything that is there is all that goes to the wheels. At the same time, we can ignore the power of the internal combustion engine, because it is important only for charging the battery, there is no direct relationship with the wheels. Therefore, there is no need to sum up the power/moment of two electric motors. Also, series hybrids typically use a larger battery; and this allows you to cover a greater distance only on electric drive.

The first acquaintance with an interesting technology – on an example Nissan Qashqai e-POWER: power 190 hp, average city consumption at the level of 5.5 liters per 100 km, acceleration to hundreds in 8.4 seconds. Only on the electric drive, such a crossover is able to cover 4-5 km, which affected fuel consumption: some city trips were successful with a result of 3.2-3.4 per 100 km. But there is another side of the coin – it seems that the gasoline 1.5-liter 3-cylinder turbo engine sometimes overstressed, trying to charge the battery as quickly as possible: it happened that fuel consumption rose to the level of 6.5 liters per 100 km. In a word, having a generally similar indicator in the city “5.5 l per 100 km”, the range of fuel consumption level (3.2-6.5 l per 100 km) in the case of Nissan was greater than that of Toyota (4.5-6 l per 100 km. By the way, sales of the Nissan X-Trail crossover, which has a similar hybrid technology and front or all-wheel drive – the latter will be realized at the expense of an additional electric motor in the drive of the rear wheels, have already started in Ukraine. It will be interesting to see what this crossover will demonstrate .

Honda’s hybrid system: everything is similar, but everything is different

And a few words about the Honda e:HEV hybrid, which is different from the two examples mentioned above. Although at first it seems that everything is simple and the Honda hybrid is built according to a sequential scheme: the wheels rotate only due to the electric motor, it receives energy from the battery, which is charged thanks to the generator and internal combustion engine – all components of the system are built into one sequential power line.

But the difference of the Honda hybrid lies in the presence of a clutch, which connects the internal combustion engine directly to the front wheels during high-speed movement (80-120 km/h) – that is, when traveling on the highway. The company claims that this is a more efficient mode than generating electricity and then feeding it to an electric motor.

True, the track indicators of the level of fuel consumption of these three hybrids are approximately similar – in the range of 80-120 km/h, we have a consumption of 4.5-6 liters per 100 km of travel. That is, under conditions of high-speed movement, body aerodynamics, tire rolling resistance, etc., are more important; than the nuances of hybrid system design and operation.

But in the city Honda HR-V e:HEV pleasantly surprising: we have a not very high power of 130 hp, but we also have a low level of fuel consumption of about 4.5 liters per 100 km (range 4.3-5.1 liters); acceleration to “hundreds” takes 10.1-10.2 seconds. Of course, someone will notice “this crossover is smaller than its competitors.” Then I suggest you look at the car Honda CR-V Hybridon the example of which the hybrid system was studied for the first time, and also to mention Honda CR-V e:HEV 4WD with all-wheel drive: power 184 hp, fuel consumption in the city at the level of 6-6.5-7 l per 100 km, acceleration to hundreds in 8.2-8.7 seconds. And all this is achieved using ordinary 1.5 or 2-liter atmospheric engines – this has a positive effect on the simplification of the engine design and, accordingly, on its reliability, durability, ease of repair in the future. Please note that the mechanical connection is used not only in the hybrid system and front-wheel drive, but also when it is necessary to implement all-wheel drive – there is a regular cardan shaft. Honda hybrids can cover a distance of 2.5-3 km with an electric drive.

So which hybrid is better?

In my opinion, the “sequential type” hybrid used by Nissan and Honda is better. After all, this type of hybrid allows the most flexible use of an electric motor, which has better efficiency (efficiency) in operation. In this case, the gasoline engine usually acts only as a generator drive to generate electricity: that is, its role is reduced. So, a regular small naturally aspirated engine with an Atkinson/Miller cycle and mid-rev settings, as done by Honda, will suffice.

Plus, the possibility of mechanical connection to the wheels provides another option for the operation of the hybrid system, which is more efficient when moving at high speed. Therefore, Honda looks like the most interesting option in this pair.

Does this mean that right now Toyota should abandon its development and start developing the hybrid all over again? Of course not.” First: I think the company still has enough ideas to improve the already existing hybrid system. Second, the maximum efforts for the future should be given to electric cars.

And there’s a third: Toyota’s hybrids are well-known and have a good reputation, with hybrid versions available for almost all of the company’s key models. May it continue to be so – we are waiting for new hybrids, good and different!