Diesel-Electric Hybrids: How It Works

Why are they still not on sale?

Hybrid cars are already driving along the roads, and it seems that in the coming years they will become more and more widespread all over the world. At least until the fully electric vehicles do not solve their problems with batteries and range.

If you look at the car market, you will find an amazing picture, despite the wide variety of offers, all hybrid cars on sale use a gasoline-electric drive. And this, despite the fact that diesel engines are more efficient, produce more torque, have less fuel consumption and, as a rule, are more durable. Diesel engines also have lower carbon dioxide emissions than gasoline engines. So why is there no diesel-electric hybrids on sale? The fact is that they will be more expensive in production.
Hybrid cars with two modes have two power units, one internal combustion and one electric. The electrical part is mainly expensive because of the cost of large, powerful and special batteries that are used in it. If you add to the equation a diesel, which is much more expensive than a similar gasoline engine, you will get two expensive power units on one chassis. On the other hand, diesel engines are often noisier, they are harder to turn on in cold weather and generate more solid particles and nitrogen oxides.
Even in Europe, where sales of diesel vehicles account for about half of new car sales, diesel prices are not equal to the prices of cars with gasoline engines. And since the diesel engine experiences much more working pressure than the gasoline, the engine itself needs to be much stronger and better made. On paper, a diesel-electric hybrid can combine the best of both spheres. But what happens in real life?

How do diesel hybrids work?
Just like their gasoline brothers. "Hybrid technology can be applied to any kind of transmission. From the perspective of the hybrid, it does not matter, "said BMW spokesman Dave Buchko in 2008. He was referring to the fact that technologically, a hybrid with a diesel engine would not at all differ from a hybrid with a gasoline engine. "Although diesel engines have a higher compression ratio and generate a greater torque," Buchko said, there is no problem with the creation of such a car. So, in diesel-electric hybrids the same principles are used as for petrol-electric hybrids.

Two sources of power in a hybrid car are differently explained. On some hybrids, the normal engine is only responsible for charging the batteries, it does not transmit power directly to the wheels of the car. The engine rotates the generator, the generator charges the batteries, the battery powers the electric motor of the car, which already in turn causes the wheels to rotate. One example of this approach is the Chevrolet Volt.
The most common type is a parallel hybrid, a car that can be powered by any of two power sources. This or that engine is used, depending on driving conditions. The Toyota Prius is an example of a parallel hybrid: it operates on electric power at low speeds and includes a gasoline engine when more power is required and at higher speeds. All prototypes of diesel hybrids currently follow the parallel hybrid model. So why are they still not in production?

Strong> expensive plus expensive is ... too expensive
And that's all, because the costs are too high. Gasoline-electric hybrids cost more than conventional gasoline cars, and diesel and more expensive than their gasoline counterparts. The combination of the two will create a very expensive car. The buyer would have to use it for a very long time in order to compensate for the high purchase price. But fuel prices are constantly rising and a diesel-electric hybrid can become a reality. At the moment, manufacturers are already preparing for this. Here are a few examples.
In 2008, Volkswagen showed the concept Golf TDI Hybrid Concept, which uses a 1.2-liter three-cylinder diesel with a common fuel highway and an electric motor. Diesel produces 74 horsepower and a torque of 178.76 Nm, and the electric motor adds to the piggy bank 27 horsepower and 139.49 Nm. According to Volkswagen, the average fuel consumption is 3.4 l / 100 km with European efficiency tests. Which is much better than the 4.35 l / 100 km for the Toyota Prius.
According to Volkswagen, the electric motor provides enough power to allow the car to move from its place. When the car is in motion, the diesel engine will only run at higher speeds or if additional acceleration is required. As we could see this spring, Volkswagen launched its first hybrid model, but it was not a diesel-electric hybrid. The hybrid Touareg is equipped with a gasoline engine, as the cost of developing a diesel-electric hybrid is too high.
In 2008, BMW introduced the hybrid X5 Vision Diesel Hybrid, which consumes about 6.53 liters per 100 km. The car uses a 2.0-liter biturbo engine, rated at 204 horsepower and a torque of 400 Nm, and an electric motor produces 20 horsepower and 209 lb-ft of torque. The figures are promising, but none of the current hybrids of BMW is diesel.

Strong> So who will be the first automaker to roll out such a hybrid?
Peugeot plans to launch the world's first diesel-electric hybrid by the end of 2010. The Hybrid4, based on the 3008 crossover platform, uses a 2.0-liter turbo-diesel engine equipped with a stop-start system that develops 163 horsepower. The electric motor mounted on the rear axle develops 36 horsepower and 200 Nm and drives the rear wheels into rotation. The total power is 200 horsepower and 500 Nm of torque, while the CO2 emissions are only 99 g / km, and the average flow is 4 liters per 100 km.
The hybrid system adds only 100 kg to the weight of the car. Peugeot 3008 Hybrid4 can work in front-wheel drive, all-wheel drive or rear-wheel drive modes (the latter with 0 emissions). The French diesel-electric hybrid is expected to cost at least 15 percent more than the standard 3008 in the top-end configuration, but prices will decrease as the hybrid system is implemented on other models, such as the 308, 407 and their Equivalents from Citroen (C4 and C5).