Why is the hybrid that is more and more fuel-efficient on the high-speed second oil tiger?
In the past six months, the most test drives have been hybrid vehicles, from DM-i, Hi4 to e-POWER, i-MMD, THS, all "hybrid" models on the technical route have been tried.
In most of the hybrid products I have driven, there is a very obvious problem, that is, the more traffic jams, the lower fuel consumption, and the driving experience in traffic jams is great.
But the expressiveness of high speed is very weak, fuel consumption is high, noise is large, all the advantages of hybrid models can not be exerted at high speed, and even inferior to some fuel vehicles.
For example, the plug-in hybrid PHEV model of the domestic car, the fuel consumption in the urban area can basically be controlled at about 5L, such as the BYD Song Pro DM-i, fuel consumption is very stable, but the performance on high speed is very pulled, as long as you dare to cruise at 120km/h, fuel consumption can easily achieve more than 7L.
The reasons mainly come from the following aspects.
On the one hand, hybrid models, especially those with large batteries, have a very high weight, weighing about 1.8 tons, which is at least 400kg heavier than ordinary fuel SUVs.
On the other hand, the wind resistance under high-speed driving is very large, and the wind resistance coefficient itself is a huge factor that wastes kinetic energy, and fuel consumption is naturally much higher than that of slow driving in urban areas.
The most important thing is that under high-speed driving conditions, the energy loss of the motor is very large, in order to ensure higher speed, the working state of the internal combustion engine is full, and the small displacement naturally aspirated engine itself is used, and the speed of the engine in the high-speed state is not low, which brings additional waste.
The most economical state of hybrid models is low-speed, fully charged state, the engine does not need to undertake the task of charging the battery, but also can enjoy the additional electric energy provided by the battery pack, the work must be motor + battery dominant, internal combustion engine auxiliary work.
If you often drive in urban areas, you can feel the advantages of hybrid models, and even do not need to refuel the whole process, and the low frequency of use of internal combustion engines will inevitably improve fuel economy.
But high speed is completely different, high speed will excessive loss of battery energy, at the same time the efficiency of the motor becomes worse, the engine in the high-voltage working state, both need to drive the vehicle, but also need to quickly charge the battery, battery charging is not enough for the motor, there will be a high-load work problem, that is, noise, high fuel consumption.
This is true for virtually all hybrid models, and even more so for vehicles with larger battery packs.
It is necessary to mention Toyota's THS and Honda's i-MMD here, in fact, these small battery pack vehicles have very low fuel consumption, on the one hand, their own weight and ordinary models are not much different, on the other hand, do not rely too much on the battery + motor, the design and positioning of the internal combustion engine is to meet the economy under all road conditions.
Therefore, the fuel consumption of these models on the high-speed will not be so bad, for example, the urban fuel consumption of the Corolla Hybrid is about 4.5L, the high-speed fuel consumption is about 5L, kinetic energy recovery can charge the battery, the internal combustion engine will also divide a small part of the energy to charge the battery, mutual remedies will naturally not have too bad fuel consumption performance.
Some large self-weight hybrid vehicles, such as the ideal L9 such a very large self-weight vehicle, once the power is insufficient, then the internal combustion engine will inevitably be very busy, both to charge and to use two motors, the fuel consumption performance of the full load will not be better than that of the fuel vehicle.
The official fuel consumption is about 8L, we measured it to 10L, a luxury SUV of the same size high-speed fuel consumption performance will not be so high at all, for example, BMW X5's high-speed cruise performance fuel consumption is only about 8L, which really shows that not all hybrid models can maintain economical fuel consumption in all road conditions.