Hybrid Electric-Combustion Cars with a 2,100 km Range
China’s new electric-combustion cars (NEV)
Dr. Peter F. Mayer, tkp.at (German)
China is now the leader in the car market too. This is partly due to low-cost offers but now also to world-leading technology. One example is the New Energy Vehicles. They have extended hybrid technology by an important element.
As reported in detail here (German), this has given them a clear lead over the hybrid market leader Toyota. The Japanese had perfected hybrid technology over more than two decades. But the ranges, for example of the Corolla, are meagre. At 130 km/h on the motorway, consumption rises to 5.7 litres or more and the range drops to somewhere between 600 and 700 km.
Hybrid technology combines the advantages of the electric motor with the high energy content of hydrocarbons, i.e. petrol and diesel. The electric motor delivers full torque and power from the very first revolution; a clutch is unnecessary. It spares the brakes and recovers energy in the process, converting kinetic into electrical energy. Its efficiency is above 95%, and in BYD hybrids even 97%.
The disadvantage is the heavy battery of 700 to 1,000 kilos, which moreover provides only a modest range. Charging from the grid takes forever and burdens the grids, which have to be expanded. The rising grid costs are then paid mainly by people who do not have an electric car. As, incidentally, are the rather considerable subsidies.
The combustion engine runs on high-energy-density fuels and air. With 50 to 60 kg of fuel you can drive 2,000 km and refuel in 5 minutes for the next 2,000 km. In the process it produces the plant fertiliser CO2, which we urgently need, since we are currently at an all-time low of 4 molecules of CO2 per 10,000 molecules of air.
The disadvantages are more wearing parts such as the clutch, greater strain on the brakes, and oil consumption. The efficiency of passenger cars is limited to a maximum of 40%, recently up to 46.06%. And during load changes or when pulling away, efficiency plummets and consumption rises. Cross-country at a constant 130 km/h, a modern diesel might need 4.3 to 4.7 litres; in town, 6 to 7 litres straight away.
With an electric vehicle it is exactly the other way round. And this is where a technological advance by BYD and other Chinese carmakers comes in.
The operating modes
The drive system has three, not just two, different operating modes, as in classic hybrid vehicles.
- Electric mode: the battery has enough energy and you drive electrically.
- Charging mode: the battery falls below a defined state of charge, and the 1.5-litre petrol engine starts, acts as a generator and charges the battery. But you still drive purely electrically! The combustion engine does not act on the wheels or the drive. It runs in its optimal range at a constant speed, with the highest efficiency, and produces electricity with the lowest petrol consumption – regardless of how you are driving, standing, pulling away, accelerating or braking. I have known this concept for decades and find it completely incomprehensible that carmakers have not used it long ago. Apparently, the classic specialist magazines did not understand it in their reporting either.
- Hybrid mode: this is what all other hybrid vehicles do as well. The wheels are driven by both the electric motors and the petrol engine. It is used for accelerating, e.g. when overtaking. If you drive at a high, steady speed on the motorway, it makes little sense to channel the energy through the battery into the electric motor; that would only lead to losses. So in this situation, as with all other hybrids, propulsion comes directly from the combustion engine. Consumption naturally rises, since air resistance grows with the square of the speed and the rolling resistance of the tyres with even higher powers. Classic hybrid vehicles therefore have the electric and the hybrid mode; the new Chinese NEVs additionally have the charging mode. And this mode makes the decisive difference in stop-and-go driving, such as in town or cross-country, when no constant speed is driven over longer distances.
Performance and models
BYD’s fifth-generation system is a further development of the fourth-generation DualMode technology. It is based on a 1.5-litre plug-in hybrid petrol engine, which can deliver a maximum output of 74 kW (102 hp) and a torque of 126 Nm.
The system uses battery packs with a capacity of 10.08 or 15.87 kWh, made from BYD’s Blade battery. The electric motor is either an EHS120 motor with a maximum output of 120 kW (163 hp) and a torque of 210 Nm, or the EHS160 motor with a maximum output of 160 kW (218 hp) and a torque of 260 Nm. A 12 V lithium iron phosphate battery is also used as part of the system; it lasts as long as the vehicle and is lead-free.
Two models were presented in 2024: the Qin L DM-i and the Seal 06 DM-i. In China these vehicles are offered from about 13,000 euros.
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Original article on tkp.at (German)
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