Why is the fuel consumption of Seal 06 so low？

BYD’s fifth-generation DM technology is "digging" out for fuel consumption.

technical background

Motor advantage

strong

The instantaneous output peak torque at low speed is large. If the engine is used for high torque output, its related technologies are basically monopolized by relevant manufacturers in Europe and America.

fast

The motor torque adjustment is 20 times faster than that of the engine. At present, there is no gearbox to adjust the conversion torque in the electric drive on the market, and the electric control cycle is only 5ms, while the intake, compression, work, exhaust and power output of the engine take 100ms in one cycle.

So it’s more direct

accurate

Compared with the oil truck, the resolver identification accuracy is 300 times higher, the former is 0.02 degrees, while the latter is 7.5 degrees. Such applications as the ESP function of the chassis system are basically mastered by Bosch.

(B) the advantages of the engine

Steady-state high-efficiency kinetic energy output, that is, the steady-state high-efficiency generator engine and the series mode function in the middle and low speed state, and the steady-state high-efficiency driving in the high-speed cruise stage, while if the speed changes frequently in the middle speed driving, the excess engine energy is recovered by means of motor parallel speed increase or motor charging.

The core of the optimal architecture selection of BYD’s power system (pay attention to the non-planetary gear architecture) lies in how to give full play to the electric driving power and how to dispatch the engine power, as shown in the following figure.

(3) Comparison between PHEV and HEV

The fuel consumption is low. After all, for DM, the engine is only an aid. In most cases, it is only used to generate electricity for extended range when commuting. With high-power motor driving, the driving experience will be much better. At the same time, it has a large battery support and has the function of external discharge.

The fifth generation DM technology

Three major architectures

Power architecture based on electricity

Plug-in special high-efficiency engine: the engine with the highest mass production thermal efficiency of 46.06% in the world, and the improvement measures include

The world’s highest ultra-high compression ratio is 16. For the problems such as knocking and thermal management that may be caused by this, measures have been taken.

In order to improve the oxygen content of intake air, a high tumble port is adopted, and the combustion efficiency is improved by oxygen-enriched environment.

The EGR system is newly designed, and the middle urging is changed to the front urging.

The shape and inner wall of the combustion chamber are specially optimized.

Intelligent EFI system (mentioned again later)

The cylinder block and the cylinder head are cooled separately, and the energy consumption of the engine cooling and cooling system itself is reduced.

An intelligent variable lubrication system is designed to reduce engine friction loss.

Optimization of engine intelligent start-stop strategy

In the process of conventional engine starting, the instantaneous current will be very large when starting with a small battery of 12V, so the engine speed can only be raised in a certain period during the process of pulling the engine; Using high-voltage power electric drive to start can reduce the current and pull up the engine speed more quickly, and also avoid the resonance chattering problem that may be caused by the motor pulling up the engine;

At the same time, in the process of quickly pulling up the engine speed, the rapid power output of the engine itself is ensured by excessive fuel injection.

The energy loss can be reduced by 16%.

Extreme control optimization of system efficiency

By using the power battery as the energy reservoir, the engine can maintain a more efficient working condition as much as possible, and make full use of the driving advantage mainly based on electricity.

EHS electric hybrid system

electrical machinery

Segmented magnetic steel & ultra-thin silicon steel sheet to reduce magnetic loss and eddy current loss.

The double mechanical pumps in the motor cooling system are upgraded to the double pump coupling-rotor oil throwing technology, that is, one mechanical pump and one electronic pump, and the latter is started and stopped as needed, so the cooling process is more detailed.

clutch

The transmission efficiency between the motor and the wheel end is improved, which is transmitted by two gears and bearings. The previous generation adopted cone bearing, which has high strength but low efficiency, so it was upgraded to ball+column bearing and high efficiency clutch.

The motor speed is 16,000 rpm (132 kW, 316N.m) in the previous generation, and now it is 18,000 rpm (120 kW, 210 N.m); And the volume, power and torque of the motor are all reduced, but the power is not weakened, and the output of the wheel end is only amplified by a larger gear ratio.

The comprehensive working condition efficiency is improved by 5%

Insert-mix special blade battery

The energy density increased by 15.9%, the discharge rate increased by 33%, and the energy recovery increased by 20.3%. Because the battery capacity is large, the weight of the vehicle is bound to increase, which puts forward higher requirements for energy consumption. Therefore, part of the solution is made by improving the energy recovery rate, making a small motor mention and weight.

Charging and discharging experience upgrade

The slow charging power is upgraded from 3.3kw to 6.6kw.

DC fast charge for 21 minutes.

The external discharge is increased from 3.3kw to 6kw to meet the needs of more outdoor vehicles.

12V Ferrous lithium phosphate starter battery.

Status decline, especially in the process of vehicle starting, which was originally powered by 12V battery and transferred to electric drive.

The weight dropped from 12kg to 2.2kg

The small battery will have the same life cycle as the whole vehicle, so there is no need to change it frequently, and there is no need for the small battery to be dead.

When the small battery loses power, the power battery will charge it; If the power of the large battery is not enough, it will start the engine stomach power battery to replenish power. So don’t be surprised to see the car parked there and no one suddenly started in the future.

The small battery has its own independent BMS, which is used to communicate with the power battery.

Full temperature range vehicle

Active air intake grille, under the condition of low temperature, when the engine needs to be warmed up, the air intake grille is closed, and the water temperature rises faster; In hot weather, open the air intake grille to exchange heat and improve the heat dissipation in the front cabin; Close the air intake grille at high speed to reduce wind resistance.

Battery thermal management system

The battery direct cooling technology is adopted, and the battery is directly blown by the cooling capacity of air conditioner.

The temperature equalization technology is improved, and the shape of the cold plate flow channel is optimized to make the effective area better. The active temperature equalization technology is used, and the control valve is arranged at the cooling port, which is actively opened when the temperature needs to be lowered, so that the temperature equalization is improved by 45%, the battery activity can be kept in the optimal temperature area better and faster, and the energy consumption is saved by 34%.

The application of pulse self-heating technology, that is, heating through high-frequency charging and discharging between batteries, improves the heating speed by 60%.

Cabin thermal management, through intelligent switch internal and external circulation, actively control the compressor, blower and internal and external circulation switch according to the temperature, light and position (such as tunnel environment) inside and outside the vehicle.

Seven-in-one power domain control, through the improvement of chip and communication speed, strengthens the integration of all components, improves the power density of electric drive system, and improves 18.3%.

Wind resistance of the whole vehicle is 0.26Cd.

Low wind resistance rim

Low drag caliper

The integrated flat chassis, which has been extensively evaluated on the Internet, is no longer an oil-to-electricity structure. The layout and technology of the whole car chassis have been improved a lot, and of course the comfort has also been significantly improved.

Electronic and electrical architecture

Combined with different scenes and different parts of vehicles (such as oil, machinery, electricity, liquid, heat, etc.), the intelligent switching of vehicle modes, intelligent power distribution and intelligent voltage adjustment are carried out through historical massive data and AI technology.

The AI energy consumption mode of the vehicle system will intelligently adjust the power consumption or oil consumption strategy according to the congestion situation and road conditions during the navigation of Gaode map.