Will cameras replace vehicle side-view mirrors?
Jaroslav Kme?
Business Leader, Director General, ex-Government CIO, ex-Deputy Minister of Transport, Telco and Post | Ex HP, CSC, DXC, Oracle | 20+ years of experience in Public sector, IT, Telco and Banking | LION >26k connections.
Michal Sura [email protected]
Climate change is caused by greenhouse gas emissions from fossil fuels, industry, transportation, agriculture, etc. The EU has set goals for reducing greenhouse gas emissions until 2050 in order to achieve climate neutrality. It is obvious that vehicle propulsion energy consumption must be reduced, as it is still linked to a certain carbon footprint. The optimization of side-view mirrors is one way to improve vehicle energy efficiency. Side-view mirrors are among the most important safety features of a vehicle because they allow the driver to see what is behind and to the right or left of the vehicle. However, side-view mirrors increase overall aerodynamic drag due to their aerodynamic drag coefficient and the increased frontal projected area.
Improving vehicle aerodynamics results in more energy-efficient vehicles. Side-view mirrors installed on the exterior of a vehicle provide a view to the side and rear of the vehicle but contribute to increased aerodynamic drag and unwanted aerodynamic noise and vibration while driving (Figure 1).
Figure 1.
Aerodynamic drag is a force that opposes the movement of an object through the air. The airflow separation caused by the side-view mirror creates a pressure difference, which causes pressure drag. The low-pressure area behind the side-view mirror causes a pressure drag force that acts in the opposite direction of the traction force (Figure 2).
Figure 2.
The aerodynamic drag of the side-mirror Fd depends on the air density ??air, the aerodynamic drag coefficient of side-mirror cd, the projected frontal area of the side-mirror Af, and the square of the vehicle’s velocity v.
Fd = 1/2 ??air cd Af v2
The drag force is primarily contributed by the frontal area Af and the drag coefficient cd.
The drag force increases as the frontal area of side-view mirrors grows.
Various studies were conducted by CDF simulations and wind tunnel tests to find the aerodynamic drag of side-view mirrors (1) (2) (3).?
We can state that the side-view mirrors increase the total amount of aerodynamic drag force by 2-7 percent. It depends on the frontal size, inclination, yaw angle, speed, drag coefficient, etc. (Figure 3).
Figure 3.
Car designers have been considering replacing side-view mirrors with a camera system. The point was obvious: side-view mirrors increase frontal area, aerodynamic drag, and contribute to unwanted aerodynamic noise and vibration while driving, so a vehicle without side-view mirrors will cover more kilometers and be even quieter to drive. Only recently has camera and display technology caught up with the concept, and side-view cameras are now legal in the European Union. However, what is legal in the EU may not be legal in other parts of the world. Tesla developed digital side cameras to replace side-view mirrors because Tesla wanted lower aerodynamic drag, but they discovered that only traditional side-view mirrors are legal in the United States, not their digital counterparts.
The Audi E-Tron, a pure-electric SUV, was one of the world's first serial passenger vehicles to offer cameras instead of side-view mirrors. Audi refers to them as "virtual door mirrors" (Figure 4).
Figure 4.
How do camera-based side-view mirrors work? These cameras capture images in real-time on each side of the vehicle and transmit them to 7.0-inch OLED screens located near the top of the door, where traditional side-view mirrors used to be (Figure 5).
Figure 5
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The 1,280 x 800-pixel 7.0-inch OLED displays come with automatic brightness adjustment and proximity sensors. These virtual exterior mirrors are adjustable using fingers to move the touch-sensitive screen, instead of tilting the mirror angle. They provide the same view as traditional side-view mirrors, but they allow you to zoom in and out (Figure 6).
Figure 6.
Because the camera reduces the virtual door mirror dimensions, aerodynamic drag and aeroacoustic noise are reduced when compared to a traditional mirror (Figure 7).
Figure 7.
Audi claims that with conventional exterior side-view mirrors, the Audi e-tron achieves a drag coefficient of 0.28. With the optional virtual exterior mirrors, this value is 0.27. Compared to the standard side-view mirrors, they not only reduce drag but also noticeably cut the already low wind noise. Thanks to these solutions, the drag coefficient for the Audi e-tron is almost 0.07 less than for a comparable, conventionally powered vehicle. With a typical usage profile, this increases the range by around 35 kilometers per battery charge in the WLTP cycle. Audi also stated that if the engineers wanted to achieve the same result by reducing a weight, the Audi e-tron would have to lose half a metric ton (4).
Audi offers "virtual exterior mirrors" as an option, with a price of ～1700 EUR (2022) in the EU.
The new Honda e - a small electric vehicle - has cameras instead of side-view mirrors as well (Figure 8).
Figure 8.
According to Bosch, the digital mirror system improves the truck driver's all-around view while also reducing aerodynamic drag, cutting truck fuel consumption by up to 2% (5) (Figure 9).
Figure 9.
Electronic mirrors can, without a doubt, reduce a vehicle's aerodynamic drag and save propulsion energy. It may seem that the reduction in propulsion energy is not great, but every percent counts. Electronic mirrors provide many benefits to the driver, such as zooming the image, adjusting the image contrast, and so on. Their disadvantage is the current high price, which may decrease as mass production increases.
References:
D-CTO in R&D Engineering
5 个月After having familiarized the reliability and accuracy from camera and how the system smart shows at HUD, I drive with flip-close the door mirrors. Except during the traffic jammed , I flip open the door mirrors just in case that I have to change the lane.
Sr. Electro-Software Engineer at ALICTRIC specialist in EPEC, MRS, HYDAC TTCONTROLLERS, IFM, SIEMENS, VIPA, ALLEN BRADLEY, DANFOSS, BOSCH REXROTH, DELPHI, VECTOR EV VCCUs, WURTH CONTROLLERS, B&R CONTROLLERS
2 年It's funny that the author keep saying that the power consumption for the 7inches display is 3W while it should be 2K resolution display not the rspi display hahaha GPU must be added to make a realtime stream average power of 100W Fan maybe to cool the system (optional)
IT technology analytik
2 年Great analysis. But I didn't expect cutting truck fuel consumption by up to 2% ????
Marketing Department Manager p? Energy Opticon AB
2 年Interesting! A new generation of cars with smart and environmentally friendly designs. It's off topic, but maybe you have heard of the Swedish company Elon Road? https://elonroad.com/ There is so much inspiring innovation going on in the field of energy and mobility. ??
Another sound study Michal Sura. As you might know I have been in charge of the development of the first vision based blindspot detection system for serial automotive application, called BLIS. It’s the mother of all ADAS with cameras and autonomous driving systems. I could add a lot more to your analysis, but I won’t do that, as that is my specific knowledge and obviously my competitive edge above others here. Three things I can add: 1. The VW XL1 was the first homologated car equipped with digital side mirrors in 2011 2. Removal of side mirrors will also reduce windnoise and dirt on side windows 3. Audi Sport introduced a center digital mirror in their Le Mans R18 racing car in 2012 acc my proposal #digitalmirror #adas #visionbased #blis #volvo #imageprocessing #blindspotdetection #camera https://www.media.volvocars.com/global/en-gb/media/photos/8152