An article to understand the past and present of the engine automatic start-stop system

At present, traffic jams often cause vehicles to be stuck in a mess, which can last from ten minutes to half an hour or even longer. When the car is stopped, the engine is in an idling state, and the resulting emission pollution is much more serious than when driving normally. How to better reduce the pollution and save fuel in the case of congestion? Therefore, a technology designed for energy saving and emission reduction when the engine is idling, the start-stop system, began to quietly emerge in the 1970s.

Today, in order to cope with increasingly stringent fuel emission regulations, vehicle manufacturers have begun to install engine start-stop technology on a large scale and use this technology as a major selling point. How does the start-stop system play its fuel-saving ability? What development history has this technology gone through since its birth? In this article, Gasgoo will start from the development history, working principle and application status of engine start-stop technology, and share the past and present of start-stop technology with the industry.

What is automatic start-stop technology

The automatic start-stop system (STOP&START), referred to as STT, is a system that can automatically control the engine shutdown and ignition. When the vehicle stops temporarily (such as waiting for a red light) during driving, if you keep pressing the brake (usually for more than 2 seconds), the engine will automatically shut down; when you release the brake or step on the accelerator (or turn the steering wheel, switch to S, M gear, etc.), the engine will automatically start immediately. The automatic start-stop system can minimize the engine idling time to reduce unnecessary fuel consumption, reduce emissions and improve fuel economy.

History of Automatic Start-Stop Technology Development

The idea of ​​engine start-stop technology appeared as early as the 1930s, and its application in cars can be traced back to the 1970s. At that time, Toyota conducted a practical test of similar technology on the Crown sedan. When the vehicle stopped for 1.5 seconds, the engine would automatically cut off the fuel and shut down. This can be said to be the prototype of the engine automatic start-stop technology. However, it was not until around 2006 that the automatic start-stop technology began to be gradually popularized in cars due to increasingly stringent environmental regulations.

Japanese

As early as 1970, Toyota had already dabbled in start-stop technology. At that time, it tried to install an electronic device on the Toyota Crown that could shut down the engine after the car was stationary for 1.5 seconds. The test results found that in the busy traffic in Tokyo, the use of this new technology could increase fuel economy by 10%.

In addition to Toyota, Mazda has also developed an i-Stop system that determines which cylinder to start first when restarting from a stationary idle state. The piston of the cylinder will stop at the appropriate position and the scavenging stroke will be completed in the cylinder. When the system determines that it will restart, it will inject fuel for rapid ignition and combustion, while driving the starter motor. The starting process takes about 0.35 seconds and is quite smooth.

German

In 1980, the start-stop system was equipped on the mass-produced Volkswagen second-generation Polo. Subsequently, the third-generation Volkswagen Golf and Lupo (3L model) in 1994, and the Audi A2 (3L model) in 1999 were equipped with this technology, but the sales of these models were not very ideal due to their high prices.

BMW has applied the start-stop technology to its models for many years, including the mini series models after 2008. BMW has been committed to reducing the loss of engine power. They use Bosch's enhanced starter motor, which can withstand more starts than ordinary starter motors in the environment of frequent shutdown and start.

Law

In 2006, Citroën of the French PSA Group developed an idling shutdown system called "start-stop", which was installed on the Citroën C2 and Citroën C3. This system combines the sensodrive automatic transmission developed by the company with the electronically controlled ISG reversible generator (ISG integrates the starter motor and generator, and was jointly developed by Valeo and Denso Corporation of Japan).

This system is also installed on the Peugeot 3008 e-HDi model, which was slightly modified in 2011. Combined with the 1.6L diesel engine and the brake energy recovery system, it can save fuel consumption by up to 15%.

How automatic start-stop technology works

The general principle of automatic start-stop is to install a battery and a starter on the vehicle. The battery is charged and stored energy through the energy recovery system or generator.

When the vehicle stops due to congestion or at an intersection, the driver presses the brake pedal to stop the car and shift gears. At this time, the Start/Stop system automatically detects: the engine is idling and not in gear; the wheel speed sensor of the anti-lock system shows zero; the electronic battery sensor shows that there is enough energy for the next start. When these three conditions are met, the engine automatically stops.

When the traffic light turns green, the driver presses the clutch, which activates the "start-stop device" and quickly starts the engine. The driver shifts gears, steps on the accelerator, and the vehicle starts quickly. With the support of efficient battery technology and corresponding engine management programs, the start-stop system can work normally at lower temperatures and can be activated after a short warm-up process.

Application Status of Automatic Start-Stop System

At present, many car models on the market are equipped with engine automatic start-stop systems. There are many European car models equipped with automatic start-stop technology, such as Audi (from A1 to A8L, Q3/Q5/Q7), Mercedes-Benz (E-Class, S-Class, etc.), BMW (1 Series to 7 Series, X1/X3), Volvo (almost all new cars), Porsche (almost all new cars), etc.

According to foreign media reports, Ford Motor plans to equip 70% of its models with automatic start-stop systems in 2017. At present, the production and sales of automobiles in my country are maintaining a high growth momentum. Sun Guozhong, vice president of Bosch's starter and motor division in China, once said that 40% of European light vehicles adopted the start-stop system in 2013, and it is expected that the proportion will increase to 90% by 2019; the Chinese market will follow the pace of Europe in this field. He predicted: "In 2019, the annual sales volume of the Chinese auto market will reach 30 million vehicles, of which 30% will be equipped with the start-stop system. By then, one in every three cars will be equipped with a start-stop system."