Rajan Wilcox
The start/stop function in cars automatically shuts off the engine when the car is idling, such as at a stoplight. This function is designed to save fuel, and while it certainly saves some amount of fuel, there is no clear consensus on how much fuel is saved. Some sources claim that the start-stop function can improve a car's fuel economy by 3-12%, while others claim that it saves very little fuel in the real world. The amount of fuel saved likely depends on the amount of time spent idling in traffic. Additionally, some people find the start-stop function annoying, as it can be difficult to permanently disable the feature.
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What You'll Learn
Stop-start systems can increase fuel efficiency by 3-12%
Stop-start systems are designed to save fuel by shutting off the engine when a car is idling, such as at a stoplight. The technology has been around since the 1990s, but it is becoming more common on new cars.
The amount of fuel saved by stop-start systems varies. Engineers estimate fuel savings of between 3-10%, with some venturing as high as 12%. A test by Edmunds found that a BMW 328i GT saved 9.5% of fuel with the stop-start system on, while a Jaguar F-Type R saved 10.9%. A study by the Society of Automotive Engineers found that using start-stop can see a car's fuel economy improve by over 8% in heavy traffic.
The amount of fuel saved depends on how much time is spent idling in traffic. A Transport Energy Emission Research study found that Australian passenger vehicles idle for about 20% of the time they are running. However, some people argue that the amount of fuel saved by stop-start systems is negligible, especially on the highway.
While stop-start systems can save fuel, they can also be annoying to live with. Some people find them pointless and reach for the off button as soon as they start the car. Additionally, they may need maintenance or repair over time.
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The longer you sit idle, the more fuel you save
The start-stop system is designed to shut off the engine when your car is idling, such as at a stoplight. The longer you sit idle, the more fuel you save. This is because fuel is consumed while idling at a stop, and this adds up over time.
A study by the Society of Automotive Engineers found that using start-stop can see a car's fuel economy improve by over eight percent in heavy traffic. Another source suggests that the range of fuel economy improvement is between 3-12 percent.
For example, a BMW 328i GT used 3.1 gallons with the system off and 2.8 gallons with it on, a savings of 9.5 percent. A Jaguar F-Type R did even better, consuming 4.1 gallons with the system off and 3.6 with it on, a reduction of 10.9 percent.
However, some people find the start-stop system annoying, especially in situations where the stops are brief and there is a need for quick acceleration to join traffic. Additionally, the system may not provide much benefit if you do not idle your vehicle for long periods.
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The system is designed to handle repeated starting and stopping
The start-stop system, also known as idling stop or micro-hybrid, is a technology that automatically shuts down and restarts an internal combustion engine to reduce idle time, lowering fuel consumption and emissions. The system is designed to handle the repeated starting and stopping of the engine, and it is most beneficial in urban environments where vehicles frequently stop and start, such as at traffic lights or in congestion.
The start-stop system was originally developed for hybrid electric vehicles but has since been introduced to a range of conventional vehicles without hybrid powertrains. The technology first gained prominence in the 1990s with the Volkswagen Polo '3L' and the Audi A2 '3L', which were the first cars in production to use as little as 3.0L/100km, thanks partly to the start-stop system.
The system typically works by shutting down the engine when the vehicle is stopped and restarting it when the vehicle is ready to move again. The engine usually restarts when the driver releases the brake pedal to press the gas pedal. To support this functionality, some vehicles have been designed with pistons that are in the idle location for an easy start-up when the engine is automatically switched off. Additionally, accessories traditionally powered by a serpentine belt may be redesigned to run electrically, and some vehicles may use a supercapacitor to temporarily power accessories when the engine is off.
The adoption of the start-stop system has also led to changes in the electrical systems of vehicles. The alternator may need to deliver higher output, and the wiring may have to handle varied loads of power. The battery must be able to handle the demand of many more cranks and deeper discharges. This has resulted in the development of new battery constructions, such as Start-Stop AGM batteries and Enhanced Flooded (EFB) batteries. Some manufacturers have even designed dual-battery systems to ensure restarting capability during a stop event.
While the start-stop system is designed to handle repeated starting and stopping, there are some potential issues to consider. Some people find the system annoying, especially in heavy traffic, and there may be a decrease in performance in air conditioning systems when the engine stops. Additionally, there have been concerns raised about the potential for additional wear on the engine due to a lack of oil lubrication with long-term use.
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The technology has been around since the 1990s
The start-stop system is designed to save fuel by shutting off the engine when the car is idling, such as at a red light or during heavy traffic. The technology has been around since the 1990s, with Volkswagen previewing the system in its 1981 Auto 2000 research car. The system was then introduced in the Volkswagen Polo '3L' and the Audi A2 '3L', which were the first cars in production to use as little as 3.0L/100km, thanks partly to the start-stop system.
In the following years, several car manufacturers began incorporating start-stop technology into their vehicles. Toyota, for example, has been selling cars with start-stop systems since 1997 in their Prius hybrid line, and since 2009 in their internal combustion engine vehicles. Mitsubishi Motors introduced the system in 1999 under its AS&G (Auto Stop & Go) branding on their Mitsubishi Pistachio model. BMW also included the technology in many of its cars and the MINI line for 2008 as part of its Efficient Dynamics brand. Mazda and Volkswagen have also been early adopters of the technology.
The start-stop system gained popularity due to fuel economy and emissions regulations. While the system is not mandated in new cars, it has been widely adopted due to federal fuel standard incentives. The system is particularly useful in reducing fuel consumption in heavy traffic or when the engine is off for a significant amount of time during an idling period. According to tests, the feature can reduce fuel consumption by anywhere from 3 to 26 percent, depending on traffic patterns and driving conditions.
However, the start-stop system has received mixed reactions from drivers. Some find it annoying or ridiculous, especially those who drive gasoline-powered cars. There are also concerns about the inability to permanently turn off the start-stop function, as well as the misconception that these systems are bad for the engine or starter. Despite this, the system is designed for repeated starting and stopping, and car manufacturers have made enhancements to reinforce engine and electrical system durability.
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It's most beneficial in heavy traffic
The start-stop system is designed to save fuel by shutting off the engine when the car is idling, such as at traffic lights. The longer the car sits idle, the more fuel is saved. A Transport Energy Emission Research study in 2020 found that Australian passenger vehicles idle for about 20% of the time they are running, so this extra fuel consumption could add up.
The start-stop system is most beneficial in heavy traffic, where cars are forced to stop and idle for longer periods. The system can help reduce fuel consumption and emissions by automatically shutting off the engine when the car is not moving. This can result in fuel savings of around 3-10%, with some sources claiming up to 12%.
For example, a test conducted by Edmunds found that a BMW 328i GT with the stop-start system used 9.5% less fuel, while a Jaguar F-Type R with the system used 10.9% less fuel.
It is important to note that some drivers find the system annoying, especially in heavy traffic. The constant stopping and starting of the engine can be frustrating, and the system may not work as well when the outside temperature is high, affecting the performance of the air conditioning system. Additionally, the system may not be as seamless in larger engines, where the engine noise and vibration during restarts can be more noticeable.
Overall, while the start-stop system can provide fuel savings in heavy traffic, it may not be well-liked by all drivers due to its potential impact on comfort and convenience.
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Frequently asked questions
Yes, auto start-stop does save fuel. The technology is designed to shut off the engine when your car is idling in traffic, preventing fuel from being burned while idling.
There is no definitive answer to how much fuel auto start-stop systems save. The amount of fuel saved depends on how long the car would have idled without the system. Engineers estimate that fuel savings range from 3-12%, with some studies placing this figure at over 8%.
Auto start-stop can be annoying to live with and may not save a significant amount of fuel for those who do not idle their cars for long periods. However, for those who idle their cars frequently, auto start-stop can save a considerable amount of fuel over time.
