How to deal with the "sudden flameout" fault of the engine while driving, and what preventive measures are there?
The root cause of flameout: oil circuit blockage
Elimination method: add gasoline that meets the standard of regular gas station and maintain it on time.
When the engine works normally, firstly, the oil pump in the oil supply system needs to pump the fuel out of the oil tank, enter the fuel distribution pipeline through the fuel filter, and then spray it from the fuel nozzle to form an oil-gas mixture. In this process, the fuel pump and fuel nozzle are the most prone to failure.
The function of electric fuel pump is to pump the fuel in the fuel tank into the fuel supply pipe to provide the required fuel for each fuel injection system. Under normal circumstances, it will be soaked in gasoline and cooled by gasoline. Its common fault is that it is blocked by impurities in gasoline, and insufficient gasoline leads to high temperature burning. In order to reduce the occurrence of this situation, we need to add gasoline that meets the label in the regular gas station during the process of using the car, and at the same time refuel in time to try not to let the amount of oil fall below the red line.
The gasoline nozzle used in EFI engine is electromagnetic, and the pressurized gasoline is ejected from the nozzle under the magnetic field of electromagnetic coil. Common faults include choke sticking, plugging and leakage, electromagnetic coil short circuit, open circuit and aging. This requires us to pay attention to whether gasoline filtration can work normally besides adding qualified oil products.
In addition, other problems that may lead to flameout in the oil supply device include: unclean fuel filter, blocked oil circuit, etc.
The second level to prevent flameout: air supply device
The root cause of flameout: throttle blockage
Elimination method: maintenance on time
The gas supply device is as important as the oil supply device, and its smoothness is also the key to ensure the normal oil-gas mixing ratio. In this system, the air passes through the air filter, the air flow meter, the intake manifold of the throttle body and finally enters the cylinder.
In the air supply device, the throttle valve is undoubtedly the most important component and the most prone to problems. In most 4S stores, the first thing to check after flameout is the throttle valve of the intake throat.
The function of the throttle valve is to control the amount of combustible mixture entering the cylinder by adjusting the opening, and the image metaphor is the throat of the engine. Due to the maximum air flow, small space, low gas temperature and the easiest condensation of impurities in the gap where the throttle valve is opened, it is necessary to clean it according to a certain period. If the throttle is blocked by impurities, it will lead to insufficient air intake, leading to flameout and unstable idle speed. However, if frequent cleaning of the throttle valve still cannot completely solve the flameout problem, it is generally a fault.
The combustible mixture must pass through the intake manifold before entering the cylinder. In the intake stroke of naturally aspirated engine, gas is mainly sucked by the vacuum degree (also called negative pressure) in the cylinder. When the intake pipe leaks, the vacuum is too small to inhale enough gas, which will lead to engine running weakness, difficult starting, unstable idle speed, substandard emission and even flameout. When there is vacuum leakage, it is characterized by strong vibration during driving, which is easy to judge.
The third level to prevent flameout: ignition system
Cause of flameout: abnormal ignition of spark plug.
Troubleshooting: Replace the spark plug according to its service life.
When the gas-oil mixture enters the cylinder normally, the flameout still occurs, so it is very likely that the ignition system has failed. The function of the ignition system is to generate enough energy sparks between the two electrodes of the spark plug at regular intervals according to the working sequence of the cylinder. Of course, the core part of this is the spark plug, which is also the most prone to failure in the ignition system, because it works in a high temperature and high pressure cylinder.
As we know, when the compression of the gasoline engine approaches the top dead center, the combustible mixture is ignited by the spark plug, so when the spark plug fails, the vehicle will naturally stall. We know that the common faults of spark plugs are leakage, abnormal flashover and electrode burning. Usually, the flameout caused by spark plugs is best solved by replacing spark plugs. When it is inconvenient to replace, it can also be temporarily solved by emergency measures such as cleaning the electrode and adjusting the length of the center electrode.
In addition, in addition to spark plug failure, generator damage, virtual connection or short circuit of lines, and battery leakage will also lead to poor ignition due to insufficient power, which will eventually lead to flameout. In this case, you can press the horn to determine whether there is electricity and check whether the belt is too loose or broken.
In addition, other problems that may lead to flameout of the ignition system include: ignition coil failure and so on.
The fourth level to prevent flameout: electronic control system
Cause of flameout: sensor failure leads to protective fuel cut-off of ECU.
Troubleshooting: Check whether all sensors and actuators work normally.
Electronic system plays an increasingly important role in EFI engine. Its electric control system consists of sensor, electric control unit and actuator, and the core component is the electric control unit. The main sensors are throttle position sensor, oxygen sensor and crankshaft position sensor. They feed back the signals to ECU, and then ECU sends working instructions to the central injector and other actuators.
However, when ECU is more and more responsible for monitoring the vehicle state, it also brings some problems: when a sensor fails, ECU will not be able to correctly judge the current situation, and then take protective measures such as stopping fuel injection, resulting in flameout. In terms of sensors, the most important ones are air flow sensor, throttle position sensor and oxygen sensor. Usually, when these components fail, it is difficult for the owner to handle them by himself. General fault codes will be recorded by the driving computer, and then the maintenance personnel will carry out fault investigation and maintenance.
The air flow meter is used to sense the current air flow and send the data to ECU for processing. When there is a problem, the air flow meter does not perceive or misperceives the current air flow, which leads to the ECU's inability to correctly estimate the current air intake situation. In order to protect the engine, ECU will stop the fuel supply system from injecting fuel into the engine, which is not difficult to explain why the engine will shut down when the air flow meter is not working properly. Similarly, there are oxygen sensors, which are also caused by ECU stopping oil supply or abnormal oil supply leading to flameout.
The function of the throttle position sensor is to convert the position or opening of the throttle into an electrical signal, which is transmitted to the electronic control unit as the basis for the electronic control unit to judge the working condition of the engine, so as to realize the fuel injection control under different throttle openings. Because it is friction parts and wearing parts, the following problems will appear when the engine fails or the circuit is poor: the engine is difficult to start or easy to stall, the idle speed is unstable and the acceleration is poor.
In addition, other problems that may lead to flameout in the electronic control system include: short circuit or open circuit of connecting wires, programming errors, etc.
Emergency treatment when flameout.
Once the vehicle is turned off, we can take the following corresponding measures to avoid danger:
1, flameout occurs at idle speed: the speed will not be very fast at idle speed, and only need to ignite again after flameout.
Note: Automatic transmission vehicles need to be put into park gear (P) or neutral gear (N) before starting the engine.
2. Turn off the engine when taxiing: First of all, don't panic, and brake slightly while stabilizing the direction. At this time, the manual transmission model can step on the clutch, hang the corresponding gear, and then release the clutch to adjust the engine at this speed; Automatic transmission models need to be put into neutral (N) and then restart the engine. According to the road conditions, you can also turn on the double flash, park the vehicle on the side of the road, and then re-ignite.
Note: Be careful not to put the wrong gear because of nervousness.
3. Turn off the engine when braking: first of all, don't panic, stabilize the direction and increase the braking force, try to avoid the obstacles ahead according to the road conditions, and stop in a safe zone before starting the engine.
Note: Because turning off the engine will lose the steering and braking force, it is necessary to increase the power control. Don't mistakenly think that the steering wheel is locked and confused; If you press the brake pedal when the engine is off, the vacuum booster will still be effective without releasing the brake.