The ignition system of the automobile is a ignited engine. In order to operate normally, the spark plug is supplied with a high-energy high-voltage (about 15,000 to 30,000 V) with a high enough energy according to the firing order of each cylinder, so that the spark plug generates a sufficiently strong spark to ignite the combustible mixture.
Traditional ignition
The working process of the mechanical ignition system is driven by the crankshaft to rotate the distributor shaft, and the cam on the distributor shaft rotates, so that the primary contact of the ignition coil is turned on and closed to generate high voltage electricity.
The ignition high-voltage power is sent to the spark plug of each cylinder in sequence according to the engine working requirements, and the spark plug emits an electric spark to ignite the gas in the combustion chamber. The distributor housing can be manually rotated to adjust the basic ignition advance angle (i.e., the ignition advance angle during idle operation), as well as a vacuum advancement device that provides different advance angles based on changes in vacuum within the intake manifold.
Electronic ignition
The electronic ignition system is completely different from the mechanical ignition system. It has an electronic control device for ignition, and there is an ignition control curve (MAP map) required for the engine under various working conditions. Determine the working state of the engine through a series of sensors such as engine speed sensor, intake manifold vacuum sensor (engine load sensor), throttle position sensor, crank position sensor, etc., and find the engine required in this working state on the MAP map. The ignition advance angle is ignited according to this requirement. The above ignition requirements are then corrected based on the knock sensor signal to operate the engine at the optimum ignition timing.
Electronic ignition system
The electronic ignition system also has closed-loop control and open-loop control: an electronic control system with a knock sensor that can correct the ignition advance angle according to whether the engine is knocked or not is called a closed-loop control system; without a knock sensor, the ignition advance control The open loop control system is only controlled according to the program set in the electronic control unit.
Qi Aite Electronic Technology Co., Ltd. is one of the largest manufacturers of ignition system components in China.
The products developed and produced are mainly hybrid integrated circuits (HIC), ignition modules, ignition coils and ignition distributors of automobile ignition systems.
Classification and structure of ignition system2.1 Classification of ignition systems
(1), traditional battery ignition system
Using the battery and the engine as the power source, the 6V, 12V or 24V low-voltage DC power supplied by the power supply is converted into high-voltage power by the action of the ignition coil and the breaker, and then distributed to the spark plugs of each cylinder through the distributor, so that the two electrodes of the spark plug are An electric spark is generated to ignite the combustible mixture.
(2) Electronic ignition system
Using the battery and the engine as the power source, the ignition coil and the ignition controller composed of the semiconductor device (transistor) convert the low voltage of the power supply into a high voltage, and then distribute the spark plug to each cylinder through the distributor to make the spark plug between the two electrodes. An electric spark is generated to ignite the combustible mixture.
(3), microcomputer controlled ignition system
Using the battery and the engine as the power source, the ignition coil converts the low-voltage electricity of the power supply into high-voltage electricity, and then the distributor distributes the high-voltage power to the spark plugs of each cylinder, and the microcomputer control system provides the engine operating conditions according to various sensors. The information is sent to the ignition control signal to control the ignition timing and ignite the combustible mixture. It can also cancel the distributor, and the high-voltage power is directly distributed to each cylinder by the microcomputer control system.
(4), magnetic motor ignition system
The high-voltage power is directly generated by the magneto motor itself, and no additional low-voltage power source is required. Compared with the traditional battery ignition system, the magnetic motor ignition system generates high voltage and high reliability in the engine and high speed range. However, when the engine is running at a low speed, the high voltage generated is low, which is not conducive to engine starting.
2.1.1 Traditional ignition system
The working process of the mechanical ignition system is driven by the crankshaft to rotate the distributor shaft, and the cam on the distributor shaft rotates, so that the secondary contact of the ignition coil is turned on and closed to generate high voltage electricity.
The ignition high-voltage power is sent to the spark plug of each cylinder in sequence according to the engine working requirements, and the spark plug emits an electric spark to ignite the gas in the combustion chamber. The distributor housing can be manually rotated to adjust the basic ignition advance angle (i.e., the ignition advance angle during idle operation), as well as a vacuum advancement device that provides different advance angles based on changes in vacuum within the intake manifold.
2.1.2 Electronic ignition system
The electronic ignition system is completely different from the mechanical ignition system. It has an electronic control device for ignition, and there is an ignition control curve (MAP map) required for the engine under various working conditions. Determine the working state of the engine through a series of sensors such as engine speed sensor, intake manifold vacuum sensor (engine load sensor), throttle position sensor, crank position sensor, etc., and find the engine required in this working state on the MAP map. The ignition advance angle is ignited according to this requirement. The above ignition requirements are then corrected based on the knock sensor signal to operate the engine at the optimum ignition timing.
The electronic ignition system also has closed-loop control and open-loop control: an electronic control system with a knock sensor that can correct the ignition advance angle according to whether the engine is knocked or not is called a closed-loop control system; without a knock sensor, the ignition advance control The open loop control system is only controlled according to the program set in the electronic control unit.
2.2 Structure of the ignition system
2.2.1 Battery ignition system
(1) Composition: power supply (battery or generator), ignition coil, distributor, spark plug, ignition switch and control circuit.
(2) Working principle: When starting: battery positive pole, starter live wire connection post, starter short circuit conductive piece, ignition coil 'switch' connection post, low voltage coil, ignition coil low voltage connection post, distributor contact, grounding, Battery negative.
(3) After starting: generator "armature", ammeter, ignition switch, ignition coil "power supply", thermal resistance, ignition coil "switch", low voltage coil, ignition coil low voltage post, distributor contact, take Iron, battery negative.
(4) High-voltage circuit: high-voltage coil, central high-voltage line, split-fire head, split-cylinder, line plug center pole, spark plug side electrode, grounding.
(5) Main components of the battery ignition system: ignition coil, distributor, capacitor, spark plug, high voltage line, etc.
When the gasoline engine is running, the breaker cam is rotated, so that the breaker is continuously closed and disconnected. When the contact is closed, the battery supplies current, and the current is electrically pulled from the positive pole of the battery through the ignition coil, and the electrical breaker is electrically shocked, and returns to the negative pole of the battery. When a current flows through the primary winding of the ignition coil, a strong magnetic field for energy storage is generated in the core. When the breaker contact is opened, the primary current rapidly decays and disappears, and the magnetic flux in the core decreases. The high voltage required for ignition is induced in the secondary winding. This voltage is delivered by the high voltage line to the distributor, where it is delivered to each respective spark plug, creating an electrical spark.
2.2.2 Contact electronic ignition system
The contact electronic ignition system is a semiconductor auxiliary ignition device for reducing the contact current, reducing the contact spark and improving the ignition performance. In addition to the same power supply, ignition switch, distributor, ignition coil and spark plug as the traditional ignition system, it also adds ignition control composed of triode VT and resistors and capacitors in the circuit of the primary winding of the ignition coil.
In the circuit, the electric shock of the breaker is connected in series in the base circuit of the triode to control the conduction and the cut-off of the triode.
2.2.3 Contactless Electronic Ignition System
The non-contact electronic ignition system uses the sensor instead of the breaker to generate electric shock, generate the ignition signal, control the ignition coil's on-off and ignition system work, can overcome all the shortcomings related to the initial stage, and is widely used in domestic and foreign automobiles. The non-contact electronic ignition system is mainly composed of an ignition signal generator (sensor), an ignition controller, an ignition coil, a distributor, a spark plug and the like.
Common fault diagnosis and repair of ignition system3.1 ignition system common faults
The ignition system is the main system of the gasoline engine, and the ignition system works well. Directly affecting the performance of the engine, so a reliable and accurate ignition system is the goal pursued. However, as the ignition system increases in operation time, there are many faults. The common faults of the ignition system are generally the ignition timing of the engine ignition system is too early, the ignition is too late, the spark plug is faulty, the engine is tempered and the shot is fired, the engine is knocked, The engine can not start, the engine is not stable, the engine power is reduced, the fuel consumption is increased, the acceleration is poor, the ignition time is improper, and the individual cylinders are not ignited.
3.2 Ignition system failure analysis and troubleshooting
(1), ignition time is too early, fault repair
Fault phenomenon: Idle speed is not stable, easy to extinguish: When accelerating, the engine has a serious deflagration sound. Fault analysis: The fault is mainly caused by misalignment of the ignition timing or misalignment of the ignition angle. Remedy: Connect the ignition tester and adjust the ignition advance angle to the specified value.
(2), ignition too late fault repair
Fault phenomenon: The sound of the silencer is heavy, the temperature of the engine coolant is high, and the car is weak. Fault analysis: The ignition angle is not correct. Remedy: Adjust the ignition angle to the specified value.
(3), spark plug failure repair
The main faults are: spark plug carbon deposit, oil stain and overheating.
Spark plug carbon deposits: The insulator ends, electrodes and spark plug shells are often covered with a relatively thick layer of dark gray powdery soft deposits.
Spark plug oil: The insulator ends, electrodes and spark plug shell are covered with a layer of oil.
The spark plug is overheated: the center electrode melts, the top of the insulator is loose and soft, and the insulator end is mostly grayish white. When there is carbon deposit, oil stain and overheating in the spark plug, find out the cause and replace it in time.
(4), engine tempering and shooting failure maintenance
If the engine has both tempering and cannoning sounds, and it is very serious, it is caused by the wrong insertion of the high-voltage line of the sub-cylinder. If the phenomenon is not serious, but it happens intermittently, it seems that there are regularities, but most of the distributors have cracks, which cause the fire between the cylinders. When the ignition advance angle deviates too much from the correct position, it may also cause tempering or exhaust pipe firing.
(5), engine knock and overheat repair
The engine is most prone to knocking at high loads and medium speeds. In the case where the fuel grade is correct, the knocking phenomenon is mostly caused by the excessive ignition advance angle.
In the event of a knock, the engine heats up quickly. On the other hand, the ignition advance angle is too backward, the ignition is too late, and the engine temperature is too high. In the absence of knocking, most of the water temperature is not caused by the electric fire system, but if the engine is weak and the acceleration is not sensitive, it should be checked whether the ignition advance angle is too small. Check the gasoline grade and adjust the correct ignition advance angle to eliminate the fault.
(6), the engine can not start
Fault location: ignition switch to distributor circuit, ammeter, ignition switch, breaker, capacitor, sensor, ignition controller, distributor cover or split head, high voltage wire, spark plug, distributor, cylinder line.
Causes and troubleshooting: short circuit, open circuit, poor contact, current meter, ignition switch damage, ignition coil damage, additional resistance open circuit, contact oxidation, ablation, poor fixed contact grounding, disconnection, grounding, Contact gap is too large, too small, damage, sensor coil short circuit, open circuit, grounding, improper gap between rotor cam and core, Hall element damage, damage, leakage, leakage or open circuit, carbon deposit or oil, excessive clearance, over Small, leakage, the installation position of the distributor is wrong, and the position of the cylinder line is inserted incorrectly.
Remedy: inspect, tighten, replace wires, replace, replace, clean or replace, repair and strengthen the grounding, repair, adjust, replace, repair or replace, adjust, replace, replace, replace, replace, clean or heat transfer characteristics Appropriate spark plugs, adjust, replace, re-align the ignition timing after re-wiring.
(7), the engine is unstable
Fault location: ignition timing, spark plug, high voltage wire.
Fault reason: improper ignition timing adjustment, ignition advance angle adjustment device failure, distributor shaft loose, breaker cam
Uneven wear, individual cylinder spark plug insulation damage or carbon deposit, individual cylinder line damage, leakage.
Remedy: Re-ignite the ignition timing, repair or replace the distributor, replace the distributor, replace the spark plug, and replace.
(8) Engine power is reduced, fuel consumption is increased, and acceleration is poor
Fault location: ignition timing, breaker.
The cause of the malfunction: improper adjustment of the ignition timing, failure of the ignition advance angle adjustment device, and excessive contact gap. Remedy: Re-calibrate the ignition timing, repair or replace the distributor, repair or replace.
Ignition system maintenance4.1 Main content
(1) Check and adjust the ignition timing;
(2) Check the spark plug electrode and carbon deposit, adjust to the specified value if necessary, use spark plug cleaner or manually remove the carbon deposit; (3) Check the gap and surface condition of the breaker contact, adjust, trim or replace if necessary ;
(4) Check the connection of high and low voltage lines, ensure that the connectors are firm and reliable, check the insulation performance and resistance of the high voltage conductors, and replace them if they are not required;
(5) Clean the inside and outside of the distributor, remove dust, oil and water, lubricate the lubrication points of the distributor, and keep the vents of the distributor cover unblocked.
4.2 Inspection and adjustment of ignition timing
(1) General inspection
Start the engine, raise the temperature of the coolant to 80 °C, accelerate rapidly, if the speed can not increase immediately, feel boring, or there is a sudden sound in the exhaust pipe, indicating that the ignition is too late; if there is a similar metal knocking sound, Explain that the ignition is too early.
(2) Check with the ignition timing meter VAG1367
1) Find and verify the 1st cylinder compression top dead center mark and ignition advance angle mark on the flywheel or crankshaft front end belt disc, wipe it to make it clearly visible. If the mark is not clear, it is best to use chalk or paint to mark the mark.
2) Connect the ignition timing meter to the engine of the car according to the diagram, unplug the vacuum hose of the vacuum adjustment device, and start.
The engine makes the oil temperature rise above 60 °C.
3) Keep the carburetor choke valve fully open, observe the engine speed displayed by the instrument, and keep it idle. At this time, the ignition advance angle displayed by the instrument is the initial ignition advance angle, which should be 6±1°. If it does not meet the requirements, Adjustments should be made.
If using the ignition timing light, the top dead center sensor should be removed, the timing light should be aligned with the flywheel cover observation hole, and the resistance should be adjusted. When the fixed mark (on the cover) and the rotary mark (on the flywheel) coincide, Measuring the advance angle.
(3), road test
After the engine is hot, drive at the highest and lowest stable speed on a flat, hard surface. In the case of rapid acceleration, if you hear a slight popping sound and disappear instantly (the engine with the knock limiter has no blast sound), the speed of the vehicle increases rapidly, and the ignition timing is correct; if the blast sound is strong and long If the time does not disappear, the ignition is too early; if the sudden sound is not heard, and the acceleration is slow, the exhaust pipe has a sudden sound, and the ignition is too late.
4.2 Repair and maintenance of the distributor
The function of the distributor is to turn on and off the low-voltage current, and distribute the high-voltage electricity generated by the ignition coil to the spark plugs of each cylinder according to the ignition sequence of the engine. The performance of the distributor will directly affect the operation of the engine. Let's talk about the repair and maintenance of the distributor.
(1), inspection of the distributor shaft
The normal fit clearance between the distributor shaft and the bushing is 0.02-0.04 mm and the maximum is not more than 0.07 mm. When checking, hold the distributor housing with one hand and hold the coupling for axial and radial clearance check with the other hand. If the shaft and bushing are found to have a large amount of looseness, the bushing should be replaced. The coupling of the distributor should not have a radial swing amount (the radial swing amount will affect the ignition timing). If there is a radial swing amount, the coupling pin should be punched out to fix the rivet pin, re-rive, and eliminate the diameter. The amount of swinging. The axial clearance of the distributor should be between 0.08 and 0.25 mm. If the axial clearance is found to be too large, an appropriate gasket can be added for adjustment.
1), inspection of contact ablation
1 burning light gray is normal;
2 burnt black indicates that it is caused by lubricating oil and grease vapor from the cam;
3 burnt blue indicates improper gap adjustment;
4 When the capacity of the capacitor is large, the contact on the negative electrode side is burned into a convex shape, and the contact on the positive electrode side is fired in a concave shape;
5 When the capacitor capacity is small, the contacts on the negative electrode side are burned into a concave shape, and the contacts on the positive electrode side are fired in a convex shape.
2), the ablation of the contact
When the contact ablation is not too heavy, you can use a small piece of "0" sandpaper to make the sand surface face outward, fold it together, rub it back and forth between the two contacts, and rub off the ablation trace. Clean, tough sheets are rubbed back and forth in the same way to remove wear debris and sand. When the contact ablation is heavy, the contact should be removed and repaired with oil stone. When grinding, special attention should be paid to the flatness of the contact surface to ensure the contact closure.
It can be fully contacted. The thickness of the contacted single piece shall not be less than 0.5 mm, otherwise the new contact shall be replaced.
3), assembly of contacts
When assembling the contacts, it should be noted that the center line of the contacts must coincide, and the deviation must not exceed 0.2 mm. If there is a vertical deviation, the upper and lower pads of the movable contact arm can be adjusted. When there is a left-right deviation, the contact arm can be corrected by bending.
4), check the tension of the contact spring arm
In the case of open contacts, the tension of the spring should be 0.5-0.7 kg force, which can be adjusted by bending the spring piece when it is not required. In addition, the movable contact and the shaft should not be installed too tightly or too loosely. Apply a little grease to the shaft before installation.
(2), the inspection of the distributor cam
The distributor cam does not allow for large uneven wear. The distance between the cam angles to the central axis shall not differ by 0.03 mm, and the angular wear of the cam shall not be greater than 0.4 mm. When visual inspection, there must be no obvious oversize or undersize lobes, otherwise the new cam should be replaced.
(3), adjustment of contact gap
The contact gap should be 0.35-0.45 mm. When adjusting, loosen the fixing screws so that the push rod of the movable contact arm is placed on a cam angle, and then rotate the adjusting screw until the clearance is appropriate, and then tighten the fixing screws. If the contact gap is too small, the arc is easy to be generated, the contact is easy to ablate, and the starting is difficult. When the speed is low, the fire is easily broken. If the contact gap is too large, the closing angle of the cam becomes small, and the fire is easily broken at high speed. Large can make the contact opening time advance, resulting in premature ignition.
(4), the distributor cover and the split fire head inspection
When inspecting, first check whether the high-voltage line jacks are dirty, cracks, and whether the center carbon is in the correct position. The distributor cap should be replaced if there is a crack, and the central charcoal should be replaced if it is abnormal.
(5) Maintenance of the ignition advance device
The spring of the centrifugal regulator can be checked by fixing the distributor shaft, pinching the cam, and screwing it to the limit position along the rotation direction of its operation, then releasing the hand, for example, the cam can automatically return to the original position, indicating that the spring works well, otherwise replace.
(6), the lubrication of the distributor
There are four lubrication points in the distributor: one is cam linoleum, each time 3-4 drops of oil; the other is the butter cup of the distributor shaft, after the inside is filled with butter, it should be screwed 1-2 times; the third is the centrifugal spring. Drip oil 1-2 drops (remember not easy to be more); Fourth, the distributor tray should be lubricated with oil on the upper and lower joints.
4.3 igniter maintenance
The electronic igniter used in automobiles differs in the type of structure and circuit used in the electronic igniter (such as discrete components, integrated circuits, thyristors, etc.) due to the different types of ignition signal generators. Even the same type of igniter, its
Different manufacturers have different circuit structures and parameters, so it is difficult to inspect and measure them in a simple and uniform way. Therefore, the inspection of the electronic igniter should be based on the type of signal generator, the working principle of the electronic igniter, the circuit characteristics, the function, and the specific connection and working conditions on the vehicle. . The commonly used inspection methods are mainly the following:
(1) Overhaul of single-function electronic igniter equipped with magnetic induction ignition signal generator
The single-function electronic igniter equipped with a magnetic induction ignition signal generator has the basic principle of using the voltage of the dry battery as the ignition input signal of the electronic igniter, and then using a multimeter or a test lamp to roughly judge the quality of the electronic igniter.
Disconnect the line connector on the distributor, turn on the ignition switch, and connect one of the positive and negative poles to the two ignition signal input lines of the electronic igniter with a 1.5V dry battery No. 1. Use the multimeter voltage file to check the voltage between the ignition coil “—†terminal and the ground, then reverse the polarity of the dry battery, and then measure the voltage between the ignition coil “—†terminal and the ground (observed test light On and off), the two measurement results should be 1~2V (test light off) and 12V (test light on), otherwise, the electronic igniter is faulty.
(2) Overhaul of electronic igniter equipped with Hall signal generator
Remove the wire on the “—†terminal of the ignition coil, connect a light bulb in series with the line, and connect the positive pole of the 3V dry battery to the terminal 6 (signal line) of the electronic igniter. Turn on the ignition switch, and then make the dry battery between the negative pole and the body (ground) open and close. If the light bulb is suddenly turned on and off, the electronic igniter is good, otherwise it is damaged. First check the ignition coil and Hall sensor, then check if the electronic igniter is faulty and check the connection of the external circuit.
Check the Hall sensor, remove the rubber sleeve on the electronic ignition junction box, measure the voltage between the terminal 4 and the ground, the measurement result is 12V; then connect a voltmeter between the 6# terminals to turn on the ignition Switch, turn the engine, the voltmeter readings swing back and forth between 0.4 and 1V, indicating that the Hall sensor is intact. Check the electronic igniter, remove the wire on the "-" terminal of the ignition coil, connect a light bulb in series with the line, and connect the positive pole of the 3V dry battery to the terminal 6 (signal line) of the electronic igniter. Turn on the ignition switch, and then make the dry battery between the negative pole and the body (ground) open and close, the bulb can not flash normally, indicating that the electronic igniter is faulty, replace the new electronic igniter, and the engine starts smoothly.
4.4 Inspection and adjustment of ignition timing
(1), ignition timing check ignition timing gun
The data flow of the decoder and the engine analyzer are generally: 8-38 degrees.
(2) Adjustment of ignition timing
Distributor timing adjustmentRotating the distributor housing against the direction of rotation of the distributor cam (in time), the ignition advances the distributor housing in the direction of rotation of the distributor cam (in time), and the ignition delay is not adjusted at the timing of the distributor. Can be adjusted by adjusting the screw
(3) Check and adjustment of ignition timing. Toyota car ignition timing check and adjustment
1) Start the engine to reach the normal working temperature.
2) After the engine is turned off, connect the tachometer and timing light to the engine, and the transmission is placed in the N position.
3) Start the engine and accelerate to 2500 rpm for 90 seconds, then return to idle.
4) Check that the idle speed should be 750 rpm.
5) The engine is turned off, and the TEI and E1 feet in the diagnostic seat are connected by wires.
6), restart the engine and keep running at 750 士 25 rpm, check the basic timing, should be 10, if the point is not correct, check whether the timing belt skips, or check the throttle idle contact (ID and E2) Whether it is connected.
7) If the belt is normal and the idle contact is good, check the air flow meter, pressure sensor and water temperature sensor. In addition, it is necessary to pay attention to whether the engine has air leakage. If everything is normal, the engine computer does not normally use the basic ignition timing check and adjustment of the distributor disk engine. The ignition timing of the engine with the distribution plate can be adjusted.
ConclusionAt present, with the development of technology, the microcomputer-controlled ignition system has replaced the traditional battery ignition system. The electronically controlled ignition system is mainly composed of sensors for monitoring engine operating conditions, processing signals and electronic control unit ECUs that issue ignition commands, and responding to ignition commands. The actuators and the like are mostly shared with electronic control systems such as gasoline injection systems and idle speed control systems, and are controlled centrally by one ECU.
Among the signals input by the sensor, the crank position signal and the camshaft position signal are basic signals for keeping the ECU controlling the ignition system to operate normally. The crankshaft position sensor provides the engine speed, the crank angle signal, and the speed signal to the ECU for determining the ignition advance angle, and the corner signal is used to control the ignition timing (ignition advance angle). The camshaft position sensor collects the position signal of the camshaft and inputs it to the ECU so that the ECU recognizes the cylinder compression top dead center, thereby performing ignition timing control and knocking control. Since the camshaft position sensor can recognize which cylinder piston is about to reach the top dead center, it is also called a cylinder sensor. The structure of the crankshaft position sensor and the camshaft position sensor varies from model to model, and there are three types of magnetic induction, photoelectric and Hall. At present, the application of Hall sensors in automobiles is increasing day by day.
Actuators mainly include ignition controllers, ignition coils, distributors and spark plugs. The ignition controller is the power output of the microcomputer controlled ignition system, which receives the ignition control signal output by the ECU and amplifies it to drive the ignition coil to operate.
After the engine is started, the electronic control unit calculates and controls the optimal ignition advance angle, the optimal ignition advance angle = initial ignition advance angle + basic ignition advance angle + corrected ignition advance angle.
The knocking sensor is a sensor dedicated to the electronically controlled ignition system. The ECU can judge whether the engine is deflagrating according to the signal output by the knocking sensor, thereby correcting the ignition advance angle and implementing the knocking feedback closed-loop control of the ignition advance angle.
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