Where is the knock sensor for the eight cylinder Hummer

Detect engine knocking to suppress the occurrence of knocking phenomena. When the engineer adjusts the knock sensor, the vibration pattern of the knock is written into the electronic control unit. If the knock sensor detects a vibration pattern, the ECU determines the engine knock and then delays the ignition advance angle.

Currently, advanced knock sensors can even tell which cylinder is knocking and delay the ignition advance angle of that cylinder separately. 

The knock sensor is mounted in the middle of the engine block. For example, a four-cylinder engine is installed between cylinders 2 and 3, or one between cylinders 1 and 2 and one between cylinders 3 and 4. It is used to measure engine shake and adjust the ignition advance angle in case of engine knocking.

Usually piezoelectric ceramics. When the engine vibrates, the ceramic inside is squeezed to produce an electrical signal. Because this electrical signal is very weak, the connecting wires of ordinary knock sensors are wrapped with shielded wires.

Knock sensors are AC signal generators, but they are very different from most other AC signal generators in cars. In addition to detecting the speed and position of rotating shafts like magnetoelectric crankshaft and camshaft position sensors, they also detect vibration or mechanical pressure. Unlike stators and magnetoresistors, they are typically piezoelectric devices.

They are made of special materials that can sense mechanical pressure or vibration (for example, when the engine starts knocking, it can generate alternating voltage).

Engine damage can occur due to premature ignition, poor exhaust gas recirculation, and engine knocking caused by low-quality fuel. The knock sensor provides a knock signal to the computer, prompting the computer to readjust the ignition timing to prevent further knocking. They actually act as "oxygen sensors" in the ignition timing feedback control loop.

The working principle of the knock sensor: when the engine vibrates or knocks the cylinder, the piezoelectric ceramic produces a voltage peak, and the greater the knock or vibration, the greater the peak. The engine control unit (ECU) processes the signals received by the detonation sensor, and if a detonation is determined, the ignition is postponed and the detonation continues.

When the engine control unit ECU does not receive the signal from the knock sensor, the ignition time is advanced to ensure the optimal output of the engine. Therefore, the purpose of using a knock sensor is to improve the dynamic performance of the engine without knocking.

The knock sensor is installed in the middle of the engine block, and in the case of a four-cylinder engine, it is installed between the 2nd and 3rd cylinders, or one between the 1st and 2nd cylinders, and one between the 3rd and 4th cylinders. It is used to measure the degree of engine shake, and is used to adjust the ignition advance angle when the engine detonation. Generally, it is piezoelectric ceramic, when the engine is shaking, the ceramic inside is squeezed to produce an electrical signal, because this electrical signal is very weak, so the connection wire of the general detonation sensor is wrapped with shielded wire.

At the middle cylinder! All cars are the same!

1.Generally, the knock sensor is installed in the middle of the BAI engine cylinder and the BAI engine is installed between the 2 cylinders and the 3 cylinders with the four-cylinder engine as an example, or one in the middle of the 1 and 2 cylinders, and one in the middle of the cylinder.

2.Function: The detonation sensor is used to measure the engine jitter, when the engine produces detonation, the detonation sensor converts the mechanical vibration of the engine into a signal voltage and sends it to calculate and correct the ignition advance angle in time according to the ignition and other data stored in its internal pre-storage, so as to adjust the ignition time and prevent the occurrence of detonation.

3.When the engine is working, it will cause engine knocking due to the influence of excessive ignition time (ignition advance angle), engine load, temperature and fuel quality. In the event of a knocking, the combustion of gases before the piston moves to the top dead center, which can cause noise and reduce the power of the engine, and damage the mechanical parts of the engine.

4.In order to prevent knocking, the knock sensor is an indispensable and important component in order to adjust the ignition advance time through the electronic control system.

There are generally several reasons for engine idle shaking, and the most common reason for car shaking caused by serious engine carbon deposition is that the throttle valve is too dirty or the fuel injector is too much carbon, because the gasoline adsorbed on the carbon deposit after the car is sucked into the cylinder by the engine for combustion, and the combustible mixture of the engine is dilute and thick, resulting in idle shaking after cold start. Solution: Siyoupu cleans the oil circuit and checks whether the idle motor has carbon deposits and should be cleaned.

Where is the Eighth-generation Accord knock sensor in the engine? Increasing the idle speed will produce the problem of increased fuel consumption, the manufacturer itself is designed in this way when designing, and the later increase is completely to cover up the phenomenon of bad combustion and jitter, and there is no problem from the root, and the high idle speed sensor also reacts sluggishly, in fact, it has a negative effect on the comprehensive effect of the vehicle. Petrochemical and petroleum clean the underground oil tank once in February, who added the oil before cleaning, how do you guarantee that the fuel is okay?

How to determine that the oil circuit is not dirty and the combustion is not good, and the long-term bad carbon deposition caused by the problem of carbon deposition is brought about? Repair is the method of elimination, do not rule out any possible problems, clean the oil circuit, add 3 divisions of fuel additives to run three tanks of oil, and your problem will probably be solved.

(1) Check whether the engine is obviously overheated, and if so, find out the cause first. (There are many related causes of engine overheating, pay attention to analysis).

2) Check if the engine knocks due to the failure of the ignition system.

If the ignition advance angle is too large, the mixture will burn too fast, resulting in engine knock combustion. The reasons for the excessive ignition advance angle are as follows: the crankshaft position sensor is installed in the wrong position (or loose), the timing belt is installed in the wrong tooth, the operation program of the power control module is faulty, the air intake detected by the air flow sensor is too small, and the detonation sensor is slow to respond.

3) Check if the pressure in the fuel system is too low.

If the pressure of the fuel system is too low, causing the mixture to be too thin, the combustion rate of the mixture will decrease, and the heat transferred through the cylinder wall to the coolant after the mixture is burned will increase, resulting in a high engine temperature. The engine temperature is too high, which is prone to detonation and combustion.

4) Check if the fuel is contaminated.

The lower the designation (i.e., octane number) of gasoline, the less resistant the gasoline is to knock off, and the more susceptible the engine is to detonation combustion when using this gasoline as fuel. In addition, if impurities are added to the gasoline with a relatively high grade, it will also cause the anti-knock ability of the gasoline to decrease.

5) Check whether the engine knocks due to the failure of the engine cooling system.

The actual working temperature of the engine is determined by the heat generated by the combustion of the mixture per unit time and the heat emitted by the heat dissipation system, if the cooling system is faulty, the former will be greater than the latter, the temperature of the engine will be higher and higher, and the tendency to detonation and combustion will be greater and greater.

6) Check if the pressure of the cylinder is too much.

If the pressure of the cylinder is too high, the combustion rate of the mixture increases, and the likelihood of detonation combustion in the engine increases. The reason for the excessive pressure of the cylinder is that the cylinder head, piston or cylinder gasket model is not the same as the working volume of the cylinder and the cylinder pressure.

7) Check whether there is too much carbon deposits in the combustion chamber of the engine.

If a large amount of carbon deposits accumulate in the cylinder, the hot spots formed by the carbon deposits may ignite the mixture in advance during the cylinder compression process, causing the pressure in the cylinder to suddenly increase during further compression, resulting in detonation and combustion. The causes of carbon deposition are as follows: the mixture is too concentrated, the ignition energy is relatively poor, the quality of gasoline is relatively poor, and the engine burns oil for some reason, etc., which can be checked separately.

8) Check if the EGR system is working properly.

If the exhaust gas recirculation system works within the working range, the system fails and cannot make the exhaust gas enter the cylinder to participate in the combustion, which will inevitably cause the combustion temperature of the mixture to rise, so that the engine will overheat and be prone to detonation combustion.

9) Check if the application and calorific value range of the spark plug are correct.

1. Detonation, commonly known as knocking cylinder and calling rod. Detonation is an abnormal combustion phenomenon that occurs during the combustion of an engine. To put it simply, "knocking" is a phenomenon of abnormal combustion of the engine.

Detonation is an abnormal pressure in the combustion chamber caused by abnormal combustion. When the engine knocks, it makes a knocking sound. The slight discontinuous knocking sound is quite crisp, somewhat similar to the sound of tapping a triangle.

In the event of severe and continuous detonation, the engine will have a "mile-mile" sound, and the engine will also be obviously weak at this time.

1. There is an irregular metal knocking sound of "clang", "click" and "dangdang" in the engine.

2. Engine tremor.

3. The engine temperature is too high.

4. The fuel combustion is incomplete, and there is black smoke in the exhaust gas.

5. The engine power decreases.

6. Increased fuel consumption.

7. During normal driving, the speed suddenly changes inexplicably.

Second, the main reasons.

1. The ignition angle is too advanced: in order to make the piston get power immediately after entering the power stroke after the end of compression top dead center, it is usually ignited in advance before the piston reaches the top dead center (because it takes a while from ignition to complete combustion). Ignition too early will cause most of the oil and gas to burn when the piston is still compressing the stroke, and the unburned oil and gas will be subjected to great pressure and spontaneous combustion, resulting in detonation.

2. Excessive carbon deposition in the engine

Excessive carbon deposition in the combustion chamber of the engine will not only increase the compression ratio (high pressure), but also produce high temperature hot spots on the surface of the carbon deposit, causing the engine to knock.

3. The engine temperature is too high.

If the engine is too hot, the inlet temperature is too high, or the engine cooling water is poorly circulated, which will cause the engine to detonate due to high temperature.

4. The air-fuel ratio is incorrect

Too thin the fuel-air mixing ratio will increase the combustion temperature, and the increase in combustion temperature will cause the engine temperature to rise, of course, it is easy to knock.

5. The octane number of fuel is too low

The octane number is an indicator of the knock resistance of the fuel, and the higher the octane number, the stronger the knock resistance. Engines with high compression ratios have higher pressure in the combustion chamber, and are prone to knocking if fuel with low knock resistance is used.

3. Inspection and maintenance.

1. Detect the change of engine combustion chamber pressure; Detect the vibration frequency of the engine block; Detection of combustion noise of gas mixtures.

2. The measurement accuracy of directly detecting the pressure change of the combustion chamber to detect the vibration of the engine is high, but the sensor is difficult to install, and the durability is poor, so it is generally used for measuring instruments, and the pressure detection sensors in practical applications are indirect detection type.

3. The fastest and most effective way to suppress detonation is to delay the ignition advance angle and reduce the combustion pressure. Therefore, the working principle of the knock sensor is that when the engine knocking is detected, the ignition advance angle will be delayed to the ignition time when the detonation will not be detonated, and then the ignition will be slowly restored in advance when the engine does not detonation.

At present, H1 has stopped civilian sales. The models available on the market are H2, H3 and H3 Alpha.

The strongest is the H2, powered by a V8 engine with 393 hp and 415 lbs of torque.

The H3 Alpha is a V8 engine with 300 hp and 320 lbs of torque.

The H3 was the worst, with an L5 engine making 242 hp and 242 lbs of torque.

Eight-cylinder diesel engine with a displacement liter.

Hummer H2 V-shaped 8-cylinder.

Hummer H3 inline 5-cylinder.

This car is known as a domestic Hummer, with a four-cylinder engine, and the price is only 120,000.

Knock sensor, on the cylinder block.