What does stroke height mean?

Question 1: Experts, what do short stroke and long stroke in cars mean? The so-called stroke ratio refers to the structure in the cylinder

1. The short stroke ratio means that the piston stroke is smaller than the piston diameter, and the engine tends to output speed

2. The long stroke ratio means If the piston stroke is greater than the piston diameter, the engine will be biased towards torque output

Question 2: What is the elevator top height? The top height refers to the elevator car top guardrail or car top anti-sheave protection when the elevator is leveling on the top floor. The vertical distance from the cover to the top of the hoistway.

Question 3: What are the appropriate values ??of the stroke and number of strokes in 6s mainly related to? Hello! The stroke refers to the length of the crude oil column lifted up by the sucker rod each time. Roughly speaking, the weight of the "ordinary sucker rod + crude oil column" is about 7 tons per kilometer; the stroke refers to the length of the sucker rod in one minute. The number of reciprocating movements. In the actual application site of oil wells, it is also necessary to distinguish between oil well working conditions (referring to oil well depth, oil pump, oil output, oil viscosity, temperature, etc.) and efficiency-benefit ratio (pointing out oil efficiency, power consumption, machine maintenance ratio, etc.). Selection and clarification of pumping unit models (beam unit and non-beam unit). The following is a detailed explanation of the strokes of various models:

1. Beam machine type: "beam machine", which is what we commonly call "kowtow machine", "Traditional models" refer to such models. This model has been used for more than 100 years since its birth. The stroke is between 1 meter and 6 meters. It is limited by the structural design and load-bearing capacity of the model. The largest model is model 16 (that is, the maximum lifting capacity is 16 tons. weight, generally the actual application is mostly type 14, and type 16 is rarely used), and is used in oil wells with well depths below 3000 meters; due to the non-renewable nature of crude oil and the development and extraction so far, as the crude oil level is pumped lower and lower, this type of machine The unsuitability in practical applications has become increasingly obvious, and non-beam models have emerged.

Example: For a 2-meter-stroke oil beam machine, if the maximum stroke rate is 8 times/minute, then the working start of the downhole oil pump of this model is also 8 times/minute, and the oil output efficiency is: 2 Meters*8 times=16 meters/minute.

2. Non-beam models: Pumping unit models that are different from "beam models" are "non-beam models", including: vertical machines, electric submersible pumps, and screw pumps ,,,, etc., it is also necessary to distinguish between well conditions and other situations to select specific products.

1. Vertical model: The structural design of this model is to achieve "long stroke" and "low stroke times", which effectively solves the "low pumping efficiency" and "supporting requirements" of traditional models. "Serious facility loss" problem, and the energy consumption of this type of machine is only 30%-80% of that of the beam machine. The general stroke of this type of machine is between 4 meters and 10 meters (since the maximum stroke of the current underground oil pump is 10 meters, the stroke height of this type of machine is limited. If the oil pump technology develops, the stroke can be extended accordingly. ), the models range from type 2 to type 40, which can be adapted to various working conditions of land oil wells and some offshore oil wells. Example:

Example: For a vertical model with an 8-meter stroke, if calculated based on the maximum stroke of 4 times/minute, the working start of the downhole oil pump of this model is also 4 times/minute, and the oil output efficiency It is: 8 meters * 4 times = 32 meters/minute

2. Electric submersible pump: suitable for various working conditions on site, but its high cost and high maintenance costs have become major problems restricting its application.

3. Screw pump: It is suitable for sites with abundant oil volume (for example: water injection wells), but it can only be applied to oil wells with a height of more than a thousand meters, and is not suitable for low-permeability and thick oil wells.

Question 4: For two-strokes and four-strokes with the same displacement, which one has more horsepower and higher speed? Hello, for two-strokes and four-strokes with the same displacement, of course, the four-stroke has more horsepower and higher speed. If my answer is correct If you found it helpful, please set it as the best answer. Thank you for your help!

Question 5: How many strokes does a car engine have? Today’s cars are all four-stroke, and there are also 5-stroke and 6-stroke engines, but they are rarely used in cars

Question 6: Stroke/cylinder bore (mm) What does 89.6/84 mean? 89.6 represents the piston working stroke, which is the distance from top dead center to bottom dead center

84 represents the diameter of the cylinder

Question 7: What do these engine parameters mean? The basic parameters of a car engine include the number of engine cylinders, cylinder arrangement, valves, displacement, maximum output power, and maximum torque.

Number of cylinders

The common number of cylinders in automobile engines are 3, 4, 5, 6, and 8 cylinders. Engines with a displacement of less than 1 liter are usually 3-cylinder, engines with a displacement of about 1.5 liters are generally 4-cylinder, engines with a displacement of about 3 liters are generally 6-cylinder, engines with a displacement of about 4 liters are 8-cylinder, and engines above 5.5 liters are generally 12-cylinder. Generally speaking, under the same cylinder diameter, the more cylinders, the larger the displacement, and the higher the power; under the same displacement, the more cylinders, the smaller the cylinder diameter, the speed can be increased, so that greater power can be obtained .

Cylinder arrangement

The cylinders of engines with less than 5 cylinders are generally arranged in an in-line manner, and a few 6-cylinder engines are also arranged in an in-line manner.

The cylinder block of the inline engine is arranged in a line. The cylinder block, cylinder head and crankshaft have a simple structure, low manufacturing cost, good low-speed torque characteristics, low fuel consumption, compact size, and wide application. The disadvantage is low power. The inline 6-cylinder has better dynamic balance and relatively small vibration. 6 to 12-cylinder engines basically adopt a V-shaped arrangement. The V-shaped engine means that the cylinders are arranged in four rows at staggered angles. The shape is compact. The length and height of the V-shaped engine are small, making it very convenient to arrange.

Number of valves

At present, most domestic engines use 2 valves per cylinder, that is, one intake valve and one exhaust valve; foreign car engines generally use a 4-valve structure per cylinder, that is, 2 intake valves and 2 exhaust valves improve the efficiency of intake and exhaust. Some foreign companies have adopted a 5-valve structure per cylinder, that is, 3 intake valves and 2 exhaust valves. The main function is to increase the intake and exhaust efficiency. Large air intake volume makes combustion more complete.

Displacement

Cylinder working volume refers to the gas volume of the piston from bottom dead center to top dead center, also known as single cylinder displacement, which depends on the cylinder diameter and piston stroke . Engine displacement is the sum of the working volumes of each cylinder, generally expressed in (L). Engine displacement is one of the most important structural parameters. It represents the size of the engine better than the bore and number of cylinders. Many indicators of the engine are closely related to the displacement.

Maximum output power

Generally expressed in horsepower (PS) or kilowatts (KW). The output power of the engine is closely related to the speed. As the speed increases, the power of the engine also increases accordingly. However, after reaching a certain speed, the power shows a downward trend. Car instructions generally indicate the maximum output power and the corresponding engine speed per minute, such as 150KW/4800r/min, that is, the maximum output power is 150KW at 4800 rpm.

Maximum torque

The torque output by the engine from the crankshaft end. The torque is expressed in N.m/r/min. The maximum torque generally appears in the medium and low speed range of the engine. As the speed increases, the torque will decrease. Of course, when choosing, you must weigh how to use it rationally and not waste existing functions.

Compression ratio

The ratio of the maximum volume of gas in the cylinder before compression to the minimum volume after compression. The national standard is represented by ε, which is also equal to the ratio of the total volume of the cylinder to the volume of the combustion chamber. When a gasoline engine is running, it inhales a mixture of gasoline and air. The greater the compression ratio, the higher the pressure and temperature of the compressed mixture. The gasoline molecules in the mixture can be vaporized more completely, and the combustion is faster. Rapidly and more fully, the greater the power the engine produces, the better the economy, and the exhaust quality can be improved accordingly. On the other hand, the combustion time of an engine with a low compression ratio is relatively prolonged, which increases energy consumption and reduces power output.

The larger the compression ratio, usually accompanied by a significant increase in buffeting when the engine is working (most of today’s engines have been specially adjusted, so it is not very obvious). If the compression ratio is too large, not only can it not further If the combustion situation is improved, abnormal combustion phenomena such as "deflagration" and "surface ignition" will occur. Deflagration will cause the engine to overheat, reduce power, increase fuel consumption, and even damage the engine. Surface ignition also increases the load on the engine and reduces its life. In addition, the increase in compression ratio is also restricted by exhaust pollution regulations.

The usual low compression ratio refers to a compression ratio below 10, and a value above 10 is considered a high compression ratio engine. The compression ratio has a great influence on the gasoline grade requirements of the engine. Generally speaking, the greater the compression ratio, the higher the gasoline grade required. If you use gasoline that is lower than the recommended grade, it may cause problems such as "cylinder knocking", increased engine vibration, uneven driving, etc. It will also damage engine performance and shorten its service life. Usually, a compression ratio lower than 7.5 can make... >>

Question 8: What does it mean when the spark plug coefficient is too high? He should be talking about the "calorific value" of the spark plug

The calorific value of the spark plug

The function of the spark plug is to introduce the high-voltage electricity (more than 10,000 volts) generated by the ignition coil into the engine cylinder. A spark is generated between the spark plug electrodes to ignite the mixture. The working environment of spark plugs is extremely harsh. Taking the spark plug of an ordinary four-stroke gasoline engine as an example, the temperature during the intake stroke is only 60°C and the pressure is 90KPa; during ignition and combustion, the temperature will instantly rise to 3000°C and the pressure will reach 4000KPa; This alternating frequency of rapid cooling and rapid heating is very high, which cannot be handled by ordinary materials. Insulation performance must also be ensured, so the material requirements for spark plugs are also very strict. Practice has proven that when the temperature of the central electrode of the spark plug is between 500°C and 800°C, the oil droplets falling on the insulator can be burned immediately without forming carbon deposits. No matter what kind of engine, this requirement must be met. When the electrode temperature is lower than 500°C, carbon deposits or oil are easily accumulated between the electrodes of the spark plug. If the temperature between the electrodes is higher than 800°C, before the spark plug jumps out, the temperature of the electrodes may have ignited the mixture, causing premature combustion.

The tip of the spark plug extends into the combustion chamber of the engine and is surrounded by high-temperature mixture. The heat from the tip must be transferred to the steel body through the porcelain core, and then to the cylinder head and radiator, dissipating the heat into the air

The official name of calorific value is "heat range", which refers to the spark plug's ability to conduct high heat from the sparking end of the ceramic insulator to the outer end of the spark plug, and then from the shell to the engine cooling system. When the engine is idling, the temperature of the spark plug's spark plug may be only 260°C. When the vehicle is traveling at high speed, the temperature of the spark plug may rise to 650°C. When vehicle oil climbs a grade, the temperature at the flashover end is more likely to rise above 870°C.

Different engines have different operating temperatures, so designers solve this contradiction by changing the length of the insulator skirt and other internal structures. For a small-power engine working at medium to low speed and low compression ratio, the heat dissipation of the Changhua plug can be slower. Those spark plugs used in high-speed, high-compression ratio and high-power engines have better heat dissipation, so that the temperature of the central electrode of the spark plug is always at the optimal temperature. We have to distinguish them only through the "degree" of caloric value. Some skirts are short and have a small heating area and fast heat dissipation, so the temperature of the skirt is lower. They are called cold spark plugs and are suitable for high-power engines that easily generate high heat. Some skirts are long and slender and have a large heating area and slow heat dissipation, so the skirt has a lower temperature. If the temperature is higher, it is called a hot spark plug, which is suitable for low-power engines with medium to low speed and low compression ratio. Therefore, when selecting a spark plug, special attention should be paid to the heat level of the spark plug. The heat rating is based on the extreme tip temperature of the center electrode of the spark plug.

The calorific value of commercially available spark plugs ranges from 2° to 13°. The larger the value, the “cooler” the spark plug, which is suitable for engines with high speed and high compression ratio; the smaller the value, the “hotter” the spark plug. (Hot type), suitable for low compression ratio engines. The cooler spark plug is made more sophisticated than ordinary products, so it can ensure the accuracy and quality of ignition when the engine rotates at high speed, thereby ensuring the maximum horsepower at the engine's limit. In addition, its resistance is also controlled to be very small, and the number of ignitions is not lost at all due to the increase in rotation speed. Therefore, using a spark plug with a higher degree is of great benefit to people who are used to shifting gears at high engine speeds or "racing". But if you switch to a spark plug with an excessive height (not suitable for your car's engine), it will be difficult to start and unstable at low speeds. Specifically, in most areas of China, 5°-8° spark plugs are more suitable (ordinary cars use 5°-6°, which can be changed to 6°, 7°, or 8°, depending on the actual reaction after installation. It is recommended that a maximum of 7° be used for ordinary cars in urban areas), and above 9° is only useful for racing in hot weather

Question 9: What does the stroke of a car engine mean? Why do some engine basic information indicate the data "bore × stroke"? The product obtained by "Bore × Stroke" (Bore × Stroke) is the displacement of a single cylinder, and then multiplied by the number of cylinders, the product obtained is the displacement of the entire engine.

On the premise that the displacement remains unchanged, each cylinder can be designed as "large bore × short stroke" or "small bore × long stroke". Both have their own advantages and disadvantages. Let’s talk about the former first. The large-bore design will increase the area of ??the engine and occupy a relatively large space in the engine room. This is a disadvantage, but it also has advantages. What are the advantages? The advantage is that it has a short stroke. With a short stroke, the height of the engine is not too high, so it can lower the center of gravity of the vehicle, which is helpful for high-speed stability and control performance!

In contrast, the advantage of the "small bore × long stroke" design is that the engine does not occupy a large area in the engine room. The front of the car has the opportunity to be designed shorter, leaving precious space for the passenger room, but The disadvantage is that the height of the entire engine becomes higher, and it is difficult to design the front of the car low and flat, which hinders the design of low wind resistance and streamlined shape. In addition to the smoothness, the high center of gravity will of course also affect the smooth control performance.

Regardless of the above explanation, engines with the same displacement will also have different engine output performance when using different "bore × stroke" designs. For those who use a long-stroke design, the rotation speed at which the peak torque occurs will be relatively low. This is because the piston has a longer stroke each time it runs in the cylinder, so the dynamic acceleration generated is higher, and the torque is easy to increase! To put it in the simplest explanation, it's like a boxer. When it pulls its fist farther back, the force of the punch must be stronger, right? This is why an uppercut is more powerful than a straight punch, and a straight punch is more powerful than a jab, because the stroke (Stroke) is longer. Therefore, using an engine with a "small bore The kinetic energy is relatively large, so the vibration when the engine is running is also relatively strong, making it difficult to balance.

On the contrary, an engine with a "large bore × short stroke" design, because each stroke of the piston is shorter, generates lower power acceleration, so it must run more times to obtain the same amount of force. output, so its attribute will be a high-speed horsepower engine. Top speed is its specialty. If you want to accelerate from a start quickly, you can only rely on increasing the engine speed. However, the relative benefit is the vibration of the engine running. It is smaller, easier to balance, and more likely to impress consumers with its refined operation.