What Causes the Abnormal Noise in Nissan CVT Transmission?

What is the specific gravity of 92-octane gasoline?

The specific gravity of one liter of 92-octane gasoline is 0.725 kilograms. Weight equals density multiplied by volume, and the density of 92-octane gasoline is 0.725g/ml, so one liter weighs 0.725 kilograms. However, the density of gasoline is not a fixed value, as it slightly varies with seasonal climate changes due to thermal expansion and contraction. Typically, the octane rating of gasoline to be used can be determined based on the engine's compression ratio. Vehicles with engine compression ratios between 8.6 and 9.9 should opt for 92-octane gasoline. Gasoline, known as 'Gasoline' in the US and 'Petrol' in the UK, appears as a transparent, flammable liquid with a distillation range of 30°C to 220°C. Its main components are C5 to C12 aliphatic hydrocarbons and cycloalkanes, along with a certain amount of aromatic hydrocarbons. Gasoline has a high octane rating for anti-knock combustion performance and is classified into grades such as 90, 93, 95, and 97 based on octane levels. It is produced by refining various gasoline components obtained from petroleum refining, including straight-run gasoline, catalytic cracking gasoline, and catalytic reforming gasoline, blended with high-octane components, primarily used as fuel for spark-ignition internal combustion engines in vehicles. The GB17930—2013 standard for automotive gasoline first specified density indicators, set at 720～775kg/m³ at 20°C, to further ensure relatively stable vehicle fuel economy. Considering the fifth-phase automotive gasoline, the reduction in octane number due to sulfur reduction and manganese prohibition, and the shortage of high-octane resources domestically, the standard adjusted the grades of automotive gasoline from 90, 93, and 97 to 89, 92, and 95, respectively, while adding 98-octane automotive gasoline. Generally, the higher the gasoline grade, the higher the octane number, and the better the anti-knock performance. 92-octane gasoline contains 92% isooctane and 8% n-heptane, while 95-octane gasoline contains 95% isooctane and 5% n-heptane. It is advised that using a higher octane gasoline in a vehicle designed for lower octane will not cause damage, but the increase in octane number can alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in poorer performance. Using lower octane gasoline in a vehicle designed for higher octane can cause engine knocking. Because the octane number is too low, the gasoline's ignition point decreases and may ignite prematurely during the compression stroke. If combustion occurs before the spark plug fires during the compression stroke, resistance will arise during the upward stroke. This resistance makes the engine run very unstably. If the knocking is imperceptible, it only increases noise without significant damage to the engine. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in severe cases.

7

2

Share

What are the lubrication methods for an engine?

Engine lubrication methods include: 1. Splash lubrication, which utilizes oil droplets splashed by rotating components such as the crankshaft and camshaft during engine operation or sprayed from oil holes on the connecting rod big end to lubricate friction surfaces. This method primarily lubricates cylinder walls, cams, and piston pins; 2. Periodic lubrication, achieved through regular greasing, mainly servicing components like generators, starters, and water pump bearings; 3. Pressure lubrication, where an oil pump delivers pressurized lubricating oil to component friction surfaces, forming an oil film of sufficient thickness to withstand mechanical loads. This ensures reliable lubrication for high-speed and heavily loaded engine components.

2

1

Share

What is the purpose of wheel alignment?

Wheel alignment ensures that the vehicle maintains stable straight-line driving without deviation, guaranteeing driving safety; it keeps the tires at the optimal angle with the vehicle body, preventing uneven tire wear; and it reduces wear between the tires and steering components during driving, extending tire lifespan. Below is relevant information: Wheel alignment refers to adjusting the relative positions and angles between the vehicle's four wheels, steering mechanism, and front and rear axles as specified by the manufacturer. If a car is driven for a long time on poor road conditions or if the tires or chassis are impacted, these relative positions can become misaligned, affecting the vehicle's performance and necessitating a wheel alignment.

4

1

Share

Which country is the Volkswagen brand from?

Volkswagen is a German brand. Volkswagen is an automobile manufacturing company headquartered in Wolfsburg, Germany, meaning 'the people's car'. Its models include Lavida, Passat, Tiguan, Tharu, Santana, Lamando, and Volkswagen Polo, among others. Taking the Volkswagen Polo as an example: it is a compact car equipped with a 1.5L naturally aspirated engine, producing a maximum horsepower of 113 hp, and comes with a 5-speed manual transmission. The dimensions of the Volkswagen Polo are 4053mm in length, 1740mm in width, and 1449mm in height, with a wheelbase of 2564mm, and a top speed of 190 kilometers per hour.

19

3

Share

What is the principle of a racing car spoiler?

Its main function is to effectively reduce air resistance and save fuel during high-speed driving. Here are the relevant introductions: 1. Upper spoiler: The upper spoiler consists of two parts, the horizontal wing is the main wing, and the inclined wing with an angle of attack is the auxiliary wing. For most tracks, the team will adjust the angle of attack of the auxiliary wing as large as possible. On high-speed tracks, the angle of attack will be appropriately reduced. 2. Louver structure: There are gaps with a louver structure on the end plates of the spoiler. The spoiler will generate a lot of resistance during operation, and these parallel gaps are used to reduce the resistance of the spoiler.

2

0

Share

Which Dotted Line to Look at for Parallel Parking?

Parallel parking involves looking at the second dotted line. Here is a related introduction to parallel parking: Practical Application: 12-word tips for parallel parking: Accurate estimation, quick steering, and steady driving. After stabilizing the car, turn the steering wheel one and a half turns to the right, then slowly release the clutch to let the car reverse. Parking Techniques: Before moving into the parking space, position the car close to the left line of the garage. Adjust the left and right rearview mirrors—lower the left mirror to see the left rear wheel, and adjust the right mirror to see the car body. Adjust the interior rearview mirror so that you can see the middle of the rear windshield when you look up.

6

0

Share

What Causes the Abnormal Noise in Nissan CVT Transmission?

What is the specific gravity of 92-octane gasoline?

What are the lubrication methods for an engine?

What is the purpose of wheel alignment?

Which country is the Volkswagen brand from?

What is the principle of a racing car spoiler?

Which Dotted Line to Look at for Parallel Parking?

Why does the tire pressure monitoring light come on in cold weather when the tires have air?

What are the applications of gasoline engines?

Is it okay to sleep in the car without opening the windows?

Can You Drive with a Coolant Leak?