Indicators

The term “Indicator” stands to represent indication of something. What are these things which are important in for your vehicle? Following indicators are most important indicators for your engine:

a.      Fuel level indicator

b.      Lube oil level indicator

c.       Water level indicator

 

   

1. Fuel Level Indicator: This indicator is directly connected to your engine’s fuel line. You can easily check the level of fuel of your tank from this indicator. It indicates fuel high and low level to give you an idea when to refuel the tank again.
2. Lube Oil level Indicator: The function of this indicator is as same as the fuel level indicator. It will show you maximum and minimum level of lube oil of your engine. So, you can easily decide when to feed lube oil to your engine.
3. Water Level Indicator: If you are using a vehicle having water cooled engine, then you will find this indicator in your engine’s cooling system. This level shows the ideal, low, and high levels of the coolant.  

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Lubrication System Components

The lubrication system of your engine consists of four major components. These components are as follows:

a.      Lube Oil Pump

b.      Pressure Relief Valve

c.       Oil Filter

d.      Oil Cooler

1. Lube Oil Pump: Actually, there are two types of lube oil pumps in the market. These are-

i. Rotary Type

ii. Gear Type

 Rotary type pumps use impellers to such and deliver lube oil from oil sump to all moving parts of the engine. However, gear type pump uses a pair of meshing gears that creates gap in between them. Lube oil is carried out at high pressure though these gaps. 

2. Pressure Relief Valve: You may find this valve in your lubrication system. The main function of this valve is to prevent excessive pressure of lube oil. You can also say it the pressure regulating valve. This type of valves contains spring loaded plunger or ball to control the oil pressure.
3. Oil Filter: The main function of this filter is to clean all impurities contained by the lube oil of your engine as like combustion impurities and products of wear. 
4. Oil Cooler: The oil cooler of your engine removes extra heat from lube oil, which is generated from all moving parts or heat taken from the engine cylinder. Practically, the oil cooler uses some tubes that contain hot oil, and the air passing through tube exteriors removes extra heat from lube oil. 

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Lube Oil Indicators

Basically, there are four types of lube oil indicators available in the market. You may find any one of the following indicators in your car:

a.      Digital Gauge

b.      Indicator Light

c.       Electronic Gauge

d.      Electric Gauge

1. Digital Gauge: If you are running a car with an electronic instrument cluster, you will find a digital lube oil gauge along with this that aids to show you the pressure of your engine’s lube oil. It will show you whether your engine’s lube oil pressure is high or low.
2. Indicator Light: If your car uses an indicator light system, then you will find it connected with the oil pressure switch, ignition switch, and with the battery in a series. If your engine’s lube oil pressure fall below the normal, then it turns on and warns you about it.
3. Electronic Gauge: You will find this type of gauge as a part cluster in cars having electronic instrument cluster. It is also similar to electronic fuel gauge system. It shows pressures as bar graphs.
4. Electric Gauge: The operation of your car’s electric lube oil gauge is as similar to the fuel gauge. You may find any one of the following electric gauge in your car:

i. Thermal Gauge 

ii. Magnetic Gauge

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Lubricating Oil Functions

Lube oil and lubrication system is really an important factor for your engine. Do you have any idea about its functions? Following points will give you a clear idea about its importance: 

1. Lubrication: The main function of your engine’s lube oil is to reduce frictional losses of all rotating parts. It also aids to move them properly and smoothly.
2. Cleaning: You can also call it a cleaning agent. It aids to resists slug formation in the engine cylinder. When piston moves up and down, piston ring scrape down accumulated carbon from the engine cylinder to oil sump. It also removes products of wear from all other moving parts and bearings.
3. Cooling: Lube oil also aids to cool surfaces by taking heat from all moving parts. Thus, it ensures proper functioning of your engine by removing extra heat generated by moving parts. You can also check it yourself. Just take a look at the navigation system of your car. You will see the increasing temperature of the lube oil.
4. Sealing: May be you are thinking how it seals. To understand its sealing capability, you have to think broadly. It functions as a good seal between cylinder walls and piston rings. To do so, you have to select quality lube oil that is capable to withstand against high temperature. Here, the lube oil should have adequate viscosity stability. 
5. Noise Reduction: If all moving parts of your engine are subjected to movement without lube oil, they will create harsh noise. Here, lube oil aids to move them smoothly without any noise.

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Engine Lubrication System

Before going on details about lubrication system, you have understand first what is it and why you have to give priority to your engine’s lubrication system. Basically, your engine’s lubrication system supplies lube oil to all moving parts including crankshaft, connecting rod, and piston and so on. May be you are thinking about its working principle. Just read the following principle to understand it clearly. 

Probably, you have already got a bit idea about lube oil pump. When you start your car, this pump aids to pick up lube oil from the oil sump, and then delivers it through the oil filter to all rotating parts of your car’s engine. It sends lube oil to main bearings that supports your engine’s crankshaft. After passing main bearings lube oil passes through oil holes to bearings of the connecting rod. Then, the lube oil is thrown off the rotating parts.

That is not all about lubrication system. Most interesting matter is that the lube oil passes through oil gallery to the cylinder head at the same time. Then, lube oil passes through valve-train parts and camshaft bearings. After passing through all these rotating parts lube oil is drawn back to the oil pan.

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Fuel Injection Pumps

There are various types of fuel injection pumps available for automotives. The Bosch fuel injection pump is a widely used one. In your fuel injection system, you will also find a specific pump designed by the manufacturer for proper fuel injection. Actually, this pump increases the pressure of the fuel to be injected by the injector. It takes the fuel from the fuel take, and then passes it through the fuel line of your engine to the injector.

Practically, you will find a rotary pump in your car for fuel injection. The inner construction of this type of pump includes an impeller that is subjected to rotation to create vacuum in the house, which aids to suck fuel from the sump and then delivers to the injector of your vehicle’s engine. This is the basic principle of a rotary pump.

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Fuel Injectors

There are two basic types of fuel injectors. You may find any one of these injectors in your car:

a. Mechanical Injector

b. Solenoid Operated Injector

a. Mechanical Injector: Practically, this type of injector is used in a continuous fuel injection system. This injector contains a mechanical needle valve, and the pressure of fuel operates this valve to control the fuel injection. The pressure of fuel intends to open and close the needle valve rapidly. When your engine is in the running condition, this rapid movement aids to atomize the fuel for proper mixing with the air. When your engine is off, a spring provided with the injector forces the valve to remain closed.

b. Solenoid Operated Injector: This is a widely used injector in the automobile industry. The ECM of your car directly controls this injector. If you start your car’s engine, the injector will get a voltage signal. Then, the solenoid of this injector will be energized. After that, the injector will be opened to spray out the fuel into the cylinder. Practically, you will find this type of fuel injector in the following fuel systems: i. Throttle Body Injection System ii. Pulsed Port Injection System.

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Actuators

Actuators are devices which work according to the command of ECM. Various sensors send signals directly to the ECM, and then ECM takes decision. After that, the ECM sends signals to different actuators to work according to the command. Practically, actuators are transducers. You can also say actuators as the electrical to mechanical signal converter. It takes electrical signals and controls mechanical motion. Basically, sensors are input devices and actuators are output devices of an ECM.

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Sensors

In the basic automobile construction system, automakers use several sensors to sense temperatures and pressures, and speed. Following are a few examples of important sensors that your car’s engine uses to get senses:


a. Engine Speed Sensor

b. Oxygen Sensor

c. Coolant Temperature Sensor

d. Air Pressure and Atmospheric Temperature Sensors

a. Engine Speed Sensor: Practically, your engine’s speed sensor is placed near to the crankshaft. It senses the engine speed by tracking the crankshaft position. Then, it sends signals to your car’s electronic control module about the tuning of the crankshaft. You may find any one of the following type of engine speed sensor in your car:

i. Magnetic Sensor
ii. Hall Effect Sensor

b. Oxygen Sensor: You may think that as it is about oxygen sensor, it is located in the air intake system. No, you are wrong. Practically, it is placed in the exhaust pipe or in the exhaust manifold. Its main function is to sense the amount of oxygen gas in the exhaust gas. Actually, it determines the voltage requirement of the spark plug for combustion. It sends the signal directly to the ECM for taking further action.

c. Coolant Temperature Sensor: It is also an important sensor for your vehicle. It continuously reports about the temperature of coolant. Actually, this type of sensor is a thermistor. It sends the signal directly to the ECM as a varying voltage signal. If the coolant temperature of your engine is very high, then this sensor sends signal to your ECM to supply charge with low fuel percentage.

d. Air Pressure and Atmospheric Temperature Sensors: It is also very important to control the density of air for proper combustion. Air pressure and temperature are vital factors to affect the density of air. At high pressure, the air becomes highly dense. However, at high temperature the air is lither enough. Thus, air pressure and temperature sensors send signals to the ECM to control the air flow accordingly. That is how your engine takes air from atmosphere according to requirements.

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Electronic Fuel Injection Systems

You may think why it is necessary to use fuel injection system as your vehicle is already using carburetor. Yes, you are right. This part is necessary to control the air-fuel mixture richness in various operating conditions. At the very beginning of your engine’s start up, it requires a very rich mixture to make it heated up. Here, the rich mixture contains high fuel percentage than air. Again it also requires a very high rich mixture when you accelerate and increase the speed. Practically, your gasoline engine uses any one of the following fuel injection systems:

a. TBI (Throttle Body Injection) system

b. PFI (Port Fuel Injection) system

 In case of any one of the following fuel injection system, your engine requires an electric pump to supply fuel into your engine at high pressure. You will also find a solenoid valve in this system, which controls the flow of fuel. It also aids to open and close the valve. You will also find an electronic control module on your car, which actually controls the fuel injection system. Various components of your fuel system send signals directly to the electronic control module (ECM), which calculates fuel requirements. Various components of your electronic fuel injection system are as follows:

a. Electronic Control Module

b. Relay Controller

c. Cannister Purge Valve

d. Fuel Pump Inertia Switch

e. Manifold Absolute Pressure Sensor

f. EGR Vacuum Regulator Valve

g. Pressure Feedback EGR Valve

h. Ignition Pickup Sensor

i. Throttle Position Sensor

j. Oxygen Sensor

k. Air-Charge Temperature Sensor

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Carburetor Explained

If you are running a car with petrol powered engine, then you have to think about the carburetor, the most important part of a petrol engine. Basically, it is a mixing device that aids air-fuel mixture to your engine. Basic construction of your carburetor contains float bowl, throttle body, and air horn as its main parts. Firstly, you have to understand the venturi clearly. It is not nothing but a narrow space through which the engine air passes to increase the velocity. It works by producing a partial vacuum in the device that is called the venturi vacuum. Actually, it creates pressure difference, which causes the fuel to be discharged from the nozzle and to be mixed with the air for combustion. Most interesting matter is that your vehicle’s carburetor requires a special fuel system to suit operating conditions. You may find any one of the following fuel systems in your vehicle to aid carburetor to change air-fuel ratio with varying conditions:

a. Main Metering System

b. Idle System c. Float System

d. Power System

e. Choke System

f. Accelerator-Pump System

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Turbocharger

Practically, turbocharger is connected to your vehicle’s exhaust line. It is a centrifugal air pump, and the exhaust gas of your engine drives this pump. You can ask why it is designed to run by exhaust gas. Yes, it is a good question. Now, be clever to think about its operation and power source. 

If automakers use engine generated power to run this device, it will require an extra energy and fuel to operate. It will add extra money to your annual operating cost. Otherwise, exhaust gases escape at high velocity and temperature. If we can utilize this energy, it will be a great saving. So, automakers have designed it to run by the energy of exhaust gases. 

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Supercharger

In the recent time, you will rarely find vehicles using supercharger. Poor fuel economy is one of the most common disadvantages of this part. But, you will see automakers prefer supercharged engines for a high performance vehicle instead of turbocharger due to turbo lag. You need not to turn at high speed as like as a turbocharged engine. Now a day, you will find new designs of a supercharger, where automakers have improved fuel economy and reduced noise. Basically, superchargers are of two types, and these are as follows:

a. Spiral type super charger
b. Roots supercharger

a. Spiral Type Super Charger: You can also say it the G-type supercharger. When you see it closely, you will find it very similar to the letter “G”. It functions as a positive displacement air pump. When the engine of your vehicle is in operation, a displacer moves inside spirals and compresses the air to a certain pressure. Things could be made easier to you; this part work eccentrically and does not rotate to compress the air. Two eccentric shafts are used to avail this. The first shaft is known as the displacer shaft, which moves and supports the displacer. However, the other part aids to prevent the rotation of displacer. The main function of this displacer is to divide the compressed air in between inner and outer chambers.

 b. Roots Supercharger: You may find this type of supercharger very common in auto industries. This part contains two long rotors. Both rotors contain 2-3 lobes, and air gets trapped in between gaps of rotor lobes. You will also find your engine’s roots supercharger is driven by a chain or a belt.

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Exhaust Systems

The exhaust system of your vehicle is really a vital factor for both human health and environment. So, you have to understand it clearly. You should remember that the basic function of your vehicle’s exhaust system is to collect, clean, and quiet exhaust gases of your engine. If you are running a car with V type engine, then you will find two exhaust systems for two cylinder banks. This system includes following important parts and elements: 

 

a. Exhaust manifold

b. Exhaust pipe

c. Tail pipe

d. Catalytic converter

e. Muffler

f. Resonator 

a. Exhaust Manifold: Are you facing problem to find out the exhaust manifold portion of your engine? It is nothing but a set of tubes of passages. It carries the exhaust gas from your engine cylinder to the exhaust pipe. It also combines exhaust gas flows into a single flow through a pipe or tube.  


b. Tail Pipe: You can easily find out this pipe from your vehicle. The pipe that delivers exhaust gases into the environment is known as the tail pipe. You can also say it an external part of your car. It takes exhaust gases from the resonator, and then delivers it to natural air. 


c. Catalytic Converter: You will find the catalytic converter of your vehicle in between the engine pipe and the muffler. Probably, you are thinking why this part exists in the exhaust system of your vehicle. Yes, this part is one of the vital parts here. It aids to purify exhaust gases of your engine. It absorbs harmful contents, and thus aids to reduce CO percentage. 


d. Muffler: If you give a close look to your vehicle’s exhaust system, then you will see a hollow cylinder like part in between the catalytic converter and the resonator. This part of your engine is widely known as the muffler. This part aids to muffle the noise of your engine’s exhaust gases. The inner construction of this part contains a series of passages, holes, and resonance chamber, where the noise produced by the high pressure exhaust gases gets damped. 


c. Resonator: This part exists in between the tail pipe and the axle pipe of your engine. The curved pipe or tube on your vehicle’s exhaust system is widely known as the axle pipe. It is also a hollow cylinder like arrangement, which further resists the thrust created by the exhaust gas. 

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Air-Fuel Mixture Distribution

The intake manifold of your engine contains the air-fuel mixture. If you give a close look to it, you will see that it would be though enough for this intake manifold to distribute the air-fuel mixture throughout cylinders. Theoretically, your engine cylinders should receive the same amount of air-fuel mixture with same richness for proper functioning. But, practically the mixture of end line cylinders is comparatively richer. 

Just take a look at the air flow passages of your engine’s intake manifold; you will see that all passages are different from each other in both shape and size. You also have to understand that liquid fuel vaporizes completely, when they enter the engine cylinder. If your intake manifold fails to deliver complete vaporization, it will contain heavy droplets. That is why, the air-fuel mixture. Chemical property of these droplets is a bit different, and they travel hazardously before hitting the end of the intake manifold. These droplets are collected in a puddle of fuel at the end of manifold. Some of these puddle fuels are collected by the air-fuel mixture, as they becomes evaporated. 

Comparatively, center cylinders of your engine will receive leaner mixture than end cylinders. This distribution becomes finer and smoother, when the intake manifold becomes heated up. After a few strokes, when the engine becomes heated up, the intake manifold of your engine also becomes heated up and it aids to vaporize fuel droplets.

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Emission Control Systems of a Vehicle

Those who are new with automobile or automotive engines have to know that there are three main control systems in each vehicle to control emissions of pollutants. These three control systems are discussed below:

a. The Control System of Exhaust Emission: You may find some important devices, which aid to reduce pollutants from exhaust gases. Catalytic converter is a great example of the exhaust emission control system. If you look closely, it will find it very similar to the muffler. You fill find it in the exhaust system of your vehicle, ahead of the muffler. At the inner of this catalytic converter, you will find some pellets made of palladium or platinum. When exhaust gases of your vehicle are passed over the converter, carbon monoxide and hydrocarbons get converted into carbon dioxide and water.

b. The Control System of Crankcase Emission: Blow by gases escaped from your engine try to find out their way through crankcase. The crankcase emission control system aids to send them back into the engine to burn them. The main purpose of this system is to resist escaping of blow by gases.  

c. Evaporative Emission Control System: Do you know your engine fuel tries to escape from your fuel system in the vapor form? Actually, fuel vapors try to escape through carburetor blow vents, fuel tank, and air cleaner. In a typical carbureted vehicle, fuel vapors are ducted to canisters, which contain activated carbon to absorb these vapors. During certain operational mode of your engine, the canister draws fresh air and pulls the pulls the fuel vapor into the engine to burn.

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Engine Fuels and Combustion

You will find gasoline as the most widely used fuel for automotive engines. Actually, gasoline contains hydrocarbon (CH) bond that aids to initiate the ignition. You may also think that gasoline means gas, which you are using on your kitchen. But, automotives use liquid form of gasoline.

Atmospheric air contains approximately 20 percent oxygen (O) and 80 percent nitrogen (N). When combustion of air-fuel mixture takes place in the cylinder, then hydrogen molecule of the gasoline gets united with the oxygen molecule of the air, and forms hydrogen oxide (H₂O)_. 

                                  

At high temperature it becomes water vapor. All carbon molecules present in the gasoline gets united with the oxygen molecule of the air, and form carbon dioxide (CO₂).

                                    

If you test the exhaust gases of engine, then you may find carbon-mono-oxide      (CO) and nitrogen oxide (N₂O), which are really harmful gasses. It happens as the air-fuel mixture does not completely burn in the engine cylinder. In an analyzer test, you will always get HC, CO, and N₂O in the engine exhaust gas.

Have you any idea about the chemical reaction of gasoline that takes place in the engine cylinder? Let us see how the CH bond of gasoline reacts in the presence of N and O of the atmospheric air.

      ->      

What do you see in this chemical reaction? May be you are thinking why there exist hydrocarbon in the right side of the reaction. This hydrocarbon stands to signify incomplete combustion. The chemical reaction of gasoline undergoes a complex process in the cylinder, where you will find some unburned gasoline as the byproduct. These byproducts are harmful for environment and human health.

Basically, you will find four important resources of air pollutants in your automotive. You have to have adequate knowledge on them to avoid further pollution. These resources are tailpipe, carburetor, crankcase, and fuel tank.

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IC Engine Applications

IC engines have very common applications on our daily life. Basically, IC engines have covered a vast field to upgrade our lifestyle. The most important applications of IC engines are in transportation on sea, air, and land.  Probably, you have not even thought like that. Okay, let us take a look at the following list to get a bit idea about its applications: 

a.      Road Vehicles: Scooters, Motor Cycles, Passenger Cars, Commercial Vehicles, and Mopeds and so on.  

b.      Railway Locomotives

c.       Marine: Ships, Motor Boats

d.      Off-Road Vehicles: Light vehicles on airport and factory, vehicles used in agricultural activities, Military vehicles, and Earth moving vehicles.

e.      Small Aircraft: Small sized airplanes, Helicopters.

f.        Lawn Mowers for Home use

Industrial Vehicles: Small vehicles and engines for gas pipeline, electric generator, and others.

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Four Stroke Cycle CI and SI Engine Comparison and Differences

Your four stroke cycle petrol engine is a great example of a SI (Spark Ignition) engine. Diesel engines are referred to as CI (Compression Ignition) Engines. How can you compare or differentiate SI and CI engines? To make things simpler to you, here is a list of some important facts:

- In the suction stroke, a SI engine draws air-fuel mixture into the cylinder. But, a CI engine draws only air in the suction stroke.

- You will find a carburetor in your petrol engine that mixes air and petrol. On the other hand, CI engines use atomizer or injector that injects the fuel at the end of the compression stroke.

 - Your petrol engine gets only 10 bar pressure at the end of the compression stroke. But, CI engines usually gets 35 bar pressure at the end of the compression stroke.

 - Spark plug provided with your petrol engine ignites the charge, but in case of a CI engine the fuel gets ignited by itself due to high pressure and temperature (Usually, it gets up to 600o C temperature).

- Practically, you will find your engine’s compression ratio in between 6-10 bars. But, the compression ratio of CI engines range from 15-35 bar.

- You will also find the speed of your petrol engine is higher than a CI engine (Diesel engine)

- Thermal efficiency of a petrol engine is a bit low than CI engines. Theoretically, thermal efficiencies of SI and CI engines are 26% and 42% accordingly.

- Your petrol engine is highly advantageous over CI engines due to low maintenance cost.

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Two Stroke and Four Stroke Engine Comparisons

You will rarely find two stroke engines now a day. If you are running a four stroke petrol engine, then you have to understand that why your engine is superior to a two stroke engine. The following are some listed points to make your concepts clear about the advantages of four stroke cycle engine:



 - Firstly, if you think about a two stroke cycle engine, then you have to understand how it completes the cycle. In a two stroke cycle engine, the working cycle is completed in only two strokes. It carries out suction and compression strokes at a time in a stroke, and working stroke and expansion strokes at a time in another stroke. So, it gives only one crankshaft revolution. But, you can achieve two crankshaft revolutions from your four stroke cycle petrol engine.

- A two stroke cycle engine can achieve less compression ratio than a four-stroke cycle engine. So, you will not get satisfactory compression ratio in case of a two stroke cycle engine.

 - Thermal efficiency of a two stroke cycle engine is quite less than your four stroke cycle petrol engine.

 - Overall performance and efficiency of a two stroke cycle engine is also less than your four-stroke cycle petrol engine.

- A two stroke cycle engine does not pose additional lubrication system as like your four-stroke cycle petrol engine. Thus, the lube oil consumption is comparatively high in a two stroke cycle engine.

- As the brunt gases of a two stroke cycle engine gets less time to exit, they creates harsh sound while escaping from the cylinder.

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