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Why Does Your Car's Oil Light Come On?
The oil circuit is probably one of the least-understood systems in a car. We explain how it works, and why the oil light on your dashboard might be turning on and off at mysterious times.
Any time the oil light goes on, it's cause for concern. Many newer and high-feature cars have oil-life monitors that determine when the oil needs to be changed, but the glowing red oil light in your Cavalier(engine as shown in diagram for example) indicates the oil pressure is low. That's bad for several reasons. Low pressure means there either isn't enough oil in the system or the oil pump isn't circulating enough oil to keep the critical bearing and friction surfaces lubricated. If the light comes on while at speed, do your best to pull off the road quickly, turn the engine off, and investigate the problem to avoid damage.
Oil is the lifeblood of any engine, but the oil circuit is probably the least appreciated engine system. The oil-supply path starts in the oil pan, where a pump sucks up the lubricating fluid and distributes it to passages cast into the block. From there oil is directed to the crankshaft bearings, the camshaft bearings, the valve shafts, and other important moving parts. Modern oil formulations include detergents, so regular oil and filter changes at intervals recommended in the owner's manual generally keep the system happy. Unfortunately, everything wears over time, which increases the tiny gaps between sliding parts. Those alone can cause a slight drop in oil pressure, as can an aging pump.
Before you go too far in diagnosing the problem, it probably makes sense to double-check the oil level and top it off to make sure that isn't the problem. Since the light comes on at low engine speeds and then shuts off, the oil pump is probably fine; if the pump were dying, you'd see low pressure at high engine speeds as well. The most likely culprit is the sensor that operates the light. The sensor is screwed into the engine and has a probe that resides in an oil passage. It's basically an on/off switch that uses the oil pressure to close an electrical circuit. Sometimes a particle of dirt or some other foreign matter gets into the probe and fouls the part. The sensor is fairly easy to replace—as long as you can get at it, which is sometimes difficult. Unhook the wiring, loosen with a wrench, and follow the instructions to replace the sensor. Take the car for a test drive and see if the light still goes on at idle. If it does, you might be due for a new oil pump after all.
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Inside the Radial Engine:
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel. This configuration was very commonly used in large aircraft engines before most large aircraft started using turbine engines. In a radial engine, the pistons are connected to the crankshaft with a master-and-articulating-rod assembly. One piston, the uppermost one in the animation, has a master rod (Red on the animation) with a direct attachment to the crankshaft. The remaining pistons pin their connecting rods (Yellow on the animation) attachments to rings around the edge of the master rod. Four-stroke radials always have an odd number of cylinders per row, so that a consistent every-other-piston firing order can be maintained, providing smooth operation. This is achieved by the engine taking two revolutions of the crankshaft to complete the four strokes, (intake, compression, power, exhaust), which means the firing order is 1,3,5,7,9,2,4,6,8 and back to cylinder 1 again. This means that there is always a two-piston gap between the piston on its power stroke and the next piston to fire (i.e., the piston on compression).
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Tiger Stone:
The labour-intensive work of paving a road has been simplified by a Dutch machine called the Tiger-Stone.Wherever the device goes, it will produce an instant road in the front.
Tiger-Stone is a Dutch made paving machine that uses gravity and an electric motor to print stone and brick roads. It’s a six meter wide machine that is capable of laying 300 square meters of road a day. The printing width is adjustable from the width of a road to as narrow as a bike lane or walkway..
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Conduction is the transfer of heat energy by microscopic diffusion and collisions of particles or quasi-particles within a body due to a temperature gradient. The microscopically diffusing and colliding objects include molecules, electrons, atoms, and phonons. They transfer microscopically disorganized kinetic and potential energy, which are jointly known as internal energy. Conduction takes place in all forms of ponderable matter, such as solids, liquids, gases and plasmas.
Convective heat transfer is often referred to simply as convection, is the transfer of heat from one place to another by the movement of fluids. Convection is usually the dominant form of heat transfer in liquids and gases. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of conduction (heat diffusion) and heat transfer by bulk fluid flow, a process technically called heat advection.
Radiation is a direct result of the random movements of atoms and molecules in matter. Since these atoms and molecules are composed of charged particles (protons and electrons), their movement results in the emission of electromagnetic radiation, which carries energy away from the surface.
Unlike conductive and convective forms of heat transfer, thermal radiation can be concentrated in a small spot by using reflecting mirrors, which is exploited in concentrating solar power generation. For example, the sunlight reflected from mirrors heats the PS10 solar power tower and during the day it can heat water to 285 °C (545 °F).
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MECHANICAL ENGINEERING JOB INTERVIEW QUESTIONS
1. What causes white smoke in two stroke locomotive engines?
: That is the engine running too lean (lack of fuel). This condition will lead to overheating and failure of the engine.
2. What is the role of nitrogen in welding?
: Nitrogen is used to prevent porosity in the welding member by preventing oxygen and air from entering the molten metal during the welding process. Other gases are also used for this purpose such as Argon, Helium, Carbon Dioxide, and the gases given off when the flux burns away during SMAW (stick) welding.
3. What does Green field project mean?
: Green field projects are those projects, which do not create any environmental nuisance (pollution), follows environmental management system and EIA (environment impact assessment). These projects are usually of big magnitude.
4. How does iron ore turn into steel?
: To make Steel, Iron Ore is refined into iron and all the carbon is burned away using very high heat (Bessemer). A percentage of Carbon (and other trace elements) are added back to make steel.
1.)What is anisotropy ?
Ans: The phenomenon of different properties in different directions is called anisotropy
2.)How you can define standard atmospheric pressure ?
Ans: By international agreement, the standard atmospheric pressure is defined as 101.325 kN/m2.
3.)What is saybolt seconds universal ?
Ans: Saybolt Seconds Universal (SSU) is the unit of viscosity and is equal to the time required for a gravity flow of 60 cc through saybolt universal viscometer.
4.)What is is entropic exponent ?
Ans: It is the ratio of the specific heat of a gas at constant pressure to the specific heat at constant volume.
1.)What do you understand by effectiveness of heat exchanger ?
Ans: Effectiveness of heat exchanger = actual heat transfer/maximum possible heat transfer.
2.)What do you understand by forced convection ?
Ans: When convection heat transfer occurs between a solid body and a fluid and where circulation of fluid is caused and controlled by some mechanical.
3.)Water/steam injection in gas turbines increases power output. What is the limit and reasons for same ?
Ans: Water/steam injection is not allowed beyond 5% of compressor flow to avoid flame out in combustion and to minimise operating cost and impact on inspection intervals.
4.)What is the frequency of secondary imbalance in four-stroke engine ?
Ans: Two times the engine speed.
1.)What do you understand by effectiveness of heat exchanger ?
Ans: Effectiveness of heat exchanger = actual heat transfer/maximum possible heat transfer.
2.)What do you understand by forced convection ?
Ans: When convection heat transfer occurs between a solid body and a fluid and where circulation of fluid is caused and controlled by some mechanical.
3.)Water/steam injection in gas turbines increases power output. What is the limit and reasons for same ?
Ans: Water/steam injection is not allowed beyond 5% of compressor flow to avoid flame out in combustion and to minimise operating cost and impact on inspection intervals.
4.)What is the frequency of secondary imbalance in four-stroke engine ?
Ans: Two times the engine speed.
1.). Under what condition a number of forces acting at a point are in equilibrium ?
Ans: When sum of the resolved parts in any two perpendicular directions is zero.
2.). What happens to two equal and opposite coplanar couples ?
Ans: They balance each other.
3.)What does the area under the stress-strain curve represent ?
Ans: Energy required to cause failure.
4.)Out of circular, square, channel, I sections, which is most economical for a component subjected to bending ?
Ans: I section.
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इंटरव्यू में सफल होने के लिए क्या करें
Interview के पहले :
1. जिस company में job करना है उसमे पहले से select होने के बारे में सोचें , law of attraction हर जगह काम करता है.
2. कभी भी कोई तेज गंध का deo या perfume लगा कर interview में ना जाएं.
3. Interview room में जाने से पहले अपना mobile switch off कर लें .
4. Job advertisement को भी दो -चार बार ध्यान से देख लें , यहाँ से आपको interview में क्या पूछा जा सकता है इस बात का अंदाज़ा लग सकता है .
5. Is series की दूसरी post में दिए गए tips पढ़ लें .
6. Company की website अच्छे से देख लें .
7. Interview venue पर 15-20 मिनट पहले पहुंचें , इससे आप की nervousness कुछ कम होगी .
Interview के दौरान :
1. पूरे panel से eye-contact बनाये रखने की कोशिश करें . किसी एक व्यक्ति को ही ना देखते रहे .
2. Question बड़े ध्यान से सुनें , और उसके ख़त्म होने पर ही अपने उत्तर शुरू करें बीच में ना टोकें
3. अगर answer के बारे में बिलकुल ही ना पता हो तो “Sorry, I don’t know “ बोल कर इस बात को accept कर लें , कभी भी interviewer को घुमाने की कोशिश ना करें .
4. अगर answer के बारे में sure ना हों , तो आप Interviewer की अनुमति लेकर उसे guess कर सकते हैं . या कुछ इस तरह से कह सकते हैं , “ I am not sure but probably……” ,”मैं sure नहीं हूँ पर शायद …..”
5. कभी भी अपने previous employer / boss / college की बुराई ना करें .
6. याद रखें की Interview में जितना बोलना जरूरी है उतना ही सुनना . इसलिए attentive हो कर questions सुनें .
7. Interview के दौरान Chewing Gum या candy ना खाएं .
8. Interview से पहले Cigarette ना पियें .
9. अगर question ना समझ आये तो उसे repeat करने के लिए request करें . कभी भी बिना question समझे answer ना दें .
10. अनावश्यक रूप से जवाब को लम्बा ना करें .
11. Salary के बारे में खुद से बात ना छेड़ें .Generally, ये बात HR personnel से होती है .
12. ऐसी body language रखें जिससे ऐसा लगे कि आप सामने वाले की respect करते हैं और एक confident individual हैं .
13. Over smart बनने का प्रयास मत करें , जितना पूछा गया है उतना ही बताएं .
14. कभी भी interviewer की knowledge को challenge ना करें , कि वो गलत है , या उसे कम पता है .
15. ये ना show करें की आप इस job के लिए बहुत desperate हैं , और किसी भी कीमत पर select होना चाहते हैं .
16. अगर आपका sense of humour अच्छा है तो एक -आध जगह आप इसका use कर के माहाल को हल्का बना सकते हैं . पर इसका प्रयोग एकदम limited करें .
17. अंत में panel को thanks जरूर करें .
Interview के बाद :
1. Ensure कर लें की follow up करने के लिए आपके पास किसी contact person की details हैं .
2. अगर बताई गए date तक कोई response नहीं आता है तो follow up करें .
3. Select ना होने पर भी contact person को interview कराने के लिए thanks करें .
