ရည္ရြယ္ခ်က္မ်ား (Objectives)

၁။ မိမိကိုယ္တိုင္ေရာ တျခားသူပါ အင္ဂ်င္နီယာ ဗဟုသုတ တိုးပြားရန္အတြက္ အၿပန္အလွန္ ေဆြးေႏြးတိုင္ပင္ၾကရန္၊
1. To widen engineering knowledge of forum members by interactive discussion in the forum.

၂။ လုပ္ငန္းပုိင္ဆုိင္ရာ ႏွင္႔ သင္ၾကားေရး (သုိ႔မဟုတ္) သုေတသန ဆုိင္ရာ ၿပႆနာ မ်ား ႏွီးေႏွာေဆြးေႏြး အေၿဖရွာရန္။
2. To discuss and find the best or optimum solutions to industrial, learning and research-related engineering problems faced by the members.

၃။ အဖြဲ႔ ၀င္မ်ား၏ Engineering English တုိးတက္လာေစရန္
3. To strengthen the members' career by promoting the engineering English skills including technical writing, communication skills, presentation skills and illustration skills etc.

၄။ အဖြဲ႔၀င္မ်ားအတြင္း သက္ဆုိင္ရာ Specialization အလုိက္ နည္းပညာ ကြာဟမႈ နည္းပါးေစရန္။
4. To narrow the gap of engineering knowledge and technolgy among different members

၅။ သိသင့္သိထိုက္သည္႔နည္းပညာမ်ား ေလ့လာသိရိွႏိုင္ရန္ နည္းလမ္းညႊန္ျပေဆြးေႏြးႏိုင္ေစရန္
5. To point out what should be learnt and to guide the best possible ways to implement the learnning scheme in order that all on-going technologies can be reached by the members.

၆။ အဖြဲ႔၀င္မ်ားအတြင္း ႏွီးေႏွာဖလွယ္မႈ၊ ေမတၱာတရားတုိ႔ကုိ ေရွ႕တန္းတင္ျပီး အေကာင္းျမင္ေသာနည္းျဖင့္အင္ဂ်င္နီယာ ပန္းတုိင္မ်ားခ်မွတ္ အေကာင္အထည္ေဖာ္ႏိုင္ရန္
6. To set engineering goals and implement them positively by taking the advantages of active participation, discussion and loving kindness among members

စည္းကမ္းမ်ား (Rules of Games)

၁။ Engineering Education and Practice၊ မိမိၾကဳံေတြ႔ေနရေသာ အင္ဂ်င္နီယာပုိင္းဆုိင္ရာ ၿပႆနာမ်ား ႏွင္႔ ပတ္သက္ေသာ ေမးခြန္းမ်ား ကုိ လုပ္ငန္းပုိင္းဆုိင္ရာ (သုိ႔ ) သုေတသန ပုိင္းဆုိင္ရာ ႏွင္႔ ဆက္စပ္ ေမးၿမန္းရမည္။
1. All questions or problems related to engineering research, practice, industry etc. should be posted with the sufficient related explanation.

၂။ ေမးခြန္းမ်ားကုိ အကုိးအကား၊ အေထာက္အထားမ်ားႏွင္႔တကြ ေၿဖဆုိ အၾကံၿပဳရမည္။
2. Answers to the above problems should be provided with enough references and evidences. This may not be an academic work. Industrial case study should be very fine.

၃။ ဤဖုိရမ္ ႏွင္႔ ပတ္သက္ေသာ Post မ်ားကုိ "Engineering Forum" ဟု Label တပ္၍ တင္ရမည္။
3. All posts must be categorized under "Engineering Forum".

၄။ အဂၤလိပ္စာတိုးတက္မႈကိုရည္ရြယ္ထားေသာေၾကာင့္ ပထမဦးစားေပး အဂၤလိပ္လိုေရးသားၾကရမည္။ (Engineering Forum အတြက္သာ)
4. English is supposed to be used in the forum since one of the main aim is to improve English language skills of the members.

၅။ ေဆြးေႏြးသည့္အခါ ပုဂၢိဳလ္ေရး ဦးတည္ခ်က္မထားဘဲ အေၾကာင္းအရာေပၚတြင္သာ ဦးတည္ေဆြးေႏြးရမည္။
5. No personal approach or attack is allowed in the forum. Discussion must be centered in the engineering issues.

၆။ Specialization အလုိက္ ေဆြးေႏြးမႈမ်ား ပုိမုိတြင္က်ယ္လာပါက ဖုိရမ္ခြဲမ်ား subforum ကုိ ဖြဲ႔စည္း ေဆြးေႏြးေစမည္။
6. It is suggested that subforums are established in case there are members of different specializations and their discussions are quite comparatively interactive.

၇။ အမ်ားသိရန္မလိုအပ္သည့္ အမွားအယြင္းအေသးအဖြဲမ်ားကို gtalk မွတဆင့္ ကူညီအသိေပးရမည္။
7. Small odds and ends should be directed to the users by their personal e-mails or chat etc.

စိတ္မီးအိမ္ အင္ဂ်င္နီယာ ဖုိရမ္ ဥယ်ာဥ္မွဴးမ်ား
Seitmeeain Engineering Forum Moderators

Wednesday, November 7, 2007

INTRODUCTION TO ELECTRONIC ENGINE CONTROL SYSTEMS

Nowadays, most of the machines use electronic controlled engines which are more powerful and consume less fuel rather than normal conventional engines. Also, these electronic engines meet environmental requirements of exhaust emission.

These engines have an ECU, Electronic Control Unit, which will collect all the information from engine operation systems, the same as with conventional engines. It is like a human brain which controls the body. It acts as the brain of the engine and it controls the engine operating systems. As the human brain receives information from eyes, ears and hands etc, the ECU incorporates sensors to know engine operation condition such as ambient air temperature, charge air temperature, coolant temperature, oil temperature and engine rpm etc. Operating software, like a reasonable thinking in the human brain, is installed in the ECU to control engine operations according to the information from the sensors. So, without the ECU the engine will not operate, and without sensors the ECU cannot control the engines
.



Electronic Control Unit and Sensors of Volvo D12C (EC 460B)

The ECU needs many sensors to know engine condition and it uses “Temperature Sensors” to know coolant temperature, charge air temperature and oil temperature, and “Pressure Sensors” to know charge air pressures, fuel pressures and oil pressures. Now the ECU knows temperatures and pressures of engine operating systems, but not yet the engine rpm nor piston position in the cylinder to inject fuel into the cylinder at the correct firing order. Piston position depends on the rotation of crankshaft, and firing order depends on the rotation of camshaft. In which case a sensor is installed over the camshaft timing gear to know which cylinder is at TDC with compression stroke to inject fuel into the cylinder. This sensor is called “Camshaft Position Sensor”, and it tells the ECU which cylinder is at TDC with compression stroke to inject fuel. In this way it detects which cylinder is ready to fire at TDC. And then a sensor is installed over the crankshaft or over the flywheel on some engines to count engine rpm and to know accurate piston position, and this sensor is called “Crankshaft Speed Sensor”. Both of these sensors are also called “Speed Sensors” because they also count engine rpm. In the Electronic Engine Control System, fuel system is electronically controlled so that each cylinder can be separately controlled. For this reason, Electronic Unit Injection Pumps or Electronic Unit Injectors are used for each cylinder. The pumps are mechanically actuated by the camshaft and electronically controlled by the ECU.


Electronic Controlled Unit Pump

Volvo D6D Engines and D7D Engines use Electronic Unit Injection Pumps. Electronic Unit Injection Pumps have solenoid-operated valves and pumping action and high pressure are due to the upward movement of the plunger in the unit pump body. The plunger is pushed upward by the cam lobe on the camshaft. High pressure fuel is injected into the cylinder from the nozzle. The ECU controls the fuel injection by energizing or de-energizing the solenoid valve to start or stop the injection into the cylinders.


Electronic Controlled Unit Injector

Volvo D12C Engine of EC460B Excavator uses Electronic Unit Injectors. Unit Injector is a combination of a pump and a nozzle. Unit Injectors are placed directly above the cylinders and this system needs overhead camshaft. Unit injectors have solenoid-operated valves and pumping action and high pressure are due to the downward movement of the plunger in the injector body. The plunger is pushed downward by the cam lobe on the camshaft. So the fuel injection is controlled by energizing or de-energizing the solenoid valve in the pump to start or stop injection into the cylinder.

In this way, the electronic control system operates the engine by controlling the Electronic Unit Injectors to deliver fuel according to a given set of engine conditions, in precise amounts, and at a precise time in relation to piston position. In order to achieve this, the control system performs the following functions:

• Constantly monitor engine operating conditions
• Precisely determines piston position
• Deliver optimum amount of fuel for a given set of operating conditions
• Deliver fuel at optimum piston position
• Provide multiple control modes
• Perform self-diagnosis

In coming up issues: “How the ECU performs during Engine Starting Mode and Engine Running Mode” will be presented.

Thursday, November 1, 2007

Somebody help us. Properties of caltex T-32 torque oil needed!

Hi !

Everybody in the forum,

One of my friend is finding the chemical and thermal properties of CALTEX T-32 torque oil. It is used in the locomotive torque converter. Maybe the torque oil is pretty old. But according to her, some locomotive industries in Myanmar are still using that type of fluid.

She needs it for her research. Hope somebody help us.