The day before yesterday I did a dangerous experiment on my engine. I wanted to test the maximum torque curve of the engine, or so called the performance curve, before I start to collect my soot samples. I thought it was alright because a previous member actually did the same experiment 2 years ago. My intention was to compare if there is any change regarding the engine. However, what I missed is that my engine is a heavily instrumented engine, and so many sensors were installed in and onto the engine.
When I was running the engine at 3400rpm, and push the throttle to 100%, the exhaust temperature was about 660C, which according to my experience was not extremely high. But after I ran it at this condition for about 10 or 15 minutes, I found the exhaust pipe had become red, and two of the signals regarding the cylinders did not function. My coworker and me realized it is really a bad test to the engine, and ran the engine at idling condition for a while.
The two signals regarding the cylinders still did not work at the first time. After the engine ran at idling for about 10 minutes, we were able to see the signals. My coworker told me probably the amplifiers of the two sensors stopped functioning because of the heat transmitted out from the engine exhaust.
Fortunately I did not break up any thing during my experiment yesterday. Of course we gave up our plan to find out the performance curve. Besides the technical aspect that I learned from this experiment, I think I need to be more modest and careful when I design an experiment. It is extremely important to take the advices from senior members and consider the testing plan over and over. If I could have kept this attitude, I would not have had such a dangerous situation on Friday.
Sunday, December 16, 2007
Thursday, October 25, 2007
Exhaust Temperature
A previous member told me about the exhaust temperature of the 2.5L engine
1800rpm 75% 380 degree C
1800rpm 25% 220 degree C
Also, I think I get to construct a full-load performance curve, and measure the temperature at each point before I start to collect my soot samples.
No need to jump to a point for collecting sample without deep consideration.
1800rpm 75% 380 degree C
1800rpm 25% 220 degree C
Also, I think I get to construct a full-load performance curve, and measure the temperature at each point before I start to collect my soot samples.
No need to jump to a point for collecting sample without deep consideration.
Thursday, October 4, 2007
How to choose engine test conditions
These days I am thinking about the engine test conditions for studying soot oxidation. At what speed and load should I operate the engine to study the soot morphology and nanostructure? Several research group analyze the speed and load of a driving cycle, such as FTP or EURO, and found some representative points of certain load and speed. Under these conditions, they operated the engine steadily, and study the engine PM emissions, and so on.
After discussing with my adviser, I found that I don't really need to do that. What I need to find out is a condition that can actually fill up the DPF without thermal regeneration, and thus collect the soot under this condition. Therefore, what I need to consider is not to have a high exhaust temperature from my combustion. On the contrary, I do want to collect soot efficiently. So, I really need to find out the operating point that can compromise these two conditions.
A previous member used a heavy-load diesel engine to collect soot under these experimental protocol, I need to find out the equivalent condition of my mid-duty diesel engine.
After discussing with my adviser, I found that I don't really need to do that. What I need to find out is a condition that can actually fill up the DPF without thermal regeneration, and thus collect the soot under this condition. Therefore, what I need to consider is not to have a high exhaust temperature from my combustion. On the contrary, I do want to collect soot efficiently. So, I really need to find out the operating point that can compromise these two conditions.
A previous member used a heavy-load diesel engine to collect soot under these experimental protocol, I need to find out the equivalent condition of my mid-duty diesel engine.
Saturday, September 29, 2007
Completed Candidacy Exam. Need to work harder.
Early this month, I have completed my Ph.D. candidacy exam. So, now I am a Ph.D. candidate according to the rule of my department. However, completing Ph.D. candidacy does not mean anything. My committee pointed out many fatal pitfalls in my research, and asked me to think about it.
For example, the hypothesis. A committee member challenged my hypothesis. "Do you know what a hypothesis is?", I was asked. I said, hypothesis is something that we speculate, we are not sure, and want to test it. Second committee member just think that I did not have a solid hypothesis because they are something already well-known. One of my hypothesis is that "The fuel formulation will impact on the soot characterization and reactivity". Indeed, my hypothesis was too broad and too general. After the exam, my advisor told me that I can make some hypothesis like this: "The percentage of oxygen contents is the reason that makes biodiesel soot more reactivitve and less ordering than the conventional diesel soot". This will be something that we are not fully sure, but want to verify or deny.
And, I have to consider the scientific impact of my research. I was kind of tongue-tied when I was asked this question by a committee member. After consideration after my exam, I think here is my answer. The difference between my research and the work done by an development engineer working in the automotive industry is that I am studying why things happened instead of design a product, or algorithm for controlling engine. For example, the automotive engineer in a car company might find that fuel composition might affects soot emissions by monitoring through very expensive PM measuring instruments. These engineers will just do nice jobs by trying different scheme and calibration data, and see the results. If it works, it can be sold, otherwise, they just have to keep trying or brainstorming. However, besides verifying that biodiesel has an positive impact on soot reactivity, my research is about why, and how biodiesel affects soot reactivy, and how this relates to soot nanostructure. With the solid understanding of soot reactivity and nanostructure, I believe that I will contribute to the academia , and also make an impacts on the industry.
The last thing, but not the least important thing, is to improve my english both in writing and speaking. I have no doubts about this. Although I have studied in the US for my master's degrees several years ago, there is still a lot of room for improving my english. Although I don't have a solid plan how I can improve my english systematically, I have to keep in mind that I have to do something consciously to polish my writing and speaking skills.
For example, the hypothesis. A committee member challenged my hypothesis. "Do you know what a hypothesis is?", I was asked. I said, hypothesis is something that we speculate, we are not sure, and want to test it. Second committee member just think that I did not have a solid hypothesis because they are something already well-known. One of my hypothesis is that "The fuel formulation will impact on the soot characterization and reactivity". Indeed, my hypothesis was too broad and too general. After the exam, my advisor told me that I can make some hypothesis like this: "The percentage of oxygen contents is the reason that makes biodiesel soot more reactivitve and less ordering than the conventional diesel soot". This will be something that we are not fully sure, but want to verify or deny.
And, I have to consider the scientific impact of my research. I was kind of tongue-tied when I was asked this question by a committee member. After consideration after my exam, I think here is my answer. The difference between my research and the work done by an development engineer working in the automotive industry is that I am studying why things happened instead of design a product, or algorithm for controlling engine. For example, the automotive engineer in a car company might find that fuel composition might affects soot emissions by monitoring through very expensive PM measuring instruments. These engineers will just do nice jobs by trying different scheme and calibration data, and see the results. If it works, it can be sold, otherwise, they just have to keep trying or brainstorming. However, besides verifying that biodiesel has an positive impact on soot reactivity, my research is about why, and how biodiesel affects soot reactivy, and how this relates to soot nanostructure. With the solid understanding of soot reactivity and nanostructure, I believe that I will contribute to the academia , and also make an impacts on the industry.
The last thing, but not the least important thing, is to improve my english both in writing and speaking. I have no doubts about this. Although I have studied in the US for my master's degrees several years ago, there is still a lot of room for improving my english. Although I don't have a solid plan how I can improve my english systematically, I have to keep in mind that I have to do something consciously to polish my writing and speaking skills.
Saturday, August 25, 2007
About my career in the future...
Now I am in the early thirties in my life. Although I have achieved something in the engineering field, I have still been confused about what I will be doing and where I am going toward.
Since I graduated from UM, I joined my previous company in japan, and doing development work in engine management system. I complete some works in catalystic deterioration control, control for fuel pump system, and turbo-charging system control. The project for fuel pump system is for reducing the fuel consumption, while the other two projects are for emission control. My current project is the study of soot nanostructure and reactivity. However, to work as an engineer, I think I do have to choose a focus field for my future career. I assume it is appropriate to define my profession as " applying technologies to study and design engine emission systems".
I still cannot decide where I should work after I leave school. My previous position is so called "advanced engineering" in the industry. However, I would like to try some places closer to the research/development field, such as some national labs or research-oriented universities. However, to keep myself competitive in the field, I get to learn some more useful techniqes in the industry, such as fast prototyping, or virtual instrumentation.
Since I graduated from UM, I joined my previous company in japan, and doing development work in engine management system. I complete some works in catalystic deterioration control, control for fuel pump system, and turbo-charging system control. The project for fuel pump system is for reducing the fuel consumption, while the other two projects are for emission control. My current project is the study of soot nanostructure and reactivity. However, to work as an engineer, I think I do have to choose a focus field for my future career. I assume it is appropriate to define my profession as " applying technologies to study and design engine emission systems".
I still cannot decide where I should work after I leave school. My previous position is so called "advanced engineering" in the industry. However, I would like to try some places closer to the research/development field, such as some national labs or research-oriented universities. However, to keep myself competitive in the field, I get to learn some more useful techniqes in the industry, such as fast prototyping, or virtual instrumentation.
Monday, July 23, 2007
Some Common Hydrogecarbon Components
1. Parafins
The paraffin family (sometimes called alkanes) are chain molecules with a carbon-hydrogen combination of C(n)H(2n+2). Examples: methane(CH4), propane(C3H8), butane(C4H10).
2. Olefins
The olefin family consists of chain molecules that contain one double carbon-carbon bond and are therefore unsaturated. Examples: Ethene(C2H2), butene-1 (C4H8)
3. Diolefins
Diolefins are chain molecules similar to olefins, except that they have two double carbon-carbon bonds. These unsaturated compounds have the chemical formula C(n)H(2n-2) and use the suffinx "diene". Example: 2,5-heptadiene
4. Acetylene
The acetylene family has unsaturated chain molecules with a triple carbon-carbon bond and the chemical formula C(n)H(2n-2). Example: acetylene (C2H2)
5. Cycloparaffins
Cycloparaffins have unsaturated molecules with a single-bond ring and a chemical formula of C(n)H(2n). Examples: cyclobutane(C4H8), cyclopetane(C5H10)
Cycloparaffins make good automobile gasoline components.
6. Aromatics
Aromatic molecules have an unsaturated ring structure with double carbon-carbon bonds and a general chemical formula of C(n)H(2n-6). Examples: benzene(C6H6), toluene(C7H8), ethybenzene(C8H10)
Aromatics generally make good gasoline fuel components, with some exceptions due to exhaust pollution. They have high densities in the liquid state and thus have high energy content per unit volume. Aromatics have high solvency characteristics, and care must be used in material selection for the fuel delivery system. Aromatics make poor CI engine fuel.
7. Alcohol
Alcohols are similar to paraffins with one of the hydrogen atoms replaced with the hydroxyl radical OH. Examples: methanol(CH3OH), ethanol(C2H5OH), propanol(C3H7OH).
The paraffin family (sometimes called alkanes) are chain molecules with a carbon-hydrogen combination of C(n)H(2n+2). Examples: methane(CH4), propane(C3H8), butane(C4H10).
2. Olefins
The olefin family consists of chain molecules that contain one double carbon-carbon bond and are therefore unsaturated. Examples: Ethene(C2H2), butene-1 (C4H8)
3. Diolefins
Diolefins are chain molecules similar to olefins, except that they have two double carbon-carbon bonds. These unsaturated compounds have the chemical formula C(n)H(2n-2) and use the suffinx "diene". Example: 2,5-heptadiene
4. Acetylene
The acetylene family has unsaturated chain molecules with a triple carbon-carbon bond and the chemical formula C(n)H(2n-2). Example: acetylene (C2H2)
5. Cycloparaffins
Cycloparaffins have unsaturated molecules with a single-bond ring and a chemical formula of C(n)H(2n). Examples: cyclobutane(C4H8), cyclopetane(C5H10)
Cycloparaffins make good automobile gasoline components.
6. Aromatics
Aromatic molecules have an unsaturated ring structure with double carbon-carbon bonds and a general chemical formula of C(n)H(2n-6). Examples: benzene(C6H6), toluene(C7H8), ethybenzene(C8H10)
Aromatics generally make good gasoline fuel components, with some exceptions due to exhaust pollution. They have high densities in the liquid state and thus have high energy content per unit volume. Aromatics have high solvency characteristics, and care must be used in material selection for the fuel delivery system. Aromatics make poor CI engine fuel.
7. Alcohol
Alcohols are similar to paraffins with one of the hydrogen atoms replaced with the hydroxyl radical OH. Examples: methanol(CH3OH), ethanol(C2H5OH), propanol(C3H7OH).
Tuesday, July 17, 2007
Review of a paper "Soot Morphology: An Application of Image Analysis in High-Resolution Transmission Electron Microscopy
I have finished reading and commenting on Dr. Sarofim's papar "Soot Morphology: An Application of Image Analysis in High-Resolution Transmission Electron Microscopy". I was surprised that they actually proposed the idea of applying image processing to TEM study of soot morphology much in 1996. I think it is one of the pioneer work in using TEM to study soot. Another pioneer work is published by RL Vander Wal in 1997.
Several properties can be extracted from the TEM images:
1. Circularity of Fringes - Defined as 4*pi*area/(Perimeter)^2
2. Elongation of Fringes - Sqrt(Mmax/Mmin) where M is a principal second moment.
3. Lateral Extent or length of fringes - La=A*B*sqrt(Mmax), A is depending on the shape of the object in question. B is a conversion factor.
4. Orientation or Angular dependence of a structural element - (not easily understandable) The angle in degrees between a line connecting the center of the image to the center of area of the structural element and the axis giving the lowest second moment of area.
5. Interplanar spacing - the distance (d002) between parallel fringes.
Many image processing ideas were mentioned in this paper. Therefore, it is needed to have both the knowledge in image processing and soot to conduct the research through this approach. Otherwise, we might not be able to get the meanful conclusion.
Several properties can be extracted from the TEM images:
1. Circularity of Fringes - Defined as 4*pi*area/(Perimeter)^2
2. Elongation of Fringes - Sqrt(Mmax/Mmin) where M is a principal second moment.
3. Lateral Extent or length of fringes - La=A*B*sqrt(Mmax), A is depending on the shape of the object in question. B is a conversion factor.
4. Orientation or Angular dependence of a structural element - (not easily understandable) The angle in degrees between a line connecting the center of the image to the center of area of the structural element and the axis giving the lowest second moment of area.
5. Interplanar spacing - the distance (d002) between parallel fringes.
Many image processing ideas were mentioned in this paper. Therefore, it is needed to have both the knowledge in image processing and soot to conduct the research through this approach. Otherwise, we might not be able to get the meanful conclusion.
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