By:
Amir Nosrat
Johan Tolosa
David Podorson
Introduction: As per required for all BELT (Bio-Diesel Longevity Test) teams to design a bio-diesel preheating kit and to implement a 500-hour Lister engine test, the BELT team of the City College of New York (CCNY) has decided to replicate an already established commercial model, the Vow2. This device is manufactured by a British company and has been originally designed for pre-heating diesel engines that operate in colder regions.
The concept is quite simple and has in fact been touched upon by the Columbia BELT team. All that needs to be done is to feed fuel through an inlet into one end of the Vow2 device so that the fuel will come into contact with glow plugs that are capable of producing tremendous amounts of heat. The heated fuel will then exit the vow 2 through an end that connects to the engine's inlet fuel line (See Figure 1). The temperature of the fuel is closely monitored by a thermostat connected to a relay. The relay will simply disconnect the circuit when the thermostat signals that the fuel has reached the indicated temperature (which in our case is 112 C, within the ideal range of feeding bio-diesel fuels to an engine).
The concept is quite simple and has in fact been touched upon by the Columbia BELT team. All that needs to be done is to feed fuel through an inlet into one end of the Vow2 device so that the fuel will come into contact with glow plugs that are capable of producing tremendous amounts of heat. The heated fuel will then exit the vow 2 through an end that connects to the engine's inlet fuel line (See Figure 1). The temperature of the fuel is closely monitored by a thermostat connected to a relay. The relay will simply disconnect the circuit when the thermostat signals that the fuel has reached the indicated temperature (which in our case is 112 C, within the ideal range of feeding bio-diesel fuels to an engine).
Figure 1- Vow2 with twin plug heater (Vow2B+)CCNY BELT has purchased a double glow plug Vow2 at the unit cost of 60 British pounds or about $100~150 US dollars. Before dismantling the device, we have decided to perform two experiments on the Vow2 to ensure that it works properly. For our first experiment which is being conducted here in CCNY, the fuel is simply fed to the Vow2 and the outlet temperature is measured to ensure that the device heats up the fluid to the desired temperature. More on this will be explained further in this report. The second experiment is to attach the Vow2 to a live engine and to run a short trial with the device pre-heating the bio-diesel. This has yet to be implemented and as of the moment CCNY lacks the resources available to carry out the experiment. Hopefully collaboration with other BELT teams will take place within the near future.
Apparatus: Since the objective is to keep the experiment as simple as possible, a primitive gravity-fed system is used to run fuel into and out of the Vow2. The team chose canola oil as our fuel, since it is the closest alternative to Jatropha oil. The oil was stored in a large bucket with a hole drilled at the bottom. The bucket was connected to the Vow2 via a foot long 5/16" inch inner diameter plastic tube. The outlet of the Vow2 is connected to another foot long plastic tube which feeds the fuel into an empty plastic container. The Vow2 itself was placed on top of a silicon mat in order to prevent transferring heat to the metal table. Originally, we wanted to control the flow of the oil with a valve, but found no gadget suitable to our purpose. So in order to stop the oil from flowing, we simply elevated the Vow2 above the fluid height. A picture of our set-up is shown in Figure 2.
Apparatus: Since the objective is to keep the experiment as simple as possible, a primitive gravity-fed system is used to run fuel into and out of the Vow2. The team chose canola oil as our fuel, since it is the closest alternative to Jatropha oil. The oil was stored in a large bucket with a hole drilled at the bottom. The bucket was connected to the Vow2 via a foot long 5/16" inch inner diameter plastic tube. The outlet of the Vow2 is connected to another foot long plastic tube which feeds the fuel into an empty plastic container. The Vow2 itself was placed on top of a silicon mat in order to prevent transferring heat to the metal table. Originally, we wanted to control the flow of the oil with a valve, but found no gadget suitable to our purpose. So in order to stop the oil from flowing, we simply elevated the Vow2 above the fluid height. A picture of our set-up is shown in Figure 2.
Figure 2- Picture of experimental setupThe circuitry of the Vow2 was then set up. A 12V car battery was connected to the relay which was then connected to the thermostat and the glow plugs, which were connected back to the battery. [T]he positive terminal was attached to the relay and to the thermostat and the negative terminal was attached to a grounding wire coming out from the Vow2. The positive terminals of the relays were connected to a 16 amp fuse to prevent any damage to the device. A simple diagram of the circuit of a single-plug Vow2 is presented in Appendix A and is very similar to that of the twin-plug.
Since a Listeroid engine takes in an average of 2 liters per hour or about half a liter per 15 minutes, the fuel storage tanks were filled up to a predetermined height. The amount of fuel entering the waste bucket was measured over a period of 15 minutes while the oil in the storage tank was kept at a constant height to ensure constant mass flow rate. If there was too much oil entering the waste bucket, the height of the oil in the storage tank was lowered and the mass flow rate was measured again. This was repeated until a desirable mass flow rate was obtained.
Since a Listeroid engine takes in an average of 2 liters per hour or about half a liter per 15 minutes, the fuel storage tanks were filled up to a predetermined height. The amount of fuel entering the waste bucket was measured over a period of 15 minutes while the oil in the storage tank was kept at a constant height to ensure constant mass flow rate. If there was too much oil entering the waste bucket, the height of the oil in the storage tank was lowered and the mass flow rate was measured again. This was repeated until a desirable mass flow rate was obtained.
We originally decided to measure the temperature at the end of the exit tube, but modified it to very beginning of the exit tube or right next to the Vow2 outlet. This is not shown in Figure 2. Once all wires were connected properly and a desirable mass flow rate was obtained, the Vow2 was fed with oil such that the glow plugs were imbued with the canola oil. This is important, since glow plugs are known to carbonize and burn quickly in the presence of air. The device was then turned on and the temperature was measured over a period of about 5-10 minutes to ensure that the Vow2 heated up the oil up to 112 C.
Result: We originally ran the experiment with only one glow plug attached to the battery. This was a safety precaution to the possibility of erroneous wiring that could have potentially damaged the glow plugs. However, this scenario gave us an undesirable result; the temperature of the fuel leaving the exit tube rose significantly until it stagnated at about 50~60 C. Since we realized that the wiring was proper, we decided to attach both glow plugs to the wire so that we could hopefully obtain the desired temperature.
Result: We originally ran the experiment with only one glow plug attached to the battery. This was a safety precaution to the possibility of erroneous wiring that could have potentially damaged the glow plugs. However, this scenario gave us an undesirable result; the temperature of the fuel leaving the exit tube rose significantly until it stagnated at about 50~60 C. Since we realized that the wiring was proper, we decided to attach both glow plugs to the wire so that we could hopefully obtain the desired temperature.
Even with both glow plugs attached, the temperature reading hovered at about 90 C and rarely exceeded 100 C. We assumed that there was a significant heat loss associated with the exit tube and that the surrounding temperature could in fact lower the oil's. Hence we cut a small hole on the exit hose near the Vow2 outlet such that we could plug in the thermocouple as close to the outlet as possible. This third trial gave us a favorable-result.
Our recordings indicate that the Vow2 was capable of very quick heating. Unfortunately, our readings were very preliminary and at times bizarre due to the sensitivity of the thermocouple; hence we could not offer an accurate tabulated result for the experiment. But we know that the oil reached 100 C as early as 1 minute and had stabilized near 112 C at about 2 minutes. We cannot be certain, however, of the experiment's validity due to the limiting factors imposed by the thermocouple. We would have a significant drop in oil temperature when the relay shut off the glow plug, even as low as 50 C, followed by a quick rise in temperature to its intended target. At other times, we would record excessively high temperatures (as high as 130 C). We were wary of accepting such readings as we learned that the thermocouple had come into contact with the Vow2, which is significantly hotter than the fuel itself. As a result, we are quite sure that the Vow2 can meet its purpose, though its long-term performance is still open to skepticism.
The Next Step: Hopefully, our team here at CCNY can begin drafting preliminary designs replicating the Vow2 as early as this month. But before we take it apart, we would like to attach it to a Lister engine and implement it for a short trial. Due to the lack of our own Lister engine for the moment, we would have to ask of Manhattan College and Columbia University to lend their engines for a day or two. There will be discussions between BELT teams as to how this can be accomplished as quickly and as smoothly as possible (as we would not like to interfere with other team's agendas). Once the preliminary designs have been completed, the Vow2 could be used for a part, if not all of our team's 500-hour longevity test.
Our recordings indicate that the Vow2 was capable of very quick heating. Unfortunately, our readings were very preliminary and at times bizarre due to the sensitivity of the thermocouple; hence we could not offer an accurate tabulated result for the experiment. But we know that the oil reached 100 C as early as 1 minute and had stabilized near 112 C at about 2 minutes. We cannot be certain, however, of the experiment's validity due to the limiting factors imposed by the thermocouple. We would have a significant drop in oil temperature when the relay shut off the glow plug, even as low as 50 C, followed by a quick rise in temperature to its intended target. At other times, we would record excessively high temperatures (as high as 130 C). We were wary of accepting such readings as we learned that the thermocouple had come into contact with the Vow2, which is significantly hotter than the fuel itself. As a result, we are quite sure that the Vow2 can meet its purpose, though its long-term performance is still open to skepticism.
The Next Step: Hopefully, our team here at CCNY can begin drafting preliminary designs replicating the Vow2 as early as this month. But before we take it apart, we would like to attach it to a Lister engine and implement it for a short trial. Due to the lack of our own Lister engine for the moment, we would have to ask of Manhattan College and Columbia University to lend their engines for a day or two. There will be discussions between BELT teams as to how this can be accomplished as quickly and as smoothly as possible (as we would not like to interfere with other team's agendas). Once the preliminary designs have been completed, the Vow2 could be used for a part, if not all of our team's 500-hour longevity test.
APPENDIX A: Vow2 Circuit Diagram
