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SCIENCE TIME (II) - How about reducing the pollution of an ignition-based engine?

A project log for Retro-futuristic automobile control panel

Conversion of dashboard from an old, Communist clone of the French Renault 12 (Dacia 1310)

skaarj[skaarj] 04/09/2016 at 15:540 Comments

Since it rained a lot this week, the painting is not yet ready due to the humidity in the air. I did not want to risk anything because the repaint was not performed in an enclosed space.

So back to science time. First, I am not going to include in this project any hydrogen source powered from the normal power grid. But I'm thinking to combine such a hydrogen electrolysis device powered by a big solar panel. I still have all the system gathering dust in some basement so there's no big deal about this - except buying a huge solar panel.

In the first part I presented the vibration diagnosis of engine block, for such a piece of technology running on hydrogen as fuel. Also I talked about some modifications performed to the (former trash dump) automobile engine which resulted in some bad side effects both for the mechanism and the pets in the neighborhood.

The second scientific article rejected by certain respectable journals in the academic neighborhood is about applying some unconventional technology to combustion engines.

As a warning: do not try this at home unless you really really know what are you doing. This is NOT SAFE. You may be severely injured if anything goes wrong.

You may try to play with this if:

Some reasons you should avoid doing this at your home:

I assume that you carefully read the above warnings and you really enjoin pain.

[above text adapted from OpenBSD operating system handbook].


VIdeo 1 - System Calibration

Oxy-Hydrogen (Hydroxy, Brown Gas or the "HHO" term widely used on internet) mixture percentage vs. ignition timing. Starting with low percentage, we try to keep the engine running as much as possible. These parameters of any successful attempt (engine spinning for more than 5 seconds) are recorded to establish the ignition timing curve.

Video 2 - System up and running.


Water as clean, nonpolluting fuel - a research in embedded systems design to control a modified gasoline engine

[skaarj] and Vladimir "жы" Bodurov

Petroleum and Gas University, Ploiesti, 100680, Romania

Abstract - This paper presents an experimental procedure for using water as fuel, as a further step into reducing the greenhouse gas emissions. The process was controlled by a high performance ARM micro controller. During the tests, two different electric generators based on a one cylinder, two-stroke and a one cylinder, four-stroke gasoline engines were heavy modified in order to use Oxy-Hydrogen gas extracted from water. Modifications in the ignition system were required in order to compensate the high-explosive characteristic of this gas. A new carburetor design was required, as the original intake system accepted air and liquid gasoline as inputs, with a fixed air-fuel mixture ratio. As different loads were connected to the electrical output of the electric generator, special care had to be taken into controlling the process by electronically modifying the quantity of the Oxy-Hydrogen gas injected into the engine. The four-stroke engine was fully converted to run on Oxy-Hydrogen gas only, and low traces of carbon monoxide from the lubrication system were detected in the exhaust gases.

Index Terms — micro controllers, embedded software, hydrogen, hydrogen storage, fuel cells, pollution reduction

Introduction

The demand for fossil fuels increases every day in almost any activity involving transport, which consumes about a quarter of the world total energy. This increasing demand from limited non-renewable quantities has resulted in huge increase in the fuel prices. The continuous usage of fossil fuels has also a negative influence over the surrounding environment due to emissions of toxic gases based on carbon compounds. During the last decade an important progress was made in reducing pollution by the complete elimination of lead compounds from gasoline. As a result we have noticed a growing interest in alternative fuels. The scientific literature reports research into hybrid and electrical automobiles, and also into alternative fuels that can be used in engines without the need for a dramatic change in vehicles design. For the first time in the scientific community, a scientific research was made on hydroxy (Oxy-Hydrogen) gas and its many anomalous properties, suggesting the existence of a new, previously unnoticed form of water which is unstable and highly explosive [1]. The research was previously initiated on gases generated by electrolysis processes, and the resulting gas is known as Brown gas according to patent [16]. Recent references of hydrogen gases as a solution in reducing fossil fuel consumption [2], [3] shows the increased interest into further research for obtaining it from fossil fuels [4] in order to observe the effects of introducing it in diesel and gasoline engines [5]. Storing hydrogen and also hydroxy gas in tanks under pressure is proven to be dangerous during transport, so special containment technologies are analyzed in [6] for safe storage. Another method of storing hydrogen inside a metal hybrid fuel stack cell is shown in [14]. This high interest in hydrogen shows it to be expected as a clean and recyclable energy source with great improvements if added in common combustion engines [7].

Also more and more increased interest is recorded in the open source community forums since the beginning of the worldwide financial problems. Many trial and error experiments are performed by enthusiastic people on hydrogen compounds as fuel, some of them even ending in bad accidents due to the lack of scientific data.

In this paper we try to design a system based on a common combustion engine and a safe source of hydrogen, both under micro controller supervision. The main purpose of the experiments is to completely eliminate the gasoline fuel from the process and to eliminate the toxicity of exhaust gases as much as possible. Fig. 1 shows the block schematic of the system.

Figure 1. Hydrogen compound ignition-combustion engine with embedded micro-controller-based monitoring and control system

Because the high instability of hydrogen and hydroxy (Oxy-Hydrogen) gases, the on-demand release method was chosen. The hydrogen source is the water inside of a special designed electrolyzis cell, which is turned into Oxy-Hydrogen gas according to patents [16] and [17]. The released quantity is set inside the micro controller according to the engine speed. Due to the high explosive property, the original ignition timing system is useless, as the Oxy-Hydrogen explodes almost instantly. The second task of the micro controller is to trigger the explosion at the right time. Also the monitoring is performed on the engine temperature and on carbon monoxide in the exhaust gases.

Experimental set-up

Reference [14] shows a method of storing hydrogen at low pressure in special designed canisters, its release and mixture with air being under micro controller supervision. For this experiment a different approach was chosen - to release the hydrogen from water. Two electrolysis cells were built in order to supply the necessary Oxy-Hydrogen gas for the experiment. For safely powering the cells, two mos-fet transistors-based switches were designed and built. Also two electric generators based on internal combustion gasoline engines were modified to run on Oxy-Hydrogen gas.

The micro controller system monitors air and Oxy-Hydrogen gas flow together with the engine speed and the level of carbon monoxide in the exhaust. Previous tests in [12] showed a PLC system is not suitable for this kind of applications due to its limited computing capabilities, as an accurate calculation must be performed for the ignition signal timing [13].

Figure 2. Experimental set-up block schematic

The control signals are issued through the warning transmission interface to control the ignition timing and to activate the Oxy-Hydrogen cells through mos-fet based power switches [15] and 50Hz pulsed continuous current supplied from the external power grid.

To avoid any explosions, the ignition signal is issued only if vibrations are detected on the engine. The signal timing is calculated based on the data received from the tachometric sensor. Fig. 2 shows the block schematic of the experimental setup.

An electric load is connected to the output of the generator in order to test the behavior under stress conditions.

Hydrogen reactor cells construction

The Oxy-Hydrogen gas source for the experiment is the water. The Oxy-Hydrogen reactor cells system is based on electrolyzers designed to minimize the wasted current in the water. Each electrolyzer contains 25, 2mm thick stainless steal plates with cut openings as shown in Fig. 3.

Figure 3. Stainless steel plate

To avoid losing current in the water at the extremities, the cells were equipped with 1mm thick rubber gaskets. The stainless steel plates were enclosed between two Plexiglas plates (like a sandwich) as shown in Fig. 4.


Figure 4. Plates separated by gaskets

The water is kept between the surfaces inside the gasket border. A bubbler attached to the electrolyzer ensures the protection from any accidental spark. Fig. 5 and 6 shows one experimental Oxy-Hydrogen reactor cell built for this experiment - both picture and schematic - containing an electrolyzer and a bubbler.

Figure 5. Experimental Oxy-Hydrogen reactor cell

Figure 6. Block schematic of the experimental Oxy-Hydrogen reactor cell

The common tap water has different concentrations of minerals, many of them corrosive in electrolyzing conditions. The distilled water does not allow any electric current to pass, however a more than 1% concentration of NaOH in the distilled water quickly increases the supply current due to the too much reduction of total electrical resistance. The NaOH and stainless steel plates are the most efficient reactors and catalysts in relation to electrical power consumed. The electrolysis process generates oxygen and hydrogen in monatomic state – a single atom per molecule. The ignited Oxy-Hydrogen gas releases a higher energy than burning oxygen into hydrogen [5].

The first hydrogen cell is powered entirely through a mos-fet switch, while the second hydrogen cell has each half separately powered by a second mos-fet switch.

Modifications on the engines

The experiment was performed on two different electric generators based on two-stroke and four-stroke internal combustion engines in order to monitor their performances. The block schematic in Fig. 7 shows a common single phase electric generator with an electric load connected to its alternator.

Figure 7. Block schematic of a single phase electric generator

The first electric generator chosen was an “Alexa 950-AT” based on a two stroke, 63cmc 1.2 horsepower single cylinder engine which originally worked on oil-gas mixture. A new custom made carburetor, shown in Fig. 8, replaced the original. The block schematic of the carburetor is shown in Fig. 9.

Figure 8. Custom made carburetor

The second electric generator chosen was based on a Honda GX200, four-stroke, 196cmc 6.5 horsepower single cylinder engine. Also a new carburetor was built and two Honeywell AWM3300V flow sensor were attached, as shown in Fig. 9.

Figure 9. Block schematic of custom-made Honda-GX200 carburetor

The system was wired according to the block schematic shown in Fig. 10.

Figure 10. Detailed block schematic of the system

The carbon monoxide sensor which was built according to [8] was attached in front of the exhaust pipe and connected as an analog input to the monitoring interface of the micro controller. A small magnet was attached to the engine shaft so its upper position matches the activation of the original igniter switch. After carefully analysis of the Honda GX200 engine, the original igniter is switched on when its shaft reached a position at 20° (before vertical) before the cylinder reaches its highest position. The spark occurs each time the cylinder reaches this point, during compression and exhaust processes, however only one spark at compression time is needed. The highest position of the cylinder inside the piston is called the Top Dead Center (TDC).

During the first tests this secondary unneeded spark proved to be dangerous because it could ignite the incoming hydrogen inside the carburetor - valves are not able to completely seal hydrogen - so the original ignition system had to be replaced with a new one with the block schematic shown in fig. 11.

Figure 11. Block schematic of the ignition system attached to micro controller

In order to activate the ignition during the fuel compression process only, the engine shaft rotation speed was divided in half using two cog wheels with 1:2 speed ratio. The magnet (used to activate a Hall sensor) was attached to the second, half-speed cog wheel according to Fig. 12.

Figure 12. Engine shaft rotation divider with magnet attached

The micro controller measures the number of rotation per second (x) using the TLE4935 hall-effect tachometric sensor. The Honda GX200 engine works in four strokes, so the ignition is activated once every two rotations of the shaft or every one complete rotation of the second cog wheel, during the compression time.

One rotation (360°) of the second cog wheel occurs in:

y (RPM) = 1 / x (seconds) (1)

One degree displacement occurs in

T = y / 360 (seconds) (2)

The magnet is set to activate the hall sensor when the shaft is 20° before TDC, the same as the original igniter switch.

According to the Honda GX200 specifications, different angles are needed for activating the ignition system according to engine speed. Also these angle values are specific to gasoline octane, so we had to estimate the new angle values by manually tuning the Hall sensor towards the secondary cog wheel shaft. These experimental angle values are shown in table 1. When the Hall sensor is activated, the micro controller must set a delay proportional with an angle value before sending the ignition signal.

According to relation (2) and the values of the angles in Table 1, the delay between the incoming hall sensor signal and the outgoing ignition signal is as following:

τ = T * angle_value (seconds) (3)

Table 1. Estimated ignition angle values for Oxy-Hydrogen gas

Experimental angle value (second cog wheel)
after TDC
Engine shaft
RPM
0 RPM(engine start) – 400 RPM
401-800
801-1200
1201-1600
11°1601-1800
12°1801-2000
13°2001-2400
14°2401-2800
15°2801-3000
16°3001-3200

The data in the above table represents a trial by error manually determined rough ignition timing curve of the Honda GX200 engine running on hydrogen-oxygen (Oxy-Hydrogen) air mixture with ratios presented in the "Experimental results" section.

So the micro controller must set a delay equal to:

delay = angle_value / 360x (seconds) (4) (x equals the current RPM)

in order to reach the right compression time. Remember that the engine shaft RPM is twice the divider cog wheel RPM.

The modified Alexa 950AT and Honda GX200 electric generators engine are shown in Fig. 13.

a) Alexa AT950 generator b)Honda GX200 generator

Figure 13. Electric generators used for the experiments


The architecture of the micro controller-based monitoring and warning system

The micro controller-based monitoring and warning system was designed around the Marvell 88F6281 micro controller by using the Marvell OpenRD development platform and the Unix FreeBSD 8.0 Release Candidate 2. The architecture of the system is presented in Fig. 14.

Figure 14. The architecture of the system

The micro controller system has a monitoring interface (MI) and a warning transmission interface (WTI), both being developed within the same board (by using of the inputs and outputs of a BMCM Messysteme USB-AD12 and connected to the micro controller unit via the USB port. The monitoring interface takes the measurements of the engine parameters provided by the sensors. The warning signals generated by the warning transmission interface are used to adjust the Oxy-Hydrogen gas quantity and to activate the engine ignition system.

We have included in the micro controller two distinct small programs for the following operations:

•Calculating the right ignition timing via tachometer measurements, modifying the Oxy-Hydrogen gas quantity according to engine speed;

•Monitoring the Oxy-Hydrogen and air flows, together with engine temperature and carbon monoxide concentration in the exhaust.

The 88F6281 micro controller is built under the System-on-a-Chip form and has a large variety of interfaces, as shown in Fig. 15. Its main destination is the mobile telephonic equipment market due to its multimedia facilities.

Figure 15. The Marvell 88F6281 interfacing options

For this micro controller we have compiled the Unix FreeBSD 8.0 operating system with the specifications of the 88F6281 micro controller according to [9] (plus our custom-made program included at kernel level accessing the GPIO interface) because of the ARM9 architecture support, high stability and simple programming. This system is also a good choice for embedded real-time applications and has all the multitasking benefits. Previous successful tests of our micro controller system were performed in [10].

The block schematics of the internal programs are presented in Fig. 16 and Fig. 17.

Figure 16. Ignition system and Oxy-Hydrogen flow control algorithm

Figure 17. Gases mixture, speed and temperature monitoring algorithm

Results and future research

During the tests it was impossible to start the two-stroke engine on Oxy-Hydrogen gas only. Any ignition timing tune had no other effect than sending the spark backwards to the Oxy-Hydrogen cells and causing huge dangerous explosions. The Alexa AT950 electric generator could start only by mixing the Oxy-Hydrogengas with the gasoline using both the original and the custom made carburetors. No monitoring was performed due to the need of fossil fuel, but according to [11] the gasoline consumption should lower considerably. The engine overheats in about 3 minutes due to low concentration of oil in the air-fuel mix, which is specific to any two-stroke engine.

To test the engine functionality on OxyHydrogen-air-gasoline mixture, the new carburetor was attached on the air intake manifold of the original carburetor. The engine started with its original ignition system and its mechanical speed control. A dramatic increase of the temperature was quickly noticed due to the low concentration of oil in the intake gas mixture. As any two-stroke engine needs oil mixed in the gasoline for the cylinder lubrication, the purpose of the experiment was no longer possible for this engine design.

The Honda GX200 engine was wired to the micro controller according to the block schematic in Fig. 9. The engine was started without any electric load on the alternator. Table 2 shows the recorded experimental data. We used a single phase variable auto transformer to set the voltage for powering the Oxy-Hydrogen cell reactors in both experiments. The electrolyte consisted of 1.5 liters of distilled with 1% concentration of NaOH.

Table 2. Experimental data measured without electrical load

The maximum electrical power load was adjusted such as the electrolyte did not heat, as the water vapors has a negative impact on the explosions inside the cylinder.

The air flow was adjusted manually. The monitoring system recorded around 16% air in the manifold intake gas mixture for the engine to be able to function.

The spark timing was adjusted manually according to the Honda GX200 manual in order to get the minimum of vibrations at startup. Table 1 shows the experimental obtained angles, which were used by the micro controller in the internal program we designed according to Fig. 16.

The micro controller ran a second monitoring program we designed in Fig. 17. A chart representation of the monitored parameters is shown in Fig. 18.

Figure 18. Variation of the parameters in time – without any electric load connected

The engine core temperature reached 60ºC after five minutes up-time, which slowly increased to 65 degree in the next 30 minutes, much lower than a single cylinder 4 strokes engine running on traditional gasoline.

Table 3 shows the monitored parameters while a 400 watt electrical load was connected to the alternator output. The electrical load consisted of four 100 watts light bulbs.

Table 3. Experimental data measured with 400 watts electrical load

The Honda GX200 engine performed well on Oxy-Hydrogen-air mix both with and without a 400-wats electric load connected to its alternator. Due to no fossil fuel usage, the recorded carbon monoxide level in the exhaust gas did not reach the minimum level of 5ppm specific to the modern automobiles [8]. Due to the lack of a Gas-Chromatography device, we were not able to perform an exact analysis of all components in the exhaust gas. Table 2 shows a low increase of carbon monoxide near the exhaust pipe which kept its level in Table 3 when the electric load was connected. The tests were performed in a closed poor ventilated closed space. The highest temperature reached by the engine was 65°C, much lower than air-cooled gasoline single cylinder engines running under the same condition. Engine kept running for almost an hour without reaching high temperature.

The second experiment showed it is possible to convert a four stroke engine to run on Oxy-Hydrogen gas stored on water. Releasing the gas needs an external electric power source. The patent [17] presents a method of decreasing the external power by pulsing it at a certain frequency, which we will investigate in the future.

References

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kernel panic: improbability coefficient below zero

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