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PaoPien
Washington DC
Interests: Solving problems
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The internal combustion engine requires a new operating cycle because existing cycles do not satisfy the law of conservation of energy.
Applying the law of conservation of energy can greatly simplify the improvement of the internal combustion engine. Since p2V2/U2 = p1V1/U1 and p2/p1 = (V1/V2)k, therefore U2/U1 = (V1/V2)k-1. Because U and V are state variables, U2/U1 = (V1/V2)k-1 is an equation of state. For more transparency and better understanding, a state is denoted by two state variables U and V instead of a numerical number. This equation of state ensures that compression work done by the moving piston compresses cylinder volume from V2 to V1 is transformed into equal internal energy U increase and vice versa. For more transparency and better understanding, a state is denoted by two state variables U and V instead of a numerical number. To demonstrate that utilizing this equation of state alone, the thermal efficiency of a GDI engine can be quickly calculated as follow. A compression stroke of a GDI engine begins from state (U1, V1) with U1 = 95.73 (cvT1) BTU, V1 = 15.6 ft3, and p1 = 14.7 psia and ends at state (U2, V2). With a assumed compression ratio of 9.0, V2 = 15.6/9.0 = 1.733 ft3, U2 = U1(V1/V2)0.4 = 230.5 BTU, T2 = T1(V1/V2)0.4 = 749.0o K, and p2 = p1(T2/T1)1.4/0.4 = 318.7 psia. An entire compression stroke increases internal energy only by 134.8 (230.5 – 95.73) BTU. It is desirable to double the cylinder gas density by extending the compression stroke from 1.733 to 0.867 ft3 and adding heat energy Q simultaneously with the extended compression stroke with U3 = U2 + U2(V2/V3)0.4 + Q. As a result, cylinder air density is doubled and the expansion ratio of 18.0 (15.6/0.867) is obtained. For preventing NOx formation, V3 is limited to 650 BTU to limit the combustion temperature to 2112o K. An expansion process from state (U3, V3) to state (U4, V1) reduce U3 to U4 with U4 = U3(V4/V3)0.4 = 204.6 BTU. Indicated thermal efficiency is equal to (U3 - U4)/U3 = 68.5%. Because of very high compression temperature in the combustion chamber, all combustible substances are completely combusted without engine out emissions. By limiting U3 to 650 BTU with T3 (U3/cv) = 21120 K, formation of NOx is prevented. This is an innovative approach to achieve improved efficiency and very-low emissions.
A reciprocating internal combustion engine with a high compression ratio of say 18.0 and burning fuel per cycle before the moving piston reaches the TDC and limiting the combustion temperature below the critical temperature of NOx formation can achieve a indicated fuel conversion efficiency (IFCE) of 68.5% without the need for aftertreatment. Therefore, there is no need for electrification or hybrid engine system.
Existing compression ignition engine can be easily modified to achieve the high performances by stripping all inlet boosting and aftertreatment equipments and injecting all fuel per cycle before the moving piston reaches TDC regardless at what rate the fuel injection takes place. Therefore any automobile manufacturing company can do the modification. The owner of the modified automobile can immediately cut the operating cost to less than one half. Running the vehicle at a fuel equivalence ratio less than 0.30, the modified vehicle could last for decades. Our nation’s automotive industries can be reduced to a small fraction of its current capacity. The new engine can be used to generate electricity locally without the need for it to be transmitted through the electric grid and it can run on fossil fuel, natural gas, bio fuel, or any other fuel that is locally available. The most important of all, the new engine requires no change in nation’s infrastructure.
By stripping all inlet boosting and aftertreatment equipments and injecting all fuel per cycle before the moving piston reaches TDC regardless at what rate the fuel injection takes place. Therefore any automobile manufacturing company can do the modification. The owner of the modified automobile can immediately cut the operating cost to less than one half. Running the vehicle at a fuel equivalence ratio less than 0.30, the modified vehicle could last for decades. Our nation’s automotive industries can be reduced to a small fraction of its current capacity. The new engine can be used to generate electricity locally without the need for it to be transmitted through the electric grid and it can run on fossil fuel, natural gas, bio fuel, or any other fuel that is locally available. The most important of all, the new engine requires no change in nation’s infrastructure. I am already 98 years old and have no means to test the new engine. It is hoped that one of the reader would carry out the engine experiment.
At 0.3 fuel equivalence ratio, the combustion temperature is only 2112 degree K and NOx formation is prevented. High compression ratio is to have high expansion ratio such that a very high indicated fuel conversion efficiency can be obtained. The combustion temperature is only 2112 degree K greatly lower the heat loss. High compression temperature with long combustion duration will completely eliminate engine out emissions including NOx and can operate on any liquid fuel. The new engine has the benefit of low temperature combustion (LTC) throughout its operate range. A BFCE greater than 0.60 is achievable.
Would you please modify your testing engine by removing the inlet boosting and after treatment equipments and change the compression ratio to 18.0 and starting the combustion process at 0.973 ft3 combustion chamber volume before the moving piston reaches TDC. Then run your engine at a load of 0.3 fuel equivalence ratio. Measure and record the fuel consumption and engine out emissions. You could achieve brake fuel conversion efficiency (BFCE) greater than 0.60 with minimal engine out emissions.
Instead of predicting the combustion chemical reaction rate, would it be simpler to increase the combustion time duration? I have developed a new combustion process which lasts one third of compression and expansion strokes. If anybody is interested, I will be more than glad to send you my new combustion process.
Engineer-poet Even through this site is not run by the US department of Energy, it should not prevent us to offer our solution to increase engine fuel efficiency and reduce engine out emissions.
Engineer-poet, My comment was intended to ask DOE to redefining the scope of the final solicitation. If I have troubled you, please accept my apology and favor me with your critical evaluation of my two-stage CVCE combustion process and my CI-CVCE RICE.
PaoPien added a favorite at Everything Typepad
Apr 17, 2014
PaoPien added a favorite at Everything Typepad
Apr 17, 2014
APPLY THE FIRST LAW OF THERMODYNAMICS FOR DESIGN A NEW INTERNAL COMBUSTION ENGINE Introduction The reciprocating internal combustion engine (RICE) is a simple device to transform energy from one form to another according to the first law of thermodynamics, pV = mRT. Because T is a measurement of the internal energy E, pV = mRT can be written as pV = mRE/cv. When T distribution of cylinder gas is multiplied by cv, an E (cvT) distribution is obtained. Both total V and total E contained within the total volume V become state variables. An equation of state relating state variables E and V is derived first. This equation of state is used to create a new constant-V constant-E two-stage combustion process. A special compression ignition reciprocating internal combustion engine (RICE) is developed to operate on the new CVCE two-state combustion process. This newly developed CI-CVCE RICE has the capacity of reducing specific fuel consumption and CO2 to less than one half of that of comparable existing conventional internal combustion engines. The Creation of a New CVCE Two-Stage Combustion Process The ratio of (p1V1/T1)/(p2V2/T2) is a constant to satisfy the law of conservation of energy. Because p1/p2 = (V2/V1)k, T1/T2 = (V1/V2)k-1. As mentioned previously, when T distribution is multiplied by cv, an E (cvT) distribution is obtained. A equation of state E2/E1 = (V1/V2)k-1 relates the E and V for any gas. Apply Dalton’s partial pressure law, E2/E1 = (V1/V2)k-1, the ET (energy transform) equation is applicable to a mixed gas with the k as the weighted average k values of all component gases. Because the velocities of piston and cylinder gas are many orders smaller than that of cylinder gas molecular, the ET equation can be used to compute change in E from the change in V and vice versa. At the beginning of a compression process 1-2 of a RICE, V1 = 15.6ft3, p1 = 14.7 pisa, T1 = 311o K, E1 = cvT1.= 95.73 Btu, and p1V1/E1 = 2.395 (to satisfy conservation of energy law). At state (E2, V2), E2 = E1(V1/V2)k-1. Following a compression process 1-2, a constant-V combustion process 2-3 converts fuel chemical energy into heat energy Q to increase E2 to E3 with E3 = E2 + Q. An expansion process 3-4 reduces E3 to E4 with E4 = E3(V3/V4)k-1. Total E input is E3 and output is E3-E4. The indicated fuel conversion efficiency (IFCE) is equal to (E3 – E4)/E3 or 1 – E4/E3. For achieving high fuel efficiency without engine out emission, a high compression ratio is chosen to provide high compression temperature for burnout whatever combustible substances. When combustion temperature reaches a critical temperature, NOx formation will take place. Therefore combustion process 2-3 is divided into 2-3a and 3a-3b two- stage. The first stage 2-3a is under constant-V from state (E2, V2) to state (E3, V2) and second stage under constant-E from state (E3a, V2) to state (E3a, V3b) under constant-E such that formation of NOx will not take place throughout the whole range of engine operation. The new two-stage combustion process is created for a new RICE to operate on. Following Table 1 gives the performance analysis of the new RICE. Table 1 1 V3b 0.867 0.956 1.055 1.163 1.283 1.415 2 E3bx 650 625.1 601.0 577.9 555.9 534.3 3 E3a - E3b 0 24.9 49.9 72.1 96.1 115.7 4 E3b 650 650 650 650 650 650 5 P3b 1796 1629 1476 1339 1214 1100 6 E3a+(3) 650 674.9 699.9 722.1 746.1 765.7 7 E4 204.6 220.9 238.3 255.6 274.7 293.1 8 IFCE 0.685 0.673 0.660 0.646 0.633 0.617 At the beginning of a compression process 1-2, V1 = 15.6 ft3, T1 = 311o K, and E1 = cvT1 = 95.73 Btu. A compression ratio of 18.0 is chosen for this discuss and V2 = 0.867 FT3. Using the ET equation, E2 = E1(V1/V2)k-1 is computed. Row 1 V3b is the combustion chamber volume begins from 0.867 ft3 in Column 3 which is the first stage combustion process. Each next step of V3b is obtained by multiplied current V3b by a properly chosen constant. In this case, the constant multiplier is 1.103. E3bx in Row 2 is the E3b at volume V3b when no heat addition takes place. Because V2/V1 is a constant of 1.103, E1/E2 is a constant and heat addition in each step to keep E3b equal to E3a is a constant. Row 3 Q3a-3b is the required heat addition to keep E3b equal to E3a in Row 4. Row 5 p3b is the pressure at V3b with p3b = 2.395(E3b/V3b) to satisfy the law of conservation of energy. Row 6 is the total E input equal to E3a plus Row 3. Row 7 E4 is the E not transformed into work done W. Row 8 IFCE is equal to 1 - Row 7/Row 6. A plot of E-V diagram is shown in Figure 1 below. Figure 1: E-V Diagram The vertical line (2) to (3a) represents the E increase from constant-volume (CV) combustion process. The horizontal line (3a) to (3b) represents the work done W transformed directly from heat energy converted from fuel chemical energy under constant-internal energy (CE) combustion process. This adiabatic E-V diagram shows various components of internal energy E input and E4 rejected from the cylinder without being transformed into work done W. For achieving ultra-high thermal efficiency, a high compression ratio of say 18.0 is chosen. At state (E2, V2), V2 = 0.867 ft3 and E2 = E1(V1/V2)k-1.= 304.2 Btu. Because T1 is same throughout the cylinder volume, E1 and E2 are in equilibrium. A New CI-CVCE RICE Operating On the Two-Stage Combustion Process A compression ignition reciprocating internal combustion engine (RICE) is developed to operate on the new CVCE two-state combustion process. In practice, the constant-V combustion process can not be realized. The constant-V combustion process, however, can be approximated by another path from state (Ex, Vx) before TDC to state (E3a, V2). As long as the sum of work done and heat addition is the same, E3a at V2 will not change. The work done from (Ex, Vx) to (E2, V2) is equal to E2 – Ex with Ex = E2(V2/Vx)k-1 and heat addition is 345.8 (650 – 304.2) Btu. Any practical path from state (Ex, Vx) to state (E3a, V2) can be taken without change state (E3a, V2). During the combustion process (Ex, Vx) to (E3a, V2), at some point pre-ignition will occur without detonation because of lean air/fuel mixture. The remaining 345.8 Btu is injected into continuously increasing temperature and turbulence cylinder gas to prevent localized high temperatures. Because state (E3a, V2) is not changed, the second stage constant-E combustion process remains the same. During the two-stage combustion process of a CI-CVCE RICE, both cylinder gas mass and k of the products of combustion vary from state (E2, V2) to state (E3a, V3b). The brake fuel conversion efficiency of a CI-CVCE RICE would be difficult to compute theoretically. The BFCE of the new engine, however, can be determined by conducting a relatively simple engine tests/experiments as follows. Engine Tests/experiments For a new production engine, two fuel injection jerk pumps are installed between intake and exhaust valves, one for the first state combustion process and the other for the second stage. For a testing engine fuel injection pulses are employed. A selected steady idling rpm is obtained first. Fuel injection quantity per cycle is gradually increased and specific fuel consumption and engine out emissions (including NOx) are measured and recorded until cylinder pressure reaches 1796 psia the upper limit of the first stage CV combustion process. This pressure is corresponding to a combustion temperature of 2112o K (E/cv) which is below the critical temperature of NOx formation. When torque/power demand is higher, the second fuel injection pump kicks in seamlessly to begin the constant-E combustion process. After the upper limit of the first stage combustion process E3a has been determined, the fuel burned in the first step of constant-E combustion process between combustion chamber volumes of 0.867 and 0.956 ft3 is gradually increased until cylinder pressure reaches the value shown in Row 5 in Table 1 to assure that E3b is equal to E3a. For each of the next four steps, this engine testing procedure is repeated. The heat addition obtained from engine experiments will be higher than that given in Row 3 of Table 1. This difference is the heat loss and friction loss at that power output. For the new CI-EVCE RICE, fuel burned between two combustion chamber volumes will increase E and the mass of the products of combustion as if there are no other gases in the combustion chamber. This fact greatly reduces engine testing time as well as shows that IFCE is a sole function of V3b at which the conversion of fuel chemical energy into heat energy Q to increase the internal energy E takes place. CONCLUSION The first law of thermodynamics pV = mRT has been converted to a energy transformation (ET) equation which is used to transform energy from one from to another for all thermodynamic processes of a reciprocating internal combustion engine. Using this single ET equation, a two-stage combustion process has been created for a newly developed CI-CVCE RICE to operate on. The CI-CVCE RICE is an entirely new energy producing power plant which can achieve the highest possible fuel efficiency under the condition that no engine out emissions is produced. Table 1 and engine experiment results show how internal energy E is increase from E1 to E3b by compression work done and two-sage combustion process and losses due to heat loss and friction loss (including pumping loss). It should be used for generating electricity instead of being replaced with electrical machines. Furthermore, a CI-CVCE RICE can greatly reduce construction and operation costs. It can also generate electricity locally to avoid power loss though electrical grid. Existing gasoline and diesel engines can be retrofitted to operate as CI-CVCE RICE.
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Mar 27, 2013