FIELD OF THE INVENTION:
Fueling and control logic method and apparatus for internal combustion engine control.
PRIOR ART:
At present (60-2) tooth logic is being used for cylinder position and cylinder number identification, where crank and cam sensor are used for synchronization.
Presently some of the existing system regulates the start of injection and duration of injection based on combustion pressure signal. But the basic calculation of fuelling is still Speed-density basis. The two Basic Working principles of Engine controls are Speed - density and Alpha-N control methods.
The speed-density engine control method monitors the intake air pressure and temperature to calculate the theoretical mass (density) of air that enters the combustion chamber on each cylinder's cycle. The speed of the engine, however, will affect the actual mass of air which enters the chamber due to various restrictions and tuning effects of the air intake and exhaust tracks. The behavior of a one-dimensional lookup table stored in memory relating to Volumetric Efficiency (Ve) values versus engine speed is analyzed. Based on the analysis of the lookup table a fuel injection mass based on the fuel's stoichiometric (for gasoline, about 14.7 parts air to one part fuel) mixture ratio is calculated. Many passenger car engine controllers use speed-density for open-loop control until emissions subsystems are operational for closed-loop control. The advantage of speed density is that when making a modification to the intake or exhaust systems, only the Ve table needs to be modified to account for the changes in volumetric efficiency.
An alpha-n engine control method is simpler because it looks up the empirical mass of air for each throttle angle (alpha) and engine speed (N) operating

point, which results in a two-dimensional look-up table of several hundred points. Many high performance and race engine controllers must rely on this method because the intake air pressure will not have enough variability over the entire throttle/load range in order to effectively use a speed-density method. When users make mechanical modifications to these engines, many or all of the operating points must be recalibrated.
Some others use a combination of these control strategies by applying speed density to low-speed and low-load operating points where intake air pressure had the most variability. An alpha-N method was applied to the rest of the operating map (manifold absolute pressure).
Gasoline Engine mainly Works With the following Systems:
The speed density system is best described as a calculation procedure used by the electronic engine control (ECC) module that involves predetermined operating parameter values, volumetric efficiency tables, pre-measured airflow-through-the-engine valves, and the known volume of fuel delivery required per combustion event for a single cylinder. Management of fuel and spark functions is based mainly on a predetermined range of preprogrammed data and also on real-time feedback data from an array of sensors.
The "speed" signal is based on the calculated volume of a single cylinder. The "density" signal is a function of temperature and pressure measurements. To determine an engine's fuel delivery requirements, the speed density system infers airflow from several monitored sources, including engine speed(in RPM), intake manifold absolute pressure(MAP, to determine load), manifold absolute temperature(MAT), throttle position, the oxygen content of the exhaust(via a heated lambda sensor or sensors), engine coolant temperature and battery voltage.
There is no airflow sensor (airflow meter) in the speed density system. Signals form the manifold absolute pressure sensor relates operating conditions that are translated into relationships (engine-speed-to-load-to-

throttle position, for example). The EEC then compares this data to ideal data curves based on the engine's volumetric efficiency. The speed density computer is preprogrammed for the desired fuel, ignition, and EGR characteristics, and it makes continuous (metering, timing, and cycling) adjustments based on those pre-mapped relationships.
Diesel Engine mainly works with the following working principle:
When a gas is compressed, its temperature rises (see the combined gas law); a diesel engine uses this property to ignite the fuel. Air is drawn into the cylinder of a diesel engine and is compressed by the moving piston at a compression ratio as high as 25:1, much higher than needed for a spark-ignition engine. At the end of the piston stroke, diesel fuel is injected into the combustion chamber at high pressure through an atomizing nozzle. The fuel ignites directly from contact with the air, the temperature of which reaches 700-900 °C (1300-1650 °F). The combustion causes the gas in the chamber to heat up rapidly, which increases its pressure, which in turn forces the piston outward. The connecting rod transmits this motion to the crankshaft, which delivers rotary power at its output end. Scavenging (pushing the exhausted gas-charge out of the cylinder and drawing in a fresh draught of air) of the engine is done either by ports or valves. To fully realize the capabilities of a diesel engine, use of a turbocharger to compress the intake air is necessary. Use of an after cooler/intercooler to cool the intake air after compression by the turbocharger further increases efficiency
Controlling the timing of the start of injection of fuel into the cylinder is a key to minimizing emissions, and maximizing fuel economy (efficiency), of the engine. The timing is usually measured in units of crank angle of the piston before reaching Top Dead Center (TDC). Where TDC is the maximum allowed upward movement of the position within the cylinder. For example, if the ECM/ECU initiates fuel injection when the piston is 10 degrees before TDC, the start of injection, or timing, is said to be 10 deg Before Top dead

center (BTDC). Optimal timing will depend on the engine design as well as its speed and load.
Advancing the start of injection (injecting before the piston reaches TDC) results in higher in-cylinder pressure and temperature, and higher efficiency, but also results in higher emissions of oxides of nitrogen (NOx) because of the higher temperatures. At the other extreme, delayed start of injection causes incomplete combustion. This results in higher particulate matter (PM) and unburned hydrocarbon (HC) emissions and more smoke blame
In common rail systems, the distributor injection pump is eliminated. Instead an extremely high pressure pump stores a reservoir of fuel at high pressure -up to 1,800 bar (180 MPa, 26,000 psi) - in a "common rail", basically a tube which in turn branches off to computer-controlled injector valves, each of which contains a precision-machined nozzle and a plunger driven by a solenoid, or even by piezo-electric actuators, which are found on experimental diesel race car engines.
Minimum requirements of parameters based on which a Diesel engine can run can be derived from the basic thermodynamics of engine. From the theoretical diesel cycle as shown in fig.12, the processes are 1-2 compression from Bottom dead center -BDC to TDC. Wherein BDC is the maximum downward movement allowed for the piston within a cylinder. The movement of the piston within the cylinder is represented by the stages -point 1,2 3 4. Point 2 is the end of compression where heat addition starts. So ideal start of injection should be at point 2.
Process 2-3 is constant pressure heat addition. So these are ideal injection duration possible. Process 3- 4 is the ideal expansion process where high pressure gas force piston towards BDC. But as ideal injection takes place at constant pressure, the actual expansion duration is 2-3-4 (Piston moves from TDC to BDC). Process 4 -1 is the ideal exhaust process where all the burnt gases are released.

So according to the ideal cycle our start of injection is at point 2 which is TDC position.
But practically this point is not at TDC, it is before TDC which depends on the engine load and other operating conditions. In order to determine the movement of the piston within the cylinder to identify different stages, cam and crank sensors are provided. Based on the output of the cam and crank sensors, start of injection is calculated.
There is one more theoretical cycle which is known as dual cycle. Practical diesel engine follows dual cycle more closely than the ideal diesel cycle. Fig.13 describes a dual cycle on pressure-volume axis. Process 1-2 is the compression process when piston moves from BDC to TDC. Point 2 is the end of compression. So the ideal start of injection is this point. Process 2-3-4 is the heat addition partly at constant volume and partly at constant pressure. Process 2-3 is constant volume heat addition and 3-4 is the constant pressure heat addition part. So during the entire 2-3-4 process can be the ideal injection duration. Process 4-5 is the theoretical expansion process. However process 3-4-5 is the actual expansion process. Process 5-1 is the ideal exhaust process.
So according to the dual cycle also the start of injection is at point 2 which is at TDC position.
But practically this point is not at TDC, it is before TDC which depends on the engine load and other operating conditions.
The conclusion of this discussion is that the start of injection (SOI) is one important parameter for diesel engine.
So for engine operation information about the start of injection is a must to know parameter.
Now the next important parameter is injection quantity. How much fuel needs to be injected, starting from the start of injection point is what need to be known. From the thermodynamic cycle only, the direct amount of injection

can't be guessed. It needs to be calculated from the parameters with the help from thermodynamic cycle.
Fig. 12 and Fig. 13 does not say anything about the quantity of injection. One way to calculate the amount of injection quantity from the calculation of air-mass trapped inside the cylinder and then uses the chemical burning equations and finds the injection quantity.
So from fig. 12 or fig. 13 at point 1 (ideal start of compression, at this point both the intake and exhaust valves are closed), the pressure and volume is known. Now if the temperature at point 1 can be measured, then the amount of air-mass can be calculated from the gas law PV=mRT. This is what done in the present invention for the calculation of air mass. Some others also use this principle for the air mass calculation but they use intake manifold pressure and temperature. A volumetric efficiency method is used to compensate the error due to the position of pressure and temperature sensor. As the manifold is not the actual position of compression, it is not possible to calculate the actual amount of air mass with a pressure and temperature sensor outside the cylinder. If actual amount of air mass can be determined accurately if and only if the pressure and temperature of air can be measured when both the intake and exhaust valves are closed.
So from the above discussion the general conclusion can be drawn that if information about the start of injection and quantity of injection is known a diesel engine can be run.
In the existing methods the position of piston inside the cylinder is known by the crank and cam sensor. Therefore there need to have synchronization between those two signals. Therefore there are dependencies between the cylinders. Once the synchronization is established then the position of the entire piston is known from the reference cylinder. The injection duration will be calculated from the rail pressure and injection quantity characteristics of the injectors.

The patents such as US5765532, US6804997 determines the start of injection of an internal combustion engine based on the crank shaft position.
Therefore there is need for an improved apparatus and method of determining efficient fuel control logic for controlling an internal combustion.
OBJECTS OF THE INVENTION:
The object of the invention is to provide a system of the kind which is simple and is convenient form and which shall not depend on the crank shaft and/or cam shaft position measured. It is an aspect of the invention, to improve upon the known methods of controlling the fuel injection in Internal Combustion Engine.
SUMMARY OF THE INVENTION:
The present invention of controlling internal combustion engine is equally relevant for both Diesel and Gasoline Direct Injection engine.
An apparatus for controlling the operation of internal combustion engine according to the present invention consist of an in-cylinder pressure sensor and a temperature indicator sensor means for each cylinder. The pressure senor measures the internal pressure of the respective cylinder. Air- mass calculating calculates the air- mass value based on the measured pressure, temperature and volume of the cylinder. A fuel calculating means calculates the start of injection based on calculated air -mass. A desired toque determination means determines the position of a acceleration pedal. The desired toque determination means determines is provided with more than one sensors. A Fuel amount based on calculated air-mass and a desired torque derived using the measured acceleration pedal position. A start of injection calculating unit calculates start of injection pressure at which the injection is started depending on measured in-cylinder pressure with respect

to calculated air-mass and the desired torque. As in the proposed method, pressure is measured for all cylinders, except lead cylinder concept, the basic fuelling also will be calculated based on pressure.
As start of injection is calculated independent of the crank shaft position, there is no heed for synchronization of crank and cam signals. The present invention enables a non-synchronous or an individual method of controlling the internal combustion engine. Advantages and further developments are described and claimed herein: This is a novel attempt to make a non-synchronous internal combustion engine running in full mode. Other objectives, advantages and novel features of the present invention will become apparent from the detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Overview of the invention are shown in the drawings and described in detail in the following description:
FIG.1: Shows main blocks of the proposal.
FIG.2: Pressure/Accelerator pedal based control, air-mass, firing order and engine speed calculation.
FIG.3: Injection quantity and start of injection correction due to accessories demands.
FIG.4: Injection quantity calculations at different load and operating conditions.
FIG, 5: Desired compression pressure calculation and cylinder pressure curve processing for other calculations.
FIG.6: Engine speed calculation logic.
FIG.7: Firing orders calculation.

FIG.8: Illustrates the compression pressure curve from BDC to TDC for varying demands.
FIG.9: Illustrates pressure curve for BDC to TDC for a specific operating condition.
FIG.10: Illustrates two different pressure points in before and after TDS as in prior art.
FIG.11: Illustrates the cylinder pressure ratio during the compression stroke and expansion stroke.
FIG.12: Theoretical diesel cycle explanation.
FIG.13: Theoretical dual cycle explanation.,
FIG.14: Parametric overview of the logic.
FIG.15 & 16 The start of injection pressure point calculation.
FIG.17 & 18 The Air/Fuel ratio map for different Torque and Air-mass point. Injection system, Communication for diagnostics may be the add-on function.
DESCRIPTION OF INVENTION:
Explanation of Fig.1
The figure 1 shows the overall circuit of the engine control logic of an internal combustion engine according to the present invention. In the 1st Block, based on the variation in the cylinder pressure curve and torque derived from accelerator pedal position, the output pressure is decided. The pressure of the cylinder is determined based on in-cylinder pressure sensors that are provided for each cylinder. The provision of in-cylinder pressure sensor enables accurate pressure measurement. Other necessary parameters such as temperatures are also measured by respective sensors. Based on the measured temperature and pressure, air-mass is calculated. In the 2nd block start of injection and injection quantity are calculated. In the 3rd block this

base values are corrected to meet different demand of other parameters such as cruise control, gear box limitation etc. In the 4th block the start of injection and injection duration will be calculated for a particular rail pressure based on the output from the 3rd block. Necessary functions for meeting emission standards and endurance can be developed along with main software algorithm of above described injection systems.
All the diesel engine and Gasoline direct injection engines are possible to control with this logic. The configuration of the logic will depend on the actual number of cylinder being used. Pressure sensors read the pressures for all the cylinders and the control logic calculates the amount of fuel needed for that particular cycle. Injection system calculates the start of injection and . duration of injection for the same cycle based on the input from the pressure sensor. The parametric view is shown in Fig. 14.
Control algorithm will read pressure values of each cylinder separately and it will decide the start of injection and duration of injection of each combustion cycle for each cylinder. Refer fig 1 for more details about this.
With reference to prior art few of which mentioned above in the invention the base value of start of injection and amount of injection are calculated. The invention is not dependent on any system except pressure sensors and temperature sensors.
Followings are the summarized building blocks of the invention.
1. Calculation of desired compression pressure, firing order, mass of air and engine speed. Engine speed is calculated as an out-put parameter. This is not mandatory for this logic to work. But it also can be used as an input to the some other module.
2. Injection quantity and start of injection calculation based on pressure and temperature sensor's inputs. This is the trigger to the injection

system to start actual start of injection before applying the correction for other parameters.
3. Correction of the base value using the demand from the different inputs of all the accessories attached with the system for all other comfort or emission function control.
4. Calculation of the actual firing start of injection and duration of injection along with the injection system.
Explanation of Fig.2:
Figure 2, shows the detailed explanation of the calculation carried out in block 1 as mentioned in figurel. Here the pressure , air-mass, firing order and engine speed are calculated based on the engine working conditions. This contains sub-block Pressure signal acquisition, desired compression pressure calculation (A), Speed calculation (B), Air-mass (C) and Cylinder Identification or Firing Order calculation. If required new functionality can be added. The input to this block is the pressure signal from the individual in-cylinder pressure sensors and the Output is the pressure value, air-mass, firing order and Engine Speed. Fig. 5 explains the basic working principle of the sub-block desired compression pressure calculation. Fig. 6 explains the working principle of the Engine speed calculation. Fig. 7 explains the working principle of Firing order calculation or Cylinder identification for firing order calculation.
Explanation of Fig.3
This explains the working principle of Block 3 of the Fig. 1. Here all the demands from the other supporting parameters such as A/C demand, cruise control, gear box limitation, lighting demand etc are converted to the equivalent injection quantity and an actual injection quantity demand are calculated. The characteristics of the different parameters will decide what will be the correction factors for them.

Explanation of Fig.4
This explains the working principle of Block 2 of the Fig. 1. Here injection quantity is calculated based on the amount of air mass trapped and the position of acceleration pedal (Accped). This implies that if, the desired demand ie. the desired position of the acceleration pedal from which the torque is derived has to be met, and then this is the injection quantity need to be injected at that particular operating condition. At present it is different MAP at different working band which will give the air-fuel (A/F) ratio applicable at that point. As the A/F and the amount of air mass are known at the operating condition, the amount of injection can be calculated. However few more sub blocks may be needed to perfect the injection quantity.
Explanation of Fig.5
Depending on engine load and speed condition, pressure at 1 and 2 i.e. P1 and P2 will vary as shown in fig.5. The pressure curve will have to be measured in detail through P1 to P2 range; P2 will decide the injection point. The pressure after point 2 will be the result of combustion. This part can still be used for feature calculation and also correction of point 2, which is the position of main combustion in our logic.
Load curves of input pressures (range) - for fuelling calculation will vary depending on the engine operating conditions (Fig. 5 will have different maps). The strategies are already designed.
The cylinder specific pressure sensors will have its own characteristics and P1 - P2 will be cylinder specific. The calibration engineer's challenge will be to find out optimum P2 for entire load range for a specific engine. There are specific techniques already decided to calibrate engine based on this logic.

Explanation of Fig.6
Using the cycle time for each pressure profile or the number of pressure (compression pressure/motored pressure) peaks, Engine speed (RPM) will be calculated. For that we need to count the pressure curve within some threshold value (note that only the compression + power) stroke pressure, 180 CA, is considered, which is very much possible to do).We only need to know the compression curve in full range or close to full range based on which the suggested injection logic will work.
The present invention is for individual cylinder control based on pressure.
1. A different logic for speed calculation and cylinder identification
(illustrated with Fig. 6.).
2. Entire fuelling logic will be changed based on pressure data,
which is very much cylinder specific. That is all the base
parameters are calculated for each cylinder separately.
In short entire logic will be pressure based control. Speed calculations (This example is for a 4 cylinder engine. For other configuration it will look different. ) are shown in Fig. 6 is an out put of the logic but it is not necessary for the basic operation of engine however it can be used as an input to the other subsystem.
Using the cycle time for each pressure profile or the number of pressure (compression pressure/motored pressure) peaks, Engine speed (RPM) will be calculated. For this there is a need to count the pressure curve within some threshold value (note that only the compression + power) stroke pressure, 180 CA, is considered, which is very much possible to do).
There is a need to know the compression curve in full range or close to full range based on which the suggested injection logic will work. Here full range means the entire duration of compression and power stroke.

Explanation of Fig.7
This explains the working principle of the Firing order calculation. Based on the hardware configuration, the cylinder specific pressure signal will be known to the system. The input to the block is pressure signal from the individual sensors and the output is the firing order required. Manufactures will decide which firing order is to be used.
Explanation of Fig.8 & 9
Temperature sensors will be placed for each cylinder. So that at point 1 , P1, V1 ( Cylinder volume) and temperature T1 is known. So at 1 we know mass of air M = P1V1/RT1, where R is the universal gas constant for air.
This is the trapped mass of the air.
Now depending on torque derived from accelerator pedal position it can be decided how much (quantity of fuel) to be injected and p2 will specify the position at which point to inject.
Explanation of Fig.10 & 11
Shows the different pressure points occurring before and after reaching TDC and the cylinder pressure ratio during the compression and expansion stroke, according to prior art.
Explanation of Fig.12 & 13
Fig.12 describes the ideal thermodynamic diesel cycle on Pressure-Volume axis. The end points are 1-2-3-4, where processes 1-2, 2-3, 3-4, 4-1 represents compression, heat addition, expansion and exhaust process respectively. The process 2-3 is the constant pressure heat addition.

Fig. 13 describes the ideal thermodynamic dual cycle on Pressure- Volume axis. The only difference with the ideal cycle is that, some part of the heat addition is at constant volume. The remaining part is at constant pressure.
Explanation of Fig.14
This explains the parametric over of the system. Pressure signal and Temperature signal are the two input to the system. Start of injection, quantity of injection, engine speed and firing order is the output from the system.
Explanation of Fig.15 & 16
This is a map which determines the start of injection pressure depending on the desired torque and Air-mass as the input parameter. The input to the map are desired torque and Air-mass. A single map can be used for all the cylinders or cylinder specific map can be used. This will be decided from the particular application.
Desired torque is determined by measuring the position of the acceleration pedal of the vehicle. This value together with the torque demand of auxiliary devices like air-conditioner or generator will lead to the desired torque of the engine, which is equivalent to the power output or load of the engine.
The out put message of this map will be the input to the injection system which then calculates the actual start of injection after taking care of the charging of the power stages.
Explanation of Fig.17 & 18
This explains the desired Air/Fuel ratio at a particular operating condition. The inputs to the map are desired torque and Air-mass and the AFR is the out put. This is calibration dependent and varies with the engine configuration. This is the input for the injection quantity calculation. The basic calculation is done below,

Injection quantity= Air-mass/AFR.
This will be corrected against all the parameters of the injection system and the accessories demand and the final corrected quantity will be injected at the actual start of injection point.
For this logic to work efficiently certain requirements will have to be met with.
They are:
1. Compression pressure needs to be measured very fast, at least as fast as crank sensor reads data or even higher.
2. Problem of cylinder identification-For firing order calculation or injection according to firing order.
This is also solved by another method described here. As the ADC channels will be used for pressure data acquisition or there will be a hardware pin for each cylinder, the firing order can be calculated from this information.
This pressure sensor pin configuration can be done in firing order as it would be possible to specifically say that pin X is for cylinder number Y and so on (Fig. 7). This way it will be known which pressure curve is for which cylinder.
This hardware configured cylinder identification logic is enough to give the firing order. In this case there is no dependency on synchronization as seen. So the engine will be a Non-Synchronous engine.
Synchronization in existing engine control system is required to complete the following tasks.
A. Valve timing control
B. Injection control
C. Spark control (Only for Gasoline engine).
In the proposed method as there is no dependency on synchronization, injection control will be a more flexible and the engine can be considered to be a non-synchronous engine which is one of the most important claim of this

invention. Eventually spark control for the gasoline engine also can be done in similar fashion.
The valve timing control based on Speed-Pressure is not required at this point. One possibility could be Solenoid controlled valve timing if required to optimize the engine valve operation.
To summarize, the invention, most of the necessary function can be designed based on this logic for engine running. For fine tuning, few more add on function may be required which will be developed as per the requirements for a specific application area.
Possible benefits:
1. Individual cylinder control. Non-Synchronous operation of the engine.
2. All four pressure sensors or as many as cylinder numbers will
be used as its own position sensor.
3. The need for crank and cam sensor can be avoided. Right now
valve timing will be same which is mechanically (best as chain
timing controlled) connected to the crank shaft.
4. There will only be few main functions like-
Pressure calculation and signal conditioning.
Desired compression pressure calculation (A) is now described.
To run an engine the minimum requirements are quantity of injection (fuel mass) and the point of start of injection for diesel engine. And similarly for gasoline engine, quantity of injection and Spark timing are the two factors. The Fig.12 & 13 are the two ideal diesel and dual cycle which also indicates the possible points for start of injection however they do not indicate any information on quantity of injection. We have to calculate the quantity of injection based on the data available form those cycles.

We will consider the case of cliesel engine first. If we can inject correct amount fuel inside the cylinder when the condition inside the cylinder (Pressure and Temp of air) is favorable for combustion (Ignition), we can run the engine with out knowing the crank angle information. This is the working principle for the invention. As there are pressure sensors inside the cylinders, we will be able to find the suitable point for start of injection for each cylinder, in the fig.5; the point P2 is the point which we have found for start of injection for a particular cylinder. All the cylinders will have similar pressure point for start of injection. Fig.16 shows the map generated from tests.
In present day engines we are calculating amount of injection and start of injection based of engine speed and Acceleration pedal demand (driver demand) in the form of torque demand. Say for an example, we want to run the engine at 2000 rpm and at 50 % driver demand. For this we may need to development 200 Newton-Meter torque. Finally this 200 N-m torque will be converted to equivalent quantity of fuel to be injected. In simple word, that quantity will be required to develop 200 N-m torque at that running condition.
Now if the operating condition changes, then the torque demand and then as result quantity of injection will vary accordingly. Now another important parameter, start of injection varies with the different operating condition as well. Presently we are deciding this start of injection based on the quantity to be injected and Rail pressure. But the actual position is with the reference to crank angle. We say that for the example explained before, start of injection is at 10 Deg Crank Angle before Top dead Center.
That is all fundamentally required for running the engine.
How we will find those points (P2 in fig.5) for all the cylinders are issue. There are different ways to find those points. Those points (P2) are the start of injection points.
Fig.16 shows the map value generated. The values will be cylinder dependent.

The process involves the following steps:
A. reading pressure of each cylinder separately, and
B, method to calculate the start of injection and duration of
injection of each combustion cycle.
Load Sharing:
It is recommended to distribute the compression and load between the cylinders. So the torque is equally distributed on all the cylinders.
The major object of the invention is to provide a control apparatus for an internal combustion engine of the type, which is not equipped with crankshaft sensor.
Having many cylinders in an engine, yield two benefits, first the engine has a larger displacement with smaller individual reciprocating masses, thus making a smoother running engine since the engine tends to vibrate as a result of pistons moving up and down. Second with a greater displacement and more pistons, more fuel can be combusted and they can be more combustion events meaning more power strokes in a given period of time, meaning that such engines can generate more torque than a similar engine with lower cylinders.
Any internal combustion engine which operates by burning its fuel inside the engine, the point in the cycle at which the fuel/air mixture is ignited, has a direct effect on the efficiency and output of ICE. For a typical 4 stroke automobile engine, the burning mixture has to each its maximum pressure when the crankshaft is 90 degrees after TDC.
A conventional control apparatus for an internal combustion engine senses various parameters of engine operations such as coolant temperature, air intake pressure, engine rotational speed and oxygen concentration in the exhaust gas amongst many other readings.
The ignition timing and the fuel injection amount are then calculated based on a predetermined mathematical relationship amongst the sensed parameters.

The relationship is usually stored in the form of a table in a Read Only Memory and gives the optimal fuel injection amount and ignition timing for a base line engine.
The fuel efficiency is more likely to increase efficiency than the power. When cylinder-to-cylinder fuel distribution is improved, less fuel is required for the same power output. When cylinder-to-cylinder distribution is less than ideal, more fuel than necessary is meted to the rich cylinders to provide enough fuel to the lean cylinders. Power output is asymmetrical with respect to air/fuel ratio. In other words, burning extra fuel in rich cylinders does not reduce power nearly as quickly as burning two little fuel in the lean cylinders. The standard fuel metering compromise is to run the rich cylinders even richer than the best air/fuel ratio, to provide enough fuel to the leaner cylinders. The net power output improves with all the cylinders making maximum power.
Deviations from perfect air/fuel distribution, however subtle it may be, affects the emission by not letting the combustion event are at the chemically ideal air/fuel ratio. Grosser distribution problems eventually begin to reduce the efficiency. Grossest distribution events finally affect the power. Increasingly poorer air/fuel distribution affects emission, efficiency and power in that order.
The output from the crankshaft sensor in conjunction with that from the manifold absolute pressure sensor provides the ideal stabilization and reference for the above injection timing.
The map sensor pressure variations information into graduated electrical signals which is read by ECM, increase and decrease in manifold pressure is an accurate representation of the load placed on engine, allowing the ECM to adjust the quantity of fuel being injected and ignition timing to achieve the optimum fuelling of the engine. Engine temperature sensor gives information to the ECM to provide the optimum drivability and emission by advancing or retarding the ignition timing.

First embodiment:
We will run an experimental engine with the existing control logic and find out the Compression pressure curve from Bottom dead center (Actually when both the intake and exhaust valves are closed and actual compression start) to Top dead center (Firing TDC).
Then decide the point P2 for all the possible operating conditions. And thus prepare engine MAP for the start of injection.Fig.16 shows the generated map. Use this MAP for starting the proposed engine. Once the engine is running, as we will be calculating all the other features, we can modify those points (As a closed loop system) for all the cylinders and for all the operating conditions based on the calculated feature. One more important thing is the interrupts point generation for start of injection. So the signal (interrupts) for start of injection will be independent of any other cylinder phenomena. That is why I can call the proposed control as non-synchronous control as there are no dependencies on individual cylinder. All the cylinders are free to choose their own operating parameters. The quantity of injection will be also calculated from the pressure data measured during the compression phase.
For this we will mount one temperature sensor to the cylinder. The mounting of these sensors requires technical expertise so that it can measure the temperature when the actual compression starts. It can be mounted close to the intake valves also. An approximate temperature is enough to calculate the inducted air mass inside the Cylinder.
So air mass = function of (Pressure, Temperature, Cylinder Volume). All the conditions of this function are at a point where intake and exhaust valves are just closed and the actual compression starts.
Now depending on the torque derived based on Acceleration pedal position d and the calculated air mass of the individual cylinder the actual amount of injection quantity will be decided.
An air/fuel mass table will be used for the suitable value of the Air/Fuel ratio at constant operating points. Fig. 18 shows a typical A/F map used. The values

of these tables will change depending on a specific engine. So for new engine it needs calibration.
Say for an example we want to run the engine at a particular speed, at 50 % Acceleration point, then the desired compression pressure(P2) required will be 20 bar or something close to it. This value again is typical to a particular engine hardware construction (Compression ratio, bore/ stroke etc). So both the requirement of injection quantity and start of injection are possible to calculate in the proposed control method and that is why the engine will run.
There is one more possibility of calibrating the desired Start of injection pressure (P2) point.
The engine can be run in motoring for the entire possible operating conditions and then the above mentioned parameter can also be determined. For this no need to have actual firing in the cylinder.
Speed calculation (B) is herein described:
This is only calculated if we want to have speed calculation for some other purpose. This is not mandatory to run the engine. This simply works on the principle of counting the pressure peaks per unit time. This can be done from one individual cylinder or from all the cylinders. The pressure peak counting can use any method for counting of sinusoidal signal.
Firing Order Calculation(C):
This is must for the running in of the engine with the proposed method. Working principle is the hardware configuration. All cylinder pressure sensors will be connected to a particular pin of the ADC (Analog to digital converter) each. So we know which pin is for which cylinder. So the pressure data will be sampled for each individual cylinder from separate pin of the ADC. Then this is what we want to know for firing order calculation. Simply arranging the pin in firing order (desired firing sequence) is serving our purpose.

The major advantages of the present invention are as follows the method is based on absolute pressure value (No ratio comparison) and is a Non-synchronous or individual cylinder control logic. The present invention is based on actual cylinder pressure and not the outside pressure fluctuation. There is no requirement for calculation for crank angle as phase calculation. This method and apparatus according to the present invention is adaptable for any number of cylinder and is independent of constrains relating to predetermined timing related to (intake air pressure fluctuation) intake valve mechanism.
As described above and understood by persons in the art, the invention is equally relevant for both diesel and gasoline engines. The forgoing description and disclosure has been set forth merely and clearly to the extent to illustrate the invention and not intended to be limiting. Since modification and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in that, the invention should be constructed to include everything within the scope of the claims and equivalents thereof.

WE CLAIM:
1. An apparatus for controlling operation of an internal combustion
engine, comprising atleast one cylinder, the said cylinder containing a
reciprocating piston and having a known volume at each position of the said
piston, a fuel supply means which selectively supplies fuel to the said cylinder
and an air supply means which supplies air to the cylinders during engine
operation, Comprising,
a. an in-cylinder pressure sensor coupled to the cylinder measures
the pressure of the cylinder and a temperature sensor
measures the temperature of the cylinder at preset timing;
b. an air mass calculating means determines air-mass inside the
cylinder at the preset timing based on measured pressure,
measured temperature and known cylinder volume;
c. a desired torque determination means determines a position of
an acceleration pedal and a fuel amount unit which determines
the fuel amount based on calculated air-mass and a desired
torque derived using the measured acceleration pedal position;
and
d. a start of injection calculating unit calculates start of injection
pressure at which the injection is started depending on
measured in-cylinder pressure with respect to calculated air-
mass and the desired torque.
2. An apparatus for controlling operation of an internal combustion
engine, according to claim 1, comprising plurality of cylinders each in-cylinder
pressure sensor supplies input to hardware pin configuration to determine a
firing order.

3. An apparatus for controlling operation of an internal combustion engine as claimed in Claim 1, wherein injection is triggered according to calculated start of injection pressure when the value of measured in-cylinder pressure sensor and a reference pressure value prestored in a table are equal, the reference input characterizes a in-cylinder combustion pressure point between top dead center to Bottom dead center for optimum engine operating conditions.
4. An apparatus for controlling operation of an internal combustion engine as claimed in Claim 1, wherein the air mass calculating means calculates air mass value for measured pressure and temperature with a gas constant (R) factor for air.
5. A method for controlling operation of an internal combustion engine, comprising atleast one cylinder, the said cylinder containing a reciprocating piston and having a known volume at each position of the said piston, a fuel supply means which selectively supplies fuel to the said cylinder and an air supply means which supplies air to the cylinders during engine operation, involves,
measuring in-cylinder pressure of the cylinder and a temperature of the cylinder at preset timing;
calculating an air-mass inside the cylinder at the preset timing based on measured pressure, measured temperature and known cylinder volume;
determining a position of an acceleration pedal;
determining fuel amount based on calculated air-mass and a desired torque derived using the measured acceleration pedal position; and

calculating start of injection pressure at which the injection is started depending on measured in-cylinder pressure with respect to calculated air-mass and the desired torque.
6. A method according to claim 5, wherein a firing order of the cylinders is based on the output of each of the pressure sensors that is received by a hardware pin-configuration.