WO2016196839A1

WO2016196839A1 - Variable pulsing of injectors

Info

Publication number: WO2016196839A1
Application number: PCT/US2016/035587
Authority: WO
Inventors: Oded Eddie Sturman
Original assignee: Sturman Digital Systems, Llc
Priority date: 2015-06-02
Filing date: 2016-06-02
Publication date: 2016-12-08

Abstract

A method of operating a fuel injector in a compression ignition engine by providing a measurement responsive to the temperature in a combustion chamber of the compression ignition engine, pulsing the fuel injector when the piston is at or near a top dead center position of a compression stroke to initiate combustion, further pulsing the fuel injector to maintain the measurement responsive to the temperature to within a predetermined measurement range, such further pulsing being varied in at least one of, a duration of the pulsing or a time between adjacent pulses, the duration of the further pulsing not exceeding a predetermined limit on the duration of the further pulsing. Various embodiments are disclosed.

Description

VARIABLE PULSING OF INJECTORS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/169,778 filed June 2, 2015. BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of

compression ignition engines.

2. Prior Art Compression ignition engines, currently operating on diesel and biodiesel fuels, previously were operated by the injection of the fuel through spray nozzles in the tip of an injector beginning at or near the top dead center position of the piston and continuing until the total amount of fuel desired had been injected. This process had the disadvantage of resulting in high levels of NOx emissions, as well as some incomplete combustion of the fuel, giving rise to the

emissions of hydrocarbons. It also caused considerable engine noise, as there was a delay between the initiation of injection and the initiation of combustion, giving rise to a pressure and temperature spike when ignition did occur, which merely increased the undesired emissions.

More recently, a small pilot injection is first used at or near the top dead center position of the piston to

initiate combustion, with the main injection starting after combustion is initiated, so that fuel injected during the main injection will immediately start to burn when injected, resulting in a smoother running and quieter engine. Still more recently, the use of a series of injection pulses has been disclosed. See for instance U.S. Patent No. 8,733,671 and U.S. Patent Application Publication 2010/0012745. The purpose of such pulsing was merely to maintain combustion over a wider crankshaft angle to improve the conversion of the energy in the combustion chamber to mechanical energy through the action of the crankshaft.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a block diagram of one embodiment of engine system with which the present invention may be practiced.

Fig. 2 is a block diagram of an alternate embodiment of engine system with which the present invention may be

practiced .

Fig. 3 is a schematic diagram illustrating an exemplary operation of an engine in accordance with Fig. 1 or Fig. 2. versus time.

Fig. 4 is a schematic diagram illustrating an exemplary operation of an engine in accordance with Fig. 1 or Fig. 2 versus crank angle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First referring to Fig. 1, a block diagram of an engine system incorporating the present invention may be seen. In this embodiment the engine 20 includes high speed fuel injectors 22 and a pressure sensor 24 (or temperature sensor) for each cylinder of the engine. The fuel injectors are high speed fuel injectors such as of the type disclosed in one or more of U.S. Patent Nos. 5,460,329, 5,720,261, 5,829,396, 5,954,030, 6,012,644, 6,085,991, 6,161,770, 6,257,499,

7,032,574, 7,108,200, 7,182,068, 7,412,969, 7,568,632,

7,568,633, 7,694,891, 7,717,359, 8,196,844, 8,282,020,

8,342,153, 8,366,018, 8,579,207, 8,628,031, 8,733,671 and 9,181,890, and U.S. Patent Application Publication Nos.

2002/0017573, 2006/0192028, 2007/0007362 and 2010/0012745. These patents and patent applications disclose electronically controllable intensifier type fuel injectors having various configurations, and include direct needle control, variable intensification ratio, intensified fuel storage and various other features. Such high speed injectors allow pulse injection of fuel using 8-12 pulses per power stroke, and perhaps even more depending on the engine operating

conditions. Of course other types of electronically

controllable injectors may also be used, provided they have the requisite high speed.

A controller 26 receives a power setting signal as well as information on environmental conditions such as intake air temperature and pressure, other engine operating conditions, and combustion chamber pressure information from the pressure sensors 24. In turn, the controller controls the injectors 22 responsive to the various inputs thereto, generally using lookup tables 28 for reference values under the various possible conditions that may exist. As an alternative, the engine may be a camless engine wherein not only the injectors, but the engine valves 22' are also electronically controlled. Such an engine is shown in Fig. 2. Electronically controllable engine valve operating systems are well known. By way of example, electronically controllable hydraulic valve actuation systems that are suitable for use in such an embodiment are disclosed in one or more of U.S. Patent Nos. 5,638,781, 5,713,316, 5,960,753, 5,970,956, 6,148,778, 6,173,685, 6,308,690, 6,360,728,

6,415,749, 6,557,506, 6,575,126, 6,739,293, 7,025,326,

7,032,574, 7,182,068, 7,341,028, 7,387,095, 7,568,633

7,730,858, 8,342,153 and 8,629,745, and U.S. Patent

Application Publication No. 2007/0113906. These patents and patent applications disclose hydraulic valve actuation systems primarily intended for engine valves such as but not limited to intake and exhaust valves, and include, among other things, methods and apparatus for control of engine valve acceleration and deceleration at the limits of engine valve travel as well as variable valve lift. The advantage of the electronically controllable valve actuation systems is that such systems provide great flexibility in the timing (and in some instances of the valve lift), providing much greater flexibility in the control of the engine operation. Of course other electronically controllable engine valve operating systems may also be used.

Now referring to Fig. 3, a very highly schematic

illustration of methods of operating an engine in accordance with the present invention using variable pulsing of the injectors may be seen. This illustration is applicable to both engines with cam driven engine valves, such as

illustrated in Fig. 1, and camless engines, as illustrated in Fig. 2. The concept of the present invention is to maintain a temperature in the combustion chamber during the power stroke that is within a predetermined range. At the lower end of the temperature range, the temperature limit is temperature any meaningful unburned fuel to be emitted through the exhaust system. The upper limit of the

temperature range is purposely set at a temperature

adequately below the temperatures at which NOx is created, thereby assuring engine operation, such as in a diesel engine, with very low emission levels. This is achieved through pulsed operation of the injectors using variable pulse spacing in terms of crankshaft angle or pulse width, or a combination of the two, as shall be subsequently described.

To achieve the foregoing, one needs a measure of the combustion chamber temperature resulting from the pilot injection and during the subsequent injection pulses of the power stroke. While combustion chamber temperature could be directly measured, there is no convenient, inexpensive and durable method of such direct measurement that would be applicable to an operating engine. In accordance with one embodiment of the present invention such as shown in Figs. 1 and 2, combustion chamber pressure is used as an indication of temperature, using the initial intake air pressure and temperature and the engine compression ratio together with the ideal gas law, preferably accounting for gas changes occurring in the combustion chamber during the injections to provide the desired indication of combustion chamber

temperature .

In Fig. 3, a curve showing combustion chamber

pressure/temperature is shown, though again this is very highly schematic in that the pressure indicative of

temperature as well as the temperature itself may well vary with crankshaft angle as well as other operating conditions, particularly the power setting, as the combustion of the fuel itself adds additional heat and gasses to the contents of the combustion chamber, which may vary the relationship between pressure and temperature in the combustion chamber. Further of course, for a fixed quantity of compressible gas,

variations in pressure with adiabatic expansion or

compression are much greater than the corresponding

variations in temperature. Accordingly, again Fig. 3 is very highly schematic, but still illustrative of certain aspects of engine operation, such as the effect of the pulsed

injections. Actually, the pressure and temperature curves will not generally have the same shape, and most likely neither will be flat. The pilot injection and the other injection pulses may result in a temperature curve that is approximately flat and near the upper temperature limit to maximize the combustion chamber temperature throughout the entire combustion event. Alternatively, the pilot injection and/or the other injection pulses may be chosen so that the temperature is toward the lower limit to extend the injection event to larger crankshaft angles. The combustion chamber temperature may also vary anywhere between the upper

temperature limit and the lower temperature limit in whatever manner desired. With respect to the injection pulses shown in Fig. 3, it will be noted that at or near top dead center there is a small (short) pilot injection pulse to initiate compression ignition. This pulse is shown as raising the combustion chamber pressure to the pressure indicative of a temperature within the desired predetermined temperature range. However, it should be noted that, alternatively, this pilot injection pulse may, in fact, not raise the pressure in the combustion chamber to a pressure indicative of a temperature within the desired temperature range, but instead raise the pressure to a pressure indicative of a lower combustion chamber

temperature. The reason for this is that the initial pilot injection pulse is simply to initiate combustion (and to continue that combustion until the next injection pulse occurs), and occurs when the crankshaft angle is very

unfavorable for the conversion of pressure energy to

mechanical energy at the engine output. In any event, for later pulses, the combustion chamber temperature will be brought up to within the desired

temperature range. As the crankshaft angle and the

acceleration of the piston toward its bottom dead center position increases, the pulse width is increased and/or the spacing between pulses is decreased because of the

increasingly rapid increase in the combustion chamber volume that causes an increasing rate of decrease of the pressure and temperature in the combustion chamber. This is

illustrated in Fig. 3, wherein the second pulse after the top dead center position is spaced from the pilot injection pulse and is wider in time than the pilot injection pulse, with the third injection pulse being even wider than the second injection pulse and being closer to the second injection pulse than the second injection pulse is from the pilot injection pulse, again primarily because of the increasing velocity of the piston resulting in an otherwise increasing rate of decrease in the combustion chamber pressure and temperature. Finally at some time, a maximum desired pulse width is achieved, after which increasing effective injection rates are achieved by successively decreasing the spacing between injection pulses, as also indicated in Fig. 3.

The reason for limiting the time of any injection pulse is to prevent an excessive buildup of the boundary layer around the injected fuel. In particular, in a more sustained injection, a boundary layer builds up around the injected fuel, part of which boundary layer will normally have a stoichiometric or near stoichiometric fuel/air ratio. On combustion, this will result in local very hot regions, hot enough to create some level of NOx. Pulsing the injections terminates the growth of the boundary layer on each injection pulse, with a new boundary layer starting on the next

injection pulse. In this way, the maximum boundary layer thickness becomes highly limited, with heat from the burning stoichiometric or near stoichiometric areas of the boundary layer being rapidly transferred to the cooler adjacent combustion chamber regions and to the fuel spray itself.

Consequently, one obtains excellent control of the maximum temperatures in the combustion chamber, and thus can

substantially eliminate the generation of NOx.

Thus in one operating mode, the invention has the further advantage of effectively maintaining the pressure in the combustion chamber during a power stroke that is near the maximum pressure corresponding to the safest high temperature above which NOx will be generated. This can provide highly efficient conversion of the pressure energy to mechanical energy while reducing emissions to near zero. In another operating mode, the combustion chamber temperature is kept close to the lower combustion chamber temperature limit to extend combustion out over more efficient crankshaft angles for conversion of the energy in the combustion chamber to mechanical energy. In still other embodiments, the

combustion chamber temperature may vary with crankshaft angle and/or power setting, as long as it stays within the two temperature limits.

In practicing the invention, the controller should note the various operating and environment condition as described above. In particular, the temperature and pressure of the intake air, and for a camless engine, the timing of the intake valving. The controller would determine both the pressure and temperature achieved by the compression stroke as well as the mass of air compressed as can be determined from the intake pressure and temperature measurements using the ideal gas law. The mass of air in the combustion chamber may affect the duration of the pilot and the duration and/or timing of subsequent injection pulses if the pressure and temperature rise on each injection pulse is to be maintained within the predetermined limits, irrespective of the these operating conditions. Among other things, the lookup tables 28 normally would store data from prior engine operation (testing) under the range of engine operating and environment conditions. This allows refining of the pulsing of the injectors for the particular engine operating and environmental conditions being encountered by making corrections to the controller calculations as conditions change. In addition, further corrections may be made on an iterative basis, cycle to cycle, to correct for any further detected deviations in engine operation from those desired. In the foregoing description and in the claims to follow, reference is made to controlling the temperature in a combustion chamber to within a predetermined temperature range. However it should be noted that there is no one temperature in a combustion chamber, particularly after combustion is initiated, as there will be some regions considerably hotter than other regions. Further, the

"temperature" in the combustion chamber is generally

estimated based at least in part on information stored in the lookup tables, which information can be established using empirical data from prior testing of an identical engine and injectors under varying conditions. The empirical data can establish a predetermined (estimated) temperature range by noting operating conditions above which NOx is generated, and setting an upper limit in a predetermined temperature range at an estimated temperature limit that is considered a safe upper limit, and to account for inaccuracies in the estimated combustion chamber temperatures and thus avoid NOx generation, at least any meaningful NOx generation. Repeatability in the estimated temperature in the combustion chamber is desired, though neither perfect repeatability nor absolute accuracy is required. As noted before, the lower limit on the

predetermined temperature range can be set at a reasonable

(achievable) estimated temperature below the upper limit, but still above a temperature below which the exhaust will contain meaningful unburned hydrocarbons.

The net result is the maintenance of an estimated temperature in a combustion chamber that is high enough to avoid generating meaningful hydrocarbons in the engine exhaust and below the temperature that will generate

meaningful NOx.

As a further alternate embodiment, it is conceivable that a single pressure sensor and single temperature sensor could be used for sensing pressure and temperature of the intake air. This would allow the calculation of the mass of air ingested in the intake stroke. In this embodiment, the lookup tables 28 could contain adequate information for operation of the engine without individual combustion chamber pressure sensors, but instead use information stored in the lookup tables from prior testing of an engine which, in fact, did include the pressure sensors (or temperature sensors) . In such operation, the controller would need to control the timing and duration of the injection pulses based on

knowledge of the compression ratio, intake pressure and temperature, and fuel characteristics, though such operation is not preferred because of its open loop characteristics after the known starting conditions. Such operation,

however, would allow the application of the present invention to preexisting diesel engines which, while not ideal, may still result in a substantial improvement in operation of the engines and reduction in the emissions thereof.

As a still further alternate embodiment of the

invention, a single combustion chamber pressure sensor might be used in a multicylinder engine, with the controller assuming that all cylinders are operating similarly to the one with the pressure sensor. This avoids the open loop problem, though does not allow balancing the operation of each the various cylinders. Regarding the boundary layer, one normally thinks of a boundary layer building up on a solid or rigid surface moving through a fluid. However a boundary layer or boundary layer like space will build up on a stream of fluid flowing through another fluid, though in that case, the boundary layer or boundary layer-like space is the space between the flowing fluid and the fluid it flows through that has a velocity somewhere between the velocity of each of the two fluids. Both fluids add to the boundary layer buildup as a function of their relative viscosities. Even when the stream is or breaks up into a spray, on a macro scale, that spray will sweep up some of the fluid it flows through in amounts increasing in time unless that spray is interrupted until things settle down or move out of the spray path due to turbulence, combustion chamber volume expansion, etc. On a micro scale, spray droplets, moving through the combustion chamber contents, will themselves build up a boundary layer. As to the individual spray droplets, droplets of normal injection spray size are not likely to cause a problem, in that the fuel in a very small droplet, and the portion that may be in a droplet boundary layer will approximately depend on the cube of the diameter of the droplet. Its surface area is proportional to the square of its diameter, so the ratio of surface area to volume is approximately proportional to 1/diameter. Thus for a very small droplet diameter, the surface area of the droplet and of its boundary layer is very large compared to the volume of the droplet and its boundary layer, so that any heat of combustion of the droplet and/or its boundary layer is essentially quenched by the local combustion chamber

contents, thereby avoiding a meaningful local hot spot.

However as to any stream, the buildup of a boundary layer will create parts of the increasingly thick boundary layer having stoichiometric or near stoichiometric mixtures of fuel and air that can create local hot spots that when thick enough, will not be quenched by the local combustion chamber contents. Also as to any overall spray, the spray will start to carry combustion chamber content with it in an amount and with a decreasing relative velocity and mixing dependent on the characteristics of the spray and how long the spray is active. This allows the fuel spray to turn into a gaseous form with relatively large regions having

stoichiometric or near stoichiometric mixtures of fuel and air, adequate to avoid immediate quenching by the spray itself and the surrounding combustion chamber contents, resulting in local hotspots adequate to create unacceptable levels of NO_x. In the prior art, pulsing of an injection has been disclosed in the context of initiating combustion and also as a means for extending the combustion event to larger

crankshaft angles for more efficient conversion of energy in the combustion chamber to mechanical energy without the combustion chamber temperature (overall) exceeding the temperature at which NOx will be generated (normally stated to be 2200 °K) . Keeping the combustion chamber temperature below 2200 °K on a macro basis itself grossly reduces the production of NOx, though given the present and particularly the future expected restrictions on NOx emissions, even the micro sources of NOx must be considered and dealt with, as herein. In any injector, the quantity of fuel delivered depends not only on the duration of the injection pulse, but also on the pressure of the fuel in the injector. Thus varying the injection pressure with engine load may be used as another variable to assure injection of an amount of fuel adequate for the then required engine power.

Referring now to Fig. 4, an illustration of a pulse injection event that has been tested may be seen. The injector tested had direct needle control for controlled injection of pre-intensified fuel. Fig. 4 illustrates the on - off pulses to the valve controlling the injector needle.

In the injector tested to verify the NOx reduction, the needle opening delay and the needle closing delay are approximately equal. Therefore the actual injection pulses were close to the same width as the on - off pulses to the valve

controlling the injector needle, but slightly delayed. Also for the pulse sequence of Fig. 4 with the engine operating at 2200 rpm, the crankshaft rotates approximately 76 usec/deg (microseconds) . Thus in Fig. 4, the smallest injection pulse is approximately 200 usee long, and the longest is

approximately 400 usee long. The first three pulses after top dead center are the shortest, primarily to initiate combustion and sustain combustion until more favorable crank angles are reached.

Then the next three pulses are longer and perhaps closer together, during which time the engine piston is accelerating downward as the combustion chamber contents expand with the associated expansion cooling, with those three intermediate pulses being followed by the two longest and more closely spaced pulses. These pulses are the primary power pulses, and in general may be longer and/or closer together than the prior pulses because of the rapid expansion of the combustion chamber contents itself tending to break up the injection, even during a single injection pulse. The final two short pulses are for soot reduction.

Given the foregoing, a minimum off time of approximately 100 to 200 microseconds is preferred, though of course longer off times can be used. However one needs to maintain

combustion throughout the entire combustion event, and longer off times might be exchanged in favor of shorter injection pulses if the engine load is low. For injection pulse durations, the shorter, the better, though pulses limited to approximately 200 to 400 microseconds are most preferred, though pulses for 600, or even 800 microseconds can be used with less favorable results. Also it should be noted that the foregoing is applicable to the use of a very high speed injector of the general type hereinbefore referred to. If a less than very high speed injector is used, then the

foregoing very short injection pulses cannot be obtained, as the injector will spend excessive time in the transitions from off to on and vice versa and not achieve the fuel droplet size needed, which may itself offset some of the advantages of the present invention. In any event, given any specific injector, one preferably could use injection pulse on times that do not significantly differ from the injection pulse on times that minimize the amount of NOx formation under the then existing engine operating conditions as established by engine emissions testing and control engine power in corresponding engines by control of pulse repetition, except as may be necessary to achieve a higher engine power output than otherwise achievable. Referring back to Fig. 1, a test engine of this

configuration with a pressure transducer in each cylinder, together with a dynamometer, fuel flow measurement and emission test equipment, allows the controller to adjust the relative on times of each injector so that each cylinder of the engine has the same pressure profile throughout the entire combustion event, including ignition time and ignition pressure profile. This set-up also provides tremendous flexibility in gathering data under various engine operating conditions. In particular, for any engine operating

conditions, one can adjust the cylinder pressure profile by adjusting the pulsing characteristics and pulse timing and obtain NOx production and engine efficiency at each power setting. By varying the pressure profile using the available variables, the optimum parameter settings can be determined for each engine operating condition for both maximum engine efficiency and minimum NOx production for engine and the (speed of the) injectors being used. Hopefully the parameter settings for both maximum engine efficiency and minimum NOx production will be similar, so that little sacrifice in one engine performance parameter is needed to maximize the other engine performance parameter. If not, a compromise must be made .

The test setup described will also allow evaluation of the sensitivity of the engine performance on variations in the engine parameter settings, which can effect final decisions on parameter settings to settle on for

incorporation into the applicable lookup tables 28. By way of example, both maximum engine efficiency and minimum NOx production may occur too close to a temperature at which substantial NOx would be generated to provide confidence in repeatedly achieving the desired result, engine to engine, and with varying engine condition, wear, tolerances in timing, pressure transducer accuracy, transducer to transducer, and transducer repeatability over time, etc.

Thus further compromises may need to be made.

Also, while implementing a test engine with a pressure transducer in each cylinder is highly advantageous for each cylinder, that may not be practical for production engines. Consequently since there can be variations in injector performance, injector to injector, and since the present invention tends to depend on approaching the limits of the injectors capabilities, each injector is preferably

characterized during it manufacture, preferably in terms of flow rate and response time, and that data added to a lookup table for the cylinder of an engine in which the injector is to be installed to allow the controller to compensate the in characteristic of each injector. Of course, the injectors for the test engine should be similarly characterized to provide a common baseline against which production injectors are measured .

Of course when a camless engine is to be used, an identical camless engine and injectors should be used for the above testing. Such an engine presents further variable parameters such as valve timing, and valve lift if

controllable, which themselves can have a great effect, particularly on engine power output and engine efficiency. For actual testing, a stock 2010 International Maxxforce 10 570 C.I. engine was used. The engine was retrofitted with a hydraulic engine valve actuation system (camless)

manufactured by Sturman Industries and high speed injectors with direct needle control also manufactured by Sturman

Industries, with different injector nozzles with differing flow characteristics being tested. Also, several different engine piston geometries and compression ratios have been tested .

Thus the present invention has a number of aspects, which aspects may be practiced alone or in various

combinations or sub-combinations, as desired. While certain preferred embodiments of the present invention have been disclosed and described herein for purposes of illustration and not for purposes of limitation, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the full breadth of the following claims.

Claims

CLAIMS What is claimed is:

1. A method of operating a direct injection internal combustion engine comprising:

for an entire injection event:

a) limiting the entire injection to a series of

injection pulses, wherein each injection pulse is limited in time duration and repeated as necessary to obtain an injected volume ;

b) the time duration of each injection pulse not exceeding 800 microseconds;

c) the time between injection pulses being at least 100 microseconds ;

whereby the buildup of a boundary layer on a fuel being injected is interrupted by the time between injection pulses so that that boundary layer is not continued during the next injection pulse.

2. The method of claim 1 wherein in b) , the time duration of each injection pulse does not exceed 600

microseconds.

3. The method of claim 1 wherein in b) , the time duration of each injection pulse does not exceed 400

microseconds .

4. The method of claim 1 wherein in c) , the time between injection pulses is approximately 200 microseconds.

5. The method of claim 1 wherein in b) , the time duration of each injection pulse is approximately 400

microseconds, and c) , the time between injection pulses is approximately 200 microseconds.

6. A method of operating a direct injection internal combustion engine comprising:

for a particular direct injection engine with particular injectors ;

testing the engine with the injectors using pulse injection to determine the injection pulse timing and

duration that results in the minimum NOx production, maximum efficiency or a compromise between minimum NOx production and maximum efficiency for various engine operating conditions and power settings and storing applicable engine operating parameters resulting from the testing; and

for each of one or more additional engines in accordance with the particular direct injection engine and with

injectors in accordance with the particular injectors tested, operating each additional engine with injection pulses determined during testing to result in the minimum NOx production, maximum efficiency or the compromise between minimum NOx production and maximum efficiency for the

additional engine operating conditions using an injector controller responsive to a power setting and engine operating conditions using applicable engine operating parameters resulting from the testing as stored in lookup tables coupled to the controller of that additional engine.

7. The method of claim 6 wherein the particular engine tested has a pressure sensor for each combustion chamber of the particular engine and testing the engine with the

injectors using pulse injection to determine the injection pulse timing and duration that results in each cylinder of the engine having the same pressure profile, and wherein each particular injector in the particular engine tested is calibrated for flow rate and/or response time to establish a baseline for injector performance, wherein each additional engine includes at least one pressure sensor in one combustion cylinder; and

wherein each injector used in an additional engine is also calibrated for flow rate and/or response time, and variations of each injector used in an additional engine in flow rate and/or response time from the baseline, together with an identification of the combustion cylinder in which it is used in the additional engine, is included in a lookup table, wherein the controller adjusts each pulse width and/or pulse timing to each injector to cause each injector to operate in accordance with the baseline for injector

performance .

8. The method of claim 7 wherein the particular engine tested is a camless engine, and wherein the applicable engine operating parameters resulting from the testing and stored in lookup tables of each additional engine include engine valve timing .

9. The method of claim 8 wherein the particular engine tested is a camless engine with variable engine valve lift, and wherein the applicable engine operating parameters resulting from the testing and stored in lookup tables of each additional engine include engine valve lift.