CN1081733C - Improved time delay ignition circuit for an internal combustion engine - Google Patents

Abstract

An internal combustion engine assembly including an internal combustion engine including an engine block having at least one cylinder, a piston mounted within the cylinder for reciprocal movement in the cylinder, a fuel injector for injecting fuel into the cylinder, the fuel injector initiating a fuel injection event at a predetermined time and a circuit for generating a spark in the cylinder a predetermined amount of time after the injection event to cause combustion of fuel in the cylinder.

Description

Improved Delayed Ignition Circuit for Internal Combustion Engines

This application claims the benefit of US Patent Application Serial No. 60/020032, filed June 21, 1996.

Attention is also drawn to US Patent Application No. 08/07664, filed July 25, 1995.

Background of the invention

The invention relates to an internal combustion engine, in particular to an ignition timing circuit for the internal combustion engine.

Spark ignition internal combustion engines require a spark to be generated at the spark plug in order to ignite the fuel-air mixture in the cylinders of the internal combustion engine. Timing control of the combustion process is particularly important during operation of the internal combustion engine. In particular, the timing control of the combustion process determines the speed and acceleration performance of the internal combustion engine and the efficiency with which fuel is burned in the cylinders. Many different methods of timing control of the combustion process are known. In particular, it is known to use various operating parameters of the internal combustion engine to control the timing of the combustion process. These parameters may include crankshaft angle, engine temperature and/or cylinder pressure.

Summary of the invention

In internal combustion engines using fuel injectors, the air/fuel mixture is atomized into a "stratified" fuel/air mist that "floats" from the injector nozzle in the cylinder toward the spark gap of the spark plug ". If the ignition spark jumps across the spark gap before the fuel/air mixture aerosol reaches the spark gap, the fuel/air mixture aerosol will not burn completely. In order to ensure complete combustion of the stratified fuel/air mixture, it is necessary to precisely control the timing of spark ignition when the fuel/air mixture reaches the spark gap.

Accordingly, the present invention provides an absolute delay ignition circuit for an internal combustion engine. The delayed ignition circuit bases the ignition timing on the time elapsed from the start of fuel injection from the injector. That is to say, the electronic control unit of the internal combustion engine generates a signal to cause injection of fuel via the fuel injector and subsequently generates a signal to cause spark ignition based on the absolute time period of the elapsed time measured from the injection signal. The ECU may be based on a fixed calibration time period, a predetermined time period stored in a look-up table based memory, or a time period for estimating various parameters (such as temperature, pressure, etc.) Arithmetic method based software calculates the time period based on which the time delay is generated.

In one embodiment, the operation of the internal combustion engine is time-based ignition control at low speeds and crank angle-based ignition control at high speeds, i.e., changes from time-based ignition control to crank angle-based ignition control. The basic ignition control depends only on the engine speed. In another embodiment, the engine is operated with ignition controlled on a time basis at low loads (as measured by throttle position) and on a crank angle basis at high loads, i.e. from The change from time-based ignition control to crank angle-based ignition control depends only on the engine load. In yet another embodiment, the internal combustion engine is operated with time-based ignition control at low loads and low speeds, and with crank angle-based ignition control at high loads or high speeds, i.e. from time-based ignition The control change to a crank angle-based ignition control depends not only on the engine speed but also on the engine load.

The present invention also provides an internal combustion engine assembly, which includes: an internal combustion engine including an internal combustion engine block with at least one cylinder; a piston mounted in the cylinder for reciprocating movement in the cylinder, and a piston for an injector for injecting fuel into the cylinder; and circuit means for generating an injection control signal representative of the injection process and for generating an ignition spark in the cylinder within a predetermined period of time after the injection control signal is generated.

The present invention also provides an internal combustion engine assembly, which includes: an internal combustion engine including an internal combustion engine block with at least one cylinder; a piston mounted in the cylinder for reciprocating movement in the cylinder, and a piston for a fuel injector for injecting fuel into the cylinder; and a circuit for generating an injection control signal representative of the fuel injection event, the circuit including a timer having a timing output for generating a timing electrical signal, the timing The signal has a predetermined duration representing the time elapsed since generation of the injection control signal.

The present invention also provides a method for controlling fuel ignition timing in an internal combustion engine, the internal combustion engine comprising an internal combustion engine body with at least one cylinder; a piston mounted in the cylinder for reciprocating movement in the cylinder; A fuel injector for injecting fuel into the cylinder, the method comprising the steps of: (A), generating an injection event; (B), generating an ignition signal based solely on the time elapsed since the injection event.

It is an advantage of the present invention to provide an ignition system which bases the ignition timing on an absolute time period measured from the start of the injection event.

It is a further advantage of the present invention to provide an ignition timing system which allows the internal combustion engine to be operated at an idle speed of less than 200 rpm.

It is a further advantage of the present invention to provide an ignition timing system which enables efficient and complete combustion of the fuel/air mixture aerosol in the cylinder.

Another advantage of the present invention is to provide an ignition timing system that resists small fluctuations in engine speed.

Other features and advantages of the invention are set forth in the following detailed description and in the description.

Brief description of the drawings

These and other features of the present invention will be more fully disclosed upon consideration of the following "Detailed Description of the Preferred Embodiments" in conjunction with the accompanying drawings, in which like reference numerals denote same element. in:

Fig. 1 is a partial cross-sectional view of an internal combustion engine embodied in the present invention;

Fig. 2 is the schematic diagram of the delay ignition circuit that a single-cylinder internal combustion engine is used;

Fig. 3 is a graph showing various relationships based on time between different electrical signals in the delayed ignition circuit;

Fig. 4 is a schematic diagram showing a delayed ignition circuit used with a six-cylinder internal combustion engine;

FIG. 5 is a graph showing injection timing for the internal combustion engine of FIG. 4 measured in angle before top dead center (DBTDC) and plotted as a function of engine speed and throttle position;

FIG. 6 is a graph showing ignition timing for the internal combustion engine of FIG. 4 measured in angle before top dead center (DBTDC) and plotted as a function of engine speed and throttle position;

FIG. 7 is a graph showing maximum ignition coil related time for the internal combustion engine shown in FIG. 4, measured in milliseconds (ms) and plotted as a function of engine speed;

Figure 8 is a graph showing ignition coil related times for the internal combustion engine shown in Figure 4, the graph being measured in milliseconds (ms) and plotted as a function of engine speed;

Figure 9 is a graph showing injection pulse times for the internal combustion engine shown in Figure 4, measured in milliseconds (ms) and plotted as a function of engine speed and throttle position;

FIG. 10 is a graph showing the transition from time-based ignition to crank angle-based ignition in the internal combustion engine shown in FIG. 4. FIG.

Before analyzing an embodiment of the present invention in detail, it should be understood that the present invention is not limited to the detailed structure and arrangement of parts described in the following description or shown in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Furthermore, it should be understood that the phrases and terms used herein are for the purpose of describing the invention and should not be regarded as limitations of the invention.

Detailed description of the optimized embodiment

FIG. 1 shows a partial sectional view of an internal combustion engine 10 in which a cylinder 14 of the internal combustion engine 10 is shown. The internal combustion engine 10 includes a crankcase 18 defining a crankcase cavity 22 within which a crankshaft 26 is rotatable. The engine block 30 defines the cylinders 14 . The block 30 also defines an intake port 34 communicating between the cylinder 14 and the crankcase chamber 22 by means of a transfer passage 38 . The body 30 also defines an exhaust port 42 . A piston 46 is reciprocatable within the cylinder 14 and is drivably connected to the crankshaft 26 by means of a connecting rod crank assembly 50 . A cylinder head 54 closes the upper ends of the cylinders 14 so as to define a combustion chamber 58 . The internal combustion engine 10 also includes a fuel injector 62 mounted on the cylinder head 54 for injecting fuel into the combustion chamber 58 . A spark plug 66 is mounted on the cylinder head 54 and extends into the combustion chamber 58 .

Internal combustion engine 10 also includes (see FIG. 2 ) a delayed ignition circuit 70 that generates an ignition spark in cylinder 14 at a predetermined time after fuel has been injected into combustion chamber 58 . As shown in FIG. 2, the delayed ignition circuit 70 includes a microprocessor 74 with a data output 78, an injection indicator output 82 and an output 86 for generating an ignition spark. The microprocessor 74 generates an ignition spark signal at output 86 as described below. However, it should be understood that the ignition spark signal can also be generated by other suitable components (such as ECU - internal combustion engine electronic control unit). The circuit 70 also includes a timer 90 having a data input 94 for receiving the time signal output from the data output 78 of the microprocessor 74 and having an 8-bit register. The timer 90 also has a trigger input 98 connected to the injection indicator output 82 of the microprocessor 74 to receive a signal from the microprocessor 74 indicating that the injection process has been initiated by the microprocessor 74. The timer 90 also includes a timing pulse output 102 .

The delayed ignition circuit 70 also includes an AND gate 106 having two inputs 110 and 114 and an output 118 . An input 110 of AND gate 106 is connected to output 102 of timer 90 . An input 114 of AND gate 106 is coupled to microprocessor 74 for receiving the spark generation signal output from spark generation output 86 in microprocessor 74 . The output 118 of the AND gate 106 is connected to an ignition coil 122 (as described in the schematic diagram shown in FIG. 1 ) to generate an ignition spark in the cylinder 14 and ignite the fuel in the cylinder 14 .

In operation, when the fuel injection event occurs, the timer 90 receives at its trigger input 98 an injection control signal output from the output 82 of the microprocessor 74 (see reference numeral 2 in FIG. signal to start counting clock pulses from the microprocessor clock signal. The timer 90 generates a high value signal or timing signal at its output 102 (see reference number 3 in FIG. 3 ) when the timer count has not overflowed. When the microprocessor 74 generates a spark signal at the output 86 (see reference number 4 in FIG. 3 ), and the spark signal is received at the input 114 of the AND gate 106, the AND gate 106 produces an output at its output 118 or An ignition signal or current is supplied to the ignition coil 122 (see reference numeral 5 in FIG. 3 ). When output 102 falls (see item 7 in FIG. 3 ) output 118 also falls (see item 6 in FIG. 3 ). While the output 118 remains high, the current through the ignition coil rises. Output 102 falls when the timer receives a count from the microprocessor that has overflowed, causing output 118 to fall, ie, when microprocessor 74 indicates that the required period of time has elapsed since the injection event. Since the current in the indicator or ignition coil cannot change immediately (V=L(di/dt)), a sudden change in the current supplied to the coil will cause the voltage in the ignition coil to rise rapidly, thus producing a fuel oil in the cylinder 14. Ignition sparks. To accommodate different sized internal combustion engines having different numbers of cylinders, the delayed ignition circuit 70 described in FIG. 2 may be repeated as many times as the number of cylinders.

Although the ignition circuit 70 can be used at any speed, it is best used at low speeds or idle speeds, that is, at crankshaft speeds of 200-2000 revolutions per minute (RPM), and it has been shown that the ignition circuit 70 operates at low speeds. Works especially well up to 200RPM. At speeds greater than 2000 RPM, the internal combustion engine is preferably controlled by a conventional crank angle based ignition system. In both the conventional internal combustion engine and the internal combustion engine 10 shown in the figures, the timing of the spark generation signal at this speed is based solely on crankshaft angle. However, in the prior art, the spark generation signal is directly connected to the ignition coil, and the ignition spark is directly excited without any other signal. The result is that the timing of the prior art ignition process is dependent on crankshaft angle rather than an absolute time value calculated in time from a fixed point. In contrast, ignition circuit 70 causes ignition to always occur for a predetermined period of time after the injection event occurs, and the predetermined period of time is not based on crankshaft angle. The fuel injection process begins with a fuel injection signal generated at output 86 of microprocessor 74 . This injection signal occurs either when the injectors are activated or is based on the actual fuel injection into the cylinder 14 .

Figure 4 shows a delayed ignition circuit 200 for a six cylinder internal combustion engine. The same components are denoted by the same reference numerals. Rather than repeating the circuit shown in FIG. 2 six times, the embodiment shown in FIG. 4 combines (multiplexes) the various signals so that an economical use of electronic components can be achieved.

As shown in FIG. 4, the circuit 200 includes a timer 204 having an 8-bit data input register 208, three trigger inputs 212, 216 and 220 corresponding to cylinders 1 and 4, 2 and 5, 3 and 6, respectively. , a clock input 224 and three outputs 228, 232, 236 corresponding to trigger inputs 212, 216 and 220, respectively. Circuit 200 also includes OR gates 240, 244, and 248 having outputs 252, 256, and 260, respectively, connected to trigger inputs 212, 216, and 220, respectively. The OR gates 240, 244 and 248 also include inputs 264 and 268, 272 and 276, and 280 and 284, respectively, connected to the microprocessor 74 to receive injection output signals indicating that an injection event has occurred in a given cylinder. . That is, the microprocessor produces output signals at outputs 288, 292, 296, 300, 304 and 308, indicating that injection has occurred in cylinders 1, 2, 5, 3 and 6, respectively.

The delayed ignition circuit 200 also includes AND gates 312, 316 and 320 having respective pairs of inputs 324, 328 and 332 connected to timer outputs 228, 232 and 236, respectively. The AND gates 312, 316 and 320 also have outputs 336, 340 and 344, respectively. This delayed ignition circuit 200 also includes an AND gate 348 having an input 352 connected to the output 336 of the AND gate 312, an input 356 and an output 360; the AND gate 364 has an output 340 connected to the AND gate 316 The input 368 of an input 372 and an output 378; The AND gate 380 has an input 384 connected to the output 344 of the AND gate 320, an input 388 and an output 392; the AND gate 396 has an output connected to the AND gate 320 An input 400 on 344, an input 404 and an output 408. Inputs 356 and 372 of AND gates 348 and 364, respectively, are coupled to microprocessor 74 to receive firing signals from outputs 412 and 416 of microprocessor 74, respectively. In delayed ignition circuit 200, the firing signals from the microprocessor for cylinders 1 and 4 are multiplexed, i.e. combined, on output 412, while the firing signals for cylinders 2 and 5 are multiplexed on output 416. road transmission. Outputs 388 and 404 of AND gates 380 and 396, respectively, are coupled to microprocessor 74 to receive firing signals from outputs 420 and 424 of microprocessor 74, respectively. Output 420 produces the firing signal for cylinder 3 and output 424 produces the firing signal for cylinder 6 . Outputs 392 and 408 of AND gates 380 and 396 provide ignition control signals for the ignition coils of cylinders 3 and 6, respectively. Alternatively, the firing control signals for cylinders 3 and 6 may be generated in multiplexed form by microprocessor 74 and combined at 344 into a timed output signal and split by a circuit similar to splitter (DMUX) 428 . Outputs 360 and 376 of AND gates 348 and 364 provide multiple ignition control signals for the ignition coils of cylinders 1 and 4, and cylinders 2 and 5, respectively.

The delayed ignition control circuit 200 also includes a splitter (DMUX) 428 . The splitter 428 includes AND gates 432 and 436 and AND gates 440 , 444 , 448 and 452 . The splitter receives as inputs the outputs 360 and 376 of the AND gates 348 and 364, respectively, and the control outputs 456 and 460 of the microprocessor 74, for cylinders 1 and 4, 2 and 5, and at outputs 360 and 376, respectively. The generated multiple ignition control signals are divided into branches. The splitter generates split firing control signals for controlling cylinders 1, 4, 2 and 5 at outputs 464, 468, 472 and 476, respectively.

In operation, the retarded ignition circuit 200 is used at low speeds, ie, crankshaft speeds of 200-2000 RPM, and has been shown to work particularly well at speeds as low as 200 RPM. At speeds greater than 2000 RPM, the ignition is preferably controlled using a conventional crank angle based timing system. The microprocessor provides an injection signal for cylinder 1 at input 264 of OR gate 240 and an injection signal for cylinder 4 at input 268 of OR gate 240 . The injection signals of cylinders 1 and 4 are thus combined at output 252 of OR gate 240 . Likewise, the injection signals for cylinders 2 and 5 are combined at output 256 of OR gate 244 and the injection signals for cylinders 3 and 6 are combined at output 260 of OR gate 248 . The injection signals are input to trigger inputs 212, 216 and 220 of the timers, respectively. From the multiplexed timing data received from the microprocessor via data input 208, a combined timing signal can be generated which is available at output 228 for cylinders 1 and 4 and available at output 232 for cylinders 2 and 5, Available for cylinders 3 and 6 at output 236 . The combined timing signal is combined with the combined firing control signals for cylinders 1 and 4 and cylinders 2 and 5, respectively, to form a pair of combined firing signals for cylinders 1 and 4 and 2 and 5. Splitter 428 splits the combined firing signal to produce absolute time based firing signals for cylinders 1, 4, 2 and 5.

The microprocessor also generates a single spark control signal at its outputs 420 and 424 for cylinders 3 and 6 respectively. The spark control signal is input to AND gates 380 and 396 for generating absolute time based firing signals for cylinders 3 and 6 at outputs 392 and 408, respectively.

While the above-described embodiments show a change between time-based ignition and crank angle-based ignition only as a function of engine speed, one or more of many other parameters of the engine may be used alone or in combination. to determine when to switch between time-based and crank angle-based ignition. Examples of other suitable parameters of the internal combustion engine include engine load, throttle position, or some other suitable parameter.

5-9 graphically illustrate injection timing, ignition timing, absolute maximum ignition coil on time, injection pulse time relative to optimum ignition coil on time and the control scheme for the ignition circuit 200. As shown in Figure 5-9, the internal combustion engine operates with time-based ignition at lower percentages of throttle opening (approximately 15% of opening or less), but at higher throttle openings Percentage (higher than 15% of the opening) is based on crank angle ignition. That is, the transition from time-based ignition to crank angle-based ignition is dependent solely on the throttle position, which is measured as a percentage of throttle opening.

The injection timing shown in Figure 5 is measured in angles before top dead center. When the ignition circuit 200 is operating on a time-based basis, ie, with a throttle position of 150 or less, the injection timing values in FIG. 5 represent the angle at which current begins to flow in the injector coil before top dead center. When the ignition circuit 200 operates in a crank angle-based manner, that is, when the throttle valve position is greater than 150°, the injection timing values in FIG. 5 indicate the angle at which fuel begins to be injected into the combustion chamber before top dead center.

FIG. 10 shows a graph for switching between time-based ignition to crank angle-based ignition for another alternative control scheme of ignition circuit 200 . As shown in Figure 10, the internal combustion engine operates with time-based ignition at low throttle percentages and low speeds, and crank angle-based ignition at high throttle percentages or high speeds. As shown in Figure 10, if the internal combustion engine speed is lower than 1000RPM, and the throttle requirement of the controller is less than 20% (that is, the throttle position detected by the throttle sensor is less than 20% of the maximum value -- "200T.P.S" in Figure 10 ”), the ignition is time-based. If the engine speed is above 1000 RPM or the controller throttle request is greater than 20%, the ignition is based on the crank angle. As mentioned above, this is controlled by the ECU (Internal Combustion Engine Electronic Control Unit). It has been found that this "dual strategy" of switching from time-based ignition to crank angle-based ignition provides good running characteristics by exchanging engine speed in an external internal combustion engine and by means of exchanging throttle position Provides good acceleration characteristics. The optimized ignition system is disclosed in the U.S. patent application No. 60/020033, dated June 21, 1996, entitled "Multi-spark Capacitor Discharge Ignition System for Internal Combustion Engines", and the patent application is here And as a reference.

Various features and advantages of the invention are set forth in the following claims.

In the following claims, the corresponding structures, materials, effects and equivalents of all means or steps plus functional elements should be considered to include: when combining the contents of specific claims with the elements of other claims, Any structure, material or action used to perform the stated function.

Claims (28)

1. An internal combustion engine assembly comprising: an internal combustion engine comprising a body having at least one cylinder; a piston mounted in said cylinder for reciprocating movement in said cylinder; a piston for injecting fuel into said cylinder; a fuel injector in said cylinder; and a circuit device for generating an injection control signal representing a fuel injection process; a timer for measuring elapsed time; and means for generating an ignition spark in said cylinder based solely on said elapsed time. 2. The internal combustion engine assembly of claim 1, wherein said circuit means includes a microprocessor having an injection output for generating said injection control signal, and said injection output is connected to said timing device for activating the timing signal. 3. The internal combustion engine assembly of claim 2, wherein said circuit arrangement further comprises: means for generating an ignition signal, and an AND gate for receiving said timing signal and said ignition signal. 4. The internal combustion engine assembly according to claim 3, wherein the AND gate generates an ignition current according to the received timing signal and the ignition signal. 5. The internal combustion engine assembly according to claim 4, wherein the ignition spark is generated when the AND gate stops generating the ignition current. 6. The internal combustion engine assembly according to claim 5, wherein the AND gate stops generating the ignition current when the timer stops generating the timing signal. 7. An internal combustion engine assembly comprising: an internal combustion engine comprising a body having at least one cylinder; a piston mounted in said cylinder for reciprocating movement within said cylinder; a piston for injecting fuel into said cylinder The fuel injector in the cylinder, and a circuit for generating an injection control signal representing the fuel injection process, the circuit includes a timer output for generating a timing electrical signal, the timing signal has a signal representing a slave A predetermined duration of the time period elapsed after the injection control signal is generated. 8. The internal combustion engine assembly of claim 7, wherein said timer includes a trigger input, and said circuit includes a microprocessor coupled to said trigger input for energizing generation of said timing signal. 9. The internal combustion engine assembly of claim 8, wherein said circuit includes an AND gate connected to said timer output, said AND gate generating a output signal. 10. An internal combustion engine assembly as claimed in claim 9, wherein said circuit includes means having an ignition output for generating an ignition signal, and said AND gate is also connected to said ignition output. 11. The internal combustion engine assembly according to claim 10, wherein the AND gate generates an ignition current according to the received timing signal and the ignition signal. 12. The internal combustion engine assembly according to claim 11, wherein said spark is generated when said AND gate stops generating said ignition current. 13. The internal combustion engine assembly according to claim 12, wherein the AND gate stops generating the ignition current when the timer stops generating the timing signal. 14. A method of timing the ignition of fuel in an internal combustion engine, said internal combustion engine comprising: a body having at least one cylinder; a piston mounted in said cylinder for reciprocating movement within said cylinder, a connecting a crankshaft mounted to the piston for rotation in accordance with the reciprocating motion of the piston, and an injector for injecting fuel into the cylinder, the method comprising the steps of: generate a jetting process; generating an injection control signal corresponding to the injection process; measuring the time elapsed after said ignition control generation of said injection control signal by generating a timing signal corresponding to said elapsed time; generate an ignition signal; and A firing current is generated in the cylinder when the firing current is determined solely by the timing signal and the presence of the firing signal. 15. The method according to claim 14, characterized in that the step of generating the ignition current further comprises: the step of generating the ignition current only according to the simultaneous occurrence of the timing signal and the ignition signal. 16. The method of claim 14, further comprising the step of generating said ignition current based on crankshaft position when the engine speed is above a predetermined threshold. 17. The method according to claim 14, further comprising the step of generating said ignition current according to the crankshaft position when the operating condition of the internal combustion engine exceeds a given range. 18. The method according to claim 17, characterized in that: the internal combustion engine operating condition is the rotational speed of the internal combustion engine. 19. The method of claim 17, wherein the internal combustion engine operating condition is a throttle position. 20. The method of claim 14, further comprising the step of generating said ignition current based on crankshaft position when one of two engine operating conditions exceeds a given range. 21. The method according to claim 20, wherein the two operating conditions of the internal combustion engine are engine speed and throttle position. 22. A method of operating an internal combustion engine, said method comprising the steps of: operating the internal combustion engine with time-based ignition when engine operating conditions are within a given range; The internal combustion engine is operated with crank angle-based ignition. 23. The method of claim 22, wherein said given range is below a predetermined value. 24. The method according to claim 22, wherein said internal combustion engine operating condition is one of internal combustion engine speed, throttle position, and internal combustion engine load. 25. A method of operating an internal combustion engine, said method comprising the steps of: operating the internal combustion engine with time-based ignition when all of a plurality of operating conditions of the internal combustion engine are within a corresponding given range; When any one of the operating conditions is out of the corresponding given range, the internal combustion engine is operated with ignition based on the crank angle. 26. A method as claimed in claim 25, wherein each given range is below a corresponding predetermined value. 27. The method of claim 26, wherein each operating condition of the internal combustion engine is one of engine speed, throttle position, and engine load. 28. A method of operating an internal combustion engine, said method comprising the steps of: To operate the internal combustion engine with time-based ignition at low speed and low load; Make the internal combustion engine operate with ignition based on crank angle at high load or high speed.

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