Constant-speed multi-pressure fuel injection system for improved dynamic range in internal combustion engine
First Claim
1. A method of controlling a fuel injection system of an internal combustion engine having an engine control module and a fuel pump for supplying pressurized fuel from a reservoir through a fuel line to a plenum in fluid communication with at least one fuel injector controlled by electronic pulse width to inject fuel pulses q to the engine, wherein the fuel injection system includes two fuel by-pass paths operable to divert a portion of the flow of fuel from the fuel line upstream of the plenum back to either the reservoir or an inlet of the fuel pump, each by-pass path having a binary control valve and a flow constraint provided by an orifice of predetermined diameter, a needle-valve-like device, or a device compressing the fuel by-pass path, wherein a first fuel pressure level PH1 in the fuel line is defined when the control valve of only one of the two fuel by-pass paths is closed, a second or the highest fuel pressure level PH2 in the fuel line is defined when the control valves of both fuel by-pass paths are closed, and a third or the lowest fuel pressure level PL in the fuel line is defined when the control valves of both fuel by-pass paths are open, the method comprising the steps of:
- A. setting a fuel pump drive, voltage or current, for operating the fuel pump at a predetermined substantially constant speed;
B. communicating with the engine control module;
detecting engine operating conditions, including but not limited to fuel pressure, engine speed, vehicle speed and throttle position, while the engine is running;
determining the engine fuel demand Q and amount of air flow for the engine, and coordinating operations including throttle valve and air accessories, turbocharger or supercharger, to provide the amount of air flow for adequate fuel/air mix in accordance with the detected operating conditions;
C. calculating the size of the fuel pulses q for satisfying the engine fuel demand Q;
D. detecting the fuel pressure level in the fuel line;
E. determining the electronic pulse width for the fuel pulses q to be sent to the fuel injector at the detected pressure level in accordance with the fuel demand Q; and
F. selecting one of the three pressure levels so that varying pulse width at the selected pressure for fuel pulse q operable within the full range of detected driving conditions for the next fuel injection cycles until the driving condition changes.
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Accused Products
Abstract
A fuel injection system operates under a predetermined substantially constant pump speed and creates multi-pressure levels by diverting the fuel flow. Fuel pressure can be switched from one steady pressure level to another level on-demand instantly. This superimposes and overlaps typical fuel injection events in the linear operating ranges under different pressure levels, significantly increasing the fuel injection dynamic range. The dynamic range is further increased when another predetermined constant pump speed is assigned. Thus, the system saves fuel and reduces exhaust emission in city driving when gas pedal is released including idle. The same system can instantly deliver additional fuel on-demand for extra power beyond engine rating producing a sport-car-like performance.
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Citations
22 Claims
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1. A method of controlling a fuel injection system of an internal combustion engine having an engine control module and a fuel pump for supplying pressurized fuel from a reservoir through a fuel line to a plenum in fluid communication with at least one fuel injector controlled by electronic pulse width to inject fuel pulses q to the engine, wherein the fuel injection system includes two fuel by-pass paths operable to divert a portion of the flow of fuel from the fuel line upstream of the plenum back to either the reservoir or an inlet of the fuel pump, each by-pass path having a binary control valve and a flow constraint provided by an orifice of predetermined diameter, a needle-valve-like device, or a device compressing the fuel by-pass path, wherein a first fuel pressure level PH1 in the fuel line is defined when the control valve of only one of the two fuel by-pass paths is closed, a second or the highest fuel pressure level PH2 in the fuel line is defined when the control valves of both fuel by-pass paths are closed, and a third or the lowest fuel pressure level PL in the fuel line is defined when the control valves of both fuel by-pass paths are open, the method comprising the steps of:
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A. setting a fuel pump drive, voltage or current, for operating the fuel pump at a predetermined substantially constant speed; B. communicating with the engine control module; detecting engine operating conditions, including but not limited to fuel pressure, engine speed, vehicle speed and throttle position, while the engine is running; determining the engine fuel demand Q and amount of air flow for the engine, and coordinating operations including throttle valve and air accessories, turbocharger or supercharger, to provide the amount of air flow for adequate fuel/air mix in accordance with the detected operating conditions; C. calculating the size of the fuel pulses q for satisfying the engine fuel demand Q; D. detecting the fuel pressure level in the fuel line; E. determining the electronic pulse width for the fuel pulses q to be sent to the fuel injector at the detected pressure level in accordance with the fuel demand Q; and F. selecting one of the three pressure levels so that varying pulse width at the selected pressure for fuel pulse q operable within the full range of detected driving conditions for the next fuel injection cycles until the driving condition changes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. The method of creating an Eco-Friendly engine using smaller engine for improved fuel economy in highway driving and lowered emissions in city driving, and still able to produce instant super power on-demand, wherein the fuel injection system has at least two fuel by-pass lines to selectively divert portions of fuel from the main fuel line not entering the plenum, through one or two fuel by-pass paths, back to the inlet of fuel pump or reservoir, instantly creating at least three stable pressure levels, namely PH2, PH1, PL, wherein PH2>
- PH1>
PL, comprising the following operating steps;setting fuel pump at a pre-determined substantially constant speed before, during and after the pressure switching; communicating with an Engine Control Module ECM, wherein ECM receives sensor signals on engine operating parameters, including engine speed, driving conditions, vehicle speed, and changes of gas pedal positions, determining the engine fuel demand Q, and the proper amount of air supply required for an adequate air/fuel mix, calculating the size of injected fuel pulses q needed at the engine speed in response to the engine fuel demand Q , programming the controller to choose one of the three pressure states PH2, PH1, or PL so that varying the pulse width at the chosen pressure level to inject fuel pulses q covers a full operating range of the vehicle at the driving conditions, and choosing the pulse width at the detected pressure level to inject fuel pulse q to the engine. - View Dependent Claims (15)
- PH1>
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16. A method of creating dual pressure levels in an engine'"'"'s fuel injection system including a fuel pump set to run at a predetermined substantially constant speed which is independent of the engine speed for sending pressurized fuel from a fuel tank through a main fuel line to a fuel plenum in fluid communication with at least one fuel injector, at least one fuel by-pass line forming a fuel recirculation loop for returning pressurized fuel from a location upstream of the plenum to either the fuel reservoir or the inlet of the fuel pump to stabilize the fuel pressure level in the main fuel line, the at least one fuel by-pass line including a flow constraint of a first fixed flow constraint value, the at least one fuel by-pass line being selectively opened/closed by a binary valve element which is either opened to establish a fuel pressure level of PL to the plenum or closed to increase the fuel pressure level to PH, wherein the pulse width of injected fuel pulses can be varied under PL in accordance with one driving condition and varied under PH in accordance with another driving condition to widen the fuel injection dynamic range, the method comprising the step of changing the flow constraint value to a second fixed flow constraint value including replacing a different flow constraint element, such that the fuel pressure assumes a different level PL1 when the valve element is in its opened position, while maintaining the higher pressure level PH unchanged when the valve element is in its closed position.
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17. A method of creating dual pressure levels in an engine'"'"'s fuel injection system including a fuel pump set to run at a predetermined substantially constant speed which is independent of the engine speed for sending pressurized fuel from a fuel tank through a main fuel line to a fuel plenum in fluid communication with at least one fuel injector, at least one fuel by-pass line forming a fuel recirculation loop for returning pressurized fuel from a location upstream of the plenum to either the fuel reservoir or the inlet of the fuel pump to stabilize the fuel pressure level in the main fuel line, the fuel by-pass line including a flow constraint of fixed flow constraint value, the at least one fuel by-pass line being selectively opened/closed by a binary valve element which is either opened to establish in the main fuel line a fuel pressure level of PL or closed to increase the fuel pressure level to PH, wherein the pulse width of injected fuel pulses can be varied under PL in accordance with one driving condition and varied under PH in accordance with another driving condition, the method comprising the step of re-setting the fuel pump speed to a different predetermined substantially constant speed which is independent of the engine speed such that the fuel pressure in the main fuel line instantly assumes different levels PL1 and PH1 when the valve element in the at least one fuel by-pass line is opened or closed, respectively.
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18. A method for regulating the pressure in a constant speed multi-pressure fuel injection system for an engine, the method comprising the steps of:
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A. setting a fuel pump to run at a predetermined substantially constant speed which is independent of the engine speed for sending pressurized fuel from a fuel tank through a main fuel line to a fuel plenum in fluid communication with at least one fuel injector;
at least one fuel by-pass line forming a fuel recirculation loop for returning pressurized fuel from a location upstream of the plenum to either the fuel reservoir or the inlet of the fuel pump to stabilize the fuel pressure level in the main fuel line, the at least one fuel by-pass line including a binary valve element and a flow constraint of fixed flow constraint value,B. receiving a signal from a gas pedal sensor indicating a desired engine power; C. determining if the signal meets a predetermined engine power request threshold; D. in response to the signal meeting the pre-determined threshold in step C, closing a fuel bypass line from fuel line to fuel tank to raise the fuel pressure in the fuel injection system; and E. maintaining the closed fuel bypass line in a closed state while the predetermined engine power request threshold is met. - View Dependent Claims (19, 20, 21)
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22. A method for regulating the pressure in a constant speed multi-pressure fuel injection system for an engine of a vehicle, the method comprising the steps of:
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A. operating a fuel pump at a substantially constant speed which is independent of engine speed for sending pressurized fuel from a fuel tank through a fuel line to fuel rail and then to a fuel injector, B. providing a fuel by-pass line forming a fuel recirculation loop for returning pressurized fuel from a location upstream of the plenum to either the fuel reservoir or the inlet of the fuel pump to stabilize the fuel pressure level in the main fuel line, the fuel by-pass line including a flow constraint of fixed flow constraint value, the at least one fuel by-pass line being selectively opened/closed by a binary valve element which is either opened or closed, and C. providing a manual override accessible to a driver of the vehicle actuable to open the valve element to instantly lower the fuel pressure.
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Specification