WO2006076407A1

WO2006076407A1 - Control system combining a continuously variable transmission or an infinitely variable transmission and an electronic throttle control

Info

Publication number: WO2006076407A1
Application number: PCT/US2006/000940
Authority: WO
Inventors: Adam R. Berman
Original assignee: Berman Adam R
Priority date: 2005-01-11
Filing date: 2006-01-11
Publication date: 2006-07-20

Abstract

A control system combining a CVT/IVT and an electronic throttle control to improve the efficiency of an internal combustion engine, while reducing harmful emissions, and simultaneously improving acceleration performance and control over the power output of the engine. The system comprises a CVT/IVT with a wide band of gear ratios, an electronic throttle control, a fuel injection system that uses a range of air/fuel mixtures, and optionally, a variable camshaft mechanism, an optional exhaust gas valve, combined with a control system that manages these components. The power regulation system combines vehicle speed and gas peddle depression angle, and controls the CVT/IVT final gear ratio.

Description

CONTROL SYSTEM COMBINING A CONTINUOUSLY VARIABLE TRANSMISSION OR AN INFINITELY VARIABLE TRANSMISSION AND

AN ELECTRONIC THROTTLE CONTROL Field of the Invention The present invention relates generally to power regulation systems and more specifically it relates to a control system combining a continuously variable transmission or an infinitely variable transmission (CVT/IVT) and an electronic throttle control for improving the efficiency of the internal combustion engine. Description of the Related Art Engine power regulation systems have been in use for many years.

Typically, the power of the internal combustion engine is controlled by regulating airflow into the engine by using a throttle.

While the throttle may be suitable for the particular purpose of controlling the power produced by the engine, it is not as suitable for improving the efficiency of the internal combustion engine. In fact, the throttle is widely known to be responsible for greatly reducing the efficiency of the internal combustion engine. The main problem with conventional power regulation systems is the efficiency loss incurred through the use of the throttle, especially when that throttle is closed. The throttle provides a parasitic drag on the engine, both lowering the volumetric efficiency and requiring work in order to pump air into the engine and pump the waste gases out of the engine. Another problem is that the transmissions of existing power train systems are not setup to provide power in linear proportion to the gas pedal depression angle under widely varying conditions of load. Also, another problem is that the engine is inefficient when the car is coasting. Finally, existing power train systems do not maintain the vehicle at maximum power when the gas pedal is fully depressed. Summary of the Invention

The control system combining a CVT/IVT and electronic throttle control according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of improving the efficiency of the internal combustion engine.

The general purpose of the present invention, which will be described in subsequently greater detail, is to provide a new control system combining a

CVT/IVT and electronic throttle control that has many of the advantages over the power regulation systems of the prior art.

To attain this, the present invention generally comprises a specially designed CVT/IVT with a wide band of gear ratios, an electronic throttle control, a fuel injection system that uses a range of air/fuel mixtures, a variable camshaft mechanism, an exhaust gas valve (optional), and a control system that manages these components. The continuously variable transmission (CVT/IVT) includes all transmissions that provide a continuous band of gear ratios, including both those offering only forward gears (the continuous type) and those offering a range of both reverse and forward gears (the infinite type.)

The fuel injection system is mechanically similar to prior art fuel injection systems but is controlled by a fuel map with three distinct regions of control. The variable camshaft mechanism may be any type of cam system that allows for different lift, timing, or phasing of the camshaft or some combination of thereof to maintain a broad torque and allow for adequate volumetric efficiency at high and low engine speeds. The exhaust gas valve may be any prior art exhaust gas valve used to recirculate or bleed exhaust gases back through the intake manifold to lower power output and engine temperatures during leaner conditions. The system does not contain an exhaust gas recirculation (EGR) valve, but rather uses the variable cam mechanism to phase the intake camshaft and create EGR under partially closed throttle conditions at low engine speeds. Of course, an EGR valve may be used in place of such variable cams or in addition thereto. An electronic throttle control is an electronic bypass used to operate the throttle. The input for this device is the gas pedal depression angle. The resulting output is the degree that the throttle is opened to allow air to flow into the engine. The power regulation system combines two inputs, vehicle speed and gas peddle depression angle, and has one output, the CVT/IVT final gear ratio.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.

The invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated. Brief Description of the Drawings

Various other objectives, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:

FIG.l is Ideal Otto Cycle.

FIG.2 is Actual Otto Cycle under Wide Open Throttle Conditions.

FIG.3 is Actual Otto Cycle under Closed Throttle Conditions.

FIG.4 is Engine Speed vs. Accelerator Depression Angle. FIG.5 is a Dyno Graph of Power & Torque vs. Engine Speed (w/Crowds).

FIG.6 is a Dyno Graph of Gram Specific Fuel Consumption vs. Engine Speed (w/Crowds).

FIG.7 is a well-known power regulation mechanism for a CVT/IVT vehicle with electronic throttle control, similar to the preferred embodiment.

FIG.8 is a typical Performance Map. It is an example of how current and prior art CVT/IVT systems operate in conjunction with throttle control to maximize efficiency using the same type performance map used in manual transmission vehicles. FIG.9 is a graph of the relationship between air/fuel ratio, power, efficiency, and various emissions byproducts.

FIGlO is the present invention's control relationship between engine speed, air/fuel ratio, and exhaust gas recirculation

FIG.l 1 is the present invention's Performance Map termed the "Triple Torque Peak".

FIG.12 describes the proposed operation of the present invention's control method in a hybrid vehicle.

FIG.13 describes the variable camshaft operation under high RPM conditions. FIG.14 describes the variable camshaft operation under low RPM conditions, and how this operation is used to generate exhaust gas recirculation. Detailed Description of the Invention

Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, the attached figures illustrate a control system combining a specially designed CVT/IVT with a wide band of gear ratios, an electronic throttle control, a fuel injection system that uses a multitude of air/fuel ratios, a variable camshaft mechanism, an exhaust gas valve, and a control system that manages these components. The continuously variable transmission (CVT/IVT) includes all transmissions that provide continuous band of gear ratio shifts. The fuel injection system is mechanically similar to prior art fuel injection systems but is controlled by a fuel map with three distinct regions of control. The variable camshaft mechanism may be any type of cam system which allows for different lift, timing, or phasing of the camshaft or some combination of thereof to maintain a broad torque and allow for adequate volumetric efficiency at high and low engine speeds. The exhaust gas valve may be any prior art exhaust gas valve used to recirculate or bleed exhaust gases back through the intake manifold to lower power output and engine temperatures during leaner conditions. An electronic throttle control is an electronic bypass used to operate the throttle. The input for this device is the gas pedal depression angle.

The resulting output is the degree that the throttle is opened to allow air to flow into the engine. The power regulation system combines two inputs, vehicle speed and gas peddle depression angle, and has one output, the CVT/IVT final gear ratio. The continuously variable transmission (CVT/IVT) includes all transmissions that provide continuous band of gear ratio shifts. The purpose of the CVT/IVT is to provide a broad range of final gear ratios. The range of this CVT/IVT shall be sufficient, and most likely greater in terms of swing in mechanical advantage from the lowest to the highest gear. This will ensure that the vehicle can generate the maximum amount of power from the engine at low speeds when it is in its lowest gear. It will also ensure that the vehicle can operate at the maximum possible efficiency. The engine would spin at low speed with the throttle opened sufficiently to create a very small amount of power sufficient to keep the engine idling. Achieving this feat at a very high vehicle speed would require a high gear at the other extreme in terms of mechanical advantage. Most manual and automatic transmissions typically have a range in mechanical advantage from the lowest to the highest gear between four and five. CVT/IVTs typically have a greater range in mechanical advantage from the lowest to highest gear. Presently, the greatest range in mechanical advantage from the lowest to highest gear for a CVT/IVT is six to one. The present invention requires a CVT/IVT with a broad range in mechanical advantage to perform its function. Thus, CVT/IVTs with a range in mechanical advantage from the lowest to the highest gear that is greater than eight are preferred. The CVT/IVT used as part of the present invention may be any type of continuously or infinitely variable transmission. Acceptable types of CVT/IVTs include belt, pulley, worm gears, and others.

The fuel injection system is mechanically encompassed by prior art technology to deliver the fuel to the engine. The control map, however, which electronically is used to control the fuel injection is significantly different from that of the prior art in that fuel ratio is not linked to throttle position, but rather the crankshaft pulse that measures engine speed (RPM). The air/fuel ratio map is divided into three distinct regions; low engine speed (idle to 1500 RPM), mid-range speed (1500-4000 RPM), and high engine speed (4000-5000+ RPM). The exact range of engine speeds contained in each of the three distinct regions will depend upon the engine and should be determined during dynamometer tuning for the particular engine employed. The ranges listed here are from a sample prototype of a modified Ford F-150 5.4L Triton engine. At low engine speed, the fuel injection system runs the engine lean (low fuel to air ratios.) At mid engine speeds, the air/fuel mixture is maintained at the stoichiometric ratio. At high RPMs, the injection system runs rich.

The variable camshaft system is preferred for the non-hybrid control system, but is not absolutely necessary to the present invention. Variable valve timing, through adjusting either lift, duration, or phasing of the camshaft serves the purpose of maximizing volumetric efficiency and overall engine efficiency throughout a broader range of engine speeds. The variable camshaft timing system phases the intake stroke to advance intake events during low engine speeds. A variable camshaft timing mechanism, serves the particular purpose in this invention, in allowing the engine to operate more efficiently at low RPM conditions, where the engine will spend a bulk of its operating time in comparison to prior art engines, while still allowing good efficiency and horsepower at high RPM conditions. If a variable camshaft engine is unavailable to the engine manufacturer, a mild camshaft with less duration that is optimized for low engine speed use is recommended, since the engine operation using this invention will run more often at low engine speeds in comparison to prior art technology. If a variable valve timing mechanism is selected, any such prior art mechanism may be employed.

An exhaust gas valve may also be desirable for use in the non-hybrid control system for use only during idle and low RPM conditions. The exhaust valve may be used to lower power output, improve exhaust emissions, lower engine temperature and to specifically provide better control for engine operation under these conditions. The system of the present invention tested to date does not contain this EGR valve and rather uses the variable camshaft to create large overlap at top dead center. This is done at low engine speeds under closed throttle conditions to use the vacuum created in the intake manifold during these conditions to intentionally induce exhaust gas recirculation.

It is considered difficult to take a large engine with great displacement under wide open throttle and still provide low power outputs at high efficiency, even at low RPM conditions. The use of the exhaust gas valve, in conjunction with the specific use of the fuel injection system to run lean at low engine speeds, shall provide much better control and allow to the driver to reach these low power output conditions as well as idle engine speeds at significantly higher efficiencies with lower exhaust gas emissions, particularly nitrous oxides, than any other prior art technology. It is understood by those of ordinary skill that the brake specific efficiency of today's naturally aspirated engines averages about 20% efficiency across the range of operation including all engine speeds and throttle conditions, depending upon the size of the engine. It is also known that throttling losses account for 10- 15% of the total loss in efficiency of these engines. Therefore, it is estimated that the theoretical gain by eliminating this throttle loss is a gain 50-75% gain in efficiency of today's engines. This loss is offset by the fact that this invention runs at low engine speed more often than prior art technology. Since it is known that engines run less efficiently at low engine speeds due to coolant losses, among other things under these conditions, the actual gain in efficiency is known to be somewhat less than the theoretical 50-75% gain. Initial testing indicates that the gain in efficiency through the present invention is approximately 35%. The exhaust gas valve, in conjunction with fuel injection map and variable valve timing serves the specific purpose of recovering the maximum amount of loss from this 50-75% theoretical gain while simultaneously reducing emissions more than any other prior art technology. While the specific design of a conventional exhaust gas valve is not considered to fall under the scope of this invention, the specific control method and pattern, especially in conjunction with the other components, is unique. The exhaust gas method used on the prototype system where the variable timing control induces EGR is however unique, especially when used in conjunction with the rest of invention described herein.

An electronic throttle control is an electronic bypass used to operate the throttle. The input for this device is the gas pedal depression angle. The resulting output is the degree that the throttle is opened to allow air to flow into the engine. The electronic throttle control used in the present is also an electronic bypass used to operate the throttle. The input for this device is the gas pedal depression angle. The resulting output is the degree that the throttle is opened to allow air to flow into the engine. One purpose of this electronic throttle control is to provide a linear throttle response, similar to the electronic throttle controls used in the prior art. The difference between the electronic throttle controls of the prior art and one used in the present is the manner in which it is controlled, which shall be described later herein. Any electronic throttle control system may be used for the implementation of the present invention.

The power regulation system combines two inputs, vehicle speed and gas peddle depression angle, and has as its output, the CVT/IVT final gear ratio. The final output is the power produced by the engine at the most efficient setting. The purpose of the power regulation system is to bypass the use of the throttle and parasitic drag. The power regulation system contains a pre-programmed set of combinations of throttle angles and gear ratio for each specific output of power required, such that there is one combination of engine speed (RPM) and throttle position angle that is achieved for each specific power output. The engine speed and degree that the throttle is opened remains constant at a level specific for each engine. The function of the power regulation system has been described herein and does not vary. The structure of the control system in terms of circuitry and logic can be programmed in any way to achieve the power regulation system's functional purpose.

The power regulation system reads the gas peddle depression angle and determines the power that the driver requests. The power regulation system then determines the most efficient engine speed and throttle position angle dependent on the power required. The electronic throttle control fixes the throttle position angle as the power regulation system requires. The power regulation system then reads the vehicle speed and selects the appropriate gear ratio in the CVT/IVT to match the desired engine speed to the present vehicle speed. The recommended interconnection is described within this submission, although all variations in the way these devices are connected is acceptable and within the scope of the invention, so long as the functional purpose of the power regulation system that is described herein is maintained. An example of such a power regulation mechanism is shown in Figure 7. Some of the losses in efficiency of the internal combustion engine include the coolant losses, frictional losses, air intake and expulsion pumping losses, difference between the Otto Cycle and the Carnot Cycle in efficiency, and the losses present in the Carnot Cycle.

The throttle is the intentional restriction that is placed in the intake of the internal combustion engine to reduce the power produced by the engine and to control the vehicle. This invention mitigates the pumping loss associated with today's internal combustion engine by eliminating the use of the throttle.

Figures 1 through 3 illustrate the pumping losses present in an internal combustion engine. Note that from Figure 1, there is no reduction in pressure during the intake stroke (wasted energy) in an attempt to pull air into the engine. Also there is no increase in pressure spent from stage 1 to stage Ia to push the exhaust gases out of the engine. This is contrasted with the actual Otto Cycle shown in Figure 2 with wide open throttle and in Figure 3 showing the actual Otto Cycle with the throttle closed. Note the wasted energy in the form of pumping losses in the actual Otto Cycle (Figure 2), and is exaggerated in the case of the closed throttle (Figure 3). Most of the pumping losses are caused by the throttle. I propose to regulate the power of the IC engine with gear ratios to reduce the engine speed rather than using a throttle. By using a CVT/IVT, one can use an infinite number of gear ratios to choose any engine desired. By using an electronic throttle control, we can replace the cable that connects the gas pedal to the butterfly valve (or any other type of throttle), and use several inputs that are used in the engine computer.

Input 1 - Vehicle Speed (MPH or other) Input 2 - Acceleration Depression Angle (Degrees depressed or other)

The faster the car is moving, the higher the gear that is used (less mechanical advantage). The more the accelerator is depressed, the lower the gear that is chosen (more mechanical advantage). Figure 4 is the graph of Accelerator Depression Angle vs. Engine Speed for a theoretical vehicle. The correlation is not necessarily linear as the rise in power produced for each additional increase in engine speed is riot linear.

Although avoiding the use of the throttle at all times with a CVT/IVT or higher gears will significantly improve fuel efficiency and falls within the scope of this invention, I recommend programming the power regulation system from dyno test results for that specific engine. This programming can also be done through other means such as computer simulations and these methods shall fall under the scope of the invention as well.

Figure 5 is a dynamometer graph from a theoretical engine and will obviously vary depending on the engine. It is often known as a "crowd" graph since it is crowded with the results of power and torque vs. engine for not only wide open throttle but also for varying degrees of throttle aperture size. The purpose of this graph is to illustrate that it is possible to determine the torque and power for each RPM and throttle position. This graph is also used to point out that there are multiple possible combinations of engine speed and throttle position angle that can produce the same amount of power.

In today's engines, the driver has freedom in selecting more than one possible combination of engine speed and throttle position angle that produce identical power. Although multiple settings may produce identical power or acceleration results, all possible combination are not equally efficient. Therefore, the most efficient combination for a give amount of power should be selected. Figure 6 is a graph of gram specific fuel consumption vs. engine speed for a theoretical engine. It illustrates several points. One point is that, for a given engine speed, opening the throttle results in a lower gram specific fuel consumption (better efficiency). It also reflects that the most efficient condition for a given throttle position angle usually falls around the maximum torque point, though this does not have to be the case. More importantly, the graph shows that for a given throttle position, efficiency falls off at both low and high engine speeds.

The power regulation works by cross-referencing Figure 5 and Figures 6 to select points of lowest gram specific fuel consumption at each power output. The control system is then programmed to produce the highest power or greatest accelerating condition when the gas pedal is fully depressed, less power as the gas pedal is relieved, and down to a zero net power condition when the driver is completely off the gas pedal. The control system would then alter the gear ratio depending on the engine speed and the required amount of power or acceleration depending upon the vehicle speed.

Figure 8 is an example of how the prior and current art function to maximize fuel economy on an internal combustion engine containing a CVT/IVT. Notice the programming of the engine is identical to that of an engine with a manual transmission. The difference in.the control of these two systems is that the CVT/IVT operates to maintain the optimum curve for the performance map (Fig 8). A manual transmission can theoretically operate at any point on the performance map (any combination of RPM and throttle position). One should note that that for every possible power output, there is one optimum combination of RPM and throttle position. This is reflected by the curve shown in Figure 8. Manual transmissions are usually more efficient than continuously variable transmissions in terms of losses incurred through the drivetrain, but CVT/IVTs are much better at maintaining this optimum curve.

Another set of points that must be noted to better understand the invention described herein is the causes of the various efficiencies shown in the performance map in Figure 8. We can see that the area lowest brake specific fuel consumption is about 40% of the maximum engine speed (RPMs) and at 80% towards the top of the torque peak. This area of the performance map is known as the sweet spot, because it is the most efficient operating point for that specific internal combustion engine. At low RPM conditions, lower efficiency results from greater losses to the coolant, whereas at high RPM conditions, lower efficiency results from increased frictional losses. Above the 80% torque mark, lower efficiency is the result of fuel enrichment used to generate additional power.

Fuel enrichment in this control system method is determined not by throttle position, since it is desirable to eliminate the reduction in efficiency incurred by the throttle, but by RPM position. In a manual transmission vehicle, one might be at wide open throttle at 2000 RPM (a relatively low engine speed) and need the maximum amount of torque available. In this particular case, it made sense to have fuel enrichment at wide open throttle, independent of engine speed. However, for this particular control system method, greater power is attained at high RPM through downshifting. Therefore, fuel enrichment only occurs at high engine speeds. Also, in addition to fuel enrichment, leaning of the air/fuel ratio at low RPMs serves the specific purpose of lowering power at low RPMs to increase control of the engine when low power output is requested. It also increases engine efficiency while lower exhaust gas emissions.

Figure 9 shows the relationships between air/fuel ratio, torque, specific fuel consumption, and concentration of various exhaust gases. Figure 9 serves as in important piece of background information to understand the specific manner of control employed in Figure 10. This results in a triple torque peak shown in Figure 11. It shall be noted that the air/fuel ratio of 17.5:1 falls beyond the lean ratio of lowest specific fuel consumption. As shown in Figure 9, the air/fuel ratio between the selected value of 17.5 and the stoichiometric value of 14.68, which produces the lowest specific fuel consumption, also produces very high nitrous oxide amounts which are very undesirable. The choice of 17.5 for the air/fuel ratio is a compromise of selecting the best combination of efficiency and emissions. The lower torque at wide open throttle produced in this case is actually desirable in this particular case while undesirable for prior art mechanisms. While prior art technology seeks to run rich to produce high torque at low RPMs for better acceleration, the present invention simply selects the gear ratio and air/fuel ratio most appropriate for delivering the specific amount of power requested. If maximum power was requested, the engine would simply stay at wide open throttle while the transmission would hold the engine at its most powerful RPM condition. It would be uneconomical to ever be at a low RPM in this condition. Furthermore, the low torque produced through using this lean ratio, while lowering the power produced at the specific RPM, happens to reduce harmful emissions while simultaneously allowing the driver better control to get the lower power requested to coast or even slowly decelerate. As an example, suppose that 12 hp was requested by virtue of the position of the gas peddle depression. Also, suppose that 8 hp was produced at the given RPM condition instead of 12 hp through a combination of enleanment and exhaust gas recirculation. In such a case, the transmission would shift to the higher RPM condition to produce the requested 12 hp. Also, since the power was produced at a slightly higher RPM (closer to the sweet spot), where coolant losses are lessened, the high air/fuel ratio, in conjunction with the exhaust gas recirculation, in addition to reducing emissions, also happens to mitigate the effect of coolant losses, which explains the exact purpose of the specific means of control for the fuel injection system and the exhaust gas valve. Coincidently, since we are idling the engine with exhaust gas recirculation and a high air/fuel ratio, we can open the throttle more during idle conditions so that the present invention allows an engine to idle more efficiently with fewer emissions than any other non-hybrid prior art system, including those that use a CVT/IVT. It is also important to note that exhaust gas recirculation is used more often at low RPMs. Figure 11 thus illustrates the control system method for a sample engine described herein and is in contrast to Figure 8 which shall be considered prior art. As illustrated in Figure 11, the sweet spot is shifted to wide open throttle at a mid-range engine speed. The ideal configuration will use EGR in this manner; however, this design also may be configured for an engine that does not have exhaust gas recirculation, as will be the case for the prototype engine. In the case without EGR, throttle position would have to be slightly more closed at low power demand to produce the same power produced in the ideal configuration. The configuration of engine programming without EGR has thus been described and falls within the scope of this invention.

Further fuel efficiency improvement can be gained through using this control system method in conjunction with a hybrid vehicle system. This is not only an improvement in efficiency over just using the aforementioned control system method, but also an improvement in efficiency above prior art hybrid vehicle systems. Under this control system method, shown in Figure 12, the engine only operates at the sweet spot. Note that this is the exact same performance map shown in Figure 11, with the exception that the lower efficiency settings are not used. The engine runs exclusively at wide open throttle at the first torque peak. In order to describe an example of this control system method for a sample vehicle, consider a 3.0L V6 210hp engine (just as an example). For this particular engine, the sweet spot occurs between 90-120 horsepower at wide open throttle using the same method shown in Figure 11. In this particular vehicle, a 90 horsepower motor accelerates the vehicle when the driver requests a power demand between 0 and 90 horsepower through depressing on the accelerator. When the driver requests this range of power, the motor accelerates the vehicle exclusively. When the driver requests between 90 and 120 horsepower for this sample vehicle, only the engine provides the required power. When the driver requests from 120 horsepower up to 210 horsepower, the engine provides 105-120 horsepower and the motor provides the rest. For this particular example, we will consider 105 horsepower to be the most efficient condition for this particular engine. This method continues until the battery contains 25% of maximum power. When this occurs, and the driver requests between 0 and 90 horsepower, the engine runs at 105 horsepower and an alternator charges the battery until its power is restored to 75% or slightly less so that regenerative braking can additional recharge the battery without overcharging or discharging extra power. This hybrid control system method differs from prior art hybrid systems and shall fall under the scope of this one entire control system method.

Figures 13 and 14 describe a novel approach to exhaust gas recirculation where the variable camshaft system serves the purpose of both varying the camshaft as well as inducing exhaust gas recirculation. In this type of variable camshaft system where the intake camshaft can be advanced under low engine speeds to increase engine efficiency under these conditions, the same variable camshaft can also be used to induce EGR at these low engine speeds during partial or complete throttling conditions. This approach is derived from the accidental or undesirable effect of exhaust gas generation on race cars that have a restrictor plate to limit the race car engine's horsepower. Normally, the wide overlap at top dead center in an unrestricted race engine is used to create a scavenging effect. When this occurs, the exiting of exhaust gases actually sucks intake gases into the engine during this overlap which raises the volumetric efficiency of the engine. This effect is also similar to emptying an above ground waterbed with a hose filled with water. If one end of the hose is thrown out of a window at the same time the other end of the hose is inserted into the waterbed, the water rushing out of one end of the hose creates suction, pulling out all of the water out of the waterbed. While emptying a waterbed does not fall under the scope of this invention, this process is useful in understanding the concept of scavenging. While scavenging occurs in a race engine with wide overlap at top dead center without a restrictor plate, the opposite occurs if a restrictor plate is added to this engine. The low pressures inside the intake manifold actually suck exhaust gases back into the intake manifold in this particular case. Although this is undesirable in a race engine, especially at high RPM conditions, it is exactly what we wish to occur under low engine speeds for this invention. And since a restrictor plate is very similar to a throttle in the effects that they create, a throttle can be used with the wider overlap created with the variable valve control at low engine to induce the exhaust gas recirculation that we want. Figures 13 and 14 show how this occurs.

Note that a vehicle which operates efficiently at low engine speed has more potential for fuel efficiency savings using this invention for two reasons. Firstly, the engine would spend more time at lower speeds. In addition, in this type of engine a greater potential for gains in efficiency exists at a given power output requirement with the throttle open wider and with the engine spinning slower. Although an engine that operates efficiently at low engine speed would have the most gains in efficiency, all engines would achieve some gains in efficiency with this use of this invention. Therefore, engine selection, as long as it uses the power regulation described above, shall also fall within the scope of this invention.

As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.

With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

I claim: 1. An internal combustion engine system having improved fuel efficiency, reduced harmful emissions, and improved acceleration comprised of sensors for vehicle speed and accelerator angle, a CVT/IVT, an electronic throttle control, a fuel injection system capable of controlling air to fuel mixture ratios, and an electronic control for controlling the final gear ratio of the CVT/IVT in accordance with vehicle speed and accelerator angle in a manner to minimize brake-specific fuel consumption. 2. The engine system of Claim 1 wherein the control of the final gear ratio is controlled to minimize variations in throttle settings, while maintaining the throttle in an open position as much as possible. 3. The engine system of Claim 1 wherein a variable cam system is employed to provide exhaust gas recirculation by increasing the overlap present between the intake and exhaust valves at low engine speeds and partially open throttle conditions. 4. The engine system of Claim 1 wherein the gear ratio range of operation (determined by low gear ratio divided by high gear ratio) of the CVT/IVT used to control the engine speed exceeds 8. 5. A gasoline-electric hybrid engine system having improved fuel efficiency, reduced harmful emissions, and improved acceleration comprising sensors for vehicle speed and accelerator angle, a CVT/IVT, an electronic throttle control, a fuel injection system capable of controlling air to fuel mixture ratios, and an electronic control for controlling the final gear ratio of the CVT/IVT in accordance with vehicle speed and accelerator angle in a manner to minimize brake-specific fuel consumption. 6. The engine system of Claim 5 wherein the control of the final gear ratio is performed to minimize variations in throttle settings, while maintaining the throttle in an open position as much as possible. 7. The engine system of Claim 5 wherein the engine operates in a more narrow band than other prior art engine systems, where low power demand is provided solely by the battery, medium power demand is provided solely by the engine at its most efficient RPM range near maximum torque, and high power demand is provided using the combination of the medium power demand provided solely by the engine in conjunction with the battery.