STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of motor vehicle control systems. More specifically, the invention comprises a module for overriding an automatic engine start-stop feature included in many modern vehicles.

2. Description of the Related Art

Increased fuel economy is a common goal in the field of motor vehicles. Government regulatory entities are mandating a steady average increase in economy for each manufacturer. A good example of this trend is the “Euro 5” standard promulgated in the European Union. The Euro 5 standard includes an enhanced driving model intended to make economy and emissions testing more closely resemble actual driving conditions. One of its components is an increased idling time—reflecting the time a vehicle sits still in traffic.

Many vehicles now incorporate automated “start-stop” functions. The goal of this feature is to switch off an internal combustion engine when it is not needed—such as when a vehicle is idling at a traffic control device. The system automatically restarts the internal combustion engine once the need for power is detected. Consider an example for a vehicle having an automatic transmission: A driver encounters a red light and brakes to a stop. After the vehicle has remained stationary for a short interval—such as five seconds—the automatic engine control unit shuts off the internal combustion engine. The engine remains off while the vehicle sits stationary and the driver keeps the brake applied.

Then the traffic light turns green. The driver lifts his or her foot off the brake pedal and begins moving it toward the accelerator. As soon as the brake pedal returns to the “off” position, the automatic start-stop system commands a restart of the internal combustion engine. For a well-designed system, the engine is ready to deliver power by the time the driver's foot reaches the accelerator.

Additional features are typically needed to ensure the smooth operation of an automated start-stop system. For example, there will be instances where the internal combustion engine is needed during periods where the vehicle is stationary and the brake is applied. The engine may be needed to: (1) Power the heating or cooling systems; (2) Provide hydraulic pressure to the power steering system; and/or (3) Provide charging current to a depleted battery. Thus, a sophisticated start-stop system may use a processor to “consider” these and other factors before triggering an automated engine stop.

Those skilled in the art will know that vehicles incorporating automated start-stop systems often include many other modifications and enhancements to make the systems operate reliably. A discussion of these additional systems is beyond the scope of this disclosure. Suffice it to say that modern manufacturers have incorporated these modifications to produce generally reliable systems. These systems do produce a measurable increase in fuel economy, with independent testing demonstrating an improvement between three and seven percent. For a vehicle spending a large amount of time in stop and go traffic, the increase can be even greater.

Nevertheless, some owners do not like the automated start-stop feature. A first reason is the fact that the long-term effects on vehicle endurance and reliability are not yet well understood. The manufacturers contend that a well-designed system will not have a negative effect, but the systems have not been around long enough to fully demonstrate this assertion. Secondly, many owners do not like the perceived lag in available power (which in some instances may be quite real). As an example, a driver may stop at an intersection and need to accelerate rapidly to merge into traffic. An automated start-stop system will often shut down the engine in this circumstance. Even if the automated system is highly reliable, it is unsettling for a driver contemplating a high speed merge to feel the engine “die.” For these reasons, manufacturers often provide a manual override for the automated start-stop feature.

A good example of this manual override is found in vehicles manufactured by the Ford Motor Corporation. Ford provides a manual override button near the instrument cluster. The user simply presses this button to deactivate the automated start-stop feature. The start-stop feature will remain “off” until the user shuts down and exits the vehicle. However, the next time the user reenters the vehicle and starts it, the automated start-stop feature will revert to the “on” state. In other words, while the manual override feature is provided, the user must activate it every time the vehicle is driven.

In other instances the manufacturer simply provides no manual override function at all. The automated start-stop feature remains active in those cases and there is nothing the user can do about it. There exists a demand for a device allowing a user to selectively turn off the automated start-stop feature, and thereafter have it remain off. The present invention provides such a solution.

Those skilled in the art will understand how digital communications occur within modern motor vehicles. However, it is nevertheless helpful to provide an exemplary top-level description of these systems. Modern vehicles include many separate processors running simultaneously. These units control the engine, the transmission, the heating and cooling systems, etc. Different manufacturers arrange these control systems in different ways. However, many now use a Controller Area Network (“CAN”) for communications. A CAN bus connects the components.

The general implementation of digital control uses a CAN data bus distributed throughout the vehicle. The data bus sends digital messages (such as the state of a controlling switch) that may be received by any component connected to the bus. The data bus does not provide electrical power to the actuating components such as a seat motor (though it may supply some low level power to other devices). Power is supplied separately to the actuating components through a power distribution harness.

As far as the user is concerned, the new digital paradigm often appears to function just like the old analog paradigm. As an example, if the user wishes to roll down a window, he or she still presses a designated button and the window rolls down. However, the button is not “making” an analog circuit and is not serving as part of the path for the electrical current driving the window motor. Instead, both the button and the motor are connected to a data bus, and the data bus is likely connected to a controlling microprocessor (sometimes called a “Body Control Unit” or “BCU”). The switch sends a digital message specifying its identity and the fact that the switch is in an “ON” state. The Body Control Unit receives and interprets this message, then makes an appropriate response. In response to the window control button being placed in the “ON” position, the body control unit sends a digital message to the CAN bus instructing the appropriate window motor to move the window. The window motor has an associated controller that receives and decodes this digital instruction. Power electronics within the window controller then activate a driving motor to move the window (The power electronics may be in a remotely located relay but the result is the same).

While the digital approach sounds complicated, it is in many instances much more efficient to install and run than a traditional system. Rather than routing dedicated wiring harnesses from switches to the components they control, the digital approach allows the vehicle manufacturer to provide a single data harness and only a few power harnesses. New components may also be added without the need to add additional wiring.

The first widely-used system implementing the digital paradigm was developed by Robert Bosch, GmbH in the early 1980's. Bosch called its system the “CAN bus,” which is how the “CAN” name became commonly used. Bosch actually released its protocol to the Society of Automotive Engineers with the initial hope of creating a unified communication platform across all vehicle makes and models, though Bosch did not propose to offer the standard free of licensing fees.

The goal of a uniform standard has largely gone unrealized, with the various vehicle manufacturers adopting proprietary systems instead. Even so, the general characteristics of the original CAN standard are found in most vehicle operating protocols. In general, a CAN network is a “masterless” system in which various microcontrollers communicate without the need for one defined “host” computer. This is a significant feature, as a modern vehicle may contain as many as 70 separate electronic control units. The two most significant control units are typically the Engine Control Unit (“ECU”) and the aforementioned Body Control Unit (“BCU”). However, as discussed in the preceding example, each individual window motor is likely to have a separate controller. Other controllers may be provided for a blower fan, an air conditioning compressor, power mirrors, air bags, air-inflated suspension “springs,” an automatic transmission, and even small things like the dimming functions of a rear-view mirror.

The CAN bus itself is typically just a twisted-pair (two conductors twisted around a common axis to help cancel unwanted emissions). However, although no universal CAN standard for connectors has evolved, it is common to include the CAN pair in a four-wire cable. The four-wire cable then carries CAN−, CAN+, Power Voltage, and Ground. Using this single connector thereby allows the simultaneous connection of a component to the control bus and the power distribution bus.

The arrangement of controllers on a communication network varies widely among manufacturers.FIG. 1shows a simplified depiction of one possible architecture. In this scheme Body Control Unit10ties multiple separate networks together. CAN bus20is used to connect the BCU to other “major” control units. These include Transmission Control Unit12, Engine Control Unit14, and ABS Control Unit16. The automated start-stop feature discussed previously is generally contained within the software running on ECU14.

In the example shown, instrument cluster18is controlled directly by BCU10. Where direct control is used, a ribbon cable may provide a connection between the BCU and the instrument cluster.

BCU10is also connected to a second CAN bus22. CAN bus22provides communication with numerous other controllers directing the actions of the climate control system, the mirrors, the power seats, etc. Significant to most embodiments of the present invention, BCU10controls the vehicle's lighting (including the brake lights). A brake pedal position sensor feeds a status signal to BCU10via CAN bus22. In this example the status signal is created by a simple switch that “tells” the BCU the brake pedal has left its home (off) position. Such a switch is commonly used to “tell” the BCU that the brake lights need to be illuminated. It does not control the actual braking of the vehicle.

In other systems the brake pedal position switch will feed directly into the BCU (via dedicated connector pins) rather than using a CAN bus message. The present invention can operate with such a system as well.

Finally, those skilled in the art will know that some manufactures use simpler and cheaper busses to connect the BCU to things like the mirrors and the wipers. A common example is a Local Interconnect Bus (“LIN” bus). The present invention is not confined to any particular type of bus, and the mention of a type of bus is properly understood as exemplary.

BRIEF SUMMARY OF THE PRESENT INVENTION

The present invention comprises an override module allowing a vehicle operator to default the status of an automated start-stop system to “off” A preferred embodiment uses a module that is installed on the vehicle's CAN bus.

