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Examing Hybrid Electric Vehicle Patents of Ford, Chrysler & GM

Although Earth Day 2013 is now behind us, our week long Earth Day 2013 series continues to looking at different ways American research and development firms are advancing green technologies. Today, we’ll look at hybrid electric vehicle patents and patent applications issued/published by the U.S. Patent & Trademark Office to the “Big Three” U.S. automobile manufactures: Ford, Chrysler and General Motors.

Hybrid electric vehicles pose a number of potential environmental and economic benefits that make it an important sector within green technology. Hybrids store an electrical charge in a battery that either reduces the amount of power required from an internal combustion engine or, in the case of all-electric vehicles, powers the entire car. This technology is in many ways still in its early developmental stages, but already some car manufacturers are selling hybrid models that reach 100 miles per gallon of gasoline, according to the U.S. Department of Energy. This reduces the amount of gasoline needed from imports and reduces fossil fuel emissions to almost nil.

Recent patent applications published by the USPTO show that much of the basic controls behind hybrid electric systems in vehicles still have much room for improvement. We’ve noticed a lot of patent applications for systems of controlling electrical charges within the hybrid vehicle or the local electrical grid, in the case of charging stations. Another patent application makes it easier to diagnose powertrain issues in hybrid vehicles.

One patent awarded by the USPTO, for a system of reducing gear rattle within hybrid electric vehicles, is also included below.


Methodologies for Implementing Smart Control of Vehicle Charging
U.S. Patent Application No. 20120286725

Electric charging stations are an important part of the future of hybrid electric car use, as easy access to charging stations will benefit hybrid vehicle owners tremendously. However, such charging stations can drain a local electrical grid of critical resources in certain situations. For example, hot weather can drain battery power quicker, requiring owners to charge their vehicle more often than normal.

This patent application, filed by General Motors, seeks to protect a new system of selectively controlling electrical charging of hybrid vehicles to reduce strain on the electrical grid. The system involves a remote call center that could control electrical substation resources in response to a utility provider or car owner’s request. The call center also communicates electronically with charging cars to log location and rate of charge information, which can help determine future electrical grid resource needs.

As Claim 1 explains, General Motors hopes to protect:

“A method for remotely controlling the charging of a group of vehicles, each vehicle have an electrical power storage facility, the method comprising: while one or more of the group of vehicles are being charged from a utility power source, receiving, at a call center, a request from the utility to modify charging behavior of the group of vehicles; and at the call center in response to the request from the utility, sending a command to each of the group of vehicles to modify their charging behavior.”

Method and Apparatus for Controlling a Hybrid Powertrain System
U.S. Patent Application No. 20120283921

The architecture of a hybrid electric vehicle’s powertrain system typically includes the engine and other devices, like a motor, to create useful torque from the engine’s power. Control systems within a vehicle log a lot of data about the powertrain system because of its importance to proper vehicle operation. Developing a system where the internal combustion engine could be removed from the rest of the hybrid’s powertrain system would be helpful for diagnostics when trying to identify a vehicle issue.

The control system developed by Chrysler and laid out in this patent application reduces the torque output of electric motors to zero while diagnostics are being run on the internal combustion engine. Isolating the engine in this way helps detect issues that reside in the engine rather than the rest of the hybrid electric powertrain.

Claim 1 of this Chrysler Group patent application explains a:

“Control system for a vehicular powertrain system including an engine and an electro-mechanical transmission and an electric machine arranged in an input-split hybrid configuration and selectively operatively controllable to transmit torque therebetween and to a driveline, the control system comprising: a control module signally connected to a plurality of input devices and configured to execute program code stored on a computer readable medium to control the powertrain, the program code comprising: code to monitor operator inputs; code to determine an intent to service the vehicle based upon the operator inputs; code to command the electric machine to generate a net torque output of zero; and code to control the engine speed correlative to an operator depression of an accelerator pedal.”

Engine Start Control System for an Electrically Variable Transmission
U.S. Patent Application No. 20130080038

This next patent application, also from the Chrysler Group, intends to protect a system of smarter motor control within a hybrid electric vehicle, specifically those with electrically variable transmissions. These variable transmissions can change the amount of power drawn from the combustion engine so that the vehicle operates in hybrid mode or entirely through a stored electric charge. As hybrid technologies are still developing, there are many operational challenges that are still posed by controlling the many parameters that affect this system.

This system introduces a computer processor into the electrically variable transmission system that can aid the system by diverting resources more efficiently. The processor would receive inputs from controllers that determine the amount of torque required by the system. In response, the processor adjusts the amount of electrical charge travelling to the vehicle’s motors, or turn on the combustion engine if needed.

As Claim 1 describes, this patent application seeks protection for:

“An engine start control system for a vehicle having an electrically variable transmission, said control system comprising: a supervisory controller adapted to input vehicle operating conditions and driver inputs, said supervisory controller adapted to determine and output a plurality of torque limits, a desired output torque, and an optimum engine speed; an input speed profiler adapted to generate and output an input speed profile and an input acceleration profile based on the optimum engine speed; a constraints evaluator adapted to generate and output a requested output torque based on the plurality of torque limits and desired output torque; a feed forward controller adapted to generate first and second feedforward motor torques based on the requested output torque and the input speed and input acceleration profiles; and a feedback controller adapted to generate first and second feedback motor torques based on a difference between the input speed profile and an actual input speed, wherein the feed forward and feedback first and second motor torques are used to control the operation of the first and second electric motors when the engine is being turned on or off.”

System and Method for Managing Electrical Loads in a Vehicle
U.S. Patent Application No. 20130082521

Lithium ion batteries being produced to store electrical charges for hybrid vehicles are capable of producing enough power to run high voltage loads. Although this provides more power to the vehicle, it’s often too much power to run low voltage loads, like a vehicle’s headlights. A low voltage battery can be included in the vehicle as well, but once this battery is drained, headlights and other low voltage systems may stop automatically during vehicle operation.

Ford Global Technologies, the assignee on this patent application, has devised a system that involves a voltage converter for running low voltage loads. A system controller would adjust the amount of voltage released by the converter and divert that power to any number of low voltage loads around the vehicle.

Claim 1 of Ford’s patent application describes:

“A system for managing electrical loads in a vehicle, comprising: a high voltage power source; an electrical converter operable to receive high voltage power from the high voltage power source and to provide low voltage power to at least one low voltage load; and a controller configured to cut power to at least one of the at least one low voltage load when the high voltage power source cannot provide full power to all of the at least one low voltage load.”

Method for Reducing Gear Rattle in a Hybrid Electric Vehicle Powertrain
U.S. Patent No. 8417431

Hybrid electric vehicles that utilize a power-split powertrain have a combustion engine and electric motors that deliver power to the vehicle separately. The internal combustion engine works like a similar gas-powered engine on any other vehicle, except that the amount of torque generated by the combustion engine can be reduced to zero. When this happens, gears and other internal components are still affected by combustion forces, creating a noise referred to as “gear rattle.”

This patent, issued earlier this month by the USPTO to Ford, protects a developed control system that helps a hybrid electric vehicle avoid a zero torque situation. The control system either increases or decreases the power distributed by the internal combustion engine to maintain a torque threshold. This keeps a motor above the near-zero torque conditions that can cause gear rattle.

As Claim 1 describes, Ford has won the right to protect:

“A method for avoiding gear rattle in a powertrain for a hybrid electric vehicle with an engine and an electric motor and with gearing defining power flow paths from the engine and from the motor to vehicle traction wheels, the method comprising: establishing a desired engine power and a desired wheel torque; determining an expected motor torque using the desired engine power and the desired wheel torque; calculating an engine power bias corresponding to an expected motor torque of about zero; and controlling the engine using a controller using the engine power bias to avoid gear rattle associated with zero motor torque.”


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Join the Discussion

One comment so far.

  • [Avatar for Daver]
    April 26, 2013 11:28 am

    These and many other patents and applications for patent also illustrate the complexity of hybrid vehicles which is a harbinger of potential additional problems which may occur as these vehicles age in service of their owners/operators. Missing from the Green Energy enthusiasts’ discussion are discussions of the costs and problems including those of environmental nature that are associated with the manufacture, operation [e.g. pollution associated with generation and distribution of the electricity consumed by plug-in vehicles which may equal or exceed the pollution caused by modern IC engined vehicles] and eventual disposal of hybrid and plug-in electric vehicles. The US Dept of Energy MPG equivalent numbers have been shown to be unrealistic [overly optimistic] in other published articles, e.g. one by Csaba Csere, an MIT engineering graduate and former editor-in-chief of Car and Driver magazine. If possible, please post a collection of patents/applications addressing these associated issues.