Griffith Hack, an independent Australian firm that specializes in intellectual property law, released a report in October 2009 that analyzes the most dominant patents in the world’s hybrid car market. The report examined nearly 20,000 patents related to hybrid electric vehicles and ranked the 10 most dominant patents.

The report ranked four of Paice’s patents among the 10 most dominant hybrid patents in the world, including the two most dominant hybrid patents. The report noted that Paice started developing hybrid technology before many leading automakers.

The report noted that Toyota has the top portfolio of hybrid patents. Toyota currently owns more than 4,000 hybrid patents and dominates hybrid sales in the United States.

The 10 Most Dominant Hybrid Car Patents

1.     Paice Corporation (1998)     US#6,209,672
Hybrid car with two electric motors, one connected to engine and one connected to car wheels

2.     Paice Corporation (1992)     US#5,343,970
Transmission that combines power from electric motor and engine

3.     Equos Research (1995)     US#5,806,617
Control system for combining electric and motor power in transmission

4.     Paice Corporation (1999)     US#6,338,391
Electric motor coupled to turbocharged motor, and control system

5.     Hybricon Inc. (1978)     US#4,351,405
Engine driving one set of wheels, and electric motor partially powered by regenerative braking driving the other set

6.     Toyota (1991)     US# 5,428,274
Control system for electric motor powered by internal combustion motor or battery

7.     Paice Corporation (2001)     US#6,554,088
Hybrid only runs when high torque is needed

8.     Ford (1992)     US#5,264,764
Controller for requesting an engine driven generator to top up the vehicle battery

9.     Hitachi (1999)     US#6,470,983
Controls battery level on hybrid drive according to navigation plans of drive

10.    Honda (2002)     US# 6,943,460
Control system for a hybrid car including cylinder deactivation program

Overview of Network Patent Analytics

Griffith Hack, a leading intellectual property law firm based in Australia and Optimice, a pioneering networking analysis firm, have developed an approach to assessing the value of patents in complex markets and industries. This approach is called Network Patent Analytics and it is used to assess and understand the competitive position created by patent ownership, as well as other business applications.

As expressed by Griffith Hack and Optimice in a recent report[2], patents represent a vast, accessible and fast growing source of knowledge. Published patent records included lists of patents considered relevant by the applicant or patent examiners. Many patents have forward and backward citations. These citations in turn lead to other citations. Mapping these citations reveals a network of citations — and from this map we can determine the most important patents based on these citations.

Griffith Hack implemented this approach in the areas of hybrid vehicles, and the result showed that when these patents were mapped, the relevant patents formed clusters.

Illustrated below are the core patents (531 in total):

The following diagram focuses in on the most central patents in the hybrid vehicle patent study – essentially the most valuable
hybrid vehicle patents:

Through this objective analysis, Griffith Hack extracted the top ten patents in the field of hybrid electric vehicles, listed in the table above.

[1]“Who holds the power? Lessons from hybrid car innovation for clean technologies.” Mike Lloyd and Justin Blows, Griffith Hack Clean & Sustainable Technologies Group, p. 11.

[2] Using Network Patent Analytics to understand and improve your competitive position. Mike Lloyd, George Mokdsi and Doris Spielhenner