Lotus have announced engine supply deals with Bryan Herta Autosport and Dreyer & Reinbold Racing for the 2012 season, meaning that three partner teams are now confirmed as running the Lotus twin turbocharged V-6 engine next year.

Earlier on Thursday, HVM Racing also confirmed that it would be running with a Lotus engine in 2012.

"These partnerships with Bryan Herta Autosport, Dreyer & Reinbold Racing and HVM Racing mean a great deal to Lotus Motorsport and mark the start of a new chapter for Lotus in the IZOD IndyCar Series," said Miodrag Kotur, Group Lotus' Director of Motorsports Operations. "These three teams have immediately become part of the Lotus legend and have joined us in our journey as one of the most innovative and successful sports and racing car brands in the world."

Team co-owner Dennis Reinbold described this week's announcement as "a huge step for Dreyer & Reinbold Racing," adding: "Many of our collective efforts are already underway and we could not be more enthusiastic about this off-season's testing and development program."

"Obviously, this is an incredibly exciting step for us," agreed Bryan Herta. "Our goal all along has been to build our foundation to eventually compete as a full-time entrant in the series. To partner with Lotus, which has such a rich history and tradition in racing including at the Indianapolis Motor Speedway, is just tremendous."

Following a full season together, Lotus will no longer be working with KV Racing Technology - which ran with the familiar green-and-gold Lotus branding in 2011 but which has since decided to sign up with Chevrolet as their 2012 engine supplier.

After six years of Honda exclusivity in engine supply, 2012 will see Lotus join Honda and Chevrolet competing for victory lane. Honda's stable of teams is led by the four-car Ganassi Racing team including current champion Dario Franchitti, while Chevrolet's return to IndyCar is being spearheaded by Roger Penske's three-car line-up consisting of Will Power, Ryan Briscoe and Helio Castroneves.

Lotus was the last of the three manufacturers to decide to enter the IndyCar engine supply competition, making the announcement exactly a year ago. There had been concerns that its late start meant that it would not be ready in time for the start of 2012; that meant teams were reluctant to commit to Lotus as their supplier until they were certain that the engine development program was on track and looking promising.

Kotur was happy to be able to prove the doubters wrong: "Exactly 12 months on, we are here with an all new Lotus engine and three teams, ready to go," he said at the official announcement at the Los Angeles Auto Show on Thursday. ""The numbers that the engine is already achieving in our dyno testing are extremely encouraging so our hard work is well and truly paying off.

"We have also managed to produce a very light powerplant, in the true spirit of Lotus," explained Kotur. "However, we are keen to test the package on track and look forward to our first test in early January, slightly later than originally planned but designed to give us more time to fine-tune our package before taking to the track."

Reinbold sais that he had no concerns about Lotus' dedication to the series: "In working closely with the team at Lotus over the past few months, we have had unique access and awareness of their strong commitment to the IndyCar Series and the Indianapolis 500," he said, also confirming that DRR intend on running a two-car line-up again in 2012. In 2011 their driver line-up began with Ana Beatriz and Justin Wilson, until Wilson was forced out of the season by a back injury sustained in practice and replaced by a succession of stand-ins including Simon Pagenaud, Tomas Scheckter and Giorgio Pantano.

Bryan Herta Autosport has not been a full time team in 2011, but won the centennial Indianapolis 500 with Dan Wheldon at the wheel. BHA and Wheldon were also awarded the task of developing the new 2012 chasis - named the 'DW12' in memory of Wheldon - that will house the new specification engines.

Kotur added that the engine deals were just the start of what Lotus hoped would be a wide-ranging partnership with the three teams. "We believe that our capabilities as a partner will pay dividends for them in the future," he said, adding that Lotus will be opening a US base of operations in Indianapolis in time for the start of the 2012 IndyCar season in March.

Curiously, there was no mention of Michael Shanks Racing in the official announcement this week. The GRAND-AM racing organisation announced that it was joining IndyCar next season last month, and had added at the time that they would be running with Lotus engines.

However, since then there has been no additional information form the team regarding its engine supply and no official announcement from Lotus itself. Their omission from this week's Lotus line-up announcement suggests that Michael Shank may have jumped the gun in his initial statement, or that there has been a hold-up in finalising the deal.