The Silicon Valley venture capital firm run by Vinod Khosla has pledged to inject an additional $85 million into the cash-starved biofuel maker Kior, and a Bill Gates fund is going to chip in $15 million, too.

Kior, which has fallen far short of its production forecasts this year, said Monday that Khosla and Gates will help finance a second refinery, which would convert wood chips into gasoline and diesel. Kior chief executive Fred Cannon said the company could be cash flow positive in 2015.

Khosla said in an interview that he will increase his total investment in the company to $125 million and that Gates will invest $15 million. The new investments are a combination of purchases of new common stock and the conversion of existing debt to convertible stock. About half the new investments have been made, and about half are commitments for future investment.

Kior says it can convert wood chips and agricultural waste into oil products identical to those based on crude oil. Other companies are trying to use similar technology to produce cellulosic ethanol.

A year ago, Kior said it expected to produce 13 million gallons of motor fuel this year, but Cannon said in an interview Sunday that he expects production to total just 1  million to 2 million gallons. A group of investors has filed a lawsuit against the company, accusing it of misrepresentation.

Khosla asserted that the delays were not worrisome and not unusual for a first-of-a-kind construction project.

Kior’s stock peaked at more than $20 a share in September 2011 but tumbled to less than $1.50 a share this year. On Friday, before the announcement of the new financing, Kior’s shares jumped 13 percent to $2.60 a share. By 11 a.m. Monday morning, the stock had dropped 3.1 percent to $2.52 a share.