DETROIT, AUG. 24 -- The Chevrolet division of General Motors Corp. said today that the total U.S. car and truck market for the 1988-model year could reach 15 million units -- and it will account for one of every five sales.

"For the 1988 model year, I'm pushing the Chevrolet organization to sell just above 1.7 million passenger cars and about 1.25 million trucks," Chevrolet General Manager Robert D. Burger said.

"It's doable," said industry analyst Thomas O'Grady, of Integrated Automotive Research Inc. of suburban Philadelphia. "But it will take a tremendous amount of support."

Currently, Chevrolet has about 25 percent of the truck market and about 18.2 percent of the car market, including its Sprint and Spectrum subcompacts imported from Japan.

Burger predicted Chevrolet's all-new pickup truck, introduced in April as a 1988-model, will come close to reaching the half-million sales mark in the next model year as three GM assembly plants reach full speed and add new body styles.

"Our chief competitor in the full-sized pickup market is going to know it's been in a real fight for sales leadership," Burger said in reference to Ford Motor Co., which has consistently beat Chevrolet in sales with its F-series truck line.

However, O'Grady said dealers indicate the new Chevrolet trucks have not been selling very well, considering it is an all new model.

Burger said next year will be the year "when all of the things we've been putting into place over the past five years begin paying dividends."

He predicted in January the division's newest cars, the 1988-model Beretta and Corsica compacts, would add two percentage points to GM's overall share of the market.

Although sales of the cars have recently been good -- partly because of strong buyer incentives and better availability as the car's production is stepped up -- they have in fact so far taken away from sales of the smaller Chevrolet Cavalier and larger Celebrity models while GM's overall slice of the market continues to erode.

Chevrolet's overall car sales for the past 30 days, a period in which Beretta-Corsica sales have been strong, are up about 8 percent from year-ago levels, industry figures show. But Cavalier sales are down 10 percent and Celebrity sales are off 26 percent, indicating the new cars are cannibilizing sales.

Burger said production of the Beretta and Corsica, built at GM's plants in Wilmington, Del., and Linden, N.J., will not reach full capacity of 250,000 units each until late this fall.

O'Grady said he doubts the plants have that much capacity. "I think all they can manage is between 420,000 and 440,000 units," he said.

Besides the Beretta, Corsica and the new pickup truck introduced this year as as 1988 models, Chevrolet is offering a redesigned Cavalier compact for 1988. Minor improvements are found among Chevrolet's other car models.

The Toyota-made 16-valve engine will be available in one version of its Nova subcompact, manufactured by New United Motor Manufacturing Inc., a joint venture between GM and Toyota. That engine, imported from Japan, also powers Toyota's FX-16 made at NUMMI as well as its MR2 sports car.