Volkswagen's US Chief Apologizes to Lawmakers About 'Deeply Troubling' Events

— -- Michael Horn, Volkswagen Group of America CEO and president, was in the hot seat on Capitol Hill today, answering questions about the company's 11 million diesel cars that may have cheated emissions standards around the world.

Rep. Peter Welch, D-Vermont, relaying questions from his constituents, asked Horn at the House Energy and Commerce subcommittee hearing how he can consider himself a member of the human race, or how he sleeps at night, and compared Horn to convicted fraudster Bernie Madoff.

“My answer to myself is that I do everything -- and I don’t sleep at night -- to help our dealers, to help our customers and to be there for my company and our employees to get us through this crisis here in the U.S.,” Horn said.

In prepared remarks, Horn said he was first informed about "possible emissions non-compliance" in the spring of 2014, but he was told that the issue would be "remedied." It was only last month, however, when the company told regulators a number of its diesel car models had been installed with "defeat device" software that causes 482,000 cars to cheat on U.S. emissions standards tests. Regulators say Volkswagen's diesel cars emit nitrogen oxides, or NOx, at 10 to 40 times the federal limit. Several lawsuits have been filed against Volkswagen and former Volkswagen Group CEO Martin Winterkorn resigned from the company last month.

Horn also said that the defeat device was intentionally installed to cheat emissions testing. He said Volkswagen has withdrawn its application for certification by U.S. regulators to sell 2016 model-year diesel-powered vehicles though the company is working with the EPA and other agencies to continue the certification process. Because the EPA has said the cars are legal and safe to drive, Horn said the company would most likely not provide loaner cars to customers who choose not to drive the affected cars. Horn said the company has not determined potential financial compensation to customers who bought the affected cars.

Horn noted that the oldest generation of the affected vehicles, with 325,000 of these cars in the U.S., would most likely need both a hardware and software fix. Horn said it could take more than one year to complete the repairs in all of these cars in question. Repairs could last five to 10 hours per car, he said.

The affected second-generation, "mostly" Passat, diesel models will “most probably” only require a software solution, which Horn said may begin in the middle of next year because of its “technical complexity.”

Volkswagen could begin repairs on the newest, or third generation models, in January, according to Horn.

Horn explained that Volkswagen has provided financial relief to its dealers who are fielding angry calls from customers, including paying maximum bonuses to dealers for each car sold, which is more than $1,500 per car.

Some lawmakers questioned whether Volkswagen's proposed fixes were enough to solve the emissions problem.

“Mr. Horn your statements don’t give me much confidence that these cars are going to be fixed,” Rep. Frank Pallone, D-New Jersey, told Horn.

Earlier this week, Matthias Mueller, Winterkorn's replacement, told a German newspaper the company will launch a recall of affected cars in January with a goal to fix all the vehicles by the end of 2016.

Volkswagen told dealers to halt sales of both new vehicles and certified pre-owned cars equipped with the 4-cylinder 2.0 TDI engine. Audi, which is owned by Volkswagen, also implemented a stop-sale for its model with that same engine, the A3 2.0 TDI.

On Tuesday, the Senate Finance Committee began investigating whether the company received tax subsidies for fuel-efficient vehicles under false pretenses. The committee said some of the hundreds of thousands of Volkswagen vehicles sold in the U.S. that included defeat devices could have been purchased using the Alternative Motor Vehicle Credit, which was created for qualifying fuel-efficient vehicles. Four Volkswagen models were deemed eligible for the credit, which amounted to $1,300 per vehicle purchase. Lawmakers are asking the IRS, EPA and Justice Department to consider whether they should levy fines or enforcement actions against Volkswagen to recoup the value of the tax credits that were provided to taxpayers who bought the affected cars.

A spokesman for Sen. Ron Wyden, D-Oregon, who wrote a letter to Treasury Secretary Jack Lew about the matter this week, said that Volkswagen car buyers shouldn’t suffer financially for the company’s “misdeeds.”

ABC News' Benjamin Siegel and Ali Weinberg contributed to this report.