VOLVO D 13 Engine

[dmatz]

At NJ Prevo for some maintenance and saw a new xl bus with the Volvo engine. Tech said he liked the new set up, the change in the gear box for the fan he said was well needed and much better. Apparently the last design has trouble dispersing the heat causing seal leaks. Something to keep an eye on

[Mark3101]

I was at Prevost TN last week and there was one with the entire driver's side stripped down to fix an oil leak. Common problem that an updated gasket / seal is meant to fix. I have heard that performance is good, but I wonder about longevity vs. the 60 Series it replaces. I think I read that the Volvo with all the extra EPA required crap also adds about 600 pounds. Remember, there is no replacement for displacement.

[Jon Wehrenberg]

Mark is right about Prevost having a fix for the seal leak. In our classes last week we learned a little about the Volvo engine and the information came from guys with a service background so I tend to think it is true. Volvo approaches the EPA standards a little differently from the others (such as Detroit) and they claimed mileage is back up where it was prior to being strangled with EGR. Volvo introduces less exhaust gas into the intake and as a result mileage has climbed. The engine also has a different torque curve from the Detroit, producing maximum torque early in the rev range and holding it longer at the maximum before it drops off. The Detroit develops maximum torque later, it peaks and drops off instead of being a nearly flat curve like the Volvo.

The significance is the Volvo is run at a lower RPM allowing it to run in high gear sooner which translates into better fuel economy. We worked near the Volvo engine when it was running and it is definitely a very quiet engine. I hope it proves to be as reliable as the Detroits have been.

[travelite]

You guys are all ready inhaling those rich Volvo exhaust vapors. A fair comparison would be to the DD15. I think DD/MTU have learned their lessons regarding the required back pressure to make EGR work. Their solution is the compound turbo which scavenges even more exhaust heat delivering power directly to the crank. The idea of torque rise and low rpm operation to deliver fuel mileage seems common to all the major manufacturers. What is Volvo doing that is necessarily different? Any brake specific fuel consumption (bsfc) figures available to compare the manufactures?

[Mark3101]

Mark is right about Prevost having a fix for the seal leak. In our classes last week we learned a little about the Volvo engine and the information came from guys with a service background so I tend to think it is true. Volvo approaches the EPA standards a little differently from the others (such as Detroit) and they claimed mileage is back up where it was prior to being strangled with EGR. Volvo introduces less exhaust gas into the intake and as a result mileage has climbed. The engine also has a different torque curve from the Detroit, producing maximum torque early in the rev range and holding it longer at the maximum before it drops off. The Detroit develops maximum torque later, it peaks and drops off instead of being a nearly flat curve like the Volvo.

The significance is the Volvo is run at a lower RPM allowing it to run in high gear sooner which translates into better fuel economy. We worked near the Volvo engine when it was running and it is definitely a very quiet engine. I hope it proves to be as reliable as the Detroits have been.

While I was talking with Bill Jensen at Prevost TN, he indicated that Prevost had to really study the proper gearing as to make sure that there was enough RPM to run the fan fast enough to get proper cooling. There is no ram air effect like in a truck, so cooling is a major concern for them. I don't know where the Volvo engine RPM runs at say 65 MPH in a Prevost compared to a truck. I also hope that the Volvo will be reliable and live as long as the Detroit. Time will tell.

[Jon Wehrenberg]

You guys are all ready inhaling those rich Volvo exhaust vapors. A fair comparison would be to the DD15. I think DD/MTU have learned their lessons regarding the required back pressure to make EGR work. Their solution is the compound turbo which scavenges even more exhaust heat delivering power directly to the crank. The idea of torque rise and low rpm operation to deliver fuel mileage seems common to all the major manufacturers. What is Volvo doing that is necessarily different? Any brake specific fuel consumption (bsfc) figures available to compare the manufactures?

David,

There are apparently enough proprietary pieces of technology employed that apart from the obvious differences that information does not seem available. I wish it was because it would tell who is winning the battle between emissions and mileage.

If you will recall Detroit told Prevost to find another engine manufacturer, a position they reversed but not before Prevost committed to the Volvo. It was revealed the Cummins was also considered as a replacement for the Detroit but the study on that was cut short. Obviously Volvo wanted its engines in the Prevost. Which engine is going to be more durable, get the best mileage, have the lowest operating costs, etc. is going to be determined by the trucking industry. The entire development of emissions systems sounds like it is still being tweaked and with each year I expect the engines will become better. But until someone emerges as a clear choice and the data from the trucking industry becomes known I doubt if any manufacturer will be making that type of information available because so much of fuel economy and durability is directly related to gearing, loads, speeds, etc.