Technology: comparison of pollutants

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Technology: comparison of pollutants

Technology: Comparison of pollutants (archive version)
Role play

Exhaust gas cleaning is not only up-to-date, it is a top priority for all motorcycles. Four middle class enduro bikes had to test their conscience on the role.

Waldemar Schwarz

05/05/2000

Motorcycles and the environment, an explosive topic in which the philosophies of the individual manufacturers are drifting miles apart. But what is important is what comes out at the back. After the test had been completed, the travel enduros had to go to the exhaust test bench of the southern German TuV Automotive.

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Mixed company

As well as Aprilia Pegaso and Suzuki Freewind – both without any exhaust gas aftertreatment – were not subject to today’s limit values ​​at the time of their homologation; there was no limit for nitrogen oxides (NOx) at that time. But the Aprilia defies the relatively low hurdles of the law at the time and emits 50.6 g / km carbon monoxide (CO), 2.3 times the permissible value. With 17.4 g / km, the Suzuki Freewind undercuts the limit by 18 percent. The hydrocarbon limit values ​​(HC) both easily meet

Clean performance

The 2000 Honda Transalp seems well equipped for the current Euro I standard with its unregulated catalytic converter and secondary air system. In fact, the CO and HC limits are drastically below the limits by 68 and 80 percent, respectively, and only 57 percent of the permitted amount of NOx is emitted. This confirms the positive experience that MOTORRAD has had with this combination as an inexpensive interim solution.

Riddle about G-Kat

The F 650 ensures excitement. Can it set the standard with a regulated catalytic converter? During the test run, the TuV engineer on the driver’s aid of the F 650 attests to the most sophisticated driving behavior of all single-cylinder units measured to date. After the subsequent analysis, however, there are long faces: At 30.4 g / km CO, it is not only far outside the limit values, but also well above the Suzuki without exhaust gas aftertreatment or the MOTORRAD endurance test F 650 with unregulated catalytic converter from 1994, the emitted just a third of the CO values.

When checking a second F 650 GS the same disaster: With 28.3 g / km carbon monoxide it underpins the miserable balance. When asked, BMW suspects a procedural error. In this case, the control unit can use parameters such as throttle valve angle and speed to recognize special driving conditions and go into the emergency program.

TuV and MOTORRAD recap: The measurement procedure was carried out exactly, however, in the preparation phase, due to time constraints, the motorcycle was moved to refuel once shortly before the measurement, and the other time the test was started with the engine warm.

So the whole thing again with the most meticulous adherence to the procedure. This time the TuV inspector notes: “Now the motorcycle jerks like other single cylinders.”

Excitement again in the evaluation, and in fact the F 650 GS now delivers sensationally good values, which are 37 times lower for CO and 17 times for HC values ​​below the values ​​initially determined.

Startled, MOTORRAD repeated the measurements and then simulated normal road trips while analyzing the exhaust gas. Something alarming comes to light: According to the current state of knowledge, the so-called emergency program is activated in normal driving mode, while the computer switches to a lean program when measuring emissions.

And suddenly the testers also remember the black smoke plumes and the sooty silencers on the two F 650s when driving on the road: phenomena, the experts agree, that can never occur with a functioning G-Kat. At the time of going to press, nothing more could be determined on this topic. MOTORRAD will continue to report.


Technology: exhaust gas cleaning


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