Are European Cars Needlessly Complex?

A simple water pump drive that isn’t so simple.

European cars have long had a reputation in America for complexity. Mechanically, most of what makes up modern internal combustion engine technology had its origin in Europe, from overhead cams and multivalve cylinder heads to fuel injection. European cars also have long had a reputation for higher maintenance costs and lower reliability than similar models from Japan. Why? Jim Anderton looks at an example of a unique, complex type of water pump drive and asks, “why do this?” 

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I’ve worked in the automotive industry for Tier 1 suppliers to the OEMs and aftermarket, as well as reporting on the industry for the trade press. When I’m not doing what I do here at engineering.com, I’m frequently under the hood. I love cars, from the A12 engine in Mom’s Datsun 1200 that I blew up at 11 years old, to the superb VQ V-6 in my old Infiniti G 35.  

The current family fleet includes everything from American light trucks to Japanese family haulers to sports cars—and significantly, a Mini.  
 
As a teenager, I owned several Austin Minis, truly awful and tiny cars that are fondly remembered by most of us that owned them. In this case, I’m talking about a new-generation Mini, specifically the R 56 model seen on streets everywhere on the planet.  
 
This is that Mini’s water pump drive wheel. Note that it is not a pulley, but a stamped steel wheel with a bonded rubber friction surface. It is driven from the crankshaft by an intermediate steel friction wheel, in a system not unlike those little bicycle dynamos that used to rub against the tire of your bike.  
 
Why not just drive it directly from the serpentine belt, like every other car on the road? Well, there are two reasons.  

 
One is that to minimize exhaust emissions, the Peugeot engineers that actually designed the engine in my R 56 attach that intermediate friction wheel to an electric actuator, which disengages the water pump during cold start, warming the engine faster for faster closed-loop operation. When the engine warms up, the actuator pulls the friction wheel into engagement, connecting the crankshaft to the water pump. This could be done with a simple mechanical or electro-mechanical thermostat that bypasses coolant flow around the cylinder head, but why use a mechanical device that lasts two decades when you can computer control the process, right?  
 
The other reason why this strange system was designed? Well, this is just a theory, but I think it is because the engine was designed by the French. If there is a universally standard way to design something in the automotive industry, French engineers have a knack for doing it differently. Sometimes, they do it better. For North American roads, sometimes it’s not better.  
 
But no one who ever looked at a Citroen DS 19 ever doubted that this was a French car. And anyone who has ever bought a Renault in North America learned quickly that everything from the dashboard controls to the suspension compliance was radically different than anything made anywhere else.  
 
Why drive a water pump with a rubber-coated tin wheel? Why not? Is it a better way to do it? I doubt it, but it is different. And for some engineers, that’s reason enough.  
 

Written by

James Anderton

Jim Anderton is the Director of Content for ENGINEERING.com. Mr. Anderton was formerly editor of Canadian Metalworking Magazine and has contributed to a wide range of print and on-line publications, including Design Engineering, Canadian Plastics, Service Station and Garage Management, Autovision, and the National Post. He also brings prior industry experience in quality and part design for a Tier One automotive supplier.