OT: another EV question

How do you park an electric vehicle safely on a hill when you can't leave it in gear as you would in a manual car? Are you solely relying on the brakes?

I think there's a parking pawl that engages within the planetary gear set.

Thanks. This is reassuring.

The original Zoe had a separate P button, separate from the automatic handbrake, and only effective when switched off. Its workshop manual mentioned a brake pawl. That button wasn't present on my later Zoe, nor on the Renault 5. So if it's there, it's now automatic.

The transmissi Parking on a slope To park on a slope or while towing a trailer, for example, pull switch 3 for a few seconds to enable maximum braking.

Suggesting that it matters to make sure the handbrake is fully applied!

Back in the 1970s I had a Moggie Thou with a useless handbrake. I learned about the turn into the kerb downhill, away from the kerb uphill method. And in gear of course!

nib

Can you remind me: if the car is pointing downhill, should it be in reverse or first gear (and vice versa if the car is pointing uphill)? No-one I know seems to remember!

Reverse gear either way because it is usually the lowest gear available and thus gives maximum resistance when coupled to an engine. Which is why when bump starting you should be in 2nd gear (or even 3rd).

Cheers

Dave R

For some reason, I always used to select the way that the engine wouldn't start, so reverse for downhill and first for uphill. So if it ran away it would be pumping air in from the exhaust and out through the carburettor. Can't imagine it matters in practice with the ignition switched off!

nib

I was always taught that the direction to point was the one that turned the engine in reverse, just in case somebody had turned on the ignition. "If it can go wrong, it will".

In San Francisco, you must park turning the wheels into the kerb, even if you are on level ground.

Er. Not exactly true. Engines are symmetrical, apart from valve and spark timing. They can (and do sometimes) run backwards...

Two strokes with no separate timing gear can easily run backwards: If they are not spark ignition or have no asymmetrical induction they develop full power in either direction, as those who ran side port or reed induction model diesel and glow engines can tell you.

I cant recall whether an engine is harder to turn over backwards or forwards

I believe it was the Bond 3-wheeler that achieved reverse by the driver stopping the engine and starting it again running backwards.

whereas in other small bubble cars you simply turned the steering so the one powered wheel was now pointing backwards...

You could drive a 3 wheeler on a motorcylce licence. To do so it could not have a reverse gear. If it had a reverse gear it was not considered a motorcycle with sidecar. On some Reliants you can see where the blocking plat was fitted to stop you engaging reverse. You could start the engine backwards on many so you could reverse without a reverse gear.

My first and only provisional motorcycle licence allowed the use of ‘rev/trics’.

They relaxed those laws quite early on. The Reliant 3-wheelers were just like a four wheeled car, with a four cylinder four stroke engine. The engine was limited to 600cc, and the vehicle weight to 8cwt. They had a fibreglass body.

It was the "luxury" Messerschmitt bubble car that had an engine that could be started in reverse. I think the Isetta (with a triangular body and a single door at the front) had reverse.

Even some (large) motorcycles had a reverse gear.

Hmm. My first car was an AC Petite. It had three wheels and a reverse gear, and I passed my first test in it soon after my 16th birthday. The test included a tricky reverse around a left-turn corner, which included a deep drain to catch the wheel near the kerb. The wheel indeed fell in, my 9.25hp engine stalled, I put the handbrake on and the gear in neutral, restarted the engine, and continued the turn, first climbing the car out of the drain hole. Also, the car had a tiny turning circle, the examiner stopped me at the side of a huge wide section of road, and asked me to do a three-point turn, which again needed reverse gear. I said that I could do it in one movement, but he asked me to show that I could do the manoeuvre. I passed the test. Maybe the no-reverse rule was not at all times?

Ah, I see that last point was answered while I was typing.

Wikipedia offers this about the Bond: "A method of reversing the car was offered on later models via a reversible Dynastart unit. The Dynastart unit, which doubled as both starter motor and dynamo on these models incorporated a built-in reversing solenoid switch. After stopping the engine and operating this switch the Dynastart, and consequently the engine, would rotate in the opposite direction."

From what I remember the Bond was actually pretty much the same. While it could run backwards, there was enough lock to reverse...

.. the Reliant was the exception. Originally reverse was blanked off as then you got the cheap tax and could drive on a motorcycle licence, but did not have great lock on the front wheel....

... sometime in the 1960s the changed the law and you could "unblank" the reverse. For some this just meant removing a wooden block, for others a metal tab in the gearlever gate...

Dave

And the Invacar.