Tuesday, April 7, 2009

The Old School Approach

Over the past few months I have been following other conversions and in the process making acquaintances with people who have been very kind and most helpful. What amazes me about some of these people is that they not only have sharp technical skills (mechanical, electrical, electronic, computer, etc) but they are also innovative and "old school" in the way they approach things. By "old school" I mean simple. This is rarely seen nowadays. Let me give you an example of the simple "old school" approach. I have been wanting to use my car's stock tachometer and had researched and shopped around for equipment to attach to the motor shaft (shaft sleeves, sensors, etc) which were quite expensive and not compatible with my stock tachometer requiring additional equipment and obviously additional expenses. Having a working tachometer can be very useful since the electrical motor is very quiet and it would be hard to tell how fast it is spinning in order to shift at optimal speeds/revolutions. While following the conversion of Dimitri's eProtege5, I realized that here was a very simple solution. I thought to myself, this is so simple that it gets overlooked. It doesn't even cross one's mind. We all seem quick to shop around without considering the obvious. So, this in my mind is "old school" and the ideal solution. After all, it is the stock equipment sitting right there in the old ICE.

In the case of the Mazda Protege, there is a Crankshaft Position Sensor (CKP sensor) located close to the crankshaft pulley at the front lower left side of the engine block as you face the front of the car. It is mounted onto the block with one bolt. The idea is to recuperate this sensor and mount it somewhere near the CE motor shaft after mounting a custom made metal strip (180 degrees) that is pointed at each end somewhere on the motor shaft. The pointed tips of the rotating strip need to be lined up with the CKP sensor with a 2mm gap. For each rotation of the motor, the sensor will generate two pulses. My understanding is that you would also disconnect the wire between the ECU and the tachometer (at the instrument cluster for example). The tach signal is generated by the ECU and wired into the instrument cluster. Pin 48 from ECU goes to instrument cluster via VW ( violet-white wire ). Since the final solution is still being tested as I write this, I must mention that other steps might need to be implemented.

Here is what a CKP sensor looks like.

Here is where the CKP is located on the ICE.

Here is the crankshaft wheel on the ICE.

This is a shot of Dimitri's eProtege5 DIY implementation of a tach sensor using the stock ICE's CKP sensor and bypassing the ECU.

When the ECU cannot be bypassed, the original crankshaft wheel or a DIY crankshaft wheel can be used. Photo below is courtesy of Dimitri.

Another useful gauge to have in an EV is a motor temperature gauge. The Warp9 comes equipped with a motor temperature switch but this does not give the driver a visual status of the motor temperature. Once again, as pointed out to me by Dimitri, the car's stock temperature can be used with a little DIY work.

First you need to recuperate the stock ICE's engine coolant temperature sensor (ECT sensor) which is located at the rear side of the ICE under the intake manifold. The next step is to epoxy it into one of the lift holes of the Warp9 motor. The ECT sensor is basically a thermistor. Since the ICE heats up much more than an electric motor, a resistor would be required to allow the gauge needle to move in a suitable range for the electric motor essentially making the thermistor (temp. sensor) more sensitive.

Here is what the ECT sensor looks like.

This is where the ECT sensor is located with its specs.

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